Inhibrx Biosciences, Inc. (INBX) Business

Item 1. Business.

Overview

We are a clinical-stage biopharmaceutical company with a pipeline of novel biologic therapeutic candidates, developed using our proprietary modular protein engineering platforms. We leverage our innovative protein engineering technologies and deep understanding of target biology to create therapeutic candidates with attributes and mechanisms we believe to be superior to current approaches and applicable to a range of challenging, validated targets with high potential.

Recent Developments

Separation from Former Parent

On May 29, 2024, Inhibrx, Inc., or the Former Parent, effected the spin-off of INBRX-101, an optimized, recombinant alpha-1 antitrypsin, or AAT, augmentation therapy in a registrational trial for the treatment of patients with alpha-1 antitrypsin deficiency, upon which the Former Parent completed a distribution to holders of its shares of common stock of 92% of the issued and outstanding shares of our common stock, or the Distribution. On May 30, 2024, the Former Parent completed a series of internal restructuring transactions, or the Separation.

On May 30, 2024, the Former Parent completed the merger, or the Merger, of Art Acquisition Sub, Inc., a wholly-owned subsidiary of Aventis Inc., or the Acquirer, a wholly-owned subsidiary of Sanofi S.A., or Sanofi, with and into the Former Parent with the Former Parent continuing as the surviving entity. Pursuant to the Merger (i) all assets and liabilities primarily related to INBRX-101, or the 101 Business, were transferred to the Acquirer; and (ii) by way of the Separation, we acquired the assets and liabilities and corporate infrastructure associated with its ongoing programs, INBRX-106 and ozekibart (INBRX-109), and its discovery pipeline, as well as the remaining close-out obligations related to its previously terminated program, INBRX-105. From and after the closing, Inhibrx continues to operate as a stand-alone, publicly traded company focused on ozekibart and INBRX-106, both of which are clinical-stage programs.

For periods prior to the spin-off, descriptions of historical business activities are presented as if the spin-off had already occurred, and the Former Parent’s activities related to such assets and liabilities had been performed by us. Refer to Note 1 to our consolidated financial statements included elsewhere in this Annual Report for further discussion of the underlying basis used to prepare the consolidated financial statements. The operating results presented in our historical financial statements prior to the Merger and in connection with the Separation and the Merger may not be indicative of our results following the Merger and Separation.

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Current Clinical Pipeline

Our current clinical pipeline of therapeutic candidates includes ozekibart and INBRX-106, both of which utilize our multivalent formats where the precise valency can be optimized in a target-centric way to mediate what we believe to be the most appropriate agonist function:

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* Currently being investigated in chondrosarcoma, Ewing sarcoma, colorectal cancer, and certain other solid tumor types.

** Currently being investigated in patients with non-small cell lung cancer, or NSCLC, and head and neck squamous cell carcinoma, or HNSCC.

Our Leadership Team

We have assembled a team with deep scientific, manufacturing, and clinical experience in discovering and developing protein therapeutics, as well as an accomplished commercial team with the expertise we believe to successfully bring our therapeutic candidates, if approved, to market. Our in-house capabilities span the disciplines of discovery, protein engineering, cell biology, translational research, chemistry, manufacturing and controls, or CMC, clinical development, and commercialization. Members of our team bring experience from multiple organizations including Genentech, Inc., Gilead Sciences, Inc., Merck & Co., Novartis AG, Pfizer Inc., and Roche. Our board of directors is comprised of individuals with proven business and scientific accomplishments and significant operating knowledge of our company.

Our Strategy

Our mission is to discover and develop effective biologic treatments applicable to a range of challenging, validated targets with high potential to help people with life-threatening conditions. We are a biopharmaceutical company aiming to develop a differentiated and sustainable product portfolio by focusing on the following:

Rapidly advance and optimize the clinical development of our lead programs.

Since entering the clinic, we have made great strides in our clinical programs, with the successful completion of two registration-enabling trials. In May 2024, we completed a successful Merger and Separation with Sanofi for the

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purchase of our INBRX-101 program for alpha-1 antitrypsin deficiency disorder. Positive data from that registrational program read out in October 2025. In October 2025, we announced positive data from our ozekibart (INBRX-109) registration-enabling trial in advanced or metastatic, unresectable chondrosarcoma.

Both ozekibart and INBRX-106 have key data or milestone events expected in 2026.

Apply our protein engineering platforms to create differentiated, next-generation therapeutics in focused disease areas with a high unmet medical need.

We continue to focus our internal clinical development where we believe we can create effective and flexible solutions to address the challenges of validated targets in areas with a high unmet medical need. Our modular protein engineering platforms enable us to efficiently identify optional therapeutic formats customized to the target biology.

Maintain our culture of innovation, execution and efficiency.

We have successfully built an innovative culture that encourages scientific risk-taking within the bounds of our data-driven philosophy. This enables our research and development team to discover numerous promising preclinical candidates cost effectively, from which we select what we believe are highly differentiated programs for clinical development.

Maximize the potential of our therapeutic pipeline.

We have a disciplined strategy to maximize the potential of our therapeutic pipeline in order to bring the greatest value to our stockholders and the most significant impact to patients. We are continuously looking to streamline operations to increase efficiency and to ensure maximum value is achieved with the capital we raise. Additionally, we will enter into strategic partnerships and transactions in instances where we believe partnering will accelerate our development timelines and/or maximize the commercial potential of any approved therapeutic candidate.

Our Pipeline

ozekibart (INBRX-109)

Ozekibart is a precisely engineered tetravalent therapeutic candidate targeting death-receptor 5, or DR5, a TNFRSF member, also known as tumor necrosis factor-related apoptosis-inducing ligand, or TRAIL, receptor 2. DR5 activation induces cancer-specific programmed cell death. The valency of ozekibart was selected to maximize the therapeutic index.

Background on DR5

Apoptosis is a critical process for maintaining healthy tissue homeostasis, but this process is frequently altered in cancer patients leading to the accumulation of malignant cells. Apoptotic signaling pathways are tightly regulated by the balance of pro- and anti-apoptotic factors, and their therapeutic modulation has the potential to be exploited for the treatment of cancer. Targeting the anti-apoptotic proteins has been a clinically successful strategy. For example, Venetoclax, an inhibitor of B-cell lymphoma 2, or Bcl-2, was approved by the FDA for the treatment of chronic lymphocytic leukemia in 2016.

Alternatively, we believe therapeutically targeting pro-apoptotic proteins such as DR5 is a promising oncology treatment strategy. DR5 signaling is induced by clustering of multiple receptors, which initiates an apoptotic signaling pathway resulting in cell death. The strength of apoptotic signaling is proportional to the degree of DR5 clustering. Importantly, although DR5 is expressed throughout the body, cancer cells have been shown to be more sensitive to DR5 signaling compared to healthy cells of normal tissues.

The promise of inducing cancer-specific cell death has led to extensive efforts by pharmaceutical and biotechnology companies to therapeutically exploit the DR5 pathway for the treatment of cancer. These initial efforts centered around developing recombinant versions of the DR5 ligand, TRAIL, and agonistic bivalent DR5 antibodies. Despite demonstrated clinical safety as single agents and in combination with chemotherapies, these first generation DR5 agonists failed to meet clinical efficacy endpoints. We believe these failures were caused by insufficient clustering of DR5, which is necessary for activation of this pathway.

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Unmet Medical Need

We are currently investigating ozekibart in chondrosarcoma, Ewing sarcoma, and colorectal cancer. These are some of the most aggressive diseases, some of which are also orphan oncology indications that have shown signs of activity in preclinical studies. These indications, particularly in advanced or refractory settings, often do not respond well to currently approved therapies and represent a significant unmet need.

Chondrosarcoma is a rare malignant bone tumor composed of cartilage matrix-producing cells. It is reported to be the second most common primary bone sarcoma with an incidence of 1 in 200,000 per year globally. The incidence in the United States is reported to be about 1,400 cases per year. There is currently no approved systemic treatment for patients with unresectable or metastatic disease.

Ewing sarcoma is a rare type of cancer that occurs in bones or in the soft tissue around the bones and is more commonly found in children. The incidence of Ewing sarcoma for all ages is approximately 1.3 cases per 1 million people in the U.S., corresponding to approximately 430 new patients diagnosed per year in the U.S. The median age at diagnosis of patients with Ewing sarcoma is 15. Current treatment for Ewing sarcoma typically includes a combination of chemotherapy, surgery, and/or radiation therapy. Despite aggressive treatment, outcomes remain poor for patients with metastatic or relapsed disease, with five-year survival rates dropping below 30% in these cases, highlighting the need for more efficacious options.

Colorectal adenocarcinoma, or CRC, is the third most frequent cancer globally and the second leading cause of cancer-related death. According to the World Health Organization, there were nearly 2,000,000 new cases of CRC in 2020, with nearly 1,000,000 deaths. Effective therapies beyond the second-line setting are limited. In the U.S., the five-year relative survival rate in patients with metastatic CRC is 15.7%, underscoring the need for better treatments.

Our Solution — ozekibart

Ozekibart is a tetravalent agonist of DR5 that we designed with our proprietary single domain antibody, or sdAb, platform to drive cancer-selective programmed cell death and to maximize potency while minimizing on-target liver toxicity arising from hepatocyte apoptosis. We believe ozekibart has the potential to overcome the limitations of previous DR5 agonists. As shown in the diagram below, ozekibart is comprised of four DR5 targeted sdAbs fused to an Fc region that has been modified to prevent Fc receptor interactions. In preclinical studies, we have observed that ozekibart has the ability to potently agonize DR5 through efficient receptor clustering, causing cancer cell death. Based upon experience with earlier generation DR5 agonists, hepatocytes appear to be a non-cancerous cell type particularly sensitive to DR5 agonism. We have engineered ozekibart with our proprietary sdAb modifications to reduce recognition by pre-existing anti-drug antibodies in humans, which can lessen the potential for hyper-clustering and thereby reduce potential hepatotoxicity.

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ozekibart: Tetravalent DR5 Agonistic Antibody

Phase 1/2 Clinical Trial of ozekibart

We initiated a Phase 1 clinical trial in the United States in November 2018. This Phase 1 clinical trial was designed as an open-label, three-part trial in patients with locally advanced or metastatic solid tumors. Part 1 of the trial completed in August 2019 and enrolled 20 patients, utilizing a traditional 3+3 dose escalation design escalating ozekibart as a single agent from 0.3 mg/kg to 30 mg/kg. Ozekibart was observed to be well-tolerated without significant toxicities observed at doses up to and including the maximum administered dose of 30 mg/kg. No MTD was reached. In September 2019, we commenced Part 2, single agent dose expansion cohorts, which enrolled 121 patients in single agent dose cohorts in the following tumor types: colorectal and gastric adenocarcinomas, malignant pleural mesothelioma, chondrosarcoma, synovial sarcoma, and solid tumors. In February 2021, we initiated chemotherapy combination cohorts in Part 3 of this trial, of which we are still investigating in Ewing sarcoma and colorectal adenocarcinoma.

Primary objectives of the Phase 1 trial were safety, tolerability, and determination of the maximum tolerated dose, or MTD, and recommended Phase 2 dose. For some of the expansion cohorts in Part 2 and Part 3, clinical anti-tumor efficacy, such as response rate, was also included as one of the primary objectives. Secondary objectives were serum exposure and immunogenicity, as measured by frequency of anti-drug antibodies. Exploratory objectives included clinical anti-tumor efficacy, based on response rate, duration of response, disease control rate, progression-free survival and overall survival, as well as evaluation of potential predictive diagnostic and pharmacodynamic biomarkers.

Colorectal Adenocarcinoma

In January 2025, we announced interim efficacy and safety data from the cohort of the Phase 1/2 trial evaluating ozekibart in combination with FOLFIRI for the treatment of advanced or metastatic, unresectable colorectal adenocarcinoma, or CRC. Efficacy was assessed in 10 of the 13 evaluable patients as of the cutoff date of December 2, 2024, who received at least one dose of ozekibart, based on RECIST v1.1 criteria. Results demonstrated one complete response, or CR, three partial responses, or PR, and six cases of stable disease, or SD. Durable disease control lasting ≥180 days was observed in 46.2% of patients, with a median progression-free survival, or PFS, of 7.85 months. All patients had received at least one prior line of systemic therapy (median: two; range: 1–6). Notably, the patient achieving a CR had undergone three prior lines of therapy, and two PRs occurred in patients who had failed prior FOLFIRI-based treatments.

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Based on the interim data observed above, we initiated an expansion cohort enrolling 44 patients, as a fourth line of therapy for approximately 70% of patients and as a third line of therapy for approximately 30% of patients. 80% of patients had been previously treated with regimens containing irinotecan. Efficacy was assessed in 26 evaluable patients who had at least one post-baseline scan as of the cutoff date of October 15, 2025. Based on RECIST v1.1 criteria, a 23% overall response rate, or ORR, was observed and an overall disease control rate of 92% was observed.

In general, ozekibart in combination with FOLFIRI was well tolerated. The most common treatment-emergent adverse events included anemia, diarrhea, nausea, and fatigue, with the majority being low-grade and consistent with the known safety profile of FOLFIRI.

We plan to provide an update on the expansion cohort during the second quarter of 2026 when the PFS data is mature. If the current response and duration trends observed continue, we plan to meet with the FDA in the second half of 2026 to discuss an accelerated approval pathway for this indication.

Ewing Sarcoma

In November 2023, we announced interim efficacy and safety data from the cohort of the Phase 1/2 trial evaluating ozekibart in combination with Irinotecan, or IRI, and Temozolomide, or TMZ, for the treatment of advanced or metastatic, unresectable Ewing sarcoma. Among the 13 patients evaluable as of the data cut of September 8, 2023, the observed disease control rate was 76.9%, or 10 out of 13 patients as measured by RECISTv1.1, with seven patients achieving partial responses (53.8%) and three patients achieving stable disease (23.1%). Four of the 13 evaluable patients at that time had prior IRI exposure, including two out of the four responses.

Based on this preliminary data, the ongoing Phase 1/2 trial in the Ewing sarcoma cohort was expanded to enroll up to an additional 50 patients. In March 2026, we provided an update at the European Society for Medical Oncology (ESMO) Sarcoma and Rare Cancers Congress. Of the 31 patients evaluable based on a cutoff date of January 15, 2026, we observed a 64.5% ORR and a disease control rate of 87.1%. At the time of the presentation, responses were ongoing in eight patients, one of which had been on treatment and progression free for more than two years.

Ozekibart in combination with IRI/TMZ was well tolerated. The most common adverse events were diarrhea, nausea, anemia, and fatigue, all consistent with the known safety profile of IRI/TMZ.

We expect to complete enrollment in the Phase 1/2 trial of ozekibart in combination with IRI/TMZ for advanced or metastatic, unresectable, relapsed, or refractory Ewing sarcoma in the second half of 2026.

If the current response and duration trends observed continue, we plan to meet with the FDA in the second half of 2026 to discuss an accelerated approval pathway for this indication.

Chondrosarcoma

Phase 1 ozekibart in Chondrosarcoma

In January 2021, the FDA granted Fast Track designation to ozekibart for the treatment of patients with unresectable or metastatic conventional chondrosarcoma. In November 2021, the FDA granted orphan drug designation for ozekibart for the treatment of chondrosarcoma. In August 2022, the European Commission granted orphan designation for ozekibart for the treatment of chondrosarcoma.

In November 2024, we announced efficacy and safety data from the Phase 1 expansion cohort evaluating ozekibart for the treatment of chondrosarcoma. Among the 54 patients evaluable, the observed disease control rate was 77.8%, or 42 out of 54 patients as measured by RECISTv1.1, with two patients achieving partial responses (3.7%) and 40 patients achieving stable disease (74.1%). Disease control was observed in patients with and without IDH1/IDH2 mutations. Of those achieving stable disease, 55.0% had decreases from baseline in tumor size. 23 of 42 patients (54.8%) who achieved disease control maintained control for longer than 6 months, and the longest duration of stable disease observed was 27 months. The median progression-free survival, or PFS, was 7.42 months.

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ChonDRAgon Trial

In June 2021, we initiated a randomized, blinded, placebo-controlled, registrational trial in patients with metastatic, unresectable conventional chondrosarcoma, which enrolled over 200 patients in total at 68 different sites worldwide. The primary objective of the trial was the evaluation of the efficacy of ozekibart as measured by median PFS, assessed by central real-time independent radiology review per RECIST 1.1. Secondary objectives were the evaluation of overall survival, median PFS by investigator assessment, quality of life, objective response rate, duration of response, disease control rate, safety and tolerability, pharmacokinetics and anti-drug antibodies to ozekibart.

Key enrollment criteria in order for patients to qualify for inclusion in the trial were grade 2 or 3 unresectable or metastatic conventional chondrosarcoma. Patients received either ozekibart or placebo every three weeks at a randomization of 2:1, stratified by the line of therapy, grade and IDH1/2 mutation status. Patients randomized to the placebo arm were allowed to crossover to receive ozekibart upon confirmation of progression as reported by central independent radiology review.

In October 2025, we announced ChonDRAgon met its primary endpoint of a statistically significant and clinically meaningful median PFS for patients with advanced or metastatic chondrosarcoma treated with ozekibart compared to placebo. Ozekibart achieved a 52% reduction in the risk of disease progression or death compared to placebo (stratified Hazard Ratio 0.479; 95% CI: 0.33, 0.68); P0.0001), more than doubling median PFS to 5.52 months versus 2.66 months for placebo. Importantly, ozekibart is the first investigational therapy to demonstrate a significant PFS benefit in a randomized trial for chondrosarcoma, a disease with no approved systemic options.

The benefit of ozekibart was consistent across all pre-specified subgroups, including patients with isocitrate dehydrogenase, or IDH, -wild-type and IDH-mutant tumors. Other key secondary endpoints, including disease control rate (54% vs 27.5%), and delay to deterioration in pain and physical function, further supported the clinical benefit observed with ozekibart.

Ozekibart was generally well tolerated, with a manageable safety profile. The most common treatment-related adverse events were fatigue, constipation, and nausea. Hepatotoxicity, a known risk for this mechanism of action, occurs during the first treatment cycle and is in patients with underlying hepatic impairment. One hepatotoxicity-related fatal event occurred early in the study, prior to the implementation of mitigation measures. Over the course of the ChonDRAgon study, this risk was effectively mitigated by excluding patients with severe liver impairment and by implementing close monitoring during early treatment cycles, allowing for prompt management of liver enzyme elevations. This approach resulted in a low overall incidence of treatment-related hepatic adverse events, 11.8% compared to 4.5% in the placebo arm, the majority of which were Grade 1 or 2 in severity.

Following recent regulatory interactions, we plan to submit a biologics license application, or BLA, early in the second quarter of 2026.

Safety Data for ozekibart

Of the 273 patients studied and evaluable in our Phase 1 trial as of the cutoff date of August 2, 2025, the treatment-related serious adverse events observed in more than one patient were (i) abnormal laboratory findings of increased alanine aminotransferase (8 or 2.9%), increased aspartate aminotransferase (8 or 2.9%), (ii) gastrointestinal disorders, which included diarrhea (4 or 1.5%), (iii) blood and lymphatic system disorders, which included anemia (3 or 1.1%), febrile neutropenia, a condition where the body has a reduced number of a certain type of white blood cells in conjunction with a fever (2 or 0.7%), (iv) hepatobiliary (liver, bile duct or gallbladder) disorders which included acute hepatic failure (3 or 1.1%).

Of the 180 patients studied and evaluable in the ChonDRAgon study as of the primary endpoint cutoff date of September 30, 2025, the serious adverse events related to study drug (ozekibart during the double blind or crossover period) that occurred in more than one patient were (i) abnormal laboratory findings of increased alanine aminotransferase (6 or 3.3%), increased aspartate aminotransferase (5 or 2.8%), (ii) hepatobiliary disorders, which included hepatic failure (2 or 1.1%).

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INBRX-106

INBRX-106 is a hexavalent OX40 agonist, currently being investigated as a single agent and in combination with KEYTRUDA® (pembrolizumab), a PD-1 blocking checkpoint inhibitor, in patients with locally advanced or metastatic solid tumors. KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Background on Immunotherapy

A notable recent success in cancer treatment is the approval of checkpoint inhibitor immunotherapies as therapeutic agents. Immune checkpoints are key mechanisms that fine-tune and control the body’s immune response. In the cancer setting, tumors have developed strategies for hijacking these checkpoints, preventing an immune response to the cancer and allowing the tumor cells to proliferate unchecked. Checkpoint inhibitor immunotherapies were developed to overcome this phenomenon by relieving immune cell inhibition, resulting in a potentially long-lasting amplification of the anti-tumor immune response. Therapies against checkpoint proteins, such as PD-1 and PD-L1, produced impressive results in clinical development, resulting in marketing approvals in a number of malignancies.

Background on OX40

OX40, a member of the TNFRSF, is predominately expressed and is a key co-stimulatory receptor on activated T-cells. Signaling through OX40 provides co-stimulation that promotes T-cell expansion, enhanced effector function and memory cell formation, and prevents activation-induced cell death. The natural mechanism of OX40 activation is via the interaction with its trimeric ligand, OX40L, which serves to effectively cluster multiple OX40 molecules and facilitate downstream signaling leading to nuclear factor kappa-light-chain-enhancer of activated B cells, or NFkB, activation. Based on the capacity for OX40 signaling to enhance anti-tumor immunity in preclinical studies, there have been many efforts to therapeutically exploit this pathway for cancer immunotherapy. Most previously developed agents were bivalent OX40 agonists, the configuration of which we believe to be poorly suited for efficient receptor clustering, evidenced by the lack of clinical responses observed for such molecules.

Unmet Medical Need

Despite unprecedented clinical response rates, the majority of patients fail to respond to therapies targeting PD-1 and PD-L1. We believe this is in part because T-cells require co-stimulation for full functionality. Thus, checkpoint inhibition alone is likely insufficient to fully enable the immune system to attack a tumor, and we believe further benefit could be derived by the addition of immune co-stimulatory agents.

Our Solution

INBRX-106 is a precisely engineered hexavalent sdAb-based therapeutic candidate targeting OX40, designed to be an optimized agonist of this co-stimulatory receptor. As shown in the diagram below, INBRX-106 is composed of six OX40 targeting sdAbs and a functional Fc domain.

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As a hexavalent therapeutic candidate, INBRX-106 is designed to bind six OX40 molecules on the cell surface to mediate efficient receptor clustering and downstream signaling. In preclinical studies, we observed that INBRX-106 elicited superior OX40 agonism when compared to the bivalent antibodies, 1A7 (analog of MOXR-0916) or 1D10 using an OX40 expressing NFkB reporter cell line, wherein clustering of OX40 receptor mediated signaling culminated in luciferase expression. We also observed that INBRX-106 can mediate T-cell co-stimulation and reduce the suppressive activity of regulatory T-cells. Additionally, INBRX-106 is able to exploit IgG-mediated effector function via the Fc domain.

Clinical Data

We initiated a Phase 1/2 clinical trial in December 2019 for INBRX-106. This trial was designed as an open-label, four-part trial in patients with locally advanced or metastatic solid tumors. Primary objectives of the trial were safety and tolerability, and the determination of the MTD and recommended Phase 2 dose of INBRX-106 as a single agent and in combination with KEYTRUDA®. For some of the expansion cohorts in part 4, clinical anti-tumor efficacy, such as response rate, was also included as one of the primary objectives. Secondary objectives were serum exposure, immunogenicity, as measured by the frequency of anti-drug antibodies, and clinical anti-tumor efficacy per RECIST (version 1.1) and immune RECIST based on response rate, duration of response, disease control rate, progression-free survival and overall survival. Exploratory objectives included evaluation of potential predictive diagnostic and pharmacodynamic biomarkers.

Part 1 of the trial utilized a traditional 3+3 algorithm for single agent dose escalation from 0.0003 mg/kg to 3 mg/kg in twenty patients. INBRX-106 was observed to be generally well tolerated in humans. The most common adverse events, or AEs, reported for INBRX-106 were Grade 1 and 2 and notably, cutaneous toxicities, which are common immune-related AEs associated with immune checkpoint inhibitors. These AEs, which were mostly mild or moderate non-serious adverse events and likely immune-related toxicities were in line with the mechanism of action of this candidate therapeutic. The maximum administered dose was 3 mg/kg and the MTD level was not reached.

Part 2 of the trial, single agent dose expansion, administered INBRX-106 in different dosing schedules to patients with tumor types responsive to checkpoint inhibitors. Part 2 treatment cohorts of this trial were in the following tumor types: NSCLC, melanoma, HNSCC, gastric or gastroesophageal junction adenocarcinoma, renal cell carcinoma, and urothelial (transitional) cell carcinoma.

In Parts 3 and 4 of this trial, INBRX-106 was evaluated in combination with KEYTRUDA®. In the all-comer Part 3 of the trial, INBRX-106 was escalated in combination with KEYTRUDA® and enrolled patients with locally

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advanced or metastatic solid tumors. It was observed to be well tolerated, with predominantly mild or moderate non-serious immune-related toxicities noted. We observed durable responses across multiple tumor types.

In Part 4, INBRX-106 combination expansion cohorts, we enrolled patients with NSCLC and HNSCC, both in combination with KEYTRUDA®. The patients had to be positive for PD-L1 expression, as determined by immunohistochemistry, and possess adequate hematologic and organ function, to qualify for enrollment.

The initial data with a cutoff date of August 2024 was observed from 24 NSCLC patients who all had previous checkpoint inhibitor exposure was tumor reduction or stabilization of target lesions in more than half the patients. Of those patients, one complete response and four partial responses were observed. The initial data with a cutoff date of August 2024 was observed from 14 HNSCC patients, seven of which were checkpoint failures and seven of which were checkpoint naive, was tumor reduction of target lesions in half the patients. Of those patients, two complete responses and five partial responses were observed. These cohorts have been expanded to recruit additional patients, and a new cohort was added in NSCLC patients with any PD-L1 status to evaluate the safety of chemotherapy when used in conjunction with the INBRX-106 and KEYTRUDA® combination. Early evaluation of the data indicate INBRX-106 in combination with pembrolizumab can be safely combined with chemotherapy, which supports further evaluation of this combination in indications where checkpoint inhibitors are used in conjunction with chemotherapy.

In November 2025, we completed enrollment of the Phase 1/2 trial evaluating 34 patients in checkpoint inhibitor refractory or relapsed NSCLC in combination with KEYTRUDA®. Primary endpoints for this cohort are objective response rate, or ORR, disease control rate, duration of response, or DOR, and safety.

In June 2024, a seamless Phase 2/3 clinical trial was initiated for INBRX-106 in combination with KEYTRUDA® as a first-line treatment for patients with locally advanced recurrent or metastatic HNSCC. This trial recruited patients who had not received prior checkpoint inhibitors and whose tumors expressed a PDL-1 combined positive score, or CPS, equal to or greater than 20. During the first quarter of 2026, we completed enrollment of 68 patients in the Phase 2 portion with a primary endpoint of ORR, supported by secondary endpoints of DOR, PFS, and safety. We plan to provide initial results from the Phase 2 trial in the second quarter of 2026. We plan to announce PFS data from this trial in the fourth quarter of 2026 at the European Society for Medical Oncology 2026 Congress.

If positive, we anticipate this data may ungate the Phase 3 portion, where we expect approximately 350 patients will be randomized to INBRX-106 or placebo in combination with KEYTRUDA®. The co-primary endpoints for the Phase 3 portion of the study are expected to be PFS and overall survival.

Safety Data for INBRX-106

Of the 272 patients studied and evaluable in our Phase 1/2 clinical trial for INBRX-106 as of the cutoff date of June 13, 2025, the treatment-related serious adverse events observed in more than one patient were (i) pyrexia, or fever (4 or 1.5%), (ii) diarrhea (3 or 1.1%), (iii) cytokine release syndrome (3 or 1.1%), (iv) infusion-related reactions (3 or 1.1%), (v) pneumonia (2 or 0.7%), and rash (2 or 0.7%).

Intellectual Property

We strive to protect the proprietary technology and information commercially or strategically important to our business. We seek to obtain and maintain, patent rights intended to cover the technologies incorporated into, or used to produce, our therapeutic candidates, the compositions of matter of our therapeutic candidates and their methods of use and manufacture, as well as other inventions that are important to our business. We also seek to obtain strategic or commercially valuable patent rights in the United States and other jurisdictions.

As of December 31, 2025, our patent estate contains 31 patent families that we solely own, 2 patent families that we co-own with Regeneron Pharmaceuticals, Inc. (formerly 2Seventy Bio, Inc.) and 2 patent families that we co-own with Poplar Therapeutics, Inc., formerly Phylaxis BioScience, LLC. The patent estate is comprised of 32 issued U.S. patents, 164 issued foreign patents in various countries around the world, including Australia, Canada, China, Europe (validated in France, Germany, Italy, Spain, the United Kingdom and other European countries), Russia, India, Israel, Japan, Mexico, New Zealand, Singapore, South Korea, South Africa and other countries as further described below, 28 pending U.S. patent applications, 3 pending Patent Cooperation Treaty, or PCT, applications, 1

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pending US provisional application, and 348 pending patent applications in various jurisdictions outside of the U.S., as further described below.

INBRX-106

With regard to INBRX-106, as of December 31, 2025, we solely own 3 patent families relating to the composition of matter of INBRX-106, its methods of use for the treatment of cancer and/or its alternative dosing regimens for the treatment of cancer. These patent families are comprised of: 3 issued U.S. patents, 11 issued patents in various countries around the world, including Australia, Chile, Indonesia, Israel, Japan, Mexico, New Zealand, Russia and Vietnam, 1 pending U.S. patent application, 2 pending PCT applications and 31 pending patent applications in various countries around the world, including Argentina, Australia, Brazil, Canada, China, Europe, Gulf Cooperation Council, Hong Kong, India, Indonesia, Israel, Japan, Malaysia, New Zealand, Philippines, Singapore, South Africa, South Korea, Taiwan, and Thailand. These patents and patents issuing from these applications, if any, are expected to expire between 2037 and 2044, absent any patent term adjustments or extensions or terminal disclaimers.

ozekibart (INBRX-109)

With regard to ozekibart, as of December 31, 2025, we solely own 4 patent families relating to the composition of matter of ozekibart, its methods of use for the treatment of cancer, its formulations, and/or its use in combination with select compounds. These patent families are comprised of: 3 issued U.S. patents, 53 issued patents in various countries around the world, including Australia, Brazil, China, Europe (validated in France, Germany, Italy, Spain, the United Kingdom and other European countries), Hong Kong, India, Indonesia, Israel, Japan, Mexico, New Zealand, Russia, Singapore, South Korea, and South Africa, 4 pending U.S. patent applications and 61 pending patent applications in various countries around the world, including Australia, Brazil, Canada, China, Eurasia, Europe, Hong Kong, Indonesia, India, Israel, Japan, Mexico, New Zealand, Russia, Singapore, South Africa, South Korea, Taiwan and Thailand. These patents and patents issuing from these applications, if any, are expected to expire between 2036 and 2043, absent any patent term adjustments or extensions or terminal disclaimers.

Single Domain Antibody and Multispecific Technologies

With regard to our single domain antibody and multispecific technologies, as of December 31, 2025, we solely own 6 patent families relating to non-immunogenic single domain antibodies, multispecific molecules having a constrained CD3 binding, molecules comprising modified IL-2 variants, and/or methods of using such molecules to treat diseases (e.g., cancer). These patent families are comprised of: 4 issued U.S. patents, 26 issued patents in Australia, Canada, China, Hong Kong, Indonesia, India, Israel, Japan, Malaysia, Mexico, New Zealand, Russia, Singapore, South Korea, and Taiwan, 6 pending U.S. patent applications and 83 pending patent applications in various countries around the world, including Argentina, Australia, Brazil, Canada, Chile, China, Europe, Gulf Cooperation Council, Hong Kong, India, Israel, Japan, Mexico, New Zealand, Philippines, Russia, Saudi Arabia, Singapore, South Africa, South Korea and Taiwan. These patents and patents issuing from these applications, if any, are expected to expire between 2036 and 2041, absent any patent term adjustments or extensions or terminal disclaimers.

We continually assess and refine our intellectual property strategy as we develop new technologies and therapeutic candidates. As our business evolves, we may, among other activities, file additional patent applications in pursuit of our intellectual property strategy, to adapt to competition or to seize potential opportunities.

The term of individual patents depends upon the laws of the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing of a non-provisional patent application. However, the term of United States patents may be extended for delays incurred due to compliance with the FDA requirements or by delays encountered during prosecution that are caused by the USPTO. For example, the Hatch-Waxman Act permits a patent term extension for FDA-approved drugs 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 drug is under regulatory review. Patent extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, and only one patent applicable to an approved drug may be extended. Similar provisions are available in Europe and other jurisdictions to extend the term of a patent that covers an approved drug. In the future, if and when our therapeutic candidates receive FDA approval, we expect to apply for patent term extensions on

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patents covering those therapeutic candidates. We intend to seek patent term extensions in any jurisdiction where these are available and where we also have a patent that may be eligible; however, there is no guarantee that the applicable authorities, including the USPTO and FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

We also rely on trade secrets to protect aspects of our technology and business not amenable to, or that we do not consider appropriate for, patent protection. We seek to protect this intellectual property, in part, by requiring our employees, consultants, sponsored researchers and other service providers and advisors to execute confidentiality agreements upon the commencement of employment or other relationship with us. In general, these agreements provide that 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. In the case of employees, the agreements further provide that inventions and discoveries conceived or reduced to practice by the individual that are related to our business, or actual, or demonstrably anticipated, research or development, or made during normal working hours, on our premises or using our equipment, supplies, or proprietary information, are our exclusive property. In many cases our agreements with consultants, sponsored researchers and other service providers and advisors require them to assign, or grant us licenses to, inventions resulting from the work or services they render under such agreements or grant us an option to negotiate a license to use such inventions.

Further, we expect to rely on data exclusivity, market exclusivity, patent term adjustment and patent term extensions when available.

We seek trademark protection in the United States and in certain other jurisdictions where available and when we deem appropriate. We currently have a registration for “Inhibrx” in the United States and have filed trademark applications for “Inhibrx Biosciences” in the United States. We intend to file applications for trademark registrations in connection with our therapeutic candidates in various jurisdictions, including the United States.

Competition

The biopharmaceutical industry is characterized by rapid evolution of technologies, fierce competition and strong defense of intellectual property. While we believe that our platforms, technology, knowledge, experience, and scientific resources provide us with competitive advantages, we face competition from major pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions, among others.

Any therapeutic candidates that we successfully develop and commercialize will compete with currently approved therapies and new therapies that may become available in the future. Key product features that would affect our ability to effectively compete with other therapeutics include the efficacy, safety and convenience of our therapeutics, the ease of use and effectiveness of any complementary diagnostics and/or companion diagnostics, and price and levels of reimbursement. Our primary competitors fall into the following groups:

•Companies developing novel therapeutics based on sdAb or alternative scaffold product candidates, including Crescendo Biologics Ltd., Molecular Partners AG, Precirix NV, Affibody Medical AB, Numab Therapeutics AG, GT Biopharma, Inc., and Sanofi;

•Antibody drug discovery companies that may compete with us in the search for novel therapeutic antibody targets, including Regeneron Pharmaceuticals, Inc., Adimab LLC, Genmab A/S, Macrogenics, Inc., Merus N.V., Numab Therapeutics AG, Amgen, Inc., Xencor, Inc., and Zymeworks Inc.; and

•Companies developing therapeutics for the treatment of autoimmune diseases, including Sanofi, Amgen Inc., AstraZeneca plc, F. Hoffmann-La Roche AG, Pfizer Inc., Merck & Co., Inc., Novartis AG, Candid Therapeutics, Inc., Hinge Bio, Inc., and Apogee Therapeutics, Inc.

Our competitors also include other large pharmaceutical and biotechnology companies who may be developing therapeutic candidates with mechanisms similar to or targeting the same indications as our therapeutic candidates.

The availability of reimbursement from government and other third-party payors will also significantly affect the pricing and competitiveness of our therapeutic candidates. Our competitors also may obtain FDA or other marketing

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approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market.

Many of the companies against which we may compete have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining marketing approvals and marketing approved products than we do. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These early stage and more established competitors also compete with us in recruiting and retaining 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.

Government Regulation

Governmental authorities in the United States, at the federal, state and local level, and other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, packaging, promotion, storage, advertising, distribution, marketing and export and import of product candidates such as those we are developing. Our therapeutic candidates must be approved by the FDA through the BLA process before they may be legally marketed in the United States and will be subject to similar requirements in other countries prior to marketing in those countries. The process of obtaining marketing approvals in the U.S. and in foreign countries and jurisdictions, and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations, require the expenditure of substantial time and financial resources. Failure to comply with the applicable FDA requirements at any time during the product development process, approval process or after approval, may subject an applicant to administrative or judicial sanctions.

The process required by the FDA before a biologic may be marketed in the United States generally involves the following:

•completion of certain preclinical laboratory tests, animal studies and formulation studies in accordance with Good Laboratory Practice, or GLP, regulations and other applicable requirements;

•submission to the FDA of an Investigational New Drug application, or IND, which must become effective before human clinical trials may begin;

•approval by an independent institutional review board, or IRB, or ethics committee at each clinical site before each trial may be initiated;

•performance of adequate and well-controlled human clinical trials in accordance with Good Clinical Practice regulations, or GCPs, to evaluate the safety, purity and potency, or efficacy, of the therapeutic candidate for its intended use;

•preparation and submission to the FDA of a BLA;

•satisfactory completion of an FDA advisory committee review, if applicable;

•satisfactory completion of an FDA inspection of the manufacturing facility or facilities at which the drug is produced to assess compliance with current Good Manufacturing Practice requirements, or cGMPs, to assure that the facilities, commercial manufacturing process, testing methods and controls are adequate to ensure manufacturing robustness and to preserve the drug’s identity, strength, quality and purity;

•satisfactory completion of potential inspection of selected clinical investigation sites to assess compliance with GCPs; and

•FDA review and approval of the BLA to permit commercial marketing of the product for particular indications for use in the United States.

Once a therapeutic candidate is identified for development, it enters the preclinical testing stage. Preclinical tests generally include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies. An IND sponsor must submit the results of the preclinical tests, together with manufacturing information and analytical data, to the FDA as part of an IND. An IND is a request for allowance from the FDA to administer an investigational drug or biological product to humans. An IND will also include a 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. Some preclinical testing may continue even after the IND is submitted. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA,

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within the 30-day time period, places the clinical trial on a clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. Submission of an IND may therefore not result in FDA allowance to begin a clinical trial. Clinical holds also may be imposed by the FDA at any time before or during clinical trials due in response to safety concerns or due to non-compliance with specific FDA requirements.

All clinical trials must be conducted under the supervision of one or more qualified investigators in accordance with GCPs, which include, among other things, the requirement that all research subjects provide their informed consent in writing for their participation in any clinical trial. Clinical trials must be conducted under protocols detailing, among other things, the objectives of the trial, dosing procedures, subject selection and exclusion criteria and any safety and effectiveness criteria to be evaluated. Each protocol must be submitted to the FDA as part of the IND, and a separate submission to the existing IND must be made for each successive clinical trial conducted during product development and for any subsequent protocol amendments. While the IND is active, progress reports summarizing the results of the clinical trials and preclinical 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 adverse events, 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.

Furthermore, an independent IRB or ethics committee at each institution participating in the clinical trial must review and approve each protocol before a clinical trial commences at that institution and must also approve the information regarding the trial and the consent form that must be provided to each trial subject or his or her legal representative, 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 or that the trial is unlikely to meet its stated objectives. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance 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.

Human clinical trials are typically conducted in three sequential phases that may overlap or be combined:

•Phase 1: The therapeutic candidate is initially introduced into healthy human subjects and tested for safety, dosage tolerance, absorption, metabolism, distribution and excretion and, if possible, to gain an early indication of its effectiveness.

•Phase 2: The therapeutic candidate is administered to a limited patient population with a specified disease or condition to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the therapeutic candidate for specific targeted diseases and to determine dosage tolerance and appropriate dosage.

•Phase 3: The therapeutic candidate is administered to an expanded patient population to further evaluate dosage, to provide substantial evidence of efficacy and to further test for safety, generally at multiple geographically dispersed clinical trial sites. These clinical trials are intended to establish the overall risk-benefit ratio of the therapeutic candidate and provide an adequate basis for product labeling.

Post-approval trials, sometimes referred to as Phase 4 studies, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the approved therapeutic indication. In certain instances, the FDA may mandate the performance of Phase 4 clinical trials as a condition of approval of a BLA.

Concurrent with clinical trials, companies usually complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug and finalize a process for

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manufacturing the product in commercial quantities in accordance with cGMPs. The manufacturing process must be capable of consistently producing quality batches of the therapeutic candidate and, among other things, the manufacturer must develop methods for testing the identity, strength, quality and purity of the final drug. In addition, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the therapeutic candidate does not undergo unacceptable deterioration over its shelf life.

U.S. Review and Approval Process

The results of product development, including results from preclinical and other non-clinical studies and clinical trials, along with descriptions of the manufacturing process, analytical tests conducted on the chemistry of the therapeutic candidate, proposed labeling and other relevant information are submitted to the FDA as part of a BLA requesting approval to market the product. Such information can come from company-sponsored clinical studies, or from a number of alternative sources, including studies initiated and sponsored by investigators. The submission of a BLA requires payment of a substantial application user fee to the FDA, unless a waiver or exemption applies.

In addition, the Pediatric Research Equity Act, or PREA, requires a sponsor to 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 the PREA, BLAs and certain supplements must contain a pediatric assessment unless the sponsor has received a deferral or waiver. The required assessment must evaluate the safety and effectiveness of the product in all relevant pediatric subpopulations and support dosing and administration for each pediatric subpopulation for which the product is deemed safe and effective. The sponsor or FDA may request a deferral of pediatric clinical trials for some or all of the pediatric subpopulations. 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.

Once a BLA has been submitted, the FDA conducts a preliminary review of the application within the first 60 days after submission, before accepting it for filing, to determine whether it is sufficiently complete to permit substantive review. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information from the application sponsor. In this event, the BLA must be resubmitted with the requested information. The resubmitted application also is subject to review before the FDA accepts it for filing.

Once filed, FDA reviews a BLA to determine, among other things, whether a therapeutic candidate is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency. Under the Prescription Drug User Fee Act, or PDUFA, guidelines that are currently in effect, the FDA has a goal to complete a standard review of an original BLA within ten months after the filing date, or, if the application qualifies for priority review, within six months after the filing date.

The FDA may refer an application for a novel drug to an advisory committee. An advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. Before approving a BLA, the FDA will typically inspect the facility or facilities where the product is manufactured. Additionally, before approving an NDA, the FDA may inspect one or more clinical trial sites to assure compliance with GCPs.

After the FDA evaluates a BLA and conducts any required inspections of manufacturing facilities where the investigational product and/or its drug substance will be produced, the FDA may issue an approval letter or a Complete Response Letter, or CRL. An approval letter authorizes commercial marketing of the drug with prescribing information for specific indications. 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 BLA identified by the FDA and may require additional clinical data, including additional clinical trials, or other significant and time-consuming requirements related to clinical trials, preclinical studies or manufacturing. If a CRL is issued, the sponsor must resubmit the BLA addressing all of the deficiencies identified in

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the letter or withdraw the application. Even if such data and information are submitted, the FDA may decide that the resubmitted application does not satisfy the criteria for approval.

If regulatory approval of a product is granted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may approve the BLA with a Risk Evaluation and Mitigation Strategy, or REMS, to ensure the benefits of the product outweigh its risks. A REMS is a safety strategy to manage a known or potential serious risk associated with a product and to enable patients to have continued access to such medicines by managing their safe use, and could include medication guides, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. The FDA may also require one or more post-market studies or surveillance programs to further assess and monitor the product’s safety and effectiveness after commercialization, and may limit further marketing of the product based on the results of these post-marketing studies.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biologic intended to treat a rare disease or condition, which is a disease or condition that affects fewer than 200,000 individuals in the United States or, if it affects more than 200,000 individuals in the United States, there is no reasonable expectation that the cost of developing and making the product available in the United States for this type of disease or condition will be recovered from sales of the product. Orphan designation must be requested before submitting a BLA. After the FDA grants orphan designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product that has orphan designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications –including full BLAs– to market the same drug for the same disease or condition for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity or inability to manufacture the product in sufficient quantities. The designation of such drug or biologic also entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. However, competitors, may receive approval of different products for the disease or condition for which the orphan product has exclusivity, or obtain approval for the same product but for a different disease or condition for which the orphan product has exclusivity. Orphan exclusivity also could block the approval of a competing product for seven years if a competitor obtains approval of the “same drug,” as defined by the FDA, or if the active ingredient of the therapeutic candidate is determined to be contained within the competitor’s product for the same disease or condition. In addition, if an orphan designated product receives marketing approval for a disease or condition broader than what is designated, it may not be entitled to orphan exclusivity.

Expedited Development and Review Programs

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 therapeutic candidates that meet certain criteria. Specifically, investigational biologics 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 specified disease or condition. The sponsor of a Fast Track therapeutic candidate has opportunities for more frequent interactions with the applicable FDA review team during product development and, once a BLA is submitted, the application may be eligible for priority review. With regard to a Fast Track candidate, the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

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A therapeutic 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 therapeutic candidate can receive Breakthrough Therapy designation if preliminary clinical evidence indicates that the therapeutic 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 therapeutic candidate, including involvement of senior managers.

Any therapeutic candidate submitted to the FDA for approval, including a therapeutic candidate with a Fast Track designation or Breakthrough Therapy designation, may also be eligible for other types of FDA programs intended to expedite development and review, such as priority review. A BLA is eligible for priority review if the therapeutic 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 will attempt to direct additional resources to the evaluation of a BLA designated for priority review in an effort to expedite the review. The FDA endeavors to review applications with priority review designations within six months of the filing date as compared to ten months for review of original BLAs under its current PDUFA review goals.

In addition, depending on the design of the applicable clinical trials, a therapeutic candidate may be eligible for accelerated approval. Specifically, biologics intended to treat serious or life-threatening diseases or conditions may be eligible for accelerated approval upon a determination that the therapeutic 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 drug or biologic 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. Drugs or biologics 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 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.

Fast Track designation, Breakthrough Therapy designation, priority review, and accelerated approval do not change the standards for approval but may expedite the development or approval process. Even if a therapeutic 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

Any products manufactured or distributed pursuant to FDA approvals are 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. After approval, most changes to the approved product, such as adding new indications, certain manufacturing changes and additional labeling claims, are subject to further FDA review and approval.

Drug and biologic manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMPs and other laws and regulations. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA approval before being implemented. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMPs and other aspects of regulatory compliance.

The FDA may withdraw or limit approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing

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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 for non-compliance include, among other things:

•restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;

•fines, warning letters, or untitled letters;

•clinical holds on ongoing or planned clinical studies;

•refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of approvals;

•product seizure or detention, or refusal to permit the import or export of products;

•consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs;

•mandated modification of promotional materials and labeling and the issuance of corrective information;

•the issuance of safety alerts, Dear Healthcare Provider letters, press releases and other communications containing warnings or other safety information about the product; or

•injunctions or the imposition of civil or criminal penalties.

In addition, the FDA closely regulates the marketing, labeling, advertising and promotion of biological products. A sponsor can make only those claims relating to safety, potency, purity and efficacy that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and failure to comply with these requirements may lead to enforcement action. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested and approved by the FDA. 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 manufacturer’s communications on the subject of off-label use of their products.

Biosimilars and Exclusivity

The Biologics Price Competition and Innovation Act of 2009. or BPCIA, created an abbreviated approval pathway for biological products that are highly similar, or “biosimilar,” to or interchangeable with an FDA-approved reference biological product. Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, is generally shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic 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 biologic. A product shown to be biosimilar or interchangeable with an FDA-approved reference biological product may rely in part on the FDA’s previous determination of safety and effectiveness for the reference product for approval, which can potentially reduce the cost and time required to obtain approval to market the product.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods for all formulations, dosage forms, and indications of the active ingredient and to patent terms. This six-month exclusivity, which runs from the end of an existing period of non-patent regulatory exclusivity protection or patent term, may be granted based on the voluntary completion of a

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pediatric study in accordance with an FDA-issued “Written Request” for such a study, provided that at the time pediatric exclusivity is granted there is not less than nine months of exclusivity or patent term remaining. Pediatric exclusivity does not require the sponsor to obtain approval for the applicable product in the studied pediatric indication.

FDA Approval and Regulation of Companion Diagnostics

If the safe and effective use of a therapeutic product depends on an in vitro diagnostic medical device, then the FDA generally will require approval or clearance of that diagnostic, known as an in vitro companion diagnostic device, at the same time that the FDA approves the therapeutic product. In August 2014, the FDA issued final guidance clarifying the requirements that will apply to approval of therapeutic products and in vitro companion diagnostic devices. According to the guidance, for novel drugs, an in vitro companion diagnostic device and its corresponding therapeutic should be approved or cleared contemporaneously by the FDA for the use indicated in the therapeutic product’s labeling. Accordingly, if the FDA determines that an in vitro companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, the FDA generally will not approve the therapeutic product or new therapeutic product indication if the in vitro companion diagnostic device is not approved or cleared for that indication. Approval or clearance of the in vitro companion diagnostic device will ensure that the device has been adequately evaluated and has adequate performance characteristics in the intended population.

Under the FDCA, in vitro diagnostics, including in vitro companion diagnostic devices, are generally regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, preclinical 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, and the FDA has generally required companion diagnostics for cancer therapies to obtain approval of a premarket approval, or PMA, application.

The PMA 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, a PMA application typically requires data regarding analytical and clinical validation studies. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation, or QSR, which imposes elaborate testing, control, documentation and other quality assurance requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA order 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.

After an in vitro device is authorized by the FDA and placed on the market, 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 currently covers the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Manufacturing sites for devices also remain subject to periodic unscheduled inspections by the FDA.

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Regulation Outside of the United States

In addition to regulations in the United States, we are subject to regulations of other jurisdictions governing any clinical trials and commercial sales and distribution of our therapeutic candidates. Whether or not we obtain FDA approval for a product, we must obtain approval by the comparable regulatory authorities of countries outside of the United States before we can commence clinical trials in such countries and approval of the regulators of such countries or economic areas, such as the European Union, or the EU, before we may market products in those countries or areas. The approval process and requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from place to place, and the time may be longer or shorter than that required for FDA approval.

Non-clinical Studies and Clinical Trials

Similarly to the United States, the various phases of non-clinical and clinical research in the EU are subject to significant regulatory controls.

Non-clinical studies are performed to demonstrate the health or environmental safety of new chemical or biological substances. Non-clinical (pharmaco-toxicological) studies must be conducted in compliance with the principles of good laboratory practice, or GLP, as set forth in EU Directive 2004/10/EC (unless otherwise justified for certain particular medicinal products, e.g., radio-pharmaceutical precursors for radio-labeling purposes). In particular, non-clinical studies, both in vitro and in vivo, must be planned, performed, monitored, recorded, reported and archived in accordance with the GLP principles, which define a set of rules and criteria for a quality system for the organizational process and the conditions for non-clinical studies. These GLP standards reflect the Organization for Economic Co-operation and Development requirements.

Clinical trials of medicinal products in the EU must be conducted in accordance with EU and national regulations and the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use, or ICH, guidelines on Good Clinical Practices, or GCP, as well as the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. If the sponsor of the clinical trial is not established within the EU, it must appoint an EU entity to act as its legal representative. The sponsor must take out a clinical trial insurance policy, and in most EU member states, the sponsor is liable to provide ‘no fault’ compensation to any study subject injured in the clinical trial.

The regulatory landscape related to clinical trials in the EU has been subject to recent changes. The EU Clinical Trials Regulation, or CTR, which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. Unlike directives, the CTR is directly applicable in all EU member states without the need for member states to further implement it into national law. The CTR notably harmonizes the assessment and supervision processes for clinical trials throughout the EU via a Clinical Trials Information System, which contains a centralized EU portal and database.

While the EU Clinical Trials Directive required a separate clinical trial application, or CTA, to be submitted in each member state in which the clinical trial takes place, to both the competent national health authority and an independent ethics committee, much like the FDA and IRB respectively, the CTR introduces a centralized process and only requires the submission of a single application for multi-center trials. The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each member state, leading to a single decision per member state. The CTA must include, among other things, a copy of the trial protocol and an investigational medicinal product dossier containing information about the manufacture and quality of the medicinal product under investigation. The assessment procedure of the CTA has been harmonized as well, including a joint assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements related to its own territory, including ethics rules. Each member state’s decision is communicated to the sponsor via the centralized EU portal. Once the CTA is approved, clinical study development may proceed.

The CTR transition period ended on January 31, 2025, and all clinical trials (and related applications) are now fully subject to the provisions of the CTR.

Medicines used in clinical trials must be manufactured in accordance with Good Manufacturing Practice, or GMP. Other national and EU-wide regulatory requirements may also apply.

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Marketing Authorization

In order to market our product candidates in the EU and many other foreign jurisdictions, we must obtain separate regulatory approvals. More concretely, in the EU, medicinal product candidates can only be commercialized after obtaining a marketing authorization, or MA. To obtain regulatory approval of a product candidate under EU regulatory systems, we must submit a MA application, or MAA. The process for doing this depends, among other things, on the nature of the medicinal product. There are two types of MAs:

–The centralized procedure provides for the grant of a single MA issued by the European Commission based on the opinion of the Committee for Medicinal Products for Human Use, or CHMP, of the European Medicines Agency, or EMA, and is valid throughout the EU. The centralized procedure is compulsory for (i) medicines derived from biotechnology, (ii) designated orphan medicinal products, (iii) advanced therapy medicinal products, or ATMPs (such as gene therapy, somatic cell therapy and tissue engineered products) and (iv) those medicines with an active substance not authorized in the EU on or before May 20, 2004 indicated for the treatment of certain diseases, such as autoimmune diseases, cancer, neurodegenerative disorders or diabetes. The centralized procedure is optional for those medicines containing a new active substance not authorized in the EU on or before May 20, 2004, for products that constitute a significant therapeutic, scientific or technical innovation, or medicines to which the granting of a MA under the centralized procedure would be in the interest of patients at the EU-level.

–The decentralized procedure provides for recognition by EU national authorities of a first assessment performed by one of the member states. Under this procedure, an identical application for MA is submitted simultaneously to the national authorities of several EU member states, one of them being chosen as the “Reference Member State,” and the remaining being the “Concerned Member States.” The Reference Member State must prepare and send drafts of an assessment report, summary of product characteristics and the labelling and package leaflet within 120 days after receipt of a valid marketing authorization application to the Concerned Member States, which must decide within 90 days whether to recognize approval. If any Concerned Member State does not recognize the MA on the grounds of potential serious risk to public health, the disputed points are eventually referred to the European Commission, whose decision is binding on all member states. The mutual recognition procedure is similar to the decentralized procedure except that a medicine must have already received a marketing authorization in at least one of the member states, and that member state acts as the Reference Member State.

Under the centralized procedure the maximum timeframe for the evaluation of an MAA by the EMA is 210 days, excluding clock stops.

Under the above described procedures, in order to grant the MA, the EMA or the competent authorities of the EU member states make an assessment of the risk benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy. MAs have an initial duration of five years. After these five years, the authorization may be renewed on the basis of a reevaluation of the risk-benefit balance.

Data and Marketing Exclusivity

In the EU, new products authorized for marketing (i.e., reference products) generally receive eight years of data exclusivity and an additional two years of market exclusivity upon MA. If granted, the data exclusivity period prevents generic and biosimilar applicants from relying on the preclinical and clinical trial data contained in the dossier of the reference product when applying for a generic or biosimilar 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 or biosimilar applicant from commercializing its product in the EU until ten years have elapsed from the initial MA of the reference product in the EU. The overall ten-year market exclusivity period can be extended to a maximum of eleven years if, during the first eight years of those ten 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 or biological entity, and products may not qualify for data exclusivity.

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Orphan Medicinal Products

The criteria for designating an “orphan medicinal product” in the EU are similar in principle to those in the United States. A medicinal product can be designated as an orphan if its sponsor can establish that: (1) the product is intended for the diagnosis, prevention or treatment of a life threatening or chronically debilitating condition (2) either (a) such condition affects not more than five in 10,000 persons in the EU when the application is made, or (b) the product, without the benefits derived from the orphan status, would not generate sufficient return in the EU to justify the necessary investment; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of the condition in question that has been authorized for marketing in the EU or, if such method exists, the product will be of significant benefit to those affected by that condition.

Orphan designation must be requested before submitting an MAA. An EU orphan designation entitles a party to incentives such as reduction of fees or fee waivers, protocol assistance, and access to the centralized procedure. Upon grant of a MA, orphan medicinal products are entitled to ten years of market exclusivity for the approved indication, which means that the competent authorities cannot accept another MAA, or grant a MA, or accept an application to extend a MA for a similar medicinal product for the same indication for a period of ten years. The period of market exclusivity is extended by two years for orphan medicinal products that have also complied with an agreed pediatric investigation plan, or PIP. No extension to any supplementary protection certificate can be granted on the basis of pediatric studies for orphan indications. Orphan designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

The orphan exclusivity period may be reduced to six years if, at the end of the fifth year, it is established that the product no longer meets the criteria for which it received orphan designation, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity or where the prevalence of the condition has increased above the threshold. Additionally, MA may be granted to a similar product for the same indication at any time if (i) the second applicant can establish that its product, although similar, is safer, more effective or otherwise clinically superior; (ii) the applicant consents to a second orphan medicinal product application; or (iii) the applicant cannot supply enough orphan medicinal product.

Pediatric Development

In the EU, MAAs for new medicinal products have to include the results of studies conducted in the pediatric population, in compliance with a PIP agreed with the EMA’s Pediatric Committee, or PDCO. The PIP sets out the timing and measures proposed to generate data to support a pediatric indication of the product candidate for which MA is being sought. The PDCO can grant a deferral of the obligation to implement some or all of the measures of the PIP until there are sufficient data to demonstrate the efficacy and safety of the product in adults. Further, the obligation to provide pediatric clinical trial data can be waived by the PDCO when these data are not needed or appropriate because the product is likely to be ineffective or unsafe in children, the disease or condition for which the product is intended occurs only in adult populations, or when the product does not represent a significant therapeutic benefit over existing treatments for pediatric patients. Once the MA is obtained in all the EU member states and study results are included in the product information, even when negative, the product is eligible for six months’ supplementary protection certificate extension (if any is in effect at the time of approval) or, in the case of orphan medicinal products, a two year extension of the orphan market exclusivity is granted.

Failure to comply with EU and member state laws that apply to the conduct of clinical trials, manufacturing approval, MA of medicinal products and marketing of such products, both before and after grant of the MA, manufacturing of pharmaceutical products, statutory health insurance, bribery and anti-corruption or with other applicable regulatory requirements may result in administrative, civil or criminal penalties. These penalties could include delays or refusal to authorize the conduct of clinical trials, or to grant MA, product withdrawals and recalls, product seizures, suspension, withdrawal or variation of the MA, total or partial suspension of production, distribution, manufacturing or clinical trials, operating restrictions, injunctions, suspension of licenses, fines and criminal penalties.

Regulatory Framework in the United Kingdom

On January 31, 2020, the United Kingdom formally withdrew from the EU, also known as Brexit. The United Kingdom and the EU entered into a trade agreement known as the Trade and Cooperation Agreement, which went

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into effect on January 1, 2021. As of January 1, 2021, the Medicines and Healthcare products Regulatory Agency, or MHRA, is the United Kingdom’s standalone medicines regulatory body. As a result of the Northern Ireland Protocol, different rules applied in Northern Ireland than in Great Britain (England, Wales, and Scotland); broadly, Northern Ireland continued to follow the EU regulatory regime. However, a new arrangement called “the Windsor Framework” went into effect on January 1, 2025 and has changed the existing system under the Northern Ireland Protocol, including the regulation of pharmaceutical products in the United Kingdom. Specifically, the MHRA is now responsible for approving all medicines intended to be marketed in the United Kingdom (i.e., Great Britain and Northern Ireland), while the EMA is no longer involved in approving medicines intended for sale in Northern Ireland. In addition, an international recognition procedure has been in place since January 1, 2024, whereby the MHRA will have regard to decisions on the approval of marketing authorizations made by the EMA and certain other regulatory bodies when determining an application for a new United Kingdom marketing authorization.

Coverage, Pricing and Reimbursement

Sales of our products for which we receive approval will depend, in part, on the extent to which they 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 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 United States.

In the United States, 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. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third-party payors are increasingly challenging the prices charged, examining the medical necessity, and reviewing the cost-effectiveness of medical products and services and imposing controls to manage costs. Third-party payors may limit coverage to specific products on an approved list, also known as a formulary, which might not include all of the approved products for a particular indication.

A payor’s decision to provide coverage for a product does not imply that an adequate reimbursement rate will be approved. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage and reimbursement for the product, and the level of coverage and reimbursement can differ significantly from payor to payor. Third-party reimbursement and coverage for our product candidates for which we receive approval may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development.

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. The U.S. 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 and biosimilar products. For example, the U.S. Department of Health and Human Services, or HHS, imposes rebates on many Medicare Part B and Medicare Part D products to penalize price increases that outpace inflation on an annual basis. HHS has also been empowered to negotiate the price of certain single-source biologics that have been on the market for at least eleven (11) years covered under Medicare as part of the Medicare Drug Price Negotiation Program. Each year up to twenty (20) products will be selected by HHS for the Medicare Drug Price Negotiation Program. Products subject to the

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Medicare Drug Price Negotiation Program are expected to experience a significant reduction in reimbursement from the Medicare program on a per unit basis. 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. If 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. Similar challenges to obtaining coverage and reimbursement for the pharmaceutical or biological products apply to companion diagnostics.

Moreover, in some foreign countries, the proposed pricing for a product and therapeutic candidate must be approved before it may be lawfully marketed. The requirements governing therapeutic pricing vary widely from country to country. For example, the EU 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. Historically, therapeutic candidates launched in the EU do not follow price structures of the United States and generally tend to be significantly lower.

Healthcare Reform

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 product and therapeutic candidates, restrict or regulate post-approval activities, and affect the ability to profitably sell product and therapeutic 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 and therapeutic 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, or collectively, the ACA, was enacted in March 2010 and has had a significant impact on the health care industry in the United States. It also included the BPCIA, which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product.

Since its enactment, certain provisions of the ACA have been subject to judicial, executive, and legislative challenges. For example, on July 4, 2025, the One Big Beautiful Bill Act, or the OBBBA, was signed into law, which narrowed access to ACA marketplace exchange enrollment and declined to extend the ACA enhanced advanced premium tax credits that expired at the end of 2025, which, among other provisions in the law, are anticipated to reduce the number of Americans with health insurance. The OBBBA also is expected to reduce Medicaid spending and enrollment by implementing work requirements for some beneficiaries, capping state-directed payments, reducing federal funding, and limiting provider taxes used to fund the program. Congress is considering proposed legislation intended to further reduce healthcare costs with alternatives to replace the expired ACA subsidies. We expect that additional U.S. federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that the U.S. federal government will pay for healthcare products and services, which could result in reduced demand for our product candidates or additional pricing pressures.

The current administration is pursuing policies to reduce regulations and expenditures across government agencies including at HHS, the FDA, the U.S. Centers for Medicare & Medicaid Services, or CMS, and related agencies.

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These actions, presently directed by executive orders or memoranda from the Office of Management and Budget, may propose policy changes that create additional uncertainty for our business. For example, the current administration has announced agreements with several pharmaceutical companies that require the drug manufacturers to offer, through a direct-to-consumer platform, or TrumpRx, U.S. patients and Medicaid programs prescription drug Most-Favored Nation pricing equal to or lower than those paid in other developed nations, with additional mandates for direct-to-patient discounts and repatriation of foreign revenues. Other recent actions, for example, include (1) directing agencies to reduce agency workforce and cut programs; (2) directing HHS and other agencies to lower prescription drug costs through a variety of initiatives; (3) imposing tariffs on imported pharmaceutical products; and (4) as part of the Make America Healthy Again Commission’s Strategy Report released in September 2025, working across government agencies to increase enforcement on direct-to-consumer pharmaceutical advertising. Additionally, the current administration recently called on Congress to enact "The Great Healthcare Plan," to codify and expand Most-Favored Nation pricing, lower government subsidies to private insurance companies, increase healthcare price transparency, expand pharmaceutical drugs available for over-the-counter purchase, and enact restrictions on pharmacy benefit manager payment methodologies, among other things. These actions and policies may significantly reduce U.S. drug prices, potentially impacting manufacturers’ global pricing strategies and profitability, while increasing their operational costs and compliance risks. In June 2024, the U.S. Supreme Court’s Loper Bright decision greatly reduced judicial deference to regulatory agencies, which could increase successful legal challenges to federal regulations affecting our operations. Congress may introduce and ultimately pass health care related legislation that could impact the drug approval process and make changes to the Medicare Drug Price Negotiation Program.

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, drug price reporting and other transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. Some states have enacted legislation creating so-called prescription drug affordability boards, which ultimately may attempt to impose price limits on certain drugs in these states.

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 health care reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for health care products and services.

Other Healthcare Laws

Our current and future business operations are subject to healthcare regulation and enforcement by the federal government and the states and foreign governments where we research, and, if approved, market, sell and distribute our therapeutic candidates. These laws include, without limitation, state and federal anti-kickback, fraud and abuse, false claims, physician sunshine and drug pricing transparency laws and regulations such as:

•    The federal Anti-Kickback Statute prohibits, among other things, any person from knowingly and willfully offering, soliciting, receiving or paying remuneration, directly or indirectly, to induce either the referral of an individual, for an item or service or the purchasing or ordering of a good or service, for which payment may be made under federal healthcare programs such as the Medicare and Medicaid programs. The federal Anti-Kickback Statute is broadly interpreted and aggressively enforced with the result that beneficial commercial arrangements can be penalized in the healthcare industry. In the past, the government has enforced the federal Anti-Kickback Statute to reach large settlements with healthcare companies based on a variety of arrangements, including sham consulting and other financial arrangements with physicians. Penalties for violating the federal Anti-Kickback Statute include imprisonment, fines and possible exclusion from federal healthcare programs such as Medicare and Medicaid. A person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the government may 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 civil False Claims Act;

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•    The federal civil and criminal false claims laws, including the civil False Claims Act, and civil monetary penalty laws, prohibit, among other things, knowingly presenting or causing the presentation of a false, fictitious or fraudulent claim for payment to the U.S. government, knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the U.S. government, or from knowingly making a false statement to avoid, decrease or conceal an obligation to pay money to the U.S. government. Actions under these laws may be brought by the Attorney General or as a qui tam action by a private individual in the name of the government. The federal government uses these laws, and the accompanying threat of significant liability, in its investigation and prosecution of pharmaceutical and biotechnology companies throughout the U.S., for example, in connection with the promotion of products for unapproved uses and other allegedly unlawful sales and marketing practices. If an entity is found to have violated the False Claims Act, it must pay three times the actual damages sustained by the government, plus mandatory and substantial civil penalties;

•    The Health Insurance Portability and Accountability Act of 1996 and its accompanying regulations, or HIPAA, created new federal, civil and criminal statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation;

•HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its implementing regulations, which also imposes certain obligations with respect to safeguarding the privacy and security of individually identifiable health information of covered entities subject to the rule, such as health plans, healthcare clearinghouses and certain healthcare providers, as well as their business associates, independent contractors of a covered entity that perform certain services involving the use or disclosure of individually identifiable health information on their behalf and their covered subcontractors;

•    The Physician Payments Sunshine Act, enacted as part of the ACA, among other things, imposes reporting requirements on 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 (defined to include doctors, dentists, optometrists, podiatrists, and chiropractors), teaching hospitals and certain advanced non-physician healthcare practitioners, as well as ownership and investment interests held by physicians and their immediate family members. The law provides for the imposition of civil monetary penalties, and payments reported also have the potential to draw scrutiny on payments and relationships with physicians, which may have implications under the Anti-Kickback Statute and other healthcare laws; and

•    Analogous state laws and regulations, such as state anti-kickback and false claims laws which may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; state laws which require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug and therapeutic biologics manufacturers to report information related to payments to physicians and other healthcare providers or marketing expenditures and pricing information; and state and local laws which require certain regulatory licenses to manufacture or distribute products commercially and/or the registration of pharmaceutical sales representatives.

U.S. and European Data Privacy and Security Laws

Numerous state, federal and foreign laws, regulations and standards govern the collection, use, access to, confidentiality and security of health-related and other personal information, and could apply now or in the future to our operations or the operations of our partners. In the United States, numerous federal and state laws and regulations, including data breach notification laws, health information privacy and security laws and consumer protection laws and regulations govern the collection, use, disclosure, and protection of health-related and other personal information. In addition, certain foreign laws govern the privacy and security of personal data, including

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health-related data. For example, the European Union General Data Protection Regulation, or the EU GDPR, and the United Kingdom General Data Protection Regulation and Data Protection Act 2018, or collectively, the UK GDPR (the EU GDPR and UK GDPR together referred to as the “GDPR”), impose comprehensive data privacy compliance obligations in relation to the collection and use of data relating to an identifiable living individual or “personal data”, including a principle of accountability and the obligation to demonstrate compliance through policies, procedures, training and audit, as well as regulating cross-border transfers of personal data out of the European Economic Area, or the EEA, and the UK. Privacy and security laws, regulations, and other obligations are constantly evolving, may conflict with each other to complicate compliance efforts, and can result in investigations, proceedings, or actions that lead to significant civil and/or criminal penalties and restrictions on data processing.

Additionally, the U.S. Department of Justice issued a rule entitled the Preventing Access to U.S. Sensitive Personal Data and Government-Related Data by Countries of Concern or Covered Persons, which places additional restriction on certain data transactions involving countries of concern (e.g., China, Russia, Iran) and covered persons (i.e., individuals and entities who are designated as such by the U.S. Attorney General or considered “foreign persons” and are majority owned by, organized under the laws of, a primary resident in, or a contractor of, a covered person or country of concern, as applicable) that may impact certain business activities such as vendor engagements, sale or sharing of data, employment of certain individuals, and investor agreements. Violations of the rule could lead to significant civil and criminal fines and penalties. The rule applies regardless of whether data is anonymized, key-coded, pseudonymized, de-identified or encrypted, which presents particular challenges for companies like ours and may impact our ability to engage in certain transactions or agreements with certain third parties in the future.

Other Laws and Regulations

Our present business is, and our future business may be, subject to regulation under the Clean Air Act, the Clean Water Act, the Comprehensive Environmental Response, Compensation and Liability Act, the National Environmental Policy Act, the Toxic Substances Control Act, the Resource Conservation and Recovery Act, national restrictions, and other current and potential future local, state, federal, and foreign regulations. See “Risk Factors — Risks Related to Government Regulation — If we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected.”

Manufacturing

We do not own or operate manufacturing facilities for the production of any of our therapeutic candidates, nor do we have plans to develop our own manufacturing operations in the foreseeable future. We presently have relationships with suppliers for the manufacture of supplies for all of our required raw materials, antibodies, and other biologics for our preclinical research, clinical trials, and if and when applicable, commercialization. We currently employ internal resources to manage our manufacturing relationships.

Human Capital Resources

Our employees are a key factor in our ability to achieve our mission to discover and develop effective biologic therapeutics for people with life-threatening conditions. We believe that our future success depends on our continued ability to identify, recruit, retain, and incentivize our management team and our clinical, scientific, and other employees. Our ability to do so depends on factors including our company culture, compensation and benefits, growth and development opportunities, and prioritization of employee safety.

Employee Profile

As of December 31, 2025, we had 110 employees, 109 of whom were full-time, 84 of whom were engaged in research and development activity, and 51 of which hold advanced degrees, including but not limited to Ph.D., M.D., PharmD, J.D., MBA, and other master’s degrees. None of the employees are represented by a labor union and we believe we maintain good relations with our employees. Our employees represent a broad range of backgrounds and bring a wide array of perspectives and experiences. We believe this allows us to better drive innovation and achieve our mission.

Employee Conduct & Ethics

We have adopted corporate policies, including a Corporate Code of Conduct and Ethics and Whistleblower Policy, or Code of Conduct, which apply to all of our employees. All employees complete a mandatory public company

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training session and are required to abide by, review and confirm compliance with our Code of Conduct, as well as our Insider Trading Policy governing trading by our personnel in our securities. We have established a whistleblower reporting hotline to enable our employees to anonymously report any suspected violations of these policies. In addition, we require employees to complete Anti-Harassment Training, with employees who work in a management capacity required to complete additional trainings in Harassment Prevention.

Employee Compensation and Benefits

Our compensation programs are designed to reward and support our employees in order to continue to attract and retain top talent. Our compensation includes:

•Employee base salaries that are competitive and consistent with employee positions, skill levels, experience, and knowledge;

•Stock-based compensation awards which help to align the interests of our stockholders with those of our employees;

•Bonus award plans for all full-time employees;

•Retirement savings options and matching contributions;

•Fully covered healthcare benefits for all full-time employees and their dependents;

•Unlimited vacation benefit for all full-time employees; and

•Parental leave and other leave options available to all employees.

Employee Growth and Development

We are committed to fostering and growing talent within the biopharmaceutical and life sciences space. We provide internship opportunities for students interested in biotechnology and science within our research and development departments. Many of our interns have continued on to join us in a full-time position after graduation. Our hiring process is transparent and we are an equal opportunity employer and prohibits all forms of unlawful discrimination in accordance with applicable law. Many of our employees hold advanced degrees, as well as professional licenses and certifications; however, we equally commit resources to advancing all of our employees with a range of educational backgrounds. We offer tuition reimbursement aimed at growth and career development, as well as the opportunity for employees to attend relevant conferences and symposiums. In addition, we offer in-house coaching opportunities to refine or develop professional skills as our employees become managers and plan their career growth.

Employee Wellness, Health, and Safety

We are strongly committed to the health and safety of our employees and strive to maintain the highest possible level of safety in our workplace. We require annual workplace safety training to reinforce workplace safety procedures that may be useful in the event of emergency situations and to assist our employees in helping to prevent workplace accidents. Our Environmental Health and Safety Committee, which is comprised of numerous cross-departmental members, meets regularly to review workplace safety and adherence to safety policies.

Corporate Information

Our company was incorporated as Ibex SpinCo, Inc. on January 8, 2024 under the laws of the State of Delaware as a direct, wholly-owned subsidiary of the Former Parent. We changed our name from Ibex SpinCo, Inc. to Inhibrx Biosciences, Inc. on January 25, 2024. Our corporate headquarters are located at 11025 N. Torrey Pines Road, Suite 140, La Jolla, CA 92037, and our telephone number is (858) 795-4220. Our website address is www.inhibrx.com. Information contained on, or that can be accessed through, our website is not part of, and is not incorporated into, this Annual Report.

Available Information

Our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and all amendments to those reports are and will be available to you free of charge through the “Investors” section on our website as soon as reasonably practicable after such materials have been electronically filed with, or furnished to, the SEC. The SEC maintains an internet site (http://www.sec.gov) that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC.

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