ArriVent BioPharma, Inc. (AVBP) Business

Item 1. Business

Overview

We are a clinical-stage biopharmaceutical company dedicated to the identification, development and commercialization of differentiated medicines to address the unmet medical needs of patients with cancers. We seek to utilize our team’s deep drug development experience to maximize the potential of our lead product candidate, firmonertinib, and advance a pipeline of novel therapeutics, such as next-generation antibody drug conjugates, including ARR-217 (MRG007), through approval and commercialization in patients suffering from cancer, with an initial focus on solid tumors. Firmonertinib is currently being evaluated in multiple clinical trials across a range of epidermal growth factor receptor (EGFR) mutations (EGFRm) in non-small cell lung cancer (NSCLC). We are conducting a pivotal Phase 3 clinical trial of firmonertinib in treatment naive, or first-line, patients with locally advanced or metastatic EGFRm NSCLC with exon 20 insertion mutations and a pivotal Phase 3 clinical trial of firmonertinib in first-line patients with locally advanced or metastatic EGFRm NSCLC with P-loop and-alpha-c-helix compressing (PACC) mutations. We are conducting a Phase 1 clinical trial of ARR-217 in patients with unresectable locally advanced or metastatic solid tumors.

We received Breakthrough Therapy Designation (BTD) for firmonertinib for first line EGFRm NSCLC with exon 20 insertion from the U.S. Food and Drug Administration (FDA) in October 2023, and Orphan Drug Designation for treatment of NSCLC with EGFRm or human epidermal growth factor receptor 2 (HER2) mutations or human epidermal growth factor receptor 4 (HER4) mutations in February 2024. A product candidate can receive BTD if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. For drugs that have received BTD, interaction and communication between the FDA and the sponsor can help to identify the most efficient path for development, although BTD may not result in a faster development process, review or approval and does not increase the likelihood that the product candidate will ultimately receive FDA approval for any indication.

In 2021, we licensed from Shanghai Allist Pharmaceuticals, Co. Ltd (Allist) the right to develop and commercialize firmonertinib worldwide, with the exception of greater China, which includes mainland China, Hong Kong, Macau and Taiwan. Firmonertinib is an investigational, novel, EGFR mutant-selective tyrosine kinase inhibitor (TKI) that we are developing for the treatment of NSCLC patients across a broader set of EGFR mutations (EGFRm) than are currently served by approved EGFR TKIs. Firmonertinib is currently only approved and commercially distributed by Allist in China as a first-line therapy to treat classical EGFRm NSCLC. The FDA has not approved firmonertinib for any use. We selected firmonertinib for global development against nonclassical, or uncommon, mutations based on preliminary reductions in tumor size observed in seven out of ten patients with EGFR exon 20 insertion mutations treated with firmonertinib in the ongoing Phase 1b clinical trial, the FAVOUR trial, conducted by Allist in China, and preclinical activity in PACC mutations, each a subtype of uncommon mutation. In a subsequent interim data readout from the FAVOUR trial of firmonertinib administered at 240 mg once daily in first-line patients with locally advanced or metastatic EGFRm NSCLC with exon 20 insertion mutations, 79% of patients (n=22 out of 28 patients) were observed to experience a reduction in tumor size of at least 30%. In a final analysis from the Phase 1b FURTHER trial of firmonertinib, which included a cohort of EGFRm NSCLC with PACC mutations, we observed 16.0 months median progression free survival (mPFS) with firmonertinib 240 mg in first-line, confirmed overall response rate (cORR) 68.2% (n=15 out of 22 1L patients at 240mg) and duration of response (DOR) 14.6 months, and confirmed CNS (central nervous system) responses with firmonertinib including complete responses (CRs).

As one of the most prevalent cancers in the world, lung cancer imposes a significant global burden on human health, and EGFRm NSCLC represents a significant proportion of those affected. Despite progress in the therapeutic landscape for EGFRm NSCLC, many patients, particularly those with uncommon mutations, such as exon 20 insertions or PACC mutations, are underserved by existing treatments. In an interim data readout from the FAVOUR trial of firmonertinib administered at 240 mg once daily in first-line patients with locally advanced or metastatic EGFRm NSCLC with exon 20 insertion mutations, 79% of patients (n=22 out of 28 patients) were observed to experience a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression as measured by Response Evaluation

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Criteria in Solid Tumors (RECIST) 1.1 criteria. This measurement of reduction is the threshold in this trial for a partial response and for inclusion in determination of the overall response rate (ORR), which is the primary endpoint of this trial. In the same interim data readout, those 79% of patients were observed to experience a 15.2 month median DOR. Interim results may not be indicative of final results; however, we believe these interim clinical results underscore firmonertinib’s potential in patients whose tumors contain an uncommon EGFRm.

We are currently conducting a pivotal Phase 3 clinical trial, the FURVENT clinical trial, in first-line locally advanced or metastatic non-squamous EGFRm NSCLC patients with exon 20 insertion mutations and we expect topline data from this trial in mid-2026. Additionally, we are conducting a pivotal Phase 3 clinical trial, the ALPACCA clinical trial, in first-line locally advanced or metastatic non-squamous EGFRm NSCLC patients PACC mutations. In September 2025, our final Phase 1b PACC data reported 68.2% of patients (n=15 out of 22 1L patients at 240 mg) were observed to experience a confirmed reduction in tumor size of at least 30% from the baseline without evidence of progression as measured by RECIST 1.1 criteria. The confirmed mPFS in these patients was 16.0 months.

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Since our inception in 2021, we have assembled a robust oncology pipeline by leveraging our global network and our experience in business development transactions. In 2021, we licensed from Allist the right to develop and commercialize firmonertinib worldwide, with the exception of greater China, which includes mainland China, Hong Kong, Macau and Taiwan. Also in 2021, we entered into a research collaboration, as amended, with Aarvik Therapeutics, Inc. (Aarvik) to leverage its proprietary multi-target, multivalent, site-specific conjugation antibody platform to discover next-generation antibody drug conjugates (ADCs) with improved activity and safety over single target bivalent ADCs. In 2024, we entered into a collaboration agreement with Jiangsu Alphamab Biopharmaceuticals Co., Ltd. (Alphamab), a wholly owned subsidiary of Alphamab Oncology, to discover, develop and commercialize novel ADCs for the treatment of cancers globally, with the exception of greater China, which includes mainland China, Hong Kong, Macau and Taiwan. In January 2025, we entered into an Exclusive License Agreement (the Lepu Biopharma Agreement) with Lepu Biopharma Co. Ltd. (Lepu Biopharma) pursuant to which Lepu Biopharma granted us the right to develop and commercialize ARR-217 (MRG007), a CD-H17-targeting ADC for gastrointestinal cancers outside greater China, which includes mainland China, Hong Kong, Macau, and Taiwan.

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We plan to continue to engage in business development activities to source additional innovative therapeutics in areas currently underserved by approved therapies. This broader strategy includes evaluating research collaborations, partnerships and licensing arrangements intended to expand our development pipeline of differentiated and next-generation oncology assets. The following table summarizes our current pipeline indicating the most advanced stage of development:

NSCLC: non-small cell lung cancer; EGFR: epidermal growth factor receptor; PACC: P-loop alpha-c helix compressing; TKI: tyrosine kinase inhibitor; BTD: Breakthrough Therapy Designation; ADC: Antibody Drug Conjugate; GI Tumors: gastrointestinal tumors; 1L: First-line therapy; Global Ex-China: Worldwide, except mainland China, Hong Kong, Macau and Taiwan.

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Currently approved EGFR TKIs have achieved considerable commercial success and have become the standard of care for patients with NSCLC with classical EGFRm which comprise approximately 69% of all EGFRm NSCLC patients. However, many of these therapies, including AstraZeneca plc’s (AstraZeneca) third-generation EGFR TKI, osimertinib (TAGRISSO®), are minimally active against or not approved for use in a significant portion of NSCLC patients with uncommon EGFRm. This unmet need leaves many EGFRm NSCLC patients with few effective treatment options. Firmonertinib is currently approved and commercially distributed by Allist in China as a first-line therapy to treat classical EGFRm NSCLC. However, firmonertinib was designed to have strong inhibitory activity, not only against classical EGFRm, but also against uncommon EGFRm, such as exon 20 insertion and PACC mutations which together account for approximately 22% of EGFRm NSCLC.

To date, firmonertinib has been evaluated in multiple clinical trials with an aggregate patient population of over 1,000 patients against a broad range of EGFRm NSCLC, including both classical and uncommon EGFRm. Based on the results of preclinical and clinical trials conducted to date, we believe that firmonertinib has the potential to retain many of the key advantages of third-generation EGFR TKIs compared to first- and second-generation EGFR TKIs, including overcoming T790M mutations that confer resistance to earlier generation TKIs, while also targeting a broader set of EGFRm. In 2022, Allist reported the results of its FURLONG clinical trial, a double blind, placebo-controlled Phase 3 clinical trial of firmonertinib in first-line NSCLC patients with classical EGFRm. In FURLONG, firmonertinib was compared with the first-generation EGFR TKI, gefitinib, and demonstrated superior progression free survival (PFS) over gefitinib, showing a median PFS of 20.8 months versus 11.1 months for gefitinib. Firmonertinib’s ability to cross the blood-brain barrier was also demonstrated in this clinical trial with a central nervous system (CNS) metastases specific ORR, which measured reduction of tumor size of at least 30% in brain metastases if present at the start of therapy, of 91% versus 65% for gefitinib. Based on observed clinical activity against exon 20 insertions in the FAVOUR clinical trial and observed activity against PACC mutations in the FURTHER clinical trial, we believe firmonertinib is potentially differentiated from third-generation EGFR TKIs approved for classical EGFRm NSCLC.

In the United States and the European Union, standard of care for first-line therapy in EGFRm NSCLC involving exon 20 insertion mutations is platinum-based chemotherapy with pemetrexed with or without amivantamab. These regimens have significantly lower response rates and DOR compared to results achieved in first-line patients with classical EGFRm who can be treated with approved third-generation EGFR TKIs. Over 9% of EGFRm NSCLC patients are estimated to have exon 20 insertion mutations. However, amivantamab appears to lack brain penetrance to effectively treat brain metastasis. In March 2024 and July 2024, amivantamab in combination with chemotherapy, was approved in the United States and Europe, respectively, for first line EGFRm NSCLC patients with exon 20 insertion mutations. However, amivantamab is an intravenously administered biologic lacking the advantages of oral therapies. Furthermore, amivantamab is being dosed in combination with chemotherapy in this setting with chemotherapy associated toxicities. We believe firmonertinib, if approved, has the potential to become a chemotherapy-free oral regimen in first-line EGFRm NSCLC patients with exon 20 insertion mutations given the clinical data generated in this patient population to date.

Guidelines employing TKIs for the treatment of many of the PACC EGFRm are not established and, as a result, chemotherapy is often used as the default course of therapy, offering limited efficacy and introducing chemotherapy-related toxicity. Afatinib (GILOTRIF®), a second-generation TKI, is also used in some patients, but has an unfavorable safety profile and is not brain penetrant. Osimertinib is frequently used in some patients, but the activity of osimertinib in such patients is less than its activity in patients with classical EGFRm NSCLC. Over 12% of EGFRm NSCLC patients are estimated to have PACC mutations. If approved, we believe firmonertinib has the potential to become a leading treatment option for first-line EGFRm NSCLC patients with PACC mutations based on firmonertinib’s preclinical and clinical activity observed against these mutations and the evaluation of firmonertinib in multiple clinical trials.

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Our Firmonertinib Development Initiative

We have designed a robust global clinical development plan across a broad spectrum of EGFRm NSCLC patient populations for which we believe firmonertinib will have a differentiated profile compared to currently available treatments. The following table describes the key planned and ongoing clinical trials of firmonertinib conducted by us or our collaboration partners:

*Allist sponsor; 1L: First-Line Therapy; 2L+: Second-line or greater therapy.

FURVENT — Our Ongoing Phase 3 Clinical Trial in First-Line Non-Squamous Locally Advanced or Metastatic EGFRm NSCLC Patients with Exon 20 Insertion Mutations

We enrolled 398 patients in FURVENT, a global, pivotal Phase 3 clinical trial of firmonertinib in first-line non-squamous locally advanced or metastatic NSCLC patients with exon 20 insertion mutations being conducted jointly with Allist. Our FURVENT clinical trial is designed to assess the safety and efficacy of firmonertinib administered at either 160 mg or 240 mg, once-daily as compared to platinum-based chemotherapy with pemetrexed, the current first-line standard of care. The primary endpoint of this study is PFS. We enrolled 398 patients globally, including from sites in the United States, Europe and certain Asian countries including China. We expect topline data from our FURVENT clinical trial in mid-2026.

FAVOUR — Phase 1b Clinical Trial in NSCLC Patients with EGFR Exon 20 Insertion Mutations

The FAVOUR clinical trial is an ongoing 90-patient Phase 1b clinical trial being conducted by Allist in China that is intended to assess the safety and efficacy of firmonertinib in locally advanced or metastatic NSCLC patients who have EGFR exon 20 insertion mutations. First-line patients receive 240 mg firmonertinib once daily. Patients that have received prior treatment are randomized to receive either 160 mg or 240 mg of firmonertinib once daily. Initial data obtained through June 15, 2023 showed a confirmed ORR (defined as a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression), among patients evaluable as of that date of 79% among the treatment-naïve patients cohort, 46% among the pretreated 240 mg cohort and 39% in the pretreated 160 mg cohort. Median DOR was 15.2 months in treatment-naïve patients, 13.1 months in the 240 mg pretreated cohort and 9.7 months in the 160 mg pretreated cohort. Firmonertinib was observed to be generally well tolerated in all clinical trial cohorts to date with a low rate of discontinuation due to treatment-related adverse events (TRAEs). As of June 15, 2023, treatment related serious adverse events (TRSAEs) were observed in 6 out of 86 of the treated patients and 2 out of 86 patients discontinued participation in the trial as a result of TRAEs.

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FURTHER — Our Ongoing Phase 1b Clinical Trial in NSCLC Patients with EGFR Activating Mutations including PACC Mutations

We have completed enrolling patients in FURTHER, an ongoing, global Phase 1b dose escalation and expansion clinical trial being conducted jointly with Allist. It is intended to evaluate the safety, pharmacokinetics and preliminary anti-tumor activity of once-daily firmonertinib when used in patients with NSCLC involving locally advanced or metastatic disease that have previously received systemic therapy and whose tumors contain EGFR activating mutations. Anti-tumor activity is measured by confirmed complete response, defined as the disappearance of all target lesions, or partial response, defined as at least a 30% decrease in target lesions in the absence of a complete response, relative to the total number of patients. The pharmacokinetics, adverse events, serious adverse events, and observed anti-tumor activity in the exon 20 patients of firmonertinib in the clinical trial to date are consistent with those observed in the FAVOUR clinical trial conducted in China. The FURTHER clinical trial includes a cohort of 60 patients with a PACC EGFRm who are TKI treatment-naïve, and has been fully enrolled. In September 2025, we announced our final data from the FURTHER trial of firmonertinib in first-line patients with locally advanced or metastatic EGFRm NSCLC with PACC mutations. In this final readout, patients treated with 240 mg of firmonertinib were observed to experience 16.0 months mPFS and 14.6 months median duration of response. Further, 68.2% of patients treated in first-line at 240 mg and 43.5% of patients treated in first-line at 160 mg were observed to experience a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression as measured by RECIST 1.1 criteria, which measurement of reduction is the threshold in this trial for determination of the ORR. In addition, 47% (n=8/17) of patients with brain metastases at baseline were observed to experience a confirmed response utilizing modified RECIST 1.1 and 42.9% (n=6/14) of first line patients with brain metastases at baseline were observed to experience a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression as measured by RECIST 1.1 criteria. Firmonertinib was generally well-tolerated and consistent with interim safety results.

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ALPACCA —  Our Ongoing Phase 3 Clinical Trial in First-Line Non-Squamous Locally Advanced or Metastatic EGFRm NSCLC Patients with PACC Mutations

In December 2025, we announced the first patient dosed and plan to enroll 480 patients in ALPACCA, a global, pivotal Phase 3 clinical trial of firmonertinib in first-line non-squamous locally advanced or metastatic NSCLC patients with PACC mutations being conducted jointly with Allist. Our ALPACCA clinical trial is designed to assess the safety and efficacy of firmonertinib administered at 240 mg, once-daily as compared to an investigator’s choice of osimertinib or afatinib. The co-primary endpoints of this study are ORR and PFS. The study design reflects design elements from the FDA’s Project FrontRunner where we have the potential to seek accelerated approval based on ORR and full approval based on PFS.

Planned Adjuvant Study in NSCLC Patients with Uncommon EGFRm, including Exon 20 Insertion and PACC Mutations

The potential for EGFR TKIs that have demonstrated efficacy, safety and tolerability in the metastatic setting to improve disease-free and overall survival when administered in the adjuvant setting has been demonstrated by osimertinib in NSCLC patients with a classical EGFRm. We believe firmonertinib similarly has the potential to improve outcomes when administered as adjuvant therapy to EGFRm NSCLC patients with uncommon EGFRm, as these patients are not eligible for treatment with osimertinib. We intend to participate in a global adjuvant study of firmonertinib in EGFRm NSCLC with uncommon mutations initiated in China, or to conduct a parallel study, depending on results obtained from currently ongoing clinical trials.

FURLONG — Completed Phase 3 Clinical Trial in Classical EGFRm First-Line NSCLC Patients

FURLONG was a 358-patient clinical trial in China conducted by Allist, with results first reported in 2022, which resulted in the approval of firmonertinib in China as a first-line therapy in patients with locally advanced or metastatic NSCLC with classical EGFRm. It was designed to compare the safety and efficacy of once daily dosing of 80 mg firmonertinib to 250 mg gefitinib. Firmonertinib demonstrated clinically meaningful and statistically significant efficacy and a favorable safety profile as compared to the first-generation EGFR TKI gefitinib. Importantly, firmonertinib exhibited superior efficacy in the treatment of CNS metastases, producing a confirmed CNS metastases specific ORR, which measured reduction in tumor size of at least 30% in brain metastases if present at the start of therapy, of 91%

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versus 65% for gefitinib among participants with measurable metastatic CNS disease, demonstrating firmonertinib’s ability to cross the blood-brain barrier.

Our Antibody Drug Conjugate Collaborations

Consistent with our focus on curating a pipeline of innovative, impactful oncology therapies across modalities, we are advancing next-generation ADCs. ADCs are a promising modality for treating cancer due to their ability to target chemotherapy directly to the tumor cells. We are using Aarvik’s proprietary multi-target, multivalent site-specific conjugation antibody platform to discover and develop ADCs with potentially improved activity and safety over single target bivalent ADCs. We identified a preclinical candidate ARR-002 and have initiated Investigational New Drug (IND)-enabling activities. We are also working with Alphamab to leverage their proprietary linker-payload platform and glycan-conjugation technology to discover, develop, and commercialize ADCs for the treatment of cancers. Pursuant to the Lepu Biopharma Agreement, we are developing ARR-217, a novel CDH17-targeting ADC for the treatment of gastrointestinal cancers, which is currently in Phase 1 clinical development.

Our Team and Approach

We were founded and acquired the rights to develop and commercialize firmonertinib worldwide, with the exception of greater China, which includes mainland China, Hong Kong, Macau and Taiwan, in 2021. We believe that our deep expertise in developing oncology drugs, executing cross border business transactions and track record building companies will allow us to expand our portfolio globally, across the oncology landscape. Our co-founder, Chief Executive Officer and Chairman is Zhengbin (Bing) Yao, Ph.D. Prior to ArriVent, Dr. Yao was Chief Executive Officer and Chairman of Viela Bio, Inc. (Viela), which he co-founded in 2018 by licensing a portfolio of therapeutics from AstraZeneca. Viela was subsequently acquired by Horizon Therapeutics plc in 2021 for $3.1 billion. Prior to Viela, Dr. Yao served as Senior Vice President at MedImmune, Inc. and as Senior Vice President and Head of the Immuno-Oncology Franchise at AstraZeneca. Our other co-founder and President of Research and Development is Stuart Lutzker, M.D., Ph.D. Dr. Lutzker joined from Genentech, Inc., where he served in a number of senior Research and Development roles. Most recently, Dr. Lutzker was Vice President and Head of Oncology, Early Clinical Development and oversaw the early clinical phase development of a number of approved products. See “Certain Relationships and Related Transactions, and Director Independence” for more information.

Our team’s deep knowledge in oncology has allowed us to identify novel therapeutic programs with strong biologic and scientific rationale that we believe have the potential to offer a differentiated profile to treat cancer patients. Based on our extensive experience working with regulatory agencies, we will pursue assets that we believe have a clear regulatory path to approval. We believe our highly selective in-licensing strategy provides us with high-quality development candidates at preclinical or clinical stages, which, if approved, would have the potential to achieve global commercial success.

While we source candidates from across the globe, our initial focus has been on compounds originally developed in China. We believe that as the world’s second-largest pharmaceutical market, with extensive biopharmaceutical research and development capabilities, China provides us with attractive opportunities to in-license innovative therapies that otherwise may not reach global populations. We believe our business development acumen positions us to build a highly competitive pipeline that we are uniquely positioned to bring to global patient communities, beginning with our lead development asset, firmonertinib.

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Our Strategy

We intend to become a leading biopharmaceutical company through the identification, development and commercialization of differentiated medicines to address the unmet medical needs of patients with cancers. To accomplish this objective, we plan to:

Maximize the potential of firmonertinib — develop and commercialize firmonertinib for the treatment of a broad array of EGFRm NSCLC indications.

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Advance novel therapeutic product candidates for unmet medical needs, leveraging innovative platforms and technologies starting with ADCs.

ARR-217 is currently enrolling patients in a Phase 1 clinical study. This is an open-label, multi-center, Phase 1 study to evaluate the safety, tolerability, efficacy, and pharmacokinetics of ARR-217 (MRG007) in patients with unresectable locally advanced or metastatic solid tumors.

Broaden our pipeline through expanded business development initiatives.

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Lung Cancer

According to the National Cancer Institute, lung cancer is predicted to account for nearly 250,000 of the two million new cancer diagnoses made in the United States in 2023. Lung cancer ranks behind both breast and prostate cancer in terms of the number of newly diagnosed cases yet is responsible for far more deaths than any other type of cancer, with the estimated 27,000 lung cancer deaths to occur in 2023, more than double the annual number of deaths attributed to colorectal, pancreatic or breast cancer, as illustrated in the chart below. Lung cancer is the cause of approximately 20% of all cancer-related deaths and the 5-year survival rate for advanced lung cancer in the United States is approximately

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6%. Worldwide, lung cancer is estimated to be responsible for 2.2 million new cancer cases annually and 1.8 million deaths.

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Non-Small Cell Lung Cancer and the EGFR Driver Mutation

Cases of lung cancer are divided into NSCLC and small cell lung cancer, with NSCLC accounting for approximately 85% of all lung cancer diagnoses. NSCLC can be further segregated into two primary classifications: non-squamous cell carcinoma and squamous cell carcinoma. Non-squamous cell carcinoma is the most prevalent type of NSCLC and makes up approximately 77% of all NSCLC cases. Adenocarcinoma is the largest subgroup of the non-squamous NSCLC, constituting 81%. Among the genetic mutations that promote the development of NSCLC, mutational activation of the EGFR gene is among the most common. EGFR is a transmembrane glycoprotein consisting of an extracellular epidermal growth factor binding domain, a hydrophobic transmembrane domain and an intracellular tyrosine kinase domain that regulates signal transduction pathways involved in cellular proliferation. Its mutation results in the constitutive activation of these pathways and uncontrolled growth of the cancer cell. The overall prevalence of the EGFR mutation among NSCLC patients varies widely between different ethnic populations. Approximately 38% of NSCLC patients from Asian countries have an EGFR mutation, while approximately 24% of NSCLC patients in the Americas and approximately 14% of NSCLC patients in Europe have EGFR mutations. EGFR mutations are also more commonly associated with NSCLC patients who have never smoked, as well as women and young adult NSCLC patients. Substantially all NSCLC cases involving an EGFR mutation are non-squamous cell carcinomas.

Numerous EGFR mutations have been identified that cluster within the EGFR kinase domain encoded by exons 18-21 in the EGFR gene. These mutations, which include amino acid insertions, deletions and substitutions, activate EGFR signaling within the tumor cell and can be categorized as either classical or uncommon mutations. Classical mutations involving a deletion in amino acids encoded by exon 19 and another involving a substitution of the amino acid arginine for leucine at codon 858, which is referred to as an L858R mutation, are responsible for approximately 69% of NSCLC patients with an EGFRm. The uncommon mutations may be categorized based on the structural change to the drug binding pocket of the EGFR kinase domain, with the two most frequent groups of uncommon mutations involving an exon 20 insertion or PACC mutations of the EGFR. These two types of uncommon mutations account for approximately 22% of patients with EGFRm NSCLC and the life expectancy for NSCLC patients with uncommon EGFRm, including exon 20 insertion and PACC mutations, is lower. The distribution of patients with EGFR-mutation positive NSCLC is presented below. EGFRm are detected by numerous commercially available FDA-approved DNA tests, either Polymerase Chain Reaction (PCR) or Next Generation Sequencing (NGS), utilizing either tumor tissue or blood samples and testing for EGFRm, as well as other activating gene mutations, is considered standard in the management of NSCLC as per national guidelines such as National Comprehensive Cancer Network (NCCN). We are working with a diagnostics company to develop an FDA-approved NGS test for confirming EGFR exon 20 insertion mutations in our clinical trial and if firmonertinib is approved, we believe it would be indicated for patients with EGFRm as detected by an FDA-approved DNA test.

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EGFR activating mutations include both classical and uncommon mutations in the kinase domain

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Current Therapeutics and their Limitations

In classical EGFRm NSCLC, the current standard of care for the treatment of locally advanced or metastatic EGFRm NSCLC involves the use of a TKI as first-line therapy. Two first-generation TKIs, gefitinib and erlotinib (TARCEVA®), received initial marketing approval by the FDA in the early 2000s. These drugs, which were designed to competitively bind with EGFR at the ATP-binding site in a reversible manner to block enzymatic activation and downstream signal transduction, provide certain NSCLC patients with EGFRm substantial benefit, offering superior efficacy and safety profiles as compared to chemotherapy. However, durability of response to treatment is limited and virtually all patients with advanced disease acquire resistance, the most common of which involves a T790M substitution mutation. In addition, rash and diarrhea, often severe, are common adverse events (AEs). Efforts to address acquired resistance to first-generation TKIs led to the approval by the FDA of the second-generation TKIs afatinib (GILOTRIF®) in 2013 and dacomitinib (VIZIMPRO®) in 2018, drugs which irreversibly block the tyrosine kinase activity. However, TRAEs are more pronounced than the first-generation designs, which have limited broader clinical application of the second-generation TKIs.

Osimertinib was the first third-generation TKI to receive FDA approval and is currently a standard of care for patients with EGFRm NSCLC involving classical mutations and the related treatment emergent T790M mutation in the majority of countries worldwide. Osimertinib provides an improved AE profile, including a reduction in severe adverse events, compared to the earlier generation EGFR targeted TKIs and displays a greater ability to cross the blood-brain barrier, enabling efficacy against metastases involving the CNS. The ability to treat CNS metastases is of notable importance as patients with EGFR-activating mutations are particularly susceptible to the development of brain metastases, which can occur in up to 70% of patients during the course of their disease. In 2024, amivantamab in combination with lazertinib was approved for the treatment of first-line NSCLC patients with EGFR exon 19 deletions

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or exon 21 L858R substitution mutations. Amivantamab is a bispecific antibody and lazertinib is a third-generation EGFR TKI. The key limitations of therapies in EGFRm NSCLC are presented in the graphic below:

Table includes approved and disclosed registrational indications

*Afatinib has limited clinical data in patients with 2 of the 70 described PACC mutations.

**Exclaim-2 study in 1L announced as negative and in July 2024, the FDA withdrew the license for mobocertinib in the United States

Dacomitinib is also approved in the United States for classical EGFR mutations

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There is currently no TKI approved as first-line therapy for NSCLC patients with EGFR exon 20 insertion mutations. Platinum-based chemotherapy with pemetrexed is a standard of care for first-line therapy in this patient population in the United States and the European Union with or without amivantamab. Of particular note, approximately one-third of NSCLC patients harboring EGFR exon 20 insertion mutations have brain metastases at the time of diagnosis, which are mainly treated with radiation therapy, as chemotherapy is less effective in the treatment of brain metastases due to low brain penetration.

In 2021, the FDA granted marketing approval to two therapeutics, mobocertinib, a TKI, and amivantamab, a bispecific antibody, to treat NSCLC patients with exon 20 insertion mutations which have progressed after administration of platinum-based chemotherapy. Both approvals were granted under accelerated approval and continued approval may be contingent upon verification and description of clinical benefit in confirmatory trial(s). Notably, in July 2023, Takeda announced the discontinuation of its Phase 3 clinical trial of mobocertinib as a monotherapy in first-line patients due to futility and subsequently withdrew the drug from the market globally. In August 2023, Johnson & Johnson announced that its Phase 3 trial of amivantamab in combination with chemotherapy in first-line patients met its primary endpoint of PFS when compared to chemotherapy alone. While the FDA approved the use of this combination in this patient population in March 2024, and by the European Commission in July 2024, the use of chemotherapy in combination with amivantamab in the first-line patients may be limited due to the need to combine with intravenous chemotherapy and lack of brain penetration of amivantamab, along with chemotherapy associated toxicities.

A distinct set of approximately 70 uncommon EGFR-activating mutations have been identified that are predicted to alter the orientation of the interior surface of the ATP-binding pocket of the EGFR P-loop or αC-terminal end of the C-helix within the tyrosine kinase domain and are referred to as PACC mutations. Over 12% of patients with EGFRm are estimated to involve PACC mutations and patients diagnosed with PACC mutations have limited treatment options. Guidelines employing TKIs for many of the PACC-specific EGFRm are not established and as a result chemotherapy is used as the default course of therapy in many patients with limited clinical benefit. Osimertinib is frequently used in some patients, but the activity of osimertinib is much less than in classical EGFRm NSCLC. The second-generation TKI

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afatinib is the only TKI to have received FDA and the European Medical Association approval in NSCLC to treat EGFRm NSCLC with limited clinical data for two of the 70 PACC mutations, G719X and S768I.

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The current treatment paradigm for the various subtypes of EGFRm NSCLC outside of China and areas of unmet medical needs where we believe firmonertinib may provide clinical utility is summarized in the chart presented below.

Firmonertinib has the potential to address significant unmet needs in the current EGFRm NSCLC treatment paradigm

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Specific to the HER2 exon 20 insertion mutation, an exon 20 insertion in the related HER2 gene, in August 2022 the FDA granted accelerated approval to fam-trastuzumab deruxtecan-nxki (ENHERTU®), a HER2-directed antibody-drug conjugate, for adults with unresectable or metastatic NSCLC who have received prior systemic therapy. Despite its approval, patients with refractory or recurrent disease remain a significant portion of the patient population and currently approved TKIs have demonstrated limited efficacy in targeted HER2 exon 20 insertion mutations.

Firmonertinib: Our Lead Development Candidate

Our lead development candidate is firmonertinib, an investigational, novel, EGFR mutant-selective TKI that we are developing for the treatment of patients with NSCLC harboring a broader set of EGFRm than are currently served by approved EGFR TKIs. Firmonertinib is currently approved and commercially distributed by Allist in China as a first-line treatment of locally advanced or metastatic NSCLC patients with classical EGFRm as well as pre-treated patients with T790M mutations. In addition, in an interim data readout from the FAVOUR trial of firmonertinib, reductions in tumor size have been observed in patients with exon 20 insertion mutations and activity in PACC mutations has been observed in an interim data readout from the FURTHER trial. Exon 20 insertion mutations and PACC mutations are each a subtype of uncommon mutation. Exon 20 insertions and PACC mutations account for approximately 22% of EGFRm NSCLC patients and are largely underserved by existing treatments. Firmonertinib has been studied in over 1000 patients, including over 450 patients outside China, across a broad dose range. We anticipate that favorable safety data, if obtained for firmonertinib, could allow for the administration of firmonertinib at different doses required for optimal activity in different EGFRm patient populations. Encouraging activity has been observed to date in both preclinical and clinical settings, including response in CNS metastases, in an interim data readout from our partner’s ongoing FAVOUR clinical trial in China with patients with exon 20 insertions, and in the FURTHER clinical trial in patients with PACC mutations globally.

Of particular note, firmonertinib exhibited elevated tissue distribution to the brain in preclinical studies. In these studies, the brain and plasma concentrations were measured in mice following a single dose of either firmonertinib or

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osimertinib and the brain-to-plasma calculated for both total drug (Kp) and unbound drug (Kp uu). Osimertinib was used as a reference compound in certain experiments as it has demonstrated clinical activity in patients with CNS metastases. As is noted in the chart below, these experiments showed that firmonertinib penetrated the blood-brain barrier at a rate similar to that of osimertinib.

Firmonertinib displayed brain penetrant properties similar to osimertinib in pre-clinical studies. When mice were administered a single dose of either firmonertinib or osimertinib, they penetrated the blood-brain barrier to a similar extent.

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We are currently awaiting topline data from our FURVENT clinical trial, a global, pivotal Phase 3 clinical trial of firmonertinib in first-line non-squamous locally advanced or metastatic NSCLC patients with exon 20 insertion mutations and we expect topline data in mid-2026. In addition, we are conducting our ALPACCA trial, a global, pivotal Phase 3 clinical trial of firmonertinib in first-line non-squamous locally advanced or metastatic NSCLC patients with PACC mutations. Data from our clinical trials are discussed below.

FURVENT — Our ongoing Phase 3 Clinical Trial in First-Line Non-Squamous Locally Advanced or Metastatic EGFRm NSCLC Patients with Exon 20 Insertion Mutations

We have completed enrolling patients in FURVENT, a global, pivotal Phase 3 clinical trial of firmonertinib in first-line non-squamous locally advanced or metastatic EGFRm NSCLC patients with exon 20 insertion mutations being conducted jointly with Allist. We designed a randomized clinical trial, integrating feedback from global regulatory agencies, that consists of three cohorts, which enrolled 398 patients in total, designed to evaluate the safety and efficacy of firmonertinib at two different dose levels, 160 mg and 240 mg, administered daily (QD) and compare therapeutic benefit to platinum-based chemotherapy cycles with pemetrexed, the clinical trial’s active control group. Participants in this clinical trial will continue to receive treatment until disease progression or discontinuation related to toxicity, with patients in the control group allowed to cross over into one of the two firmonertinib arms after disease progression. The primary endpoint of this trial is PFS per blinded independent central review utilizing RECIST 1.1 criteria. Secondary endpoints include ORR, overall survival (OS) and DOR, as well as brain-specific ORR and PFS in patients with brain metastases. We have completed enrolling patients in this clinical trial and anticipate top-line data for the use of

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firmonertinib as first-line therapy in patients with non-squamous locally advanced or metastatic EGFRm NSCLC with exon 20 insertion mutations in mid-2026. The FURVENT clinical trial’s study design is illustrated below:

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FURTHER — Our Ongoing Phase 1b Clinical Trial in NSCLC Patients with EGFR Activating Mutations including PACC Mutations

We completed enrolling patients in FURTHER, an ongoing, global Phase 1b dose escalation and expansion clinical trial being conducted jointly with Allist. It is intended to evaluate the safety, pharmacokinetics and reduction in tumor size as a result of once-daily firmonertinib when used in locally advanced or metastatic non-squamous EGFRm NSCLC patients that have previously received systemic therapy and whose tumors contain EGFR activating mutations, including both classical and uncommon, as well as HER2 exon 20 insertion mutations. Cohort 4 specifically enrolls patients with EGFR PACC mutations. PACC mutations represent a group of approximately 70 EGFR activating mutations characterized by a structural displacement of the P-loop and/or αC-helix within EGFR’s kinase domain which impact drug binding for third generation EGFR TKIs such as osimertinib. PACC mutations can be identified along with the classical EGFR mutations using commercially available NGS panels. Currently, afatinib, a second-generation EGFR TKI has data supporting its use in two of the approximately 70 PACC mutations (S768I and G719X). Our preclinical data to date suggest that firmonertinib may have activity against a significantly broader number of PACC mutations. The

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first stage of the FURTHER clinical trial enrolled a broad group of EGFRm NSCLC patients to evaluate pharmacokinetics and safety in patients outside of China and identify a dose for the expansion cohorts shown below.

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Pharmacokinetic data obtained in the first stage of the FURTHER clinical trial as of June 15, 2023 were consistent with initial pharmacokinetic data obtained in the FAVOUR clinical trial as of June 15, 2023 with similar steady-state levels of firmonertinib and its major metabolite, AST5902 (see figure below). The AEs in the FURTHER clinical trial have been consistent with the EGFR targeted TKI class in general, with diarrhea, stomatitis and rash being the most commonly observed TRAEs. The frequency of dose reduction and discontinuation due to AEs has remained low. Initial

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evidence of reduction in tumor size has been observed, with confirmed and unconfirmed partial responses to firmonertinib noted in NSCLC patients with mutations involving EGFR exon 20 insertions.

Firmonertinib has shown similar drug levels at steady state in both the FAVOUR and the FURTHER clinical trials

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Reduction in tumor size observed in preclinical studies with firmonertinib in uncommon EGFR mutations

We advanced firmonertinib into clinical trials as a potential treatment for EGFR mutation-positive NSCLC involving uncommon mutations based on compelling data demonstrating reduction in tumor size in preclinical studies using mouse xenografts, as presented below.

As is detailed in the illustration presented below, in this LU0387 patient derived tumor xenograft model with an EGFR exon 20 insertion mutation H773_V774insNPH, once daily oral dosing of firmonertinib at 20 mg/kg, 30 mg/kg or 50 mg/kg, which equates to an approximate human dose of 40 mg, 160 mg or 240 mg respectively, was observed to induce significant tumor growth inhibition with regression of tumors at the 50 mg/kg dose with minimum change to bodyweight.

Firmonertinib displayed reduction in tumor size in EGFR exon 20 insertion mutations tumor model

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Similar reduction in tumor size was observed in a Ba/F3 subcutaneous tumor xenograft model harboring a G724S PACC mutation as shown below. This PACC mutation is less sensitive to firmonertinib than other PACC mutations based on cell line data. The oral administration of 15 mg/kg, 30 mg/kg or 50 mg/kg firmonertinib one time per day produced pronounced significant inhibition of tumor growth with regression of tumors at the two higher doses. We believe the limited loss of body weight suggests that the drug was generally well tolerated.

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Tumor growth inhibition was observed in an EGFR G724S PACC mutation tumor model with firmonertinib

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The in vivo efficacy of firmonertinib was also evaluated in a subcutaneous Ba/F3 tumor xenograft model with a HER2 exon 20 insertion mutation V777_G778insGC as illustrated below. B-NDG mice administered an oral dose of 15 mg/kg, 30 mg/kg or 50 mg/kg firmonertinib once daily were observed to exhibit significant tumor growth inhibition with regression at the two higher doses. Moreover, firmonertinib appeared generally well tolerated with minimal change in body weight.

Reduction in tumor size was observed in a HER2 exon 20 insertion mutation tumor model with firmonertinib

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FURTHER Cohort 4 — Our Ongoing Phase 1b Clinical Trial in NSCLC Patients with EGFR Activating PACC Mutations

The FURTHER clinical trial cohort 4 enrolled 60 patients with locally advanced or metastatic NSCLC with EGFR PACC mutations who are TKI-treatment naive. Patients in Cohort 4 are randomized into two groups, one group of up to 30 patients administered 160 mg firmonertinib once-daily and the other group of up to 30 patients administered 240 mg firmonertinib once-daily. Patients with asymptomatic metastases involving the CNS are allowed to participate in the trial. The primary endpoint of this trial is ORR as measured by the Response Evaluation Criteria In Solid Tumors (version 1.1) by Blinded Independent Central Review. Secondary endpoints include DOR sustained, disease controlled without progression of the disease (DCR), PFS, OS and safety. Follow-up evaluations with trial participants are

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conducted every six weeks. The baseline characteristics of the 60 patients enrolled in the FURTHER clinical trial are described in the following table.

As of June 3, 2025, the final data was available from the 45 patients who have had measurable disease at baseline by blinded independent central review committee (BICR), had received at least two tumor assessments, had progressive disease or death, or discontinued from treatment. Of these 45 patients 22 are in the 240mg first line PACC patient group and 23 are in the 160mg first line PACC patient group. Safety data were available for all 60 patients. Based on these data, reduction in tumor size was observed across all cohorts. Confirmed ORRs by BICR (defined as a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression) were 68% among the 240mg cohort and 43% among the 160 mg cohort. The DCR by BICR, which includes complete responses, partial responses and stable disease, was 100% and 91% for each of these respective trial cohorts, respectively.

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The extent of change in tumor size was evaluated across patients and shown in the figure below taken from the final data cut of June 3, 2025. Patients on average achieved greater tumor size reduction in the 240 mg dose versus the 160 mg dose. Tumor size reduction was observed across the different PACC mutations such as frequent (G719X, S78I), less frequent (other), single and compound mutations.

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Tumor size reduction was observed in different PACC mutations with firmonertinib

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Responses occurred rapidly with most patients having a partial response by the first tumor assessment at six weeks with responses ongoing in many patients as denoted in the figure below.

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The confirmed median PFS as of the final data cut of June 3, 2025 was 16.0 months at the 240mg dose and 11.1 months at the 160mg dose. The median duration of follow-up was 16.5 months.

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Confirmed CNS responses were also observed in response evaluable patients as denoted in the figure below.

Firmonertinib was observed to be generally well tolerated and demonstrated safety results similar to prior firmonertinib trials. The table below summarizes this safety and tolerability data collected in the FURTHER trial as a whole and in Cohort 4 specifically, as of the final data cut date of June 3, 2025:

FAVOUR — Phase 1b Clinical Trial in NSCLC Patients with EGFR Exon 20 Insertion Mutations

The FAVOUR clinical trial is a 90-patient, Phase 1b clinical trial being conducted by Allist in China that is intended to assess the safety and efficacy of firmonertinib in locally advanced or metastatic NSCLC patients who have EGFR exon 20 insertion mutations. This 90-patient clinical trial consists of 3 treatment cohorts of 30 patients each. Eligibility criteria include both adult patients with one or more measurable lesions who are either treatment-naïve, or first-line patients, or have previously received systemic therapy. Patients with asymptomatic metastases involving the CNS are allowed to participate in the trial. First-line patients receive 240 mg firmonertinib once daily. Patients that have received prior treatment are randomized to receive either 160 mg or 240 mg of firmonertinib once daily. The primary endpoint of this trial is ORR as measured by the RECIST version 1.1 by BICR. Secondary endpoints include DOR, DCR, PFS,

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overall survival (OS) and safety. OS is not reported due to the data being immature as of the data cutoff date of June 15, 2023. Follow-up evaluations with trial participants are conducted every six weeks. In the treatment-naïve population, firmonertinib is being evaluated as a first-line therapy. The baseline characteristics of the 86 patients enrolled in the FAVOUR clinical trial as of June 15, 2023 are described in the following table.

As of June 15, 2023, initial interim data was available from the 80 patients who have had measurable disease at baseline by blinded independent central review committee, had received at least two tumor assessments, had progressive disease or death, or discontinued from treatment. Of these 80 patients 28 are in the treatment-naïve patient group and 52 were previously treated, split evenly between the 160 mg and the 240 mg cohort. Safety data were available for all 86 patients. Based on these data, reduction in tumor size was observed across all cohorts. Confirmed ORRs (defined as a reduction in tumor size of at least 30% from the baseline in a patient without evidence of progression) were 79% among the treatment-naïve patients cohort, 46% among the previously treated 240 mg cohort and 39% in the previously treated 160 mg cohort. Median DOR was 15.2 months in treatment-naïve patients, 13.1 months in the 240 mg previously treated cohort and 9.7 months in the 160 mg previously treated cohort. Median PFS was 10.7 months in the treatment-naïve patients, 7.0 months in the 240 mg previously treated cohort and 5.7 months in the 160 mg previously treated cohort. The DCR, which includes complete responses, partial responses and stable disease, was 100%, 92% and 85% for each of these respective trial cohorts. These initial interim PFS and DOR data continue to mature with patients continuing in the clinical trial. Interim data from clinical trials may change as more patient data becomes available and are subject to audit

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and verification procedures that could result in material changes in the final data. The following table describes these data.

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The extent of change in tumor size was evaluated across patients and shown in the figure below. Median tumor size reduction of 51% was observed in the treatment-naïve patients cohort, 54% was observed among pretreated patients in the 240 mg cohort and 36% in the pretreated 160 mg patient cohort. Patients on average achieved greater tumor size reduction in the 240 mg dose versus the 160 mg dose. Tumor size reduction was observed across the different locations of the exon 20 insertion (near loop, far loop and helical mutations).

Tumor size reduction was observed in all EGFR exon 20 insertion mutation subtypes with firmonertinib

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Responses occurred rapidly with most patients having a partial response by the first tumor assessment at six weeks with responses ongoing in many patients as denoted in the figure below.

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Firmonertinib was observed to be generally well tolerated and demonstrated safety results similar to prior firmonertinib trials. As of June 15, 2023, the following six (n=86) TRSAEs were observed: abnormal hepatic function (1), decreased platelet count (2), abnormal uterine bleeding (1), interstitial lung disease (1) and diarrhea (1). As of June 15, 2023, the following 21 (n=86) treatment-emergent serious adverse events (TESAEs) were observed: pleural effusion (6), pulmonary embolism (2), dyspnoea (1), interstitial lung diseases (1), decreased platelet count (2), increase lipase (1), pericardial effusion (3), pneumonia (3), cerebral infarction (1), abnormal uterine bleeding (1), depression (1), abnormal hepatic function (1), diarrhea (1), colon adenocarcinoma (1) and venous thrombosis (1). When AEs occurred, they were generally consistent with known class effects of EGFR TKIs. TRAEs of Grade 3 or higher deemed related to the study drug were noted in 13% among treatment-naïve patients, and 18% and 29% among previously treated patients dosed at the 160 mg and 240 mg daily level, respectively. TRAEs that led to dose interruption occurred in 14% of patients who received a 160 mg daily dose, 32% among previously treated patients who received a 240 mg daily dose and 23% among patients in the first-lint patient cohort. TRAEs that led to a reduction in dose occurred in 13% of untreated patients at the 240 mg dose and 11% and 18% among previously treated patients who received a 160 mg or 240 mg daily dose, respectively. The rate of trial discontinuation related to TRAEs was low, with only two trial patients

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ending trial participation because of AEs across all treatment cohorts. The table below summarizes this safety and tolerability data as of June 15, 2023:

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The most frequent TRAEs as of June 15, 2023 are detailed in the table below. The majority of these AEs were grade 1 or 2 and commonly associated with EGFR TKIs as a class.

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Planned Adjuvant Study in NSCLC Patients with Uncommon EGFRm, including Exon 20 Insertion and PACC Mutations

We intend to participate in, or to conduct in parallel, a single multicenter, randomized, global pivotal Phase 3 clinical trial initiated in China to investigate the potential benefit of firmonertinib when administered to adult patients with Stage IIB to IIIB EGFRm NSCLC, after surgical resection. Eligibility in this clinical trial is restricted to patients with uncommon EGFR mutations including PACC, exon 20 insertion and other uncommon EGFRm. Participants are to be randomized on a 1:1 basis to receive either firmonertinib or placebo for three years and stratified based on stage of disease, mutation type and geographic origin. Participants are to receive firmonertinib daily over a three-year period with the primary endpoint to be disease free survival with secondary endpoints being OS and safety. We intend to participate in, or to conduct in parallel, this clinical trial in 2026, depending on the timing and results of the FURVENT study.

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FURLONG — Completed Phase 3 Clinical Trial in Classical EGFRm First-Line NSCLC Patients

FURLONG was a 358-patient randomized, double-blinded, multi-center clinical trial with an active control arm, conducted in China by Allist, designed to compare the safety and efficacy of once daily dosing of 80 mg firmonertinib to 250 mg of gefitinib as first-line therapy in patients with locally advanced or metastatic NSCLC with classical EGFRm. Data from this trial supported the 2022 approval of firmonertinib in China for this patient population. The 358 patients enrolled in this Phase 3 trial were randomized on a 1:1 basis to receive either 80 mg of firmonertinib or 250 mg gefitinib orally as monotherapy in three-week cycles. All patients in the FURLONG clinical trial had either advanced Stage 3 or Stage 4 disease. Each cohort enrolled a similar number of women and non-smokers, and the distribution of classical mutation type was comparable, as was the number of patients with metastatic disease involving the central nervous system. The patient demographic information is illustrated below.

Firmonertinib demonstrated improved efficacy results as compared to gefitinib in the FURLONG clinical trial

Firmonertinib demonstrated clinically meaningful and statistically significant therapeutic benefit as compared to gefitinib in the FURLONG clinical trial. In this clinical trial, we saw patients with firmonertinib lived longer without progression of disease. Median PFS in the patient cohort that was treated with firmonertinib was 20.8 months as compared to 11.1 months for the cohort that received gefitinib, representing a hazard ratio of 0.443 with p value 0.0001. The ORR in the firmonertinib cohort, which included clinical trial participants exhibiting either a complete

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response or a partial response to therapy, was 89% as compared to 84% in the gefitinib arm of the trial. The Kaplan-Meier curve of progression free survival in both cohorts is illustrated in the chart presented below.

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Firmonertinib demonstrated improved safety results as compared to gefitinib in the FURLONG clinical trial

Firmonertinib also demonstrated favorable safety results as compared to gefitinib in the FURLONG clinical trial. Despite an extended median duration of exposure to firmonertinib of 18.3 months as compared to 11.2 months among patients in the gefitinib cohort, firmonertinib administration resulted in fewer Grade 3 TRAEs as compared to gefitinib, 11.2% versus 17.9%, and fewer treatment-related serious adverse events, 5.6% versus 6.1%. The following TRSAEs were observed in ten patients (n=178) in the FURLONG study: increased alanine aminotransferase (4), increased aspartate aminotransferase (3), cerebral infraction (2), abnormal hepatic function (1), decreased blood fibrinogen (1), decreased platelet count (1), diarrhea (1), cholecystitis (1), cholelithiasis (1), pancreatitis (1), gastroenteritis (1), and gastritis (1). The following TESAEs were observed in 44 patients (n=178) in the FURLONG study: pleural effusion (5), cerebral infarction (5), increased alanine aminotransferase (4), increased aspartate aminotransferase (3), pneumonia (3), dyspnoea (2), respiratory failure (2), pulmonary embolism (2), abnormal hepatic function (1), decreased blood fibrinogen (1), decreased platelet count (1), diarrhea (1), cholecystitis (1), cholelithiasis (1), pancreatitis (1), gastroenteritis (1), gastritis (1), and death (1). The rate of trial discontinuation related to TRAEs was 3.4%, with six trial patients ending trial participation because of AEs, one as a result of each of interstitial lung disease, hyperbilirubinemia, visual impairment, ECG QT prolongation, ALT/AST elevation and decreased platelet count.

Firmonertinib exhibited superior efficacy results in the treatment of CNS metastases in the FURLONG clinical trial

Of the 358 patients enrolled in FURLONG, 60 had measurable CNS lesions that could be evaluated. Among trial participants with measurable CNS metastases, firmonertinib produced a confirmed CNS metastases specific ORR of 91% vs. 65% for gefitinib. In the full analysis set of 133 patients who had measurable or non-measurable CNS metastases the median CNS metastases specific progression free survival was 20.8 months for firmonertinib versus 9.8 months for the cohort that received gefitinib. Additionally, in a post-hoc analysis of patients that did not present with CNS lesions at enrollment, none of the patients who were treated with firmonertinib developed new lesions related to CNS metastases during the trial period. Among gefitinib patients, 8 trial participants developed such lesions. We believe this difference reflects firmonertinib’s enhanced potential to cross the blood-brain barrier which we believe may enable the prevention of CNS metastases.

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Molecular Structure of Firmonertinib

The molecular structure of firmonertinib is shown below. Firmonertinib contains an acrylamide side chain to confer irreversible binding to the EGFR kinase domain that may result in prolonged target inhibition and a flexible trifluoroethoxy side chain linked to a pyridine to provide additional contact points in the drug binding pocket, which we believe may enable improved binding across EGFR mutants as modeled below. It is believed that these two features of firmonertinib work together to enable broad inhibition of both classical and uncommon EGFR mutations such as exon 20 insertions and PACC mutations. In addition, the active metabolite of firmonertinib, AST5902 retained mutation specificity in vitro, which we believe may minimize toxicity due to EGFR inhibition in non-cancer cells.

The molecular structure of firmonertinib contains numerous advantageous features

The chemical structure of Firmonertinib

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A trifluoroethoxy side chain was included to provide additional contact points across different EGFR mutant subtypes

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Our Antibody Drug Conjugate Collaborations

ADCs have emerged as an important therapeutic approach to delivering potent chemotherapy more directly to tumor cells which express a target on its cell surface while avoiding toxicity to normal cells which express the target at lower levels. However, currently available ADCs that utilize conventional antibodies that bind a single target as the drug delivery vehicle are still plagued by dose limiting and chronic toxicities. In addition, target expression tends to be heterogeneous within a tumor which can limit efficacy and/or restrict ADC use to only tumors that have high and mostly homogenous target expression.

Our Lepu Biopharma Antibody Drug Conjugate Collaboration

We also established an ADC collaboration with Lepu Biopharma in January 2025, to gain ex-Greater China, which includes mainland China, Hong Kong, Macau and Taiwan, rights to ARR-217, a CDH-17 targeted ADC, with the potential to treat gastrointestinal malignancies.

Our Aarvik Antibody Drug Conjugate Collaboration

To overcome the limitations of conventional ADCs we are advancing the development of next-generation ADCs through a research collaboration with Aarvik. Leveraging Aarvik’s proprietary multi-target, multivalent antibody and site-specific conjugation platform, we have an ongoing research collaboration in an effort to develop an ADC that is potentially both safer and more effective than a conventional single target bivalent ADC. We identified a lead candidate (ARR-002) and initiated IND-enabling activities.

Our Alphamab Antibody Drug Conjugate Collaboration

In addition to our Aarvik ADC Collaboration, we established an ADC collaboration with Alphamab in June 2024. We are working with Alphamab to leverage their proprietary linker-payload platform and glycan-conjugation technology to identify novel ADCs for oncology indications globally, except greater China, which includes mainland China, Hong Kong, Macau and Taiwan where Alphamab retains the right to develop and commercialize ADCs.

Licenses, Partnerships and Collaborations

Allist Agreements

Global Technology Transfer and License Agreement

On June 30, 2021 (the Effective Date), we entered into a Global Technology Transfer and License Agreement with Allist, as amended on November 6, 2023 (the Allist License Agreement), pursuant to which (i) Allist granted to us an exclusive (even as to Allist and its affiliates), royalty-bearing, sublicensable license under certain intellectual property (including patents and know-how) owned or controlled by Allist to develop, manufacture and commercialize any product (the Licensed Product) containing firmonertinib or any of its salts or derivatives as an active ingredient (the Licensed Compound), for all uses (the Field), in all countries and territories (the Licensed Territory) other than greater China, which includes mainland China, Hong Kong, Macau and Taiwan (the Retained Territory); and (ii) we granted Allist a non-exclusive sublicensable license to use (1) any information, data and results that relate solely and exclusively to the Licensed Product and which we generate or collect in the conduct of clinical trials or preclinical activities in the Licensed Territory and (2) any improvements or enhancements that we make or discover under the License Agreement to the know-how licensed to us and is owned or controlled by us, to develop, manufacture, and commercialize the Licensed Compound and the Licensed Product for all uses in the Retained Territory.

The parties have appointed a joint collaboration committee, comprised of representatives from both us and Allist (the Collaboration Committee), to oversee the parties’ development activities related to the Licensed Compound under the Allist License Agreement.

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Under the terms of the Allist License Agreement, we are required to use commercially reasonable efforts to (i) develop the Licensed Product in the Licensed Territory, (ii) prepare and submit regulatory filings and seek regulatory approvals in all major market countries in the Licensed Territory and (iii) perform all commercialization activities for the Licensed Product in each country in the Licensed Territory in which the Licensed Product has received regulatory approval, and we are solely responsible for all the expenses associated with the foregoing (i)-(iii). We are also responsible for the manufacture and supply of the Licensed Product in the Licensed Territory, by ourselves or through a third-party manufacturer, for the purpose of conducting clinical trials, obtaining regulatory approval and commercializing the Licensed Product in the Licensed Territory.

In consideration of the licenses and rights granted to us under the Allist License Agreement, we granted to Allist a total of 1,276,250 shares of common stock for a purchase price of $0.0001 per share pursuant to that certain Subscription Agreement executed concurrently with the Allist License Agreement.

As additional consideration for the licenses and rights granted to us under the Allist License Agreement, we made an upfront, non-creditable and non-refundable cash payment of $40.0 million to Allist on the Effective Date (the Initial Payment). We are obligated to make development and regulatory approval milestone payments to Allist upon the achievement of specific milestone events related to the Licensed Product in an aggregate amount up to $110.0 million, of which we have paid $5.0 million upon meeting certain clinical milestones, and commercial milestone payments to Allist upon the achievement of specified net sales thresholds of the Licensed Product in an aggregate amount up to $655.0 million. We are also obligated to pay Allist tiered royalties ranging from high single digits to low mid-teens percentages on an incremental aggregated net sales basis on the net sales of any Licensed Products in the Licensed Territory made by or on behalf of us or our sublicensees. Our obligation to pay royalties for each Licensed Product begins from the date of the first commercial sale of such Licensed Product in a given country and extends until the latest of (i) the expiration of the last valid patent claim related to such Licensed Product’s composition or approved indications in such country, (ii) the termination of any regulatory-based exclusivity period in such country, or (iii) ten years after the initial commercial sale of such Licensed Product in such country (the Allist License Royalty Term). Our obligation to make milestone payments also ceases upon the expiration of the Allist License Royalty Term on a product-by-product and country-by-country basis.

The Allist License Agreement will remain in force until the earlier occurrence of (i) the expiration of our obligation to pay royalties for all Licensed Products and (ii) the date that the Allist License Agreement is terminated pursuant to its early termination provisions (the Term). Either party has the right to terminate the Allist License Agreement, subject to specified cure periods, for the material breach by the other party or the bankruptcy or insolvency of the other party. In addition, we have the right to terminate the Allist License Agreement upon 60 days’ prior written notice to Allist at any time, at our sole discretion, either in its entirety or on a Licensed Product-by-Licensed Product and country-by-country basis. Upon termination of the License Agreement, Allist will have certain specified reversion rights with respect to the Licensed Product if the termination is for any reason other than by us for the material breach by Allist, and if the termination is by us for the material breach by Allist, we would have the right to continue under the License Agreement in lieu of termination but with our milestone and royalty payment obligations being substantially reduced.

Joint Clinical Collaboration Agreement

On December 24, 2021, we entered into a Joint Clinical Collaboration Agreement (the Allist Collaboration Agreement) with Allist to govern the conduct of any global clinical trials to be conducted with the Licensed Products as specified in the Allist License Agreement (each, a Global Study). Pursuant to the Allist Collaboration Agreement, if either party or both parties wish to jointly conduct a Global Study, one or both parties (as the case may be) shall prepare and submit the proposed strategy, protocol design, budget, proposal for budget sharing and internal process timeline for such proposed Global Study to the Collaboration Committee that was appointed pursuant to the Allist License Agreement for its review at least 90 days in advance of the applicable protocol filing with the relevant regulatory authorities. Upon the approval by the collaboration committee of a development plan for the proposed Global Study that includes the allocation of the sponsorship for the conduct of the proposed Global Study and other details for conducting the proposed Global Study as specified in the Allist Collaboration Agreement, the proposed Global Study shall be deemed to be a “Joint Global Study” and such development plan a “Joint Global Development Plan.” The parties have agreed in the Allist Collaboration Agreement that (i) we will be the sponsor of any Joint Global Study in the Licensed

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Territory (as defined in the Allist License Agreement), (ii) Allist will be the sponsor of any Joint Global Study in the PRC (as defined in the Allist License Agreement) and (iii) the Collaboration Committee shall designate the party that will be the sponsor of any Joint Global Study in certain territories (Joint Territories). The parties will mutually agree on the global regulatory strategy for each Joint Global Study. The party that is the sponsor of a Joint Global Study will be responsible for (1) selecting the sites and investigators to be used in the conduct of the applicable Joint Global Study, and (2) developing strategies for, and preparing and submitting, all regulatory filings and applications for regulatory approval for the Licensed Products, in the sponsor’s sponsored territory, except that Allist shall be responsible for developing strategies for, and preparing and submitting, all regulatory filings and applications for regulatory approval for the Licensed Products in the Joint Territories regardless of whether we are the sponsor in these territories. The parties will review the budget for each Joint Global Study and agree through the Collaboration Committee on the model to be used to share the expenses to be incurred in the conduct of such Joint Global Study.

Subject to applicable cure periods, the Allist Collaboration Agreement may be terminated by a party upon a material breach of the Allist Collaboration Agreement by the other party.

Aarvik Research Collaboration Agreement

On December 21, 2021, we entered into a Research Collaboration Agreement, as amended effective June 30, 2023 (the Aarvik Collaboration Agreement), with Aarvik, pursuant to which we and Aarvik agreed to collaborate on the discovery and characterization of novel ADCs with a goal to identify ADCs that may be suitable for further development by us in accordance with the applicable statements of work (each a SOW, collectively, the SOWs) until the completion of all activities in accordance with the applicable SOWs (collectively, the Aarvik Collaboration).

On August 9, 2024, we entered into an amendment and restatement of the Aarvik Collaboration Agreement (the Amended and Restated Aarvik Collaboration Agreement). Under the Amended and Restated Aarvik Collaboration Agreement, Aarvik granted us an exclusive option (the Option) to obtain exclusive rights to certain of Aarvik’s intellectual property for the research, development, manufacture, use, commercialization, or other exploitation of the novel ADCs. Under the Amended and Restated Aarvik Collaboration Agreement, we are required to pay Aarvik a collaboration initiation fee and research fees as provided in the SOWs. We exercised the exclusive option simultaneously with entry into the Amended and Restated Aarvik Collaboration Agreement.

The parties have appointed a joint research committee, comprised of our representatives and representatives from Aarvik, to oversee the parties’ research collaboration activities under the Amended and Restated Aarvik Collaboration Agreement. Aarvik has agreed, during the term of the Aarvik Collaboration and following our exercise of the Option, to certain exclusivity and ownership provisions with respect to ADCs.

Under the Amended and Restated Aarvik Collaboration Agreement, we are required to pay Aarvik a collaboration execution fee and research fees as provided in the SOWs. We further agreed to reimburse Aarvik for actual costs incurred in procuring other materials Aarvik will actually use in performing activities under the applicable SOWs. Because we have exercised the Option, we were required to make a one-time non-refundable option exercise payment of low single-digit millions and we will be obligated to make milestone payments to Aarvik upon the achievement of specific regulatory and sales milestone events related to the Aarvik Collaboration as specified and determined in the Amended and Restated Aarvik Collaboration Agreement. Combined regulatory milestone payments and sales milestone payments will not exceed $98.0 million per product. During the Aarvik Collaboration Royalty Term (as defined below), we are also obligated to pay Aarvik tiered royalties on aggregate net sales of products developed under the Aarvik Collaboration and commercialized by us or on our behalf at royalty rates in the mid-single digits, and we must also pay to Aarvik’s upstream licensor a royalty of less than 1% on such net sales. Our obligation to pay royalties for each product, calculated on a product-by-product and jurisdiction-by-jurisdiction basis, begins from the date of the first commercial sale of each product within a given jurisdiction and extends until the earliest of (a) the first approval of a biosimilar product related to such product in such jurisdiction, which is made and sold by a different company, meeting specific government regulatory standards, (b) an anniversary of the date of the first commercial sale of such product in such jurisdiction, or (c) the expiration of the last valid claim of a patent included in the Collaboration IP that pertains to the any ADC generated within Aarvik Collaboration or any derivative thereof featured in such product within such jurisdiction (the Aarvik Collaboration Royalty Term).

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The Amended and Restated Aarvik Collaboration Agreement will remain in full force and effect until the expiration of all Aarvik Collaboration Royalty Terms for all products under the Amended and Restated Aarvik Collaboration Agreement, unless terminated earlier. On a jurisdiction-by-jurisdiction and product-by-product basis, following the expiration of the Aarvik Collaboration Royalty Term, the license granted to us hereunder will become nonexclusive, perpetual, irrevocable, fully-paid and royalty-free. We can terminate the Amended and Restated Aarvik Collaboration Agreement for convenience. Either party can terminate the Amended and Restated Aarvik Collaboration Agreement for material breach that is not cured within a specified period, or for the other party’s insolvency or certain bankruptcy events. Upon termination of the Amended and Restated Aarvik Collaboration Agreement with respect to the Target Pair or any given product, the licenses granted by Aarvik will terminate with respect to the applicable terminated Target Pair or product, and unless the Amended and Restated Aarvik Collaboration Agreement is terminated by us for Aarvik’s uncured breach or insolvency, then the Collaboration IP will be assigned back to Aarvik. If the Amended and Restated Aarvik Collaboration Agreement is terminated only with respect to a particular jurisdiction (but not all jurisdictions) and a specific Target Pair or product, then we will grant to Aarvik an exclusive and fully paid-up right and license to use the licensed IP with respect to the terminated Target Pair or product in such jurisdiction.

InnoCare Clinical Collaboration Agreement

On June 23, 2023, we entered into a Clinical Collaboration Agreement (the InnoCare Collaboration Agreement) with InnoCare, pursuant to which we and InnoCare agreed to contribute resources to a clinical trial evaluating the use of firmonertinib in combination with InnoCare’s ICP-189, a SHP2i (the InnoCare Collaboration Clinical Trial). Pursuant to the InnoCare Collaboration Agreement, we and InnoCare have mutually granted to each other a non-exclusive license to certain of the granting party’s intellectual property solely for the purpose of conducting the InnoCare Collaboration Clinical Trial.

Under the InnoCare Collaboration Agreement, InnoCare has the right to use firmonertinib solely for the InnoCare Collaboration Clinical Trial. We and InnoCare have agreed that InnoCare is the regulatory sponsor for the InnoCare Collaboration Clinical Trial and has the sole right and responsibility to prepare all regulatory filings related to the InnoCare Collaboration Clinical Trial, including the protocol and IND filings, conduct the InnoCare Collaboration Clinical Trial, and communicate with regulatory authorities with respect to the InnoCare Collaboration Clinical Trial.

We maintain the right to review, comment on, and approve the protocol and IND related to the InnoCare Collaboration Clinical Trial and have the right to attend InnoCare’s meetings with regulatory authorities regarding the InnoCare Collaboration Clinical Trial. InnoCare must also provide us with periodic updates regarding the InnoCare Collaboration Clinical Trial with respect to progress, safety and toxicity, and data and results.

Upon the completion of the InnoCare Collaboration Clinical Trial, InnoCare will lead the analysis of the results of the InnoCare Collaboration Clinical Trial and will provide us with the final report for the InnoCare Collaboration Clinical Trial for our comments. InnoCare has also agreed to provide us with any raw data generated from the InnoCare Collaboration Clinical Trial to the extent permissible by law. The final report and any raw data (collectively, the InnoCare Collaboration Report) from the InnoCare Collaboration Clinical Trial are jointly owned by us and InnoCare. We may not, without InnoCare’s prior consent, use the InnoCare Collaboration Report for purposes of developing or commercializing ICP- 189 alone or in combination with firmonertinib. InnoCare may not, without our prior consent, use the InnoCare Collaboration Report for purposes of developing or commercializing firmonertinib alone or in combination with ICP-189.

Under the InnoCare Collaboration Agreement, we and InnoCare have agreed to equally share all incurred costs associated with the InnoCare Collaboration Clinical Trial in accordance with a mutually agreed upon budget and have agreed to provide each other with periodic expense reports detailing costs related to the InnoCare Collaboration Clinical Trial. As of December 31, 2025, we recognized approximately $0.9 million of research and development expenses related to incurred costs associated with the InnoCare Collaboration Clinical Trial. We and InnoCare have agreed to discuss such expense reports and determine the calculation of net amounts owed by one party to the other to ensure the appropriate equal sharing of costs associated with the InnoCare Collaboration Clinical Trial. If we or InnoCare become aware of any costs that may be in excess of the costs set out in the budget for the InnoCare Collaboration Clinical Trial, then the respective party shall notify the other party and we and InnoCare shall discuss such costs in order to determine

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if such costs are permissible. InnoCare shall have the sole right to make the final decision on matters relating to the excess costs related to the InnoCare Collaboration Clinical Trial; however, we maintain the right to opt out of participating in the InnoCare Collaboration Clinical Trial if the costs surpass a certain threshold above the budget, provided that we will not have rights to the InnoCare Collaboration Report.

The InnoCare Collaboration Agreement will remain in full force and effect until the delivery of the InnoCare Collaboration Report, unless terminated earlier. The InnoCare Collaboration Agreement may be terminated for material breach upon written notice with a period to cure such material breach. The InnoCare Collaboration Agreement may also be terminated immediately by either party if either one believes that there is a material safety issue in the conduct of the InnoCare Collaboration Clinical Trial that cannot be resolved by a protocol amendment satisfactory to both parties after discussion thereof.

Alphamab Collaboration

On June 4, 2024, we entered into a Research and Collaboration Agreement with Alphamab, a wholly owned subsidiary of Alphamab Oncology, pursuant to which the Company and Alphamab will discover, develop and commercialize novel antibody drug conjugates for the treatment of cancers (the Alphamab Agreement).

Under the Alphamab Agreement, and subject to our payment to Alphamab of the applicable research costs, Alphamab will grant us an exclusive, royalty-bearing, sublicensable license under certain Alphamab intellectual property and joint intellectual property to develop and commercialize such products in all fields of use worldwide, except greater China, which includes mainland China, Hong Kong, Macau and Taiwan (the Retained Territory). Alphamab retains the right to develop and commercialize such products in the Retained Territory. Under the Alphamab Agreement, we granted to Alphamab a royalty-free, perpetual license, which is exclusive during the term of the Alphamab Agreement and non-exclusive thereafter, under all intellectual property rights conceived, discovered, developed or otherwise made solely by us or jointly with Alphamab pursuant to the activities under the Alphamab Agreement for any and all purposes within the Retained Territory. Upon commencement of activities to manufacture the products for use in certain clinical trials, Alphamab will grant us a royalty-bearing license under certain Alphamab intellectual property to manufacture the applicable products. Under the Alphamab Agreement, Alphamab is entitled to an upfront payment and potential development and sales milestone payments of up to an aggregate of $615.5 million from us. Additionally, Alphamab is entitled to receive royalties in the low- to mid- single digit percent range on net sales of products outside greater China that may arise from the Alphamab Agreement.

The Alphamab Agreement is subject to termination (i) by either party for customary purposes, including the material breach by or bankruptcy of the other party, (ii) by us for convenience, (iii) by Alphamab due to our challenge of certain patents held by Alphamab, or (iv) by Alphamab on a product-by-product basis due to our failure to carry out certain diligence obligations or in certain instances if there is a change of control of the Company.

Lepu Biopharma Agreement

On January 21, 2025, we entered into the Lepu Biopharma License Agreement with Lepu Biopharma, pursuant to which Lepu Biopharma granted us a right to develop and commercialize ARR-217 (MRG007), an antibody drug conjugate for gastrointestinal cancers, outside greater China, which is mainland China, Hong Kong, Macau and Taiwan.

Under the Lepu Biopharma Agreement, Lepu Biopharma granted to us: (i) an exclusive, royalty-bearing, sublicensable license under certain intellectual property owned or controlled by Lepu Biopharma, to develop, manufacture and commercialize any product containing ARR-217 for all uses in all countries and territories other than Greater China, which is mainland China, Hong Kong, Macau and Taiwan (the ArriVent Territory); and (ii) a non-exclusive license under certain intellectual property controlled by Lepu Biopharma to develop, manufacture and commercialize any product containing ARR-217 for use in oncology in the ArriVent Territory. Under the Lepu Biopharma Agreement, Lepu Biopharma is entitled to receive a one-time upfront payment and near-term milestone payments totaling $47.0 million in cash and is eligible to receive up to $1.16 billion in development, regulatory and sales milestones and tiered royalties in high single-digit to low-teen percentages on net sales in the ArriVent Territory.

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The Lepu Biopharma Agreement is subject to termination: (i) by either party, subject to specified cure periods, for the material breach by the other party or the bankruptcy or insolvency of the other party, (ii) by us for convenience, subject to a specified notice period, (iii) by Lepu Biopharma due to our challenge of certain patents controlled by Lepu Biopharma, or (iv) by Lepu Biopharma due to our failure to carry out certain diligence obligations.

Manufacturing

We oversee and manage third party CMOs to support development and manufacture of product candidates for our clinical trials, and, if we receive marketing approval, we will rely on such manufacturers to meet commercial demand. We expect this strategy will enable us to maintain a more efficient infrastructure, avoiding dependence on our own manufacturing facility and equipment, while simultaneously enabling us to focus our expertise on the clinical development and future commercialization of our products.

Currently, we rely on, and have agreements with, two third-party contract manufacturers, Zhejiang Raybow Pharmaceutical Company., Ltd. (Raybow) and SynTheAll Pharmaceutical Co., Ltd. (WuXi STA) to supply the drug substance for firmonertinib to be used in on-going and planned clinical trials and with WuXi STA, with whom we have executed technology transfer related to the manufacture of drug product, to manufacture the clinical trial and initial commercial launch supplies of firmonertinib drug product. Both of our third-party contract manufacturers are located in China, but WuXi STA has manufacturing capabilities globally, including in the United States and Europe. We expect to enter into commercial supply agreements with WuXi STA for both drug substance and drug product prior to any potential approval of firmonertinib. We expect to rely on manufacturers in China for ARR-217 drug substance and drug product for use in initial clinical studies and also expect to rely on WuXi XDC Cayman, Inc., (WuXi XDC) for the manufacture of ARR-002 drug product and drug substances for initial clinical studies.

Firmonertinib drug product is manufactured via conventional pharmaceutical processing procedures, employing commercially available excipients and packaging materials. The procedure and equipment employed for manufacture and analysis are consistent with standard organic synthesis or pharmaceutical production, and are transferable to a range of manufacturing facilities, if needed. We intend to also maintain the current drug substance manufacturer as part of our supply chain strategy.

The National Defense Authorization Act for Fiscal Year 2026, enacted in December 2025, included a section titled “Prohibition on Contracting with Certain Biotechnology Providers,” aimed at discouraging federal contracting with certain biotechnology companies for biotechnology equipment or services in China and other countries of concern, also known as the BIOSECURE Act. The statute prohibits federal executive agencies from procuring any biotechnology equipment or service from a biotechnology company of concern or contracting with any such company or any entity that procures or uses equipment or services from a biotechnology company of concern. Such prohibitions may limit our ability to obtain federal government grants for research involving our products, if approved, or product candidates manufactured in China or to enter contracts to sell any such products, if approved, to the federal government. Accordingly, we are taking measures to strengthen our supply chain in the event that Raybow, WuXi STA, or one of our other manufacturers is impacted. We intend to identify alternative potential manufacturers to ensure we have a sufficient stockpile of drug substance and drug product in the United States. We will also continue to closely monitor geopolitical risk and implement additional mitigations and supply chain redundancies, as needed. See the risk factor entitled “We currently rely on a Chinese third party for the manufacture of firmonertinib and ARR-217, for clinical development, and future supply of firmonertinib, and expect to continue to rely on third parties for the foreseeable future. This reliance on third parties increases the risk that we will not have sufficient quantities of firmonertinib or ARR-217 or such quantities at an acceptable cost, which could delay, prevent or impair our development or potential commercialization efforts.”

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Competition

The biotechnology and pharmaceutical industries have made substantial investments in recent years into the rapid development of novel treatments for NSCLC.

We face substantial competition from multiple sources, including large and specialty pharmaceutical and biotechnology companies, academic research institutions and governmental agencies and public and private research

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institutions. Our competitors compete with us on the level of the technologies employed, or on the level of development of product candidates. In addition, many small biotechnology companies have formed collaborations with large, established companies to (i) obtain support for their research, development and commercialization of products or (ii) combine several treatment approaches to develop longer lasting or more efficacious treatments that may potentially directly compete with our current or future product candidates. We anticipate that we will continue to face increasing competition as new therapies and combinations thereof, technologies and data emerge within the field of oncology and, furthermore, within the treatment of NSCLC.

In addition to the current standard of care treatments for patients with NSCLC, numerous commercial and academic preclinical studies and clinical trials are being undertaken by a large number of parties to assess novel technologies and product candidates.

Companies that compete with us directly on the level of commercialization or development of product candidates targeting EGFR mutation-positive NSCLC include, but are not limited to, AstraZeneca, Johnson & Johnson, Blossom Hill Therapeutics, Dizal Pharmaceutical, Oric Pharmaceuticals, Black Diamond Therapeutics, Inc., Cullinan Therapeutics, Inc., Taiho Pharmaceutical Co., Ltd., Boehringer Ingelheim and Bayer AG.

Many of our competitors, either alone or in combination with their respective strategic partners, have significantly greater financial resources and expertise in research and development, manufacturing, the regulatory approval process and marketing than we do. Mergers and acquisition activity in the pharmaceutical, biopharmaceutical and biotechnology sector is likely to result in greater resource concentration among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through sizeable collaborative arrangements with established companies. These competitors also compete with us in recruiting and retain qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

Our commercial opportunity could be reduced or eliminated if one or more of our competitors develop and commercialize products that are safer, more effective, better tolerated, or of greater convenience or economic benefit than our proposed product offering. Our competitors also may be in a position to obtain FDA or other regulatory approval for their products more rapidly, resulting in a stronger or dominant market position before we are able to enter the market. The key competitive factors affecting the success of all of our programs are likely to be product safety, efficacy, convenience and treatment cost.

Intellectual Property

Intellectual property is of vital importance in our field and in biopharmaceuticals generally. We seek to protect and enhance proprietary technology, inventions and improvements that are commercially important to the development of our business by seeking, maintaining and defending patent rights, whether developed internally or licensed from third parties. We will also seek to rely on regulatory protection afforded through inclusion in expedited development and review, data exclusivity, market exclusivity and patent term extensions where available.

Firmonertinib

Through our licensor Allist, we have sought and obtained patent protection in the United States and internationally related to firmonertinib. For firmonertinib and our future product candidates our strategy is to pursue patent protection covering compositions of matter and methods of use. In addition, we seek to identify additional means of obtaining patent protection including formulation and dosing regimen-related claims, as well as manufacturing-related claims, which may enhance our commercial success. We may also rely on trade secrets that may be important to the development of our business. Trade secrets are difficult to protect and provide us with only limited protection. As of December 31, 2025, our intellectual property portfolio for firmonertinib includes issued patents and pending patent applications in the U.S. and internationally.

With regard to the firmonertinib molecule itself, we exclusively license from Allist two issued patents in the US, and one issued patent in each of, Canada, Europe, Japan and South Korea. These patents are expected to expire as

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indicated in the table below (composition of matter). The U.S. patents are reissue patents covering firmonertinib, other compounds represented by a general formula, and pharmaceutically acceptable salts of such compounds. The patents also cover related pharmaceutical compositions, methods for treating an EGFR activating or resistant mutation mediated lung cancer and methods for selectively inhibiting an EGFR activating or resistant mutation over a wild-type EGFR to a lung cancer patient.

With regard to mesylate salts of firmonertinib, we exclusively license from Allist one issued patent in each of the United States, Canada, Europe, Japan and South Korea. The U.S. patent covers mesylate salts of firmonertinib, as well as pharmaceutical compositions, methods for preparing such mesylate salts and methods for treating a patient suffering from cancers. With regard to crystalline forms, we also exclusively license from Allist one issued patent in each of the United States, Canada, Europe, Japan and South Korea. The U.S. patent covers two crystalline forms of mesylate salts of firmonertinib, as well as pharmaceutical compositions, methods for preparing such crystalline forms, and methods for treating a patient suffering from cancers. Collectively, these patents are expected to expire as indicated in the table below (composition of matter).

With regards to methods of manufacturing firmonertinib, we exclusively license from Allist two pending patent applications in each of the United States and Europe. These applications, if issued, would expire as indicated in the table below (composition of matter).

With regard to methods of use for firmonertinib, we exclusively license from Allist three families of national stage patent applications pending in multiple countries, including United States, Canada, Europe, Japan and South Korea. The national stage patent application families relate to use of firmonertinib to treat disease, such as NSCLC, in patients (a) having exon 20 insertion mutations or (b) having an HER2 exon 20 insertion mutation and/or EGFR rare mutation and (c) use of firmonertinib to treat disease, such as NSCLC, in patients having EGFR PACC mutations, , as well as pharmaceutical compositions containing therapeutically effective amounts of firmonertinib.. Any U.S. or foreign patents issued from the national stage applications are expected to expire as indicated in the table below (composition of matter).

ARR-217

Lepu Biopharma has exclusively licensed us two PCT applications relating to antibodies and ADCs, including ARR-217. Any U.S. or foreign patents issued from such PCT applications are expected to expire as indicated in the table below (composition of matter).

ARR-002

Aarvik has exclusively licensed us one PCT application relating to antibody scaffolds and ADCs comprising such scaffolds and one PCT application relating to antibody scaffolds and ADCs comprising such scaffolds, including ARR-002. Any U.S. or foreign patents issued from national stage filings of the PCT patent applications, are expected to expire as indicated in the table below (composition of matter).

ARR-421

We are joint owners with Alphamab of a provisional application relating to the ARR-421 program and Alphamab has exclusively licensed us a PCT application relating to camptothecin derivatives and conjugates comprising the same. Any U.S. or foreign patents issued from such applications are expected to expire as indicated in the table below (composition of matter).

We may file additional patent applications in support of current and new product candidates as well as new platform and core technologies.

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Patent Expiration Dates* of Product Candidates Patents/Applications by Category

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*Expiration dates of granted patents assume payment of all appropriate maintenance, renewal, annuity or other governmental fees.  Expiration dates of pending patent applications assume grant of the patent applications.  The expiration dates in this table do not take into account potential patent term extensions or adjustments. Actual expiration dates may vary based on interpretations of laws in the jurisdictions in which patents have granted.

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Our commercial success will depend in part on obtaining and maintaining patent protection and trade secret protection of our current and future product candidates and the methods used to develop and manufacture them, as well as successfully defending any such patents against third-party challenges and operating without infringing on the proprietary rights of others. Our ability to stop third parties from making, using, selling, offering to sell or importing our product candidates will depend on the extent to which we have rights under valid and enforceable patents or trade secrets that cover these activities. We cannot be sure that patents will be granted with respect to any of our pending patent applications or with respect to any patent applications filed by us in the future, nor can we be sure that any patents that may be granted to us in the future will be commercially useful in protecting our product candidates, discovery programs and processes. For this and more comprehensive risks related to our intellectual property, please see “Risk Factors — Risks Related to Our Intellectual Property.”

The terms of individual patents depend upon the legal term of the patents in the countries in which they are obtained. In most jurisdictions, including the United States, the patent term is 20 years from the earliest date of filing a non-provisional patent application. In the United States, a patent’s term may be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the U.S. Patent and Trademark Office (USPTO), in examining and granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier filed patent. In the United States, the term of a patent that covers an FDA-approved drug may also be eligible for extension, which permits patent term restoration as compensation for the patent term lost during the FDA regulatory review process. The Hatch-Waxman Act permits a patent term extension of up to five years beyond the expiration of the patent. The length of the patent term extension is related to the length of time the subject drug candidate is under regulatory review. Patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent applicable to an approved drug may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. Similar provisions to extend the term of a patent that covers an approved drug are available in Europe and other foreign jurisdictions. In the future, if and when our products receive FDA approval, we expect to apply for patent term extensions on patents covering those products. We plan to seek patent term extensions to any issued patents we may obtain in any jurisdiction where such patent term extensions are available, however there is no guarantee that the applicable authorities, including the FDA in the United States, will agree with our assessment that such extensions should be granted, and if granted, the length of such extensions. For more information regarding the risks related to our intellectual property, see “Risk Factors — Risks Related to Our Intellectual Property.”

In some instances, we may submit patent applications directly to the USPTO as provisional patent applications. Corresponding non-provisional patent applications must be filed not later than 12 months after the provisional application filing date. While we intend to timely file non-provisional patent applications relating to our provisional patent applications, we cannot predict whether any such patent applications will result in the issuance of patents that provide us with any competitive advantage.

U.S. non-provisional applications and PCT applications may claim the benefit of the priority date of earlier filed provisional applications, when applicable. The PCT system allows a single application to be filed within 12 months of

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the original priority date of the patent application, and to designate all of the PCT member states in which national patent applications can later be pursued based on the international patent application filed under the PCT. The PCT searching authority performs a patentability search and issues a non-binding patentability opinion which can be used to evaluate the chances of success for the national applications in foreign countries prior to having to incur the filing fees. Although a PCT application does not issue as a patent, it allows the applicant to seek protection in any of the member states through national-phase applications. At the end of the period of two and a half years from the first priority date of the patent application, separate patent applications can be pursued in any of the PCT member states either by direct national filing or, in some cases by filing through a regional patent organization, such as the European Patent Office. The PCT system delays expenses, allows a limited evaluation of the chances of success for national/regional patent applications and enables substantial savings where applications are abandoned within the first two and a half years of filing.

For all patent applications, we determine claiming strategy on a case-by-case basis. Advice of counsel and our business model and needs are always considered. We seek to file patent applications containing claims for protection of all useful applications of our proprietary technologies and any products, as well as all new applications and/or uses we discover for existing technologies and products, assuming these are strategically valuable. We continuously reassess the number and type of patent applications, as well as the pending and issued patent claims to pursue maximum coverage and value for our processes and compositions, given existing patent office rules and regulations. Further, claims may be modified during patent prosecution to meet our intellectual property and business needs.

We recognize that the ability to obtain patent protection and the degree of such protection depends on a number of factors, including the extent of the prior art, the novelty and non-obviousness of the invention, and the ability to satisfy the enablement requirement of the patent laws. In addition, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted or further altered even after patent issuance. Consequently, we may not obtain or maintain adequate patent protection for any of our future product candidates or for our technology platform. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Any patents that we hold may be challenged, circumvented or invalidated by third parties.

In addition to patent protection, we also rely on trademark registration, trade secrets, know how, other proprietary information and continuing technological innovation to develop and maintain our competitive position. We seek to protect and maintain the confidentiality of proprietary information to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. Although we take steps to protect our proprietary information and trade secrets, including through contractual means with our employees and consultants, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. Our agreements with employees also provide that all inventions conceived by the employee in the course of employment with us or from the employee’s use of our confidential information are our exclusive property. However, such confidentiality agreements and invention assignment agreements can be breached and we may not have adequate remedies for any such breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our consultants, contractors or collaborators use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting trade secrets, know-how and inventions. For more information regarding the risks related to our intellectual property, see “Risk Factors — Risks Related to Our Intellectual Property.”

The patent positions of biotechnology companies like ours are generally uncertain and involve complex legal, scientific and factual questions. Our commercial success will also depend in part on not infringing upon the proprietary rights of third parties. Third-party patents could require us to alter our development or commercial strategies, or our products or processes, obtain licenses or cease certain activities. Our breach of any license agreements or our failure to obtain a license to proprietary rights required to develop or commercialize our future products may have a material

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adverse impact on us. If third parties prepare and file patent applications in the United States that also claim technology to which we have rights, we may have to participate in interference or derivation proceedings in the USPTO to determine priority of invention. For more information, see “Risk Factors — Risks Related to Our Intellectual Property.”

When available to expand market exclusivity, our strategy is to obtain, or license additional intellectual property related to current or contemplated development platforms, core elements of technology and/or clinical candidates.

Government Regulation

Regulation Within the United States

Government authorities in the United States, at the federal, state and local level and in other countries and jurisdictions extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting and import and export of pharmaceutical and biological products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

FDA Approval Process

In the United States, pharmaceutical products are subject to extensive regulation by the FDA under the Federal Food, Drug, and Cosmetic Act (FDC Act) and its implementing regulations and while biological products are regulated under the FDC Act, the Public Health Service Act (PHS Act), and their implementing regulations. Both drugs and biologics also are subject to other federal, state and local statutes and regulations. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions brought by the FDA and the Department of Justice (DOJ) or other governmental entities. Such sanctions could include, but are not limited to, FDA refusal to approve pending marketing applications, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties and criminal prosecution.

Pharmaceutical and biological product development for a new product or certain changes to an approved product in the U.S. typically involves nonclinical laboratory, animal tests and formulation studies conducted according to good laboratory practices and other applicable regulations and guidance; the submission to the FDA of an IND which must become effective before clinical testing may commence; and completion of adequate and well-controlled clinical trials to establish the safety and effectiveness of the drug for each indication for which FDA approval is sought. Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity and novelty of the product or disease.

Once a pharmaceutical or biological candidate is identified for development, it enters the preclinical or nonclinical testing stage. Nonclinical tests include laboratory evaluation of product chemistry, formulation and toxicity, as well as potentially animal studies to assess the characteristics and potential safety and activity of the product. The Consolidated Appropriations Act for 2023, signed into law on December 29, 2022, amended both the FDC Act and the PHS Act to specify that nonclinical testing for drugs may, but is no longer required to, include in vivo animal testing. According to the amended language, a sponsor may fulfill nonclinical testing requirements by competing various in vitro assays (e.g., cell-based assays, organ chips, or microphysiological systems), in silico studies (i.e., computer modeling), other human or non-human biology-based tests (e.g., bioprinting), or in vivo animal tests.

The results of nonclinical testing are submitted to the FDA as part of an IND along with other information, including information about product chemistry, manufacturing and controls, analytical data and a proposed clinical trial protocol detailing, among other things, the objectives of the clinical trial, the parameters to be used in monitoring safety, and the effectiveness criteria to be evaluated, if the trial includes an efficacy evaluation. Long-term nonclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has not otherwise notified the sponsor of the IND within this 30-day period, then the clinical trial proposed in

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the IND may begin, unless the FDA, within the 30-day time period, imposes a clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. Clinical holds also may be imposed by the FDA at any time before or during clinical trials due to safety concerns about ongoing or proposed clinical trials or non-compliance with specific FDA requirements, and the trials may not begin or continue until the FDA notifies the sponsor that the hold has been lifted.

Clinical trials involve the administration of the investigational new drug or biologic to healthy volunteers or patients under the supervision of one or more qualified investigators. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with good clinical practice (GCP) (an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators and monitors), which includes, among other things, the requirement that all research subjects provide their informed consent in writing for their participation in any clinical trial; as well as (iii) under protocols detailing the objectives of the trial, dosing procedures, subject selection and exclusion criteria, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of the IND. While the IND is active, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last progress report, among other information, must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA and investigators for serious and unexpected suspected AEs, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs, findings from animal or in vitro testing suggesting a significant risk to humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the protocol or investigator brochure.

The FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. The study protocol and informed consent information for patients in clinical trials must also be submitted to an independent institutional review board (IRB) or ethics committee for approval at each clinical site before each trial may be initiated, and the IRB must monitor the study until completed and otherwise comply with IRB regulations. The FDA or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB may also require the clinical trial at the site to be halted, either temporarily or permanently (or impose other conditions), for failure to comply with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. In addition, some clinical trials are overseen by an independent group of qualified experts organized by the sponsor, known as a data safety monitoring board or committee. Depending on its charter, this group may determine whether a trial may move forward at designated check points based on access to certain data from the trial. There are also requirements governing the reporting of ongoing clinical studies and clinical study results to public registries, including clinicaltrials.gov.

Clinical trials to support new drug applications (NDAs) or biologics license applications (BLAs) for marketing approval of pharmaceutical or biological products, respectively, are typically conducted in three sequential phases, but the phases may overlap or be combined. In Phase 1, the initial introduction of the product candidate into healthy human subjects or patients, the drug is tested to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence of effectiveness. Phase 2 usually involves trials in a limited patient population with a specified disease or condition to preliminarily evaluate the effectiveness of the product candidate for a particular indication, determine dosage tolerance and optimum dosage, and to identify possible adverse effects and safety risks. If a product candidate demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 trials are undertaken to further evaluate dosage, obtain substantial evidence of clinical efficacy and further test for safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit FDA to evaluate the overall benefit-risk relationship of the product candidate and to provide adequate information for the labeling of the drug. In most cases, the FDA requires two adequate and well-controlled clinical trials to demonstrate the efficacy of the therapeutic product candidate. Results from a single adequate and well-controlled trial may be sufficient in certain instances, such as: (i) where the study is a large multicenter trial demonstrating internal consistency and a statistically very persuasive finding of a clinically meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and confirmation of the result in a second trial would be practically or ethically impossible; or (ii) when submitted in conjunction with other confirmatory evidence.

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Moreover, post-approval trials, sometimes referred to as “Phase 4” clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, the FDA may mandate the performance of “Phase 4” clinical trials

Congress also recently amended the FDC Act to require sponsors of a Phase 3 clinical trial, or other “pivotal study” of a new drug or biologic to support marketing authorization, to design and submit a diversity action plan for such clinical trial. The action plan must include the sponsor’s diversity goals for enrollment, as well as a rationale for the goals and a description of how the sponsor will meet them. Sponsors must submit a diversity action plan to the FDA by the time the sponsor submits the relevant clinical trial protocol to the agency for review. The FDA may grant a waiver for some or all of the requirements for a diversity action plan. If the FDA objects to a sponsor’s diversity action plan or otherwise requires significant changes to be made, it could delay initiation of the relevant clinical trial.

Concurrent with clinical trials, companies usually complete nonclinical animal studies and must also develop additional information about the chemistry and physical characteristics of the product and finalize a process for manufacturing the product in commercial quantities in accordance with current good manufacturing practices (cGMPs). The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, the manufacturer must develop methods for testing the identity, strength, quality and purity of the final drug product. For biologics in particular, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined in order to help reduce the risk of the introduction of adventitious agents. In addition, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

Assuming successful completion of the required clinical testing, an NDA/BLA is prepared and submitted to the FDA. FDA approval of the NDA/BLA is required before marketing of the product may begin in the U.S. The NDA/BLA must include the results of all product development, nonclinical, clinical and other testing, a compilation of data relating to the product’s pharmacology, chemistry, manufacture and controls, along with proposed labeling and other relevant information. The cost of preparing and submitting an NDA/BLA is substantial. The submission of most prescription drug marketing applications is additionally subject to a substantial application user fee, and the applicant under an approved NDA/BLA is also subject to an annual program fee for each prescription product. These fees are typically increased annually. A waiver of such fees may be obtained under certain limited circumstances.

Congress is required to re-authorize the agency’s user fee programs every five years, and current legislative provisions supporting the prescription drug-specific program are set to expire on September 30, 2027. The FDA has 60 days from its receipt of an NDA/BLA to determine whether the application will be filed based on the agency’s threshold determination that it is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA/BLA for filing, in which case the FDA may issue a Refuse to File letter. In this event, the NDA/BLA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA accepts it for filing. If the submission is filed, the FDA begins an in-depth review to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing is cGMP-compliant to assure and preserve the product’s identity, strength, quality and purity. Under the Prescription Drug User Fee Act (PDUFA) guidelines that are currently in effect, the FDA has a goal of ten months from the date of “filing” of a standard NDA for a new molecular entity, or an original BLA, to review and act on the submission. This review typically takes twelve months from the date the NDA/BLA is submitted to FDA because the FDA has approximately two months to make a “filing” decision after it the application is submitted. Most applications designated for priority review products are reviewed in six months of the date of the FDA’s filing determination. Priority review can be applied to NDAs or BLAs for products that are designed to treat a serious condition, where the FDA determines the product may offer significant improvements in safety or effectiveness or provide a treatment where no adequate therapy exists. The review process for both standard and priority review may be extended by the FDA on one occasion for three additional months to consider a “major amendment,” which may include certain late-submitted information, or information intended to clarify information already provided in the submission.

The FDA may also refer applications for novel drug/biologic products, or drug/biologic products that present difficult questions of safety or efficacy, to an independent advisory committee — typically a panel that includes clinicians and other scientific experts — for review, evaluation and a recommendation as to whether the application

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should be approved and under what conditions. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA/BLANDA/BLA, the FDA may inspect one or more clinical sites to assure that the trials support the application were conducted compliance with GCP. Additionally, the FDA will typically inspect the facility or the facilities at which the product is manufactured to assess compliance with cGMPs, to assure that the facilities, methods and controls are adequate to preserve the drug’s identity, strength, quality and purity and, for a biologic, its potency. The FDA will not approve the product unless compliance with cGMP, is satisfactory and the NDA/BLA contains data that provide substantial evidence that the product is safe and effective in the indication sought.

After the FDA evaluates the NDA/BLA and the manufacturing facilities, it issues either an approval letter or a complete response letter (CRL). A CRL indicates that the review cycle of the application is complete, and the application will not be approved in its present form. A CRL usually describes the specific deficiencies in the submission and may require additional clinical data, such as an additional clinical trial or other significant and time-consuming requirements related to clinical trials, nonclinical studies or manufacturing, in order for the FDA to reconsider the application. In September 2025, the FDA began publishing CRLs soon after issuing them to the respective sponsors, breaking with long standing agency tradition of publishing CRLs with approval documentation after the product is approved. If a CRL is issued, the sponsor must resubmit the NDA/BLA, addressing all of the deficiencies identified in the letter, or withdraw the application. Even if such data and information are submitted, the FDA may decide that the NDA/BLA does not satisfy the criteria for approval. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications.

If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. As a condition of NDA/BLA approval, the FDA may also require a risk evaluation and mitigation strategy (REMS) to help ensure that the benefits of the drug outweigh the potential risks. If the FDA concludes a REMS is needed, the sponsor of the marketing application must submit a proposed REMS. The FDA will not approve the NDA/BLA without an approved REMS, if required. REMS can include medication guides, communication plans for healthcare professionals, and elements to assure safe use (ETASU). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the product. Moreover, product approval may require substantial post-approval testing and surveillance to monitor the product’s safety or efficacy. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are later identified.

Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of a new NDA/BLA or NDA/BLA supplement before the change can be implemented. A supplement seeking a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing efficacy supplements as it does in reviewing original NDAs and BLAs.

Disclosure of Clinical Trial Information

Sponsors of clinical trials of FDA regulated products, including prescription drugs and biologics, are required to register and disclose certain clinical trial information on a public registry maintained by the U.S. National Institutes of Health (NIH). Information related to the product, patient population, phase of investigation, study sites and investigators and other aspects of the clinical trial is made public as part of the registration. Sponsors are also obligated to report the results of their clinical trials after completion, although such results disclosure can be delayed in certain circumstances for up to two years after the date of completion of the trial. Failure to timely register a covered clinical study or to submit study results as provided for in the law can give rise to civil monetary penalties and also prevent the non-compliant party from receiving future grant funds from the federal government.

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Pediatric Information

Under the Pediatric Research Equity Act (PREA) sponsors must conduct pediatric clinical trials for most drugs, for a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration. Under PREA, original NDAs and BLAs, as well as certain supplements to approved NDAs and BLAs, must contain data to assess the safety and effectiveness of the drug for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the drug is safe and effective. FDA may grant full or partial waivers, or deferrals, for submission of data. A deferral may be granted for several reasons, including a finding that the drug is ready for approval for use in adults before pediatric clinical trials are complete or that additional safety or effectiveness data needs to be collected before the pediatric clinical trials begin. The FDA must send a non-compliance letter to any sponsor that fails to submit the required assessment, keep a deferral current or fails to submit a request for approval of a pediatric formulation. With certain exceptions, PREA does not apply to any drug for an indication for which orphan designation has been granted.

The Best Pharmaceuticals for Children Act (BPCA) provides NDA and BLA holders a six-month extension of any exclusivity — patent or nonpatent — for a drug if certain conditions are met. Conditions for exclusivity include FDA’s determination that information relating to the use of a new drug in the pediatric population may produce health benefits in that population, FDA making a written request for pediatric studies, and the applicant agreeing to perform, and reporting on, the requested studies within the statutory timeframe. Applications submitted under the BPCA are treated as priority review applications, with all of the benefits that designation confers.

Congress periodically considers enacting new incentives or mandates applicable to pediatric drug development, and the regulatory requirements applicable to pediatric drug developers may change in the future. For example, in February 2026, bipartisan legislation was signed into law and will grant FDA authority to assess penalties against companies that do not complete required pediatric studies.

Expedited Development and Review Programs & Accelerated Approval Pathway

The FDA has a number of programs intended to expedite the development or review of a marketing application for an investigational drug or biologic. For example, the Fast Track designation program is intended to expedite or facilitate the process for developing and reviewing product candidates that meet certain criteria. Specifically, investigational products are eligible for Fast Track designation if they are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. The sponsor of a Fast Track product candidate has opportunities for more frequent interactions with the applicable FDA review team during product development and, once an NDA/BLA is submitted, the application may be eligible for priority review. With regard to a Fast Track product candidate, the FDA may consider for review sections of the marketing application on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the application, the FDA agrees to accept sections of the application and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the NDA/BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for breakthrough therapy designation to expedite its development and review. A product candidate can receive breakthrough therapy designation if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs or biologics, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

Any product candidate submitted to the FDA for approval, including a product candidate with a Fast Track designation or breakthrough designation, may also be eligible for other types of FDA programs intended to expedite development and review, such as priority review and accelerated approval. An NDA/BLA is eligible for priority review if the product candidate is designed to treat a serious condition, and if approved, would provide a significant improvement in safety or efficacy compared to available therapies. The FDA endeavors to review applications with

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priority review designations within six months of the filing date as compared to ten months for review of new molecular entity NDAs or original BLAs under its current PDUFA review goals.

In 2025, the FDA created a new voucher program called the Commissioner’s National Priority Voucher (CNPV), with the goal of radically expediting therapeutic product review and approval processes. The agency may award a CNPV to a company or a specific product candidate that demonstrates alignment with certain national health priorities. The FDA aims to take action on a marketing application for which a CNPV is used within one to two months after the filing date.

In addition, a product candidate may be eligible for accelerated approval. Drugs or biologics intended to treat serious or life-threatening diseases or conditions may be eligible for accelerated approval upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. As a condition of approval, the FDA generally requires that a sponsor of a product receiving accelerated approval perform adequate and well-controlled confirmatory clinical trials, and may require that such confirmatory trials be underway prior to granting accelerated approval. Product receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required confirmatory trials in a timely manner or if such trials fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition of accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

None of these FDA programs change the standards for approval but they may expedite the development or approval process. Even if a product candidate qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

Post-Approval Requirements

Once an NDA/BLA is approved, a product will be subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to record-keeping, reporting of adverse experiences, periodic reporting, product sampling and distribution, and advertising and promotion of the product. For instance, the FDA closely regulates the post-approval marketing, labeling, advertising and promotion of drugs, including through its enforcement of standards and regulations for direct-to-consumer advertising, industry-sponsored scientific and educational activities and promotional activities involving the internet. Drugs may be marketed only for the approved indications and in accordance with the provisions of the approved labeling. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested by the company and approved by the FDA. Such off-label uses are common across medical specialties. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturers’ communications on the subject of off-label use of their products. Companies may share truthful and not misleading information that is not inconsistent with the labeling, and the FDA recently published guidance for industry that outlines modernized recommendations for how drug manufacturers can share truthful, scientifically sound, and clinically relevant information on unapproved uses with health care providers in a non-promotional way.

Moreover, if there are any modifications to the product, including changes in indications, labeling or manufacturing processes or facilities, the applicant may be required to submit and obtain FDA approval of a new NDA/BLA or an NDA/BLA supplement, which may require the applicant to develop additional data or conduct additional nonclinical studies and clinical trials. In particular, securing FDA approval for new indications is similar to the process for approval of the original indication and requires, among other things, submitting data from adequate and well-controlled clinical trials to demonstrate the product’s safety and efficacy in the new indication. Even if such trials are conducted, the FDA may not approve any expansion of the labeled indications for use in a timely fashion, or at all.

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Adverse event reporting and submission of periodic reports are required following FDA approval of an NDA/BLA. The FDA also may require post-marketing testing, known as Phase 4 testing (to gain additional experience from the treatment of patients in the intended therapeutic indication), REMS or surveillance to monitor the effects of an approved product, or FDA may place conditions on an approval that could restrict the distribution or use of the product. In addition, quality control, drug manufacturing, packaging and labeling procedures must continue to conform to cGMPs after approval. Drug manufacturers and certain of their subcontractors are required to register their establishments with FDA and certain state agencies. Registration with the FDA subjects entities to periodic unannounced inspections by the FDA and certain state agencies to assess compliance with cGMPs and other laws and regulations. Accordingly, manufacturers must continue to expend time, money and effort in the areas of production and quality-control to maintain compliance with cGMPs.

FDA regulations also require, among other things, the investigation and correction of any deviations from cGMP and the imposition of reporting and documentation requirements upon the NDA/BLA sponsor and any third-party manufacturers involved in producing the approved therapeutic product. Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards or if it encounters problems following initial marketing.

Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of requirements for post-market studies or clinical studies to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things:

In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act (PDMA), which regulates the distribution of drugs and drug samples at the federal level and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription pharmaceutical product samples and impose requirements to ensure accountability in distribution. The Drug Supply Chain Security Act (DSCSA) was enacted in 2013 with the aim of building an electronic system to identify and trace certain prescription drugs distributed in the United States, including most biological products. The DSCSA mandated resource-intensive obligations for manufacturers, wholesale distributors and dispensers over a 10-year period that culminated in November 2023. Most recently, the FDA announced a one-year stabilization period to November 2024 followed by trading partner-specific exemptions through specified dates in 2025, giving entities subject to the DSCSA additional time to finalize interoperable tracking systems and to ensure supply chain continuity. From time to time, new legislation and regulations may be implemented that could significantly change the statutory provisions governing the approval, manufacturing and marketing of products regulated by the FDA. It is impossible to predict

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whether further legislative or regulatory changes will be enacted, or FDA regulations, guidance or interpretations changed or what the impact of such changes, if any, may be.

Orphan Drug Designation

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Under the Orphan Drug Act, the FDA may grant Orphan Drug Designation to a drug intended to treat a rare disease or condition, which is defined as one affecting fewer than 200,000 individuals in the United States or more than 200,000 individuals where there is no reasonable expectation that the product development cost will be recovered from product sales in the United States. Orphan Drug Designation must be requested before submitting an NDA or BLA. After the FDA grants orphan drug designation, the identity of the drug and its potential orphan use will be disclosed publicly by the FDA; the posting will also indicate whether a drug is no longer designated as an orphan drug. More than one product candidate may receive an Orphan Drug Designation for the same indication. Orphan Drug Designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

Under PREA, submission of a pediatric assessment is not required for pediatric investigation of a product that has been granted Orphan Drug Designation. However, in 2017, the scope of PREA was extended to require pediatric studies for products intended for the treatment of an adult cancer that are directed at a molecular target and that are determined to be substantially relevant to the growth or progression of a pediatric cancer. In addition, the FDA finalized guidance in 2018 indicating that it does not expect to grant any additional Orphan Drug Designation to products for pediatric subpopulations of common diseases. Nevertheless, the FDA intends to still grant Orphan Drug Designation to a drug or biologic that otherwise meets all other criteria for designation when it prevents, diagnoses or treats either (i) a rare disease that includes a rare pediatric subpopulation, (ii) a pediatric subpopulation that constitutes a valid orphan subset, or (iii) a rare disease that is in fact a different disease in the pediatric population as compared to the adult population.

If an orphan drug-designated product subsequently receives FDA approval for the disease for which it was designed, the product will be entitled to seven years of product exclusivity, which means that the FDA may not approve any other applications to market the same drug for the same indication, except in very limited circumstances (such as a showing of clinical superiority to the product with orphan exclusivity by means of greater effectiveness, greater safety or providing a major contribution to patient care or in instances of drug supply issues), for seven years. Orphan exclusivity does not block the approval of a different drug or biologic for the same rare disease or condition, nor does it block the approval of the same drug or biologic for different conditions. If a competitor obtains approval of the same drug, as defined by the FDA, or if our product candidate is determined to be the same drug as a competitor’s product for the same indication or disease, the competitor’s exclusivity could block the approval of our product candidate in the designated orphan indication for seven years, unless our product is demonstrated to be clinically superior to the competitor’s drug.

A product with Orphan Drug Designation may not receive orphan exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

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FDA Regulation of Companion Diagnostics

Certain of our product candidates may require an in vitro diagnostic to identify appropriate patient populations for investigation and/or use of our product candidates. These diagnostics, often referred to as companion diagnostics, are regulated as medical devices. In the United States, the FDC Act and its implementing regulations, and other federal and state statutes and regulations, govern, among other things, medical device design and development, nonclinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance, and premarket approval (PMA). Most companion diagnostics for oncology product candidates utilize the PMA pathway.

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If use of companion diagnostic is deemed essential to the safe and effective use of a drug or biological product, then the FDA generally will require approval or clearance of the diagnostic contemporaneously with the approval of the therapeutic product. On August 6, 2014, the FDA issued a final guidance document addressing the development and approval process for “In Vitro Companion Diagnostic Devices.” According to the guidance, for novel product candidates, a companion diagnostic device and its corresponding drug candidate should be approved or cleared contemporaneously by FDA for the use indicated in the therapeutic product labeling. The guidance also explains that a companion diagnostic device used to make treatment decisions in clinical trials of a drug generally will be considered an investigational device, unless it is employed for an intended use for which the device is already approved or cleared. If used to make critical treatment decisions, such as patient selection, the diagnostic device may be considered a significant risk device under the FDA’s Investigational Device Exemption (IDE) regulations. In which case, the sponsor of the diagnostic device will be required to submit and obtain approval of an IDE application, and subsequently comply with the IDE regulations. However, according to the guidance, if a diagnostic device and a drug are to be studied together to support their respective approvals, both products can be studied in the same investigational study, if the study meets both the requirements of applicable IDE regulations and the IND regulations. The guidance provides that, depending on the details of the study plan and degree of risk posed to subjects, a sponsor may seek to submit an IND alone, or both an IND and an IDE.

The FDA has generally required companion diagnostics intended to select the patients who will respond to cancer treatment to obtain approval of a PMA for that diagnostic simultaneously with approval of the therapeutic. The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality Management System Regulation (QMSR), which imposes elaborate testing, control, documentation and other quality assurance requirements. The QSR was developed and implemented to harmonize the FDA’s previous medical device current good manufacturing practice regulations (referred to as the Quality System Regulation, or QSR) with the International Organization for Standardization standard for device quality management systems (ISO 13485:2016) and it became effective on February 2, 2026.

If the FDA’s evaluation of the PMA application is favorable, the FDA may issue an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA’s evaluation of the PMA or manufacturing facilities is not favorable, the FDA will deny approval of the PMA or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the PMA approval may be delayed for several months or years while the trials are conducted and then the data submitted in an amendment to the PMA. If and when the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution. Once granted, PMA approval may be withdrawn by the FDA if compliance with post approval requirements, conditions of approval or other regulatory standards are not maintained, or problems are identified following initial marketing.

In November 2025, the FDA issued a proposed rule to reclassify certain nucleic acid-based test systems indicated for use with a corresponding approved oncology therapeutic product from Class III (PMA) into Class II, subject to 510(k) premarket notification with special controls. This change, if finalized in 2026, will decrease the regulatory burden on industry because manufacturers of these kinds of in vitro diagnostic products will no longer have to submit a PMA and receive FDA approval before marketing the test.

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After a device is commercialized, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA and comparable state agencies. The FDA also may inspect foreign facilities that export products to the United States.

The Hatch-Waxman Amendments & Marketing Exclusivity for Small Molecule Drug Products

Orange Book Listing

In seeking approval for a drug through an NDA, applicants are required to list with the FDA each patent whose claims cover the applicant’s product. Upon approval of a drug, each of the patents listed in the application for the drug is then published in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book. Drugs listed in the Orange Book can, in turn, be cited by potential generic competitors as part of an abbreviated new drug application, or ANDA. An ANDA provides for marketing of a drug product that has the same active ingredients in the same strengths and dosage form as the listed drug and has been shown through bioequivalence testing to be therapeutically equivalent to the listed drug. Other than the requirement for bioequivalence testing, ANDA applicants are not required to conduct, or submit results of, nonclinical or clinical tests to prove the safety or effectiveness of their drug product. Drugs approved in this way are commonly referred to as “generic equivalents” to the listed drug and can often be substituted by pharmacists under prescriptions written for the original listed drug pursuant to each state’s laws on drug substitution.

The ANDA applicant is required to certify to the FDA concerning any patents listed for the approved product in the FDA’s Orange Book. Specifically, the applicant must certify that (i) the required patent information has not been filed; (ii) the listed patent has expired; (iii) the listed patent has not expired but will expire on a particular date and approval is sought after patent expiration; or (iv) the listed patent is invalid or will not be infringed by the new product. The ANDA applicant may also elect to submit a section viii statement certifying that its proposed ANDA label does not contain (or “carves out”) any language regarding the patented method-of-use rather than certify to a listed method-of-use patent. If the applicant does not challenge the listed patents, the ANDA application will not be approved until all the listed patents claiming the referenced product have expired. A certification that the new product will not infringe the already approved product’s listed patents, or that such patents are invalid, is called a Paragraph IV certification. If the ANDA applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days of the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA until the earlier of 30 months, expiration of the patent, settlement of the lawsuit, or a decision in the infringement case that is favorable to the ANDA applicant.

The ANDA application also will not be approved until any applicable non-patent exclusivity listed in the Orange Book for the referenced product has expired.

Exclusivity

Regulatory exclusivity provisions under the FDC Act can delay the submission or the approval of certain marketing applications for small-molecule drug products. Upon NDA approval of a new chemical entity (NCE), which is a drug that contains no active moiety (which is the molecule or ion responsible for the action of the drug substance) that has been approved by FDA in any other NDA, that NDA receives five years of non-patent data and marketing exclusivity within the United States during which FDA cannot accept for review any (i) ANDA seeking approval of a generic version of that drug, or (ii) any NDA submitted under Section 505(b)(2) (505(b)(2) NDA) of the Act (also referred to as a submitted by another company for another drug based on the same active moiety, regardless of whether the drug is intended for the same indication as the original innovative drug or for another indication, where the applicant does not

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own or have a legal right of reference to all the data required for approval. An application referencing the protected NDA may be submitted one year before NCE exclusivity expires if a Paragraph IV certification is filed, i.e., certification of patent invalidity or non-infringement to one of the patents listed with the FDA by the innovator NDA holder. If there is no listed patent in the Orange Book, there may not be a Paragraph IV certification, and, thus, no application may be filed before the expiration of the five-year exclusivity period.

Certain changes to a drug, such as the addition of a new indication to the package insert, or new dosages or strengths of an existing drug, can be the subject of a three-year non-patent period of data exclusivity if the NDA (or supplement to an existing NDA) contains reports of new clinical investigations (other than bioavailability studies) conducted or sponsored by the applicant that are deemed by the FDA to be essential to the approval of the application. This three-year exclusivity covers only the modification for which the drug received approval on the basis of the new clinical investigations and does not prohibit the FDA from approving ANDAs or 505(b)(2) NDAs for drugs containing the active agent for the original indication or condition of use. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA that is does not reference data in another drug’s approved application. However, an applicant submitting a full NDA would be required to conduct, or obtain a right of reference to, all of the nonclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

Reference Product Exclusivity for Biological Products

In March 2010, the Patient Protection and Affordable Care Act was enacted in the United States and included the Biologics Price Competition and Innovation Act of 2009 (BPCIA). The BPCIA amended the PHS Act to create an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. This amendment to the PHS Act, in part, attempts to minimize duplicative testing. We expect that our ADC product candidates are regulated as biological products that will be submitted for approval pursuant to a BLA and will be subject to the BPCIA.

Since that time, the FDA has approved more than 80 biosimilars, including the first interchangeable biosimilars in 2021. The FDA has also issued several guidance documents outlining its approach to reviewing and approving biosimilars and interchangeable biosimilars. It has also created a public database that contains information on all FDA-licensed biological products, including biosimilars, called the Purple Book.

Biosimilarity requires that the follow-on biological product be highly similar to the reference product notwithstanding minor differences in clinically inactive components and that there be no clinically meaningful differences between the follow-on product and the reference product in terms of safety, purity and potency. The biosimilar applicant must demonstrate that its product is biosimilar based on data from (1) analytical studies showing that the biosimilar product is highly similar to the reference product; (2) toxicity assessments; and (3) for some biological products, one or more clinical studies to demonstrate safety, purity and potency in one or more appropriate conditions of use for which the reference product is approved. In addition, the applicant must show that the biosimilar and reference products have the same mechanism of action for the conditions of use on the label, route of administration, dosage and strength, and the production facility must meet standards designed to assure product safety, purity and potency. Interchangeability requires that a biological product be biosimilar to the reference product and that the product can be expected to produce the same clinical results as the reference product in any given patient and, for products administered multiple times to an individual, that the product and the reference product may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biological product without such alternation or switch. Upon licensure by the FDA, an interchangeable biosimilar may be substituted for the reference product without the intervention of the health care provider who prescribed the reference product.

A reference biological product is granted twelve years of data exclusivity from the time of first licensure of the product, and the first approved interchangeable biologic product will be granted an exclusivity period of up to one year after it is first commercially marketed. As part of the Consolidated Appropriations Act for 2023, Congress amended the PHS Act in order to permit multiple interchangeable products approved on the same day to receive and benefit from this one-year exclusivity period. If pediatric studies are performed and accepted by the FDA as responsive to a written request from FDA, as described above, the 12-year exclusivity period will be extended for an additional six months. In

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addition, the FDA will not accept an application for a biosimilar or interchangeable product based on the reference biological product until four years after the date of first licensure of the reference product. “First licensure” typically means the initial date the particular product at issue was licensed in the United States. Date of first licensure does not include the date of licensure of (and a new period of exclusivity is not available for) a biological product if the licensure is for a supplement for the biological product or for a subsequent application by the same sponsor or manufacturer of the biological product (or licensor, predecessor in interest, or other related entity) for a change (not including a modification to the structure of the biological product) that results in a new indication, route of administration, dosing schedule, dosage form, delivery system, delivery device or strength, or for a modification to the structure of the biological product that does not result in a change in safety, purity, or potency. Therefore, one must determine whether a new product includes a modification to the structure of a previously licensed product that results in a change in safety, purity or potency to assess whether the licensure of the new product is a first licensure that triggers its own period of exclusivity. Whether a subsequent application, if approved, warrants exclusivity as the “first licensure” of a biological product is determined on a case-by-case basis with data submitted by the sponsor.

The BPCIA is complex and continues to be interpreted and implemented by the FDA. In addition, policy proposals have sought to reduce the 12-year reference product exclusivity period and, more recently, to potentially eliminate the separate statutory definition of an interchangeable biological product. As a result, the ultimate impact, implementation and meaning of the BPCIA continue to be subject to uncertainty.

U.S. Patent Term Extension

After NDA/BLA approval, owners of relevant drug patents may apply for up to a five-year patent extension, under the Hatch-Waxman Amendments provisions that permit the extension of eligible patents as compensation for patent term lost during product development and FDA regulatory review process. The allowable patent term extension is calculated as half of the product’s testing phase (the time between IND application and NDA/BLA submission) and all of the review phase (the time between NDA/BLA submission and approval up to a maximum of five years). The time can be shortened if the FDA determines that the applicant did not pursue approval with due diligence. The total patent term after the extension may not exceed 14 years, and only one patent can be extended. The USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. For patents that might expire during the application phase, the patent owner may request an interim patent extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For each interim patent extension granted, the post-approval patent extension is reduced by one year. The USPTO director must determine that approval of the drug covered by the patent for which such interim patent extension is being sought is likely. Interim patent extensions are not available for a drug for which an NDA/BLA has not been submitted.

Regulation Outside of the United States

In addition to regulations in the United States, we are subject to a variety of regulations in other jurisdictions governing clinical trials, commercial sales, and distribution of our products. Most countries outside of the United States require that clinical trial applications be submitted to and approved by the local regulatory authority for each clinical study. In addition, whether or not we obtain FDA approval for a product, we must obtain approval of a product by the comparable regulatory authorities of countries outside the United States before we can commence clinical trials or marketing of the product in those countries. The approval process and requirements vary from country to country, so the number and type of nonclinical, clinical, and manufacturing studies needed may differ, and the time may be longer or shorter than that required for FDA approval.

European Union (EU) Drug Development

As in the United States, drugs and biologics, which are referred to collectively in Europe as medicinal products, can be marketed only if a marketing authorization from the competent regulatory agencies has been obtained. Similar to the United States, the various phases of nonclinical and clinical research in the European Union are subject to significant regulatory controls. Although the EU Clinical Trials Directive 2001/20/EC sought to harmonize the EU clinical trials regulatory framework, setting out common rules for the control and authorization of clinical trials in the EU, the EU Member States transposed and applied the provisions of the Directive differently. This led to significant variations in the

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member state regimes. Under the previous regime, before a clinical trial could be initiated, a clinical trial application must have been approved in each of the EU countries where the trial was to be conducted by two distinct bodies: the National Competent Authority (NCA) and one or more Ethics Committees (ECs). All suspected unexpected serious adverse reactions to the investigated drug that occur during the clinical trial would have to be reported to the NCA and ECs of the Member State where they occurred.

The EU clinical trials legislation has since been reformed with the aims of harmonizing and streamlining clinical-trial authorization, simplifying adverse event reporting procedures, improving the supervision of clinical trials and increasing their transparency. Specifically, the new Clinical Trials Regulation, (EU) No 536/2014 (Clinical Trials Regulation) came into application on January 31, 2022. The Clinical Trials Regulation is directly applicable in all the EU Member States, repealing the previous Clinical Trials Directive 2001/20/EC. The extent to which ongoing clinical trials are governed by the Clinical Trials Regulation depends on when the Clinical Trials Regulation became applicable and on the duration of the individual clinical trial. If a clinical trial continues for more than three years from the day on which the Clinical Trials Regulation became applicable the Clinical Trials Regulation will at that time begin to apply to the clinical trial. In addition, use of the new EU-wide application procedure being implemented via the Clinical Trial Information System, became mandatory for new clinical trial application submissions as of February 1, 2023.

With respect to marketing applications for a new medicinal product, there are two types of marketing authorizations available in the European Economic Area (EEA), which is comprised of the 27 Member States of the European Union plus Norway, Iceland and Liechtenstein. In the EEA, medicinal products can only be commercialized after obtaining an appropriate Marketing Authorization (MA):

Under the above-described procedures, before granting the MA, the EMA or the competent authorities of the Member States of the EEA make an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

Similar to the United States, the EU regulatory framework also provides opportunities for market exclusivity. Upon receiving an MA, reference product candidates generally receive eight years of data exclusivity and an additional two years of market exclusivity. If granted, the data exclusivity period prevents generic applicants from relying on the

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nonclinical and clinical trial data contained in the dossier of the reference product when applying for a generic MA in the EU during a period of eight years from the date on which the reference product was first authorized in the EU. The market exclusivity period prevents a successful generic applicant from commercializing its product in the EU until 10 years have elapsed from the initial MA of the reference product in the EU. The overall 10-year market exclusivity period can be extended to a maximum of eleven years if, during the first eight years of those 10 years, the MA holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. However, there is no guarantee that a product will be considered by the EU’s regulatory authorities to be a new chemical entity, and products may not qualify for data exclusivity.

In April 2023, the European Commission proposed widespread changes to the existing pharmaceutical legislation that would, among other things, alter the data exclusivity periods available to MA holders. As of December 2025, the three EU institutions, the European Commission, the European Parliament and the Council of the EU, are in the process of negotiating the final content of the new Directive and Regulation. Once negotiations are complete, the European Parliament and the Council of the EU will vote on whether to approve the Directive and Regulation. If adopted and implemented, these revisions will significantly change several aspects of drug development and approval in the European Union.

EU Post-Approval Requirements

Similar to the United States, both MA holders and manufacturers of medicinal products are subject to comprehensive regulatory oversight by the EMA, the European Commission and/or the competent regulatory authorities of the member states. The holder of an MA must establish and maintain a pharmacovigilance system and appoint an individual qualified person for pharmacovigilance who is responsible for oversight of that system. Key obligations include expedited reporting of suspected serious adverse reactions and submission of periodic safety update reports (PSURs).

All new MA applicants must include a risk management plan (RMP) describing the risk management system that the company will put in place and documenting measures to prevent or minimize the risks associated with the product. The regulatory authorities may also impose specific obligations as a condition of the MA. Such risk- minimization measures or post-authorization obligations may include additional safety monitoring, more frequent submission of PSURs, or the conduct of additional clinical trials or post-authorization safety studies.

The advertising and promotion of medicinal products is also subject to laws concerning promotion of medicinal products, interactions with physicians, misleading and comparative advertising and unfair commercial practices. All advertising and promotional activities for the product must be consistent with the approved summary of product characteristics, and therefore all off-label promotion is prohibited. Direct-to-consumer advertising of prescription medicines is also prohibited in the EU, which is different from the legal framework in the United States. Moreover, although general requirements for advertising and promotion of medicinal products are established under EU directives, the details are governed by regulations in each Member State and can differ from one country to another. In recent years, advertising and promotion by pharmaceutical companies in the EU and UK marketplaces have received heightened scrutiny from regulatory authorities and in some cases, fines have been issued.

Brexit and the Regulatory Framework in the United Kingdom (UK)

The UK formally withdrew from the EU on January 31, 2020 (known as Brexit), following which the UK licensing decisions were transferred from the EMA to the Medicines and Healthcare Products Regulatory Agency (MHRA) the UK’s regulatory body. Between January 1, 2021 and January 2023, the UK continued to adopt decisions taken by the European Commission on the approval of new marketing authorizations, although companies were required to submit an identical application to the MHRA upon the CHMP positive opinion of the application and the MHRA followed the European Commission decision on approval. In March 2023, the UK government and the European Commission reached agreement on a regulatory framework, referred to as the Windsor Framework. The Windsor Framework became effective January 1, 2025 and changed the system that was previously in effect under the Northern Ireland Protocol, including for the regulation of pharmaceutical products in the UK. Specifically, the MHRA will be responsible for

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approving all medicines intended to be marketed in the United Kingdom (including Northern Ireland), while the EMA will no longer be involved in approving medicines intended for sale in Northern Ireland.

Other Healthcare Laws

Manufacturing, sales, promotion and other activities following product approval may also be subject to regulation by other regulatory authorities in the United States in addition to the FDA. Depending on the nature of the product, those authorities may include the Centers for Medicare and Medicaid Services (CMS), other divisions of the U.S. Department of Health and Human Services (HHS), the Department of Justice, the Drug Enforcement Administration, the Federal Trade Commission (FTC), the Occupational Safety and Health Administration, the Environmental Protection Agency and state and local governments.

For example, in the United States, sales and marketing for prescription pharmaceutical products must comply with state and federal fraud and abuse laws. These laws include the federal Anti-Kickback Statute, which makes it illegal for any person, including a prescription drug manufacturer (or a party acting on its behalf), to knowingly and willfully solicit, receive, offer or pay any remuneration that is intended to induce or reward referrals, including the purchase, recommendation, order or prescription of a particular drug, for which payment may be made under a federal healthcare program, such as Medicare or Medicaid. Violations of this law are punishable by imprisonment, criminal fines, administrative civil money penalties and exclusion from participation in federal healthcare programs. In addition, the Patient Protection and Affordable Care Act (discussed further below), among other things, amended the intent requirement of the federal Anti-Kickback Statute and two of the five criminal healthcare fraud statutes created by the Health Insurance Portability and Accountability Act of 1996 (HIPAA). A person or entity no longer needs to have actual knowledge of these two provisions in the statute or specific intent to violate them; specifically with respect to the prohibition on executing or attempting to execute a scheme or artifice to defraud or to fraudulently obtain money or property of any health care benefit program and the prohibition on disposing of assets to enable a person to become eligible for Medicaid. Moreover, the government may now assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the False Claims Act, which generally prohibits, among other things, any person or entity from knowingly presenting, or causing to be presented, a false claim for payment to, or approval by, the federal government or knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the federal government. Manufacturers can be held liable under the civil False Claims Act even when they do not submit claims directly to government payors if they are deemed to “cause” the submission of false or fraudulent claims. Biotechnology and other healthcare companies have been prosecuted under these laws for, among other things, allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the companies’ marketing of the product for unapproved, and thus generally non-reimbursable, uses and purportedly concealing price concessions in the pricing information submitted to the government for government price reporting purposes.

Pricing and rebate programs must comply with the Medicaid rebate requirements of the U.S. Omnibus Budget Reconciliation Act of 1990 and more recent requirements passed by Congress. If pharmaceutical products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. There also are federal transparency requirements under the Physician Payments Sunshine Act that require manufacturers of FDA-approved drugs, devices, biologics and medical supplies covered by Medicare or Medicaid to report, on an annual basis, to CMS information related to payments and other transfers of value to physicians, teaching hospitals, and certain advanced non-physician health care practitioners and physician ownership and investment interests. Prescription drug products also must meet applicable child-resistant packaging requirements under the U.S. Poison Prevention Packaging Act.

Manufacturing, sales, promotion and other activities are also potentially subject to federal and state consumer protection and unfair competition laws. Also, many states have similar fraud and abuse statutes or regulations that apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines, or the relevant compliance guidance promulgated by the federal government, in addition to requiring drug manufacturers to report information related to payments to physicians and other health care providers or

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marketing expenditures to the extent that those laws impose requirements that are more stringent than the Physician Payments Sunshine Act.

Efforts to ensure that business arrangements with third parties comply with applicable state, federal and foreign healthcare laws and regulations involve substantial costs. If a drug company’s operations are found to be in violation of any such requirements, it may be subject to significant penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, the curtailment or restructuring of its operations, loss of eligibility to obtain approvals from the FDA, exclusion from participation in government contracting or other federal or state government healthcare programs, including Medicare and Medicaid, integrity oversight and reporting obligations, imprisonment and reputational harm. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action for an alleged or suspected violation can cause a drug company to incur significant legal expenses and divert management’s attention from the operation of the business, even if such action is successfully defended.

Healthcare Reform and Potential Changes to Healthcare Laws

In the United States and some foreign jurisdictions, there have been, and continue to be, several legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of therapeutic product candidates, restrict or regulate post-approval activities, and affect the ability to profitably sell therapeutic product candidates that obtain marketing approval. The FDA’s and other regulatory authorities’ policies may change and additional government regulations may be enacted that could prevent, limit or delay marketing approval of our product candidates. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we otherwise may have obtained and we may not achieve or sustain profitability, which would adversely affect our business, prospects, financial condition and results of operations. Moreover, among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access.

For example, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (ACA), was enacted in March 2010 and has had a significant impact on the healthcare industry in the U.S. The ACA expanded coverage for the uninsured while at the same time containing overall healthcare costs. With regard to biopharmaceutical products, the ACA, among other things, increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees on manufacturers of certain branded prescription drugs, and created a new Medicare Part D coverage gap discount program. As another example, the 2021 Consolidated Appropriations Act signed into law on December 27, 2020 incorporated extensive healthcare provisions and amendments to existing laws, including a requirement that all manufacturers of drugs and biological products covered under Medicare Part B report the product’s average sales price (ASP), to the HHS, beginning on January 1, 2022, subject to enforcement via civil money penalties. We expect that further legislative changes or additions to the ACA, the Medicare and Medicaid programs, and changes stemming from other healthcare reform measures, especially with regard to healthcare access, financing or other legislation in individual states, could have a material adverse effect on the health care industry in the United States.

Moreover, there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, in August 2022, President Biden signed into the law the Inflation Reduction Act of 2022 (IRA). Among other things, the IRA has multiple provisions that may impact the prices of drug and biological products that are both sold into the Medicare program and throughout the United States. Starting in 2023, a manufacturer of drugs covered by Medicare Parts B or D must pay a rebate to the federal government if their drug product’s price increases faster than the rate of inflation. This calculation is made on a drug product by drug product basis and the amount of the rebate owed to the federal government is directly dependent on the volume of a drug product that is paid for by Medicare Parts B or D. Additionally, CMS is negotiating drug prices annually for a select number of single source Part D drugs

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without generic competition and will also negotiate drug prices for a select number of Part B drugs starting for payment year 2028. If a product is selected by CMS for negotiation, it is expected that the revenue generated from such product will decrease. CMS has begun to implement these new authorities by entering into agreements with pharmaceutical manufacturers to conduct price negotiations and ultimately announcing annual rounds of negotiated prices; those negotiated “maximum fair prices” will be effective initially as of January 1, 2026 (payment year 2026), with subsequent rounds adding additional drugs with negotiated maximum fair prices effective ins subsequent years. However, the IRA’s impact on the biopharmaceutical industry in the United States remains uncertain, in part because multiple large pharmaceutical companies and other stakeholders (e.g., the U.S. Chamber of Commerce) have initiated federal lawsuits against CMS arguing the program is unconstitutional for a variety of reasons, among other complaints. The outcome of such ongoing lawsuits, as well as potential legislative changes enacted by Congress or programmatic changes implemented at CMS by the Trump Administration, may impact the IRA drug price negotiation program in the future.

Separately, the Trump Administration announced the creation of a government website called TrumpRx, which will allow consumers to purchase certain drugs at reduced prices as negotiated between the drug manufacturers and the administration. As of January 2026, the Trump Administration had secured deals with 16 major drug manufacturers to offer certain drugs at most-favored-nation prices.

Individual states in the United States have also increasingly passed legislation and implemented regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In December 2020, the U.S. Supreme Court held unanimously that federal law does not preempt the states’ ability to regulate pharmacy benefit managers (PBMs) and other members of the health care and pharmaceutical supply chain, an important decision that has led to further and more aggressive efforts by states in this area. The FTC in mid-2022 also launched sweeping investigations into the practices of the PBM industry, and published interim reports with its findings in mid-2024 and January 2025, that could lead to additional federal and state legislative or regulatory proposals targeting such entities’ operations, pharmacy networks, or financial arrangements, as PBM reform continues to be a bipartisan priority. In February 2026, President Trump signed into law several PBM regulatory reforms as part of a federal budget package, including but not limited to requirements for PBMs to pass back 100% of rebates and fees to commercial health plan sponsors; to provide extensive informational disclosures related to patients’ coverage and benefits; and to accept only bona fide service fees from drug companies when providing services under Medicare Part D. The Department of Labor (DOL) also issued a proposed rule in January 2026 that would mandate specific PBM fee disclosures to self-insured plan fiduciaries under the Employment Retirement Income Security Act (ERISA). If finalized as proposed, the DOL rule would also allow plan fiduciaries to audit those PBM disclosures to confirm accuracy. Additional proposals and legislative changes aimed at PBMs and their business practices are likely to continue to be introduced and considered in Congress and by executive agencies. Significant efforts to change the PBM industry as it currently exists in the U.S. may affect the entire pharmaceutical supply chain and the business of other stakeholders, including pharmaceutical product developers like us.

We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services.

Coverage, Pricing and Reimbursement

Sales of our future products will depend, in part, on the extent to which our products will be covered by third-party payors, such as government health programs, commercial insurance and managed healthcare organizations. There may be significant delays in obtaining coverage and reimbursement for approved products, and coverage may be more limited than the purposes for which the product is approved by the FDA or regulatory authorities in other countries. It is time consuming and expensive to seek reimbursement from third-party payors. Moreover, eligibility for reimbursement does not imply that any product will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim payments for new products, if applicable, may also not be sufficient to cover

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our costs and may not be made permanent. Payment rates may vary according to the use of the product and the clinical setting in which it is used, may be based on payments allowed for lower cost products that are already reimbursed and may be incorporated into existing payments for other services. Net prices for products may be reduced by mandatory discounts or rebates required by third-party payors and by any future relaxation of laws that presently restrict imports of products from countries where they may be sold at lower prices than in the U.S. In the U.S., third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies, but they also have their own methods and approval process apart from Medicare coverage and reimbursement determinations. Accordingly, one third-party payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product.

Additionally, the containment of healthcare costs has become a priority of federal and state governments and the prices of therapeutics have been a focus in this effort. Recent U.S. federal actions include initiatives incorporating “most favored nation” (international reference pricing) concepts for certain prescription drugs, as well as agency testing of new payment models that could tie Medicare reimbursement or manufacturer rebates to prices in specified reference countries. The United States government, state legislatures and foreign governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. In late 2025, the CMS proposed multiyear pilot models for Medicare Parts B and D that would require manufacturer rebates when U.S. prices exceed prices in designated reference countries; in parallel, the Trump Administration announced a series of manufacturer specific arrangements reflecting most favored nation style pricing commitments in certain programs and channels. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit our net revenue and results. Although the scope, timing and ultimate impact of these most favored nation style initiatives are uncertain and subject to rulemaking, program design and potential legal challenges, if implemented or expanded they could reduce reimbursement or net realized prices for affected products and adversely impact our margins and market access, particularly for products reimbursed under Medicare. Further, if these third-party payors do not consider our products to be cost-effective compared to other therapies, they may not cover our products after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis. In addition, companion diagnostic tests require coverage and reimbursement separate and apart from the coverage and reimbursement for their companion pharmaceutical or biological products.

Moreover, in some foreign countries, the proposed pricing for a therapeutic product must be approved before it may be lawfully marketed. The requirements governing therapeutic pricing vary widely from country to country. For example, the European Union provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. A member state may approve a specific price for the medicinal product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our therapeutic candidates, if approved. Historically, therapeutic candidates launched in the European Union do not follow price structures of the United States and generally tend to be significantly lower.

U.S. Foreign Corrupt Practices Act

In general, the Foreign Corrupt Practices Act of 1977, as amended (FCPA) prohibits offering to pay, paying, promising to pay, or authorizing the payment of money or anything of value to a foreign official in order to influence any act or decision of the foreign official in his or her official capacity or to secure any other improper advantage in order to obtain or retain business for or with, or in order to direct business to, any person. The prohibitions apply not only to payments made to “any foreign official,” but also those made to “any foreign political party or official thereof,” to “any candidate for foreign political office” or to any person, while knowing that all or a portion of the payment will be offered, given, or promised to anyone in any of the foregoing categories. “Foreign officials” under the FCPA include officers or employees of a department, agency, or instrumentality of a foreign government. The term “instrumentality” is broad and can include state-owned or state-controlled entities.

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Importantly, U.S. authorities that enforce the FCPA, including the Department of Justice, deem most health care professionals and other employees of foreign hospitals, clinics, research facilities and medical schools in countries with public health care or public education systems to be “foreign officials” under the FCPA. When we interact with foreign health care professionals and researchers in testing and marketing our products abroad, we must have policies and procedures in place sufficient to prevent us and agents acting on our behalf from providing any bribe, gift or gratuity, including excessive or lavish meals, travel or entertainment in connection with marketing our future products and services or securing required permits and approvals such as those needed to initiate clinical trials in foreign jurisdictions. The FCPA also obligates companies whose securities are listed in the United States to comply with accounting provisions requiring the maintenance of books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and the development and maintenance of an adequate system of internal accounting controls for international operations. The SEC is involved with the books and records.

In February 2025, President Trump issued an executive order directing the DOJ to pause enforcement of the FCPA and to issue new enforcement guidelines that take into consideration U.S. national security and the competitiveness of U.S. companies abroad. On June 10, 2025, the DOJ issued guidelines for investigations and enforcement of the FCPA. It is unclear how this presidential directive and DOJ guidelines may affect the biopharmaceutical industry as a whole or our business in particular.

Employees and Human Capital Resources

As of December 31, 2025, we had 77 employees, all of whom were full-time and 45 of whom were engaged in research and development activities. 33 of our employees hold Ph.D. or M.D. degrees. None of our employees are represented by a labor union or covered under a collective bargaining agreement. We consider our relationship with our employees to be good.

Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and new employees, advisors and consultants. The principal purposes of our equity and cash incentive plans are to attract, retain and reward personnel through the granting of stock-based and cash-based compensation awards, in order to increase stockholder value and the success of our company by motivating such individuals to perform to the best of their abilities and achieve our objectives.

Corporate Information

We were incorporated in Delaware in April 2021 under the name of ArriVent BioPharma, Inc. Our principal executive offices are located at 18 Campus Boulevard, Suite 100, Newtown Square, PA 19073. Our telephone number is (628) 277-4836. Our website address is www.arrivent.com. Information contained on, or that can be accessible through, our website is not a part of this Annual Report.

Available Information

Our Internet address is www.arrivent.com. We will file or furnish periodic reports and amendments thereto, including our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K (and amendments to those reports), proxy and information statements and other information filed or furnished pursuant to Sections 13(a) and 15(d) of the Securities Exchange Act of 1934, as amended (Exchange Act) with the SEC. The SEC maintains a website that contains reports, proxy and information statement, and other information regarding issuers that file electronically, which may be accessed through the SEC at http://www.sec.gov. Our reports, amendments thereto, proxy statements and other information are also made available, free of charge, on our investor relations website at ir.arrivent.com as soon as reasonably practicable after we electronically file or furnish such information with the SEC. The information contained on the websites referenced in this Annual Report is not incorporated by reference into this filing. Further, our references to website URLs are intended to be inactive textual references only. All statements made in any of our securities filings, including all forward-looking statements or information, are made as of the date of the document in which the statement is included, and we do not assume or undertake any obligation to update any of those statements or documents unless we are required to do so by law.

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Our code of ethics, other corporate policies and procedures, and the charters of our Audit Committee, Compensation Committee and Nominating and Corporate Governance Committee are available through our Internet website at www.arrivent.com.

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