Zymeworks Inc. (ZYME) Business

Item 1.    Business

Overview

Zymeworks is a global biotechnology company managing a portfolio of licensed healthcare assets and developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat conditions, including cancer, inflammation, and autoimmune disease. We believe our asset and royalty aggregation strategy differentiates us from other biotechnology companies because it provides us with an opportunity to optimize future milestone and royalty cash flows and selectively invest in high-quality assets while retaining the flexibility to return capital to stockholders.

Our Strategy

Our strategy is focused on compounding long-term stockholder value through a combination of royalty growth, strategic acquisitions, and internal innovation, supported by disciplined capital allocation and a strengthened financial foundation through expected milestone payments and royalties from existing commercial partners. We pursue this strategy by discovering or acquiring and developing a diversified portfolio of preclinical or clinical healthcare assets while also evaluating strategic partnership opportunities to transfer certain costs and risks related to clinical development and/or commercialization to our strategic partners and secure the right to receive potential future royalty and milestone revenues. The following elements collectively support the execution of our strategy.

Proprietary Technology Platforms and R&D Engine

We seek to leverage our expertise in protein engineering and drug chemistry to discover and develop next-generation antibody-based therapeutics to address significant unmet medical needs, particularly in hard-to-treat diseases. Our proprietary structure-guided molecular modeling, combined with internal antibody discovery and generation technologies, supports a fully integrated drug development engine capable of efficiently advancing a pipeline of innovative product candidates.

Our pipeline of multifunctional therapeutics is supported by our multispecific antibody therapeutics (“MSATs”) and antibody-drug conjugates (“ADCs”) technology platforms, which enable the development of novel therapeutics in cancer, inflammation, and autoimmune disease and create opportunities for new partnerships.

Strategic Partnerships and Risk-Sharing

Partnerships and collaborations are central to our strategy as a potential source of funding for ongoing research and development while also reducing reliance on internal capital for later-stage clinical development of partnered assets. These arrangements enable risk sharing, particularly in late-stage development, and support disciplined R&D investment, which can reduce the need to use future milestone and royalty payments to fund planned operations.

Royalty Portfolio and Cash Flow Generation

Through our asset and royalty aggregation strategy, we seek to optimize future cash flows from a growing portfolio of licensed products and product candidates, including Ziihera (zanidatamab-hrii) and pasritamig. As partnered therapies advance through late-stage development and commercialization, we expect to grow durable and predictable cash flows that can be deployed by us in order to seek attractive risk-adjusted returns for stockholders.

Stockholder Returns and Capital Allocation Discipline

Our capital allocation strategy is focused on balancing investment in long-term growth with returning capital to stockholders. As our royalty portfolio matures and generates excess capital beyond the needs of our operations and strategic investments, we maintain the flexibility to opportunistically allocate capital to stock repurchases. We view stock repurchases as a potential tool to strategically reduce our share count and enhance total stockholder return over time, while continuing to prioritize investments that can help support sustainable value creation. Decisions regarding capital returns are evaluated within the context of our liquidity position, future cash flow outlook, and overall strategic objectives.

Strategic Acquisitions

We intend to evaluate and selectively acquire programs, technologies, product candidates and/or companies with high-quality assets or partnerships that align with our strategic objectives. By applying our scientific expertise, development capabilities, and

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operational efficiencies, we seek to enhance asset value and generate new royalty streams. In evaluating acquisition opportunities, we consider multiple factors, including:

•Strategic fit;

•Royalty potential;

•Differentiated assets or platform;

•Potential to address an unmet medical need;

•Adequate intellectual property protection; and

•Favorable cash or tax attributes.

Royalty and Milestone Opportunities

Zanidatamab (Ziihera)

We maintain a portfolio of partnered programs that leverage our technology platforms and scientific expertise while enabling risk-sharing and the potential for near-term milestone and royalty-based returns.

Zanidatamab, our first internally developed product candidate to receive regulatory approval, illustrates the execution of this partnership-based approach. Ziihera (zanidatamab-hrii), a bispecific antibody targeting HER2-expressing tumors developed using our Azymetric platform, has demonstrated positive late-stage clinical results and achieved regulatory approvals for the treatment of HER2-positive (“HER2+”) (IHC 3+) biliary tract cancer (“BTC”) in multiple jurisdictions including the United States, China, Europe and Canada. We have entered into separate collaboration and license agreements with BeOne Medicines Ltd. (formerly BeiGene, Ltd. and, together with its affiliates, “BeOne”) and Jazz Pharmaceuticals Ireland Limited, a subsidiary of Jazz Pharmaceuticals plc (collectively with their affiliates, “Jazz”), granting each partner exclusive rights to develop and commercialize zanidatamab in different territories. Jazz intends to complete the supplementary biologic license application (“sBLA”) submission for zanidatamab in the first quarter of 2026 for the treatment of first-line HER2+ locally advanced or metastatic gastroesophageal adenocarcinoma (“GEA”) under the real-time oncology review program in the United States, where zanidatamab has been granted Breakthrough Therapy Designation for patients with HER2+ GEA. Additionally, zanidatamab is currently being evaluated in multiple global clinical trials for treatment of broader HER2-expressing indications including neoadjuvant populations, breast cancer, and other HER2-expressing cancers. Our partnerships with Jazz and BeOne reflect our strategy of advancing internally discovered programs through collaborations that share development risk while preserving the potential for long-term royalty and milestone revenues.

In addition to $53.0 million already received for regulatory approval of Ziihera in BTC, we are entitled to receive up to $440.0 million in near-term milestone payments from Jazz and BeOne related to approvals of Ziihera in GEA in the United States, Europe, Japan and China as follows: U.S. - $250.0 million; EU - $100.0 million; Japan - $75.0 million; China - $15.0 million. We also expect that royalty revenue from Ziihera sales will increase as potential regulatory approvals are obtained in global markets for GEA.

We also have the potential to receive milestone payments related to future regulatory approvals in a third indication totaling $89.0 million, collectively, from Jazz and BeOne. For Jazz this includes a $50.0 million milestone payment upon regulatory approval of zanidatamab from the FDA in a third indication and a $25.0 million milestone payment upon regulatory approval of zanidatamab from the European Commission in a third indication. For BeOne this includes $4.0 million payable upon first patient dosed with zanidatamab in a third registrational study in the territory and $10.0 million upon approval of zanidatamab by a regulatory authority for the third indication in the territory.

In addition, we could be eligible to receive future commercial milestones and increased royalties as additional indications of Ziihera are developed, approved and commercialized by Jazz and BeOne. Under our collaboration agreement with Jazz, we are eligible to receive tiered royalties of ten to high teens percentages on global (outside of Asia (other than Japan), Australia and New Zealand) annual net sales of Ziihera up to $2.0 billion and 20% on annual net sales above $2.0 billion. Under the collaboration agreement with BeOne, we are eligible to receive tiered royalties of mid-single to mid-double digit percentages on annual net sales of Ziihera in Asia (other than Japan), Australia and New Zealand up to $1.0 billion and 19.5% on annual net sales above $1.0 billion (with royalty rates increasing by 0.5% when cumulative amounts forgone as a result of a royalty reduction of 0.5% reaches a cap in the low double-digit millions of dollars).

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Pasritamig (JNJ-78278343)

Pasritamig is a first-in-class, bispecific T cell engager (“TCE”) targeting human kallikrein 2 (“KLK2”), and was engineered using Zymeworks’ Azymetric platform. Pasritamig has demonstrated promising safety and antitumor activity in Phase 1 clinical trials. In September 2025, Johnson & Johnson Innovative Medicine (formerly Janssen Inc., “J&J”) announced the initiation of multiple Phase 3 clinical trials evaluating pasritamig as both monotherapy and in combination regimens in castration resistant prostate cancer.

Platform Partnerships

In 2025, we earned $69.9 million in milestone payments, an option exercise fee and a research period extension fee from collaboration partners Celgene Corporation and Celgene Alpine Investment Co. LLC (now a Bristol-Myers Squibb company, “BMS”), GlaxoSmithKline Intellectual Property Development Limited (“GSK”), Daiichi Sankyo Co., Ltd. (“Daiichi Sankyo”), J&J, Merck Sharp & Dohme Research GmbH (“Merck”), primarily related to legacy platform collaboration agreements, as well as from BeOne related to our zanidatamab collaboration agreement. For additional information regarding these agreements, see the section titled “Strategic Partnerships and Collaborations” below.

Royalty Pharma Loan Arrangement

On March 2, 2026, Zymeworks BC entered into a sale agreement (the “Sale Agreement”) with Zymeworks Royalty Limited Partnership (the “Subsidiary”), a special purpose entity newly formed by Zymeworks BC and by its general partner Zymeworks General Partner ULC (“Zymeworks GP”), under which Zymeworks BC sold to the Subsidiary 30% of future royalty payments (not to exceed 120% of the maximum amount payable (excluding indemnification and other similar obligations) by the Subsidiary under the Loan Agreement (as defined below) related to Ziihera receivable under the Jazz Collaboration Agreement and Zanidatamab Agreement (each as defined below, and together, the “Covered Agreements”) at a purchase price of $250.0 million (such Ziihera-related assets and rights sold to the Subsidiary, the “Royalty Interest”).

Following the sale and transfer of the Royalty Interest, the Subsidiary entered into a Loan Agreement (the “Loan Agreement”), dated March 2, 2026, with Royalty Pharma Development Funding, LLC (“Royalty Pharma”) as administrative agent and lender, pursuant to which the lenders party to the Loan Agreement made a term loan to the Subsidiary (the “Loan”) in an aggregate principal amount of $250.0 million (the “Loan Amount”), that bears interest at a fixed rate and matures on December 31, 2042 (the “Maturity Date”). Under the terms of the Loan Agreement, the amount payable to the lenders no later than the Maturity Date is approximately $481.3 million, provided that if the Loan is repaid in full on or before December 31, 2033, the amount payable to the lenders is $412.5 million, in each case inclusive of all applicable interest, yield protection premiums, early redemption fees, exit fees and other amounts payable under the Loan Agreement (excluding indemnification and similar obligations). Any amount borrowed and repaid by Subsidiary may not be reborrowed.

We will retain 70% of royalties on Ziihera annual net sales, with full royalty rights reverting to us once the Loan and other amounts payable under the Loan Agreement to Royalty Pharma have been repaid in full. All earned regulatory and commercial milestone payments under the Covered Agreements will be retained by us. For additional information regarding this arrangement, see the section titled “Liquidity and Capital Resources” under Part II. Item 7. “Management’s Discussion and Analysis of Financial Condition and Results of Operations” below.

Wholly-Owned Pipeline

Our wholly-owned programs include novel ADC and MSAT candidates, such as TCEs, focusing on highly-expressed targets which provide opportunities for benchmarking in preclinical development and expected clinical differentiation. Our ADC candidates exploit our proprietary topoisomerase 1 inhibitor (“TOPO1i”) payload, ZD06519, while exploring alternate mechanisms of action for longer-term development and leveraging validated peptide-cleavable linkers and stochastic conjugations. With potential for enhanced activity compared to combination therapy, our current MSAT candidates (ZW209 and ZW1528) include trispecific TCEs (“TriTCE”) incorporating conditional co-stimulation to enhance immune-mediated killing of cancer cells, and multi-cytokine blockers for treatment of autoimmune and inflammatory diseases. Our TriTCE molecules are carefully designed to optimize tumor cell engagement and enhance T cell activation to increase anti-tumor activity while also minimizing cytokine release and off-tumor toxicities.

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Solid Tumors in Oncology: Antibody-Drug Conjugates (ADCs)

ZW191: A clinical-stage ADC that targets folate receptor alpha (“FRα”)-expressing tumors including ovarian cancer, endometrial cancer, and non-small cell lung cancer (“NSCLC”), is built using our novel, bystander-active, TOPO1i payload technology, ZD06519. The FRα-targeting monoclonal antibody incorporated in ZW191 was selected based on compelling internalization characteristics to enable targeting of high, mid, and low levels of FRα expression. A drug-antibody-ratio (“DAR”) of eight was selected due to the restricted expression profile of FRα in normal tissues and to enhance our ability to deliver payload to tumors with lower levels of FRα. FRα is a clinically validated target, found in approximately 75% of high-grade serous ovarian carcinomas, 50% of endometrial cancers, and in 70% of NSCLC. Preclinical data demonstrate strong ZW191 activity across a range of FRα-expressing patient-derived xenografts, including models with low levels of FRα. The ability to target lower levels of FRα is in part due to the DAR-eight format and the observed superior internalization, payload delivery, and tissue penetration derived from the ZW191 monoclonal antibody compared to other FRα monoclonal antibodies used in ADCs currently or previously in development. In a good laboratory practices (“GLP”) toxicology study, ZW191 achieved a highest non-severely toxic dose (“HNSTD”) in non-human primates of 60 mg/kg, which presents a compelling profile and enables the expectation of potentially achieving an efficacious dose level in the Phase 1 clinical trial. We are currently recruiting patients in an ongoing global Phase 1, open-label, multicenter study of ZW191, registered under NCT06555744 on clinicaltrials.gov. The study aims to enroll approximately 145 participants with advanced solid tumors, including ovarian, endometrial, and non-small cell lung cancers, across North America, Europe, and the Asia-Pacific region. The study is designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity of ascending doses of ZW191. In October 2025, we presented initial clinical data from the Phase 1 trial. Based on the preliminary efficacy data and the tolerable safety profile observed, we have initiated dose optimization in ovarian cancer to further evaluate ZW191’s clinical activity and safety to help inform the product candidate’s registrational strategy.

ZW251: A potential first-in-class clinical-stage ADC molecule designed for the treatment of glypican 3 (“GPC3”)-expressing hepatocellular carcinoma (“HCC”), incorporates the same Zymeworks proprietary bystander-active TOPO1i payload utilized in ZW191 (anti-FRα) and ZW220 (anti-NaPi2b), ZD06519. The GPC3-targeting monospecific antibody incorporated in ZW251 was selected based on favorable binding and internalization properties to enable targeting of a range of GPC3-expressing tumors. A DAR of four was selected for this program as a lower DAR potentially could unlock a broader range of dose levels, a potential benefit as HCC patients are commonly challenged by impairment of liver function as a result of chronic liver disease and cirrhosis. GPC3, a glycosylphosphatidylinositol (“GPI”)-anchored cell surface oncofetal antigen, is over-expressed in most HCC patients (75%), and displays minimal normal adult tissue expression, making it an appealing ADC target. In preclinical studies, anti-tumor activity for ZW251 was observed in multiple patient-derived xenograft models of HCC reflecting a range of GPC3 over-expression. In GLP toxicology studies performed in non-human primates, ZW251 achieved a highest non-severely toxic dose (“HNSTD”) of 100 mg/kg, suggesting the potential for high doses in humans. We are encouraged by published research demonstrating the potential of targeting GPC3 with an antibody in HCC patients as evidenced by tumor localization of iodine radio-labeled condrituzumab, a clinical-stage anti-GPC3 monoclonal antibody, and believe that ADC-based targeting of GPC3 could enable a novel and effective approach to treatment of HCC. In July 2025, we announced that the investigational new drug (“IND”) application for ZW251 was cleared by the FDA. We are currently recruiting patients in an ongoing global Phase 1, open-label, multicenter study of ZW251, registered under NCT07164313 on clinicaltrials.gov. The study aims to enroll approximately 100 participants with advanced solid tumors, including HCC, across North America, Europe, and the Asia-Pacific region. The study is designed to evaluate the safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity of ZW251.

ZW220: An ADC that targets NaPi2b-expressing NSCLC and ovarian cancer, is built, like ZW191, using our proprietary bystander active TOPO1i payload technology, ZD06519. The strong and persistent bystander effect of the ZD06519 payload that we have observed in preclinical studies may help overcome NaPi2b heterogeneity across different cancers. The NaPi2b-targeting monospecific antibody incorporated in ZW220 was selected based on a favorable binding profile and enhanced internalization properties to enable targeting of both Napi2b-high and NaPi2b-low expressing tumors. Distinct from ZW191, ZW220 utilizes a DAR-four format paired with mutations in the fragment crystallizable (“Fc”) region to attenuate binding to Fc-gamma family receptors. These features were incorporated in ZW220 with the goal of minimizing potential toxicities associated with expression of NaPi2b in normal lung tissue. NaPi2b is expressed in approximately 83% of ovarian (serous) cancer, 81% of endometrial cancer, and 77% of adenocarcinoma NSCLC. Preclinical data demonstrate that ZW220 is active in models of ovarian cancer and NSCLC with strong anti-tumor activity observed in patient-derived xenograft models and growth inhibition observed in three-dimensional spheroid models. ZW220 is tolerated at high doses in non-GLP animal studies with a maximum tolerated dose (“MTD”) ≥90 mg/kg in non-human primates and ≥200 mg/kg in rats, suggesting the potential for high doses in humans. NaPi2b is a compelling ADC target, and we believe the design of ZW220 may overcome some of the challenges encountered with other NaPi2b-targeted ADCs, including Lifa-V, UpRi, and XMT-1592, and may potentially provide a safe and meaningful benefit to patients with NaPi2b-expressing tumors. We have paused the preparations for the

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commencement of a Phase 1 study of ZW220 to help facilitate the accelerated development of ZW251. However, we believe ZW220 remains a highly differentiated, IND-ready asset with strong clinical, commercial, and partnership potential.

Solid Tumors in Oncology: Multispecific Antibody Therapeutics (MSATs)

ZW209: A novel TriTCE targeting Delta-like ligand 3 (“DLL3”)-expressing tumor cells, is designed using our clinically validated Azymetric and EFECT platforms. By leveraging obligate cis-T cell binding and conditional cluster of differentiation 28 (“CD28”) engagement, this potentially first-in-class molecule has been designed to prevent unintended T cell activation, while enabling tumor-targeted cytotoxicity. The innovative design has demonstrated differentiated long-term cytotoxicity in vitro at low E:T (effector to target) ratios, with enhanced T cell proliferation and survival, offering significant potential to increase durability of responses in DLL3-expressing cancers. We expect to submit an IND to commence Phase 1 clinical studies for ZW209 in 2026, with equivalent non-U.S. applications to be submitted thereafter.

Autoimmune and Inflammatory Diseases (AIID)

ZW1528: Our first program in AIID, is a novel IL-4R⍺ x IL-33 bispecific molecule designed to address respiratory inflammation such as mixed-type chronic obstructive pulmonary disease (“COPD”) by inhibiting multiple pathways. By blocking three cytokines (IL-4, IL-13, and IL-33) in a single biologic, ZW1528 offers a unique approach to inhibit clinically validated pathways. The bispecific antibody is designed to provide complete, prolonged IL-4R⍺ blockade with simultaneous blockade of IL-33. Based on non-clinical in vitro studies, the bispecific can independently suppress IL-4, IL-13, and IL-33 driven cell signaling equivalent to that achieved with anti-IL-4R⍺ monoclonal antibody (“mAb”) or anti-IL-33 clinical benchmarks mAbs. Furthermore, in preclinical studies, ZW1528-mediated blockade of cytokine-driven activation of human epithelial cells was superior to that achieved with mAbs targeting either IL-4R⍺ or IL-33, indicating potential benefits of dual blockade. Additionally, preclinical studies with human peripheral blood mononuclear cells (“PBMCs”) demonstrate ZW1528 provides blockade of IL-33 mediated effects beyond that achievable with an anti-IL33 benchmark mAb. With native Immunoglobulin G (“IgG”)-like geometry, ZW1528 demonstrates the potential for high manufacturability and incorporates half-life extending Fc modifications. We expect to submit a non-U.S. regulatory filing to commence Phase 1 clinical studies for ZW1528 in 2026.

Continued Pipeline Development

Going forward, we currently expect to focus our ADVANCE research efforts primarily on multispecific antibody and engineered-cytokine platforms. We anticipate that these activities will be partially supported through early-stage partnerships and collaborations. ZW1528 is currently expected to be the first ADVANCE program to enter clinical studies in 2026. We also intend to continue disseminating scientific findings through peer-reviewed publications and data presentations across our preclinical and clinical programs, as appropriate.

With respect to our ADC portfolio, we currently expect to continue conducting Phase 1 clinical studies for ZW191 and ZW251 during 2026. We also intend to advance our other ongoing ADC research programs, including potential clinical development of ZW220, ZW327, and ZW418, a biparatopic PTK7-targeting ADC incorporating a novel pan-RAS inhibitor payload, only if and when partnerships, collaborations, and/or other sources of external funding become available.

We intend to continue innovating with increased novelty in targets and unique mechanisms of action through bispecific or biparatopic ADCs, dual-payload ADCs, multi-specific immune cell engagers and immune-oncology, subject to strategic priorities, and the availability of resources.

Our Proprietary Therapeutic Platforms

Our expertise in protein engineering has enabled the development of our proprietary therapeutic platforms, a complementary suite of highly tailored biologics solutions. Our therapeutic platforms can be used alone or in combination to develop multifunctional fit-for-purpose biotherapeutics with bispecific capabilities (Azymetric), targeted cytotoxin payload delivery and linker technologies (drug conjugate platforms), finely tuned immune function modulation (EFECT), and tumor-specific immune co-stimulation (ProTECT). The modular design and ease of use of our therapeutic platforms allow for the design and evaluation of multiple candidates with different formats to determine the optimal therapeutic combination early in development. We continue to leverage these therapeutic platforms to expand our pipeline of next-generation multispecific and ADCs that we believe could represent significant improvements to the standard of care in multiple cancer types and other serious diseases.

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Azymetric Multispecific Antibody Platform

The Azymetric multispecific antibody platform is our foundation platform, which can produce either the backbone of our ADCs or be the base of our multispecific therapeutics that can be combined with both our TriTCE technology and our ProTECT platform to develop potential best-in-class trispecifics. The FDA approval of zanidatamab in 2024 provides validation of our proprietary Azymetric technology and capabilities for design and development of novel medicines. The Azymetric platform consists of a library of proprietary amino acid substitutions that enable the transformation of monospecific antibodies into bispecific or trispecific antibodies, which gives them the ability to simultaneously bind two non-overlapping epitopes. The Azymetric platform enables the development of biotherapeutics with dual-targeting of receptors/ligands and simultaneous blockade of multiple signaling pathways, increasing tumor-specific targeting and efficacy while reducing toxicities and the potential for drug resistance. In preclinical studies, the dual targeting of Azymetric antibodies has demonstrated synergistic activity relative to the application of an equivalent dose of the corresponding monospecific antibodies. Azymetric multispecifics can also be engineered to enhance internalization of the antibody into the tumor cell and consequently increase the delivery of cytotoxins. Azymetric multispecifics retain the desirable drug-like qualities of monoclonal antibodies, including long half-life, stability and low immunogenic potential, which increases their probability of success. Azymetric multispecifics are also compatible with standard manufacturing processes with high production yields and purity.

The Azymetric platform is the foundation for the development of trispecific and trivalent antibodies. Our complementary suite of technologies can incorporate multiple targets and mechanisms of action within a single antibody-based therapeutic. To achieve efficacy and durability in a difficult tumor microenvironment, we have developed a TriTCE strategy that integrates checkpoint inhibition (“TriTCE-CPI”) and costimulatory technologies (“TriTCE-costim”). TriTCE-CPI technology is designed to navigate suppressive tumor microenvironments and enhance the activity of TCEs through incorporation of a checkpoint pathway binder to restore and enhance T cell engagement and overcome secondary resistance to provide durable responses. TriTCE-costim technology can increase T cell fitness, activation and proliferation via tumor-dependent T cell co-stimulation. Further, TCE technologies can integrate with ProTECT, a technology built to mask an antibody arm to improve selectivity to minimize off-target, and mitigate on-target, adverse events.

Drug Conjugate Platforms

Our drug conjugate platforms are a suite of proprietary cytotoxins (including both topoisomerase and microtubulin inhibiting toxins), stable linkers, and conjugation technologies that are compatible with and complementary to our product candidates and enable delivery of cytotoxins directly to target cells. We believe that our platforms provide multiple competitive advantages over existing ADC approaches, including optimized activity and tolerability profiles through increased drug delivery to target cells with reduced off-target effects, as well as improved pharmacokinetics and stability. Our drug conjugate platforms can be used in conjunction with our other therapeutic platforms to potentially increase safety and efficacy as compared to existing ADC platforms.

Our TOPO1i ADC platform is one of several proprietary Zymeworks linker-payload platforms. TOPO1i-based technologies have shown meaningful clinical benefit in a wide range of solid tumors, including hard-to-treat solid tumors, and have been validated across many targets. Our novel camptothecin ZD06519 (FD1) has been specifically designed for its application as an ADC payload. A panel of camptothecin analogs with different substituents at the C-7 and C-10 positions of the camptothecin core were prepared and tested in vitro. Selected compounds spanning a range of potency and hydrophilicity were elaborated into drug-linkers, conjugated to trastuzumab, and evaluated in vitro and in vivo. ZD06519 was selected based on its favorable properties as a free molecule and as an antibody conjugate, which include moderate free payload potency (~1 nanomolar (“nM”)), low hydrophobicity, strong bystander activity, robust plasma stability, and high-monomeric ADC content. When conjugated to different antibodies using a clinically validated MC-GGFG-based linker, ZD06519 demonstrated impressive efficacy in multiple cell-derived xenograft models and noteworthy tolerability in healthy mice, rats, and non-human primates.

EFECT Antibody Effector Function Modulation Platform

The EFECT platform consists of sets of modifications to the Fc region of antibodies that enable the selective modulation of recruited cytotoxic immune cells for diverse therapeutic applications. This allows us to rationally tailor the selective enhancement or suppression of immune effector function to optimize product candidates.

ProTECT Tumor-Specific Immune Co-stimulation Platform

The ProTECT platform is a novel conditionally active antibody technology that can simultaneously increase the tolerability and efficacy for therapeutics, thereby potentially enhancing therapeutic window and clinical utility. Functional, natural

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immunomodulatory heterodimers are introduced to sterically block antigen binding outside the tumor, enabling therapeutics with limited activity in normal healthy tissue, avoiding on-target, off-tumor toxicities. Once in the tumor microenvironment, specific proteases cleave and release one half of the functional block activating both the targeting antibody and the immunomodulatory function. The resulting activated multifunctional therapeutic enables immune modulation in concert with antigen binding, which enables an overall increase in the therapeutic window through selective tumor activity and enhanced potency.

Strategic Partnerships and Collaborations

Our novel product candidates, together with our combination of proprietary protein engineering capabilities and resulting therapeutic platform technologies, have enabled us to enter into a number of strategic partnerships, many of which were subsequently expanded in scope. Our strategic partnerships and collaborations provide us with the ability to accelerate clinical development of our product candidates in certain geographical regions and provide our strategic partners with access to components of our proprietary therapeutic platforms for their own therapeutics development. In addition, these strategic partnerships have provided us with non-dilutive funding as well as access to proprietary therapeutic assets, which increase our ability to rapidly advance our product candidates while maintaining commercial rights to our own therapeutics.

Through collaboration agreements with Jazz and BeOne relating to our programs for zanidatamab and zanidatamab zovodotin, we have received an aggregate of $491.0 million through December 31, 2025 in the form of non-refundable upfront payments and milestone payments. In addition, through these partnerships with Jazz and BeOne with respect to zanidatamab, as of December 31, 2025, we remain eligible to receive up to $1.51 billion in potential regulatory, development and commercial milestone payments, as well as tiered royalties on potential future product sales, pending receipt of applicable regulatory approvals.Under our collaboration agreement with Jazz, we are eligible to receive tiered royalties of ten to high teens percentages on global (outside of Asia (other than Japan), Australia and New Zealand) annual net sales of Ziihera up to $2.0 billion and 20% on annual net sales above $2.0 billion. Under the collaboration agreement with BeOne, we are eligible to receive tiered royalties of mid-single to mid-double digit percentages on annual net sales of Ziihera in Asia (other than Japan), Australia and New Zealand up to $1.0 billion and 19.5% on annual net sales above $1.0 billion (with royalty rates increasing by 0.5% when cumulative amounts forgone as a result of a royalty reduction of 0.5% reaches a cap in the low double-digit millions of dollars).

These partnerships have provided us with a significant source of non-dilutive funding and provide for additional future direct funding by our strategic partners for our lead asset, zanidatamab. These partnerships also leverage our strategic partners’ commercial infrastructure, helping accelerate the development and expanding the potential reach of our lead product candidates.

The information included in the table below presents a summary of key aspects of our collaboration and licensing agreements as of December 31, 2025.

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(1) Current stage and therapeutic indication reflects the current preclinical, clinical or commercial stage of development for the most advanced program under the partnership, as applicable.

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(2) Figures reflect all potential future milestone payments under the applicable agreement, including, but not limited to, the lead asset. See further discussion of each partnership below.

(3) Tiered royalties of up to 19.5% of annual net sales in BeOne territories, increasing to up to 20% when cumulative amounts forgone as a result of a royalty reduction of 0.5% reaches a cap in the low double-digit millions of dollars.

Product Partnerships

Jazz

In October 2022, we entered into a license and collaboration agreement with Jazz (“Original Jazz Collaboration Agreement”; as amended in April 2023, “Amended Jazz Collaboration Agreement” and collectively with the Original Jazz Collaboration Agreement, the “Jazz Collaboration Agreement”). Under the Jazz Collaboration Agreement, Jazz is solely responsible for all development and commercialization rights for zanidatamab throughout the world, excluding existing Asia-Pacific territories (other than Japan) already governed by Zymeworks BC Inc.’s (“Zymeworks BC”) agreement with BeOne (“Territory”).

As part of our collaboration, we granted to Jazz certain exclusive and non-exclusive licenses, under our intellectual property, to research, develop, manufacture, and commercialize pharmaceutical products containing or incorporating zanidatamab or certain related antibodies excluding ADCs (such antibodies, collectively, “Licensed Antibodies,” and such pharmaceutical products, “Licensed Products”).

Jazz also granted us certain licenses, under Jazz’s intellectual property, to develop, commercialize, and manufacture the Licensed Antibodies and Licensed Products including to make and have made such antibodies for incorporation into zanidatamab zovodotin for development and commercialization purposes.

During the Term (as defined below), Jazz and its affiliates are prohibited from performing any clinical development of, or commercialization of, any pharmaceutical product containing a bispecific antibody directed to the ECD2 and ECD4 domains of HER2 in the Territory, other than Licensed Products. During the Term, Zymeworks BC and its affiliates are prohibited from (i) performing any preclinical development (except for certain independent, internal preclinical development by Zymeworks BC or its affiliates) or clinical development of, or commercializing, any pharmaceutical product that is directed to HER2 in the Territory (each, a “Zymeworks Competing Product”), other than Licensed Products and (ii) using clinical data resulting from certain clinical trials regarding zanidatamab that were being conducted or initiated by Zymeworks BC (the “Program”) to perform any pre-clinical development or clinical development, or commercialization of, any pharmaceutical product that is directed to HER2; provided that zanidatamab zovodotin is excluded from each restriction. Zymeworks BC retains the right to grant third parties rights to apply any of Zymeworks BC’s platforms to derive or generate, without any assistance from Zymeworks BC, antibodies directed to any biological target where Zymeworks BC is not aware of the identity of any such target, and Zymeworks BC retains the right to fulfill its obligations under agreements with its existing platform partners; provided, however, that Zymeworks BC cannot generate, or grant development or commercialization licenses to, Zymeworks Competing Products in new platform-based agreements entered into after the effective date of the Original Jazz Collaboration Agreement.

Jazz is required to use commercially reasonable efforts to develop and obtain regulatory approval for a Licensed Product in certain major market countries for the treatment of certain diseases. Jazz will be the holder of regulatory approvals and regulatory submissions for Licensed Products in the Territory.

Zymeworks BC will continue to supply zanidatamab and Licensed Product to certain clinical sites pursuant to the terms of the Jazz Collaboration Agreement.

Zanidatamab (Ziihera) received accelerated approval from the FDA in November 2024 for the treatment of adults with previously treated, unresectable or metastatic HER2+ (IHC 3+) BTC. Jazz is conducting the confirmatory trial for Ziihera related to the accelerated approval. In July 2025, Zymeworks’ partner, Jazz, announced that the European Commission granted conditional marketing authorization of zanidatamab for the treatment of adults with unresectable locally advanced HER2+ (IHC 3+) BTC. In January 2026, the New Drug Submission for Ziihera was approved by Health Canada for the treatment of adults with previously treated, unresectable locally advanced or metastatic HER2+ (IHC 3+) BTC, as monotherapy. Ziihera’s market authorization in Canada has been issued with conditions, pending the results of trials to verify its clinical benefit. Our strategic partner Jazz expects to complete the sBLA submission for zanidatamab in the first quarter of 2026 for first-line HER2+ locally advanced or metastatic GEA under the real-time oncology review program in the United States, where zanidatamab has been granted Breakthrough Therapy Designation for patients with HER2+ GEA.

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Jazz is solely responsible for commercializing the Licensed Products in the Territory and is required to use commercially reasonable efforts to commercialize in each specified major market country each Licensed Product that obtains regulatory approval in such country. Jazz is required to conduct such commercialization at its sole cost and expense. Under the Jazz Collaboration Agreement, as of December 31, 2025 we have received (i) a non-refundable $50.0 million upfront payment following receipt of HSR Clearance and delivery of licenses and technology transfer to Jazz, (ii) a further payment of $325.0 million following Jazz’s decision to continue the collaboration after readout of the top-line clinical data from HERIZON-BTC-01, in addition to our delivery of other data, analyses and other information, and (iii) a milestone payment of $25.0 million in relation to FDA approval of Ziihera (zanidatamab-hrii) for the treatment of HER2+ BTC. As of December 31, 2025, we remain eligible to receive up to an aggregate of $500.0 million in certain regulatory milestones payments and up to an aggregate of $862.5 million in potential commercial milestone payments. We are also eligible to receive tiered royalties between 10% and 20% on annual net sales of Licensed Products in the Territory, with customary reductions in specified circumstances. Royalties are payable on a Licensed Product-by-Licensed Product and country-by-country basis until the latest of (i) ten years after the first commercial sale of such Licensed Product in such country, (ii) the expiration of the last valid licensed patent claim within certain Zymeworks BC intellectual property covering such Licensed Product in such country, and (iii) the expiration of regulatory exclusivity of such Licensed Product in such country. The term of the Amended Jazz Collaboration Agreement will continue on a Licensed Product-by-Licensed Product and country-by-country basis until the expiration of the royalty term for such Licensed Product in such country (the “Term”). The Amended Jazz Collaboration Agreement contains customary termination rights for Jazz and us, including the right for Jazz to terminate the agreement in its sole discretion with advance notice to us. We may also terminate the Amended Jazz Collaboration Agreement if Jazz or its affiliates file or initiate a patent challenge against us.

In May 2023, we also entered into a stock and asset purchase agreement with Jazz Pharmaceuticals, Inc. (“Jazz Inc.”) (as amended, the “Transfer Agreement”) to provide for a series of steps designed to simplify, focus, and potentially expedite the clinical development and commercialization of zanidatamab in partnership with Jazz Inc. by transferring certain assets, contracts and employees associated with the clinical trials for zanidatamab to Jazz Inc. and its affiliates.

Pursuant to the Transfer Agreement, at the closing thereunder, (i) Jazz acquired from Zymeworks Biopharmaceuticals Inc. (“ZBI”) 100% of the issued and outstanding capital stock of Zymeworks Zanidatamab Inc. (“ZZI,” a subsidiary of ZBI); (ii) Jazz engaged certain Zymeworks BC and ZZI employees associated with the development of zanidatamab, and the Company transferred to Jazz or one of its affiliates contracts with respect to the engagement of certain independent contractors of Zymeworks BC and ZBI that worked on the Program; (iii) Jazz and its affiliates acquired from Zymeworks BC and ZBI and their affiliates the Acquired Assets (as defined in the Transfer Agreement); and (iv) Jazz and its affiliates assumed certain liabilities arising following the closing under the Transfer Agreement related to the Acquired Assets and the Program, including with respect to the transferred service providers, in each case subject to the terms and conditions of the Transfer Agreement. No shares of the Company’s common stock were sold by the Company or acquired by Jazz Inc. and its affiliates in connection with such transactions under the Transfer Agreement.

BeOne

In November 2018, we entered into agreements with BeOne whereby we granted BeOne royalty-bearing exclusive licenses for the research, development, and commercialization of zanidatamab and zanidatamab zovodotin in Asia (excluding Japan but including the People’s Republic of China, South Korea and other countries), Australia, and New Zealand (such agreement relating to zanidatamab, as amended or modified, the “Zanidatamab Agreement,” and such agreement relating to zanidatamab zovodotin, the “Zovodotin Agreement”). In September 2023, Zymeworks BC and BeOne entered into a termination agreement relating to the Zovodotin Agreement (the “Termination Agreement”).

For the research, development and commercialization licenses to zanidatamab and zanidatamab zovodotin, we received an upfront payment of $40.0 million. Under the Zanidatamab Agreement, as of December 31, 2025 we have received milestone payments of $51.0 million, including $28.0 million in milestone payments received from BeOne in relation to the acceptance by the Center for Drug Evaluation (“CDE”) of the National Medical Products Administration (“NMPA”) in China of the BLA for zanidatamab for second-line treatment of HER2+ BTC and subsequent approval of this BLA. As of December 31, 2025, we remain eligible to receive development and commercial milestone payments of up to $144.0 million, together with tiered royalties of up to 19.5% of annual net sales in BeOne territories, increasing to up to 20% when cumulative amounts forgone as a result of a royalty reduction of 0.5% reaches a cap in the low double-digit millions of dollars. In May 2025, BeOne announced that the NMPA in China granted conditional approval of zanidatamab for the treatment of patients with previously treated, unresectable or metastatic HER2+ (IHC3+) BTC. Under the Zanidatamab Agreement, Zymeworks and BeOne are collaborating on certain global clinical studies and both Zymeworks and BeOne will independently conduct other clinical studies in their own respective territories. Each of Zymeworks and BeOne are responsible for all of the development and commercialization costs in

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their own territories. Unless earlier terminated, the Zanidatamab Agreement will terminate on a licensed product-by-product and country-by-country basis upon the expiration of the royalty term in such country for such licensed product. The Zanidatamab Agreement may be terminated by BeOne upon prior written notice or by either party upon the other party’s bankruptcy or uncured material breach.

As noted above, the Zovodotin Agreement was terminated under the Termination Agreement. The Termination Agreement does not relieve us or BeOne from obligations under the Zovodotin Agreement that accrued prior to the termination and certain other provisions expressly indicated to survive the termination, including certain licenses to BeOne intellectual property with respect to zanidatamab zovodotin.

Platform Partnerships

In addition to the payments we have received through our collaboration agreements with Jazz and BeOne relating to zanidatamab and zanidatamab zovodotin, as of December 31, 2025, we have received $233.4 million in the form of non-refundable upfront and milestone payments from platform partnership and collaboration agreements. We continue to have revenue-generating strategic partnerships and collaborations with respect to our Azymetric, EFECT and drug conjugate therapeutic platforms with the following pharmaceutical companies: BMS, GSK, Daiichi Sankyo, J&J, and Merck. As of December 31, 2025, we remain eligible to receive up to $0.98 billion in preclinical and development milestone payments and up to $3.08 billion in commercial milestone payments, as well as tiered royalties on potential future product sales, pending regulatory approval. It is possible, however, that our strategic partners’ programs will not advance as currently contemplated, which would negatively affect the amount of development and commercial milestone payments and royalties on potential future product sales we may receive. Importantly, these partnerships include predominantly non-target-exclusive licenses for any of our therapeutic platforms, so we maintain the ability to develop therapeutics directed to many high-value targets using our platforms.

BMS

In December 2014, we entered into a collaboration agreement with Celgene (now BMS) to research, develop and commercialize bispecific antibodies generated through the use of our Azymetric platform. This agreement was expanded in 2018 to increase the number of programs from eight to ten and to extend BMS’s research period. Under the terms of the agreement, we granted BMS a right to exercise options to worldwide, royalty-bearing, antibody sequence pair-specific exclusive licenses to research, develop and commercialize certain licensed products. We received an upfront payment of $8.0 million and an expansion fee of $4.0 million. As of December 31, 2025, BMS had exercised two commercial license options and we have received $15.0 million of option payments in total, but in 2023 BMS stopped development of one program. BMS’s right to exercise options on eight programs expired in 2024 after the conclusion of BMS’s research period. As at December 31, 2025, we remain eligible to receive up to $313.0 million for the two remaining programs (or $156.5 million not including the one program for which BMS stopped development in 2023), comprised of development milestone payments of up to $101.5 million per program and commercial milestone payments of up to $55.0 million per program. In addition, we are eligible to receive tiered royalties calculated upon the global net sales of the resulting products. BMS will have exclusive worldwide commercialization rights to products derived from the agreement for those product candidates that BMS elected to exercise its commercial license option. As BMS’s research period has concluded, BMS is solely responsible for the research, development, manufacturing and commercialization of the products.

In June 2020, our existing collaboration agreement with BMS was amended to expand the license grant to include the use of our EFECT platform for the development of therapeutic candidates and to extend the research term. We received an upfront expansion fee of $12.0 million and all other financial terms were unchanged.

The agreement contains customary termination rights for BMS and us, including the right of BMS to terminate the agreement in its entirety or on a product-by-product basis in its sole discretion with advance notice to us. The agreement will terminate on a product-by-product and country-by-country basis upon the later of the expiration of the last-expiring patent related to the BMS licensed product, or ten years after the first commercial sale of the BMS licensed product in such a country. If BMS does not exercise its option for the commercial license, the agreement will terminate on a product-by-product basis for which the option was not exercised.

GSK

In December 2015, we entered into a collaboration and license agreement with GSK to research, develop and commercialize up to ten Fc-engineered monoclonal and bispecific antibodies generated through the use of our EFECT and Azymetric platforms.

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Under the terms of the agreement, we granted GSK a worldwide, royalty-bearing antibody target-exclusive license to new intellectual property generated with the EFECT platform under this collaboration and a non-exclusive license to the Azymetric platform to research, develop and commercialize future licensed products. We are eligible to receive up to $1.1 billion, including research, development and commercial milestone payments of up to $110.0 million for each product. In addition, we are eligible to receive tiered royalties in the low single digits on net sales of products. No development or commercial milestone payments or royalties have been received as of December 31, 2025. We retained the right to develop up to four products, free of royalties, using the new intellectual property generated in this collaboration, and after a period of time, to grant licenses to such intellectual property for development of additional products by third parties. Under this agreement, we are sharing certain research and development responsibilities with GSK to generate new Fc-engineered antibodies. Each party will bear its own costs for the responsibilities assigned to it during the research period. After the conclusion of the research period, each party will be solely responsible for the further research, development, manufacturing and commercialization of its own respective products. The agreement contains customary termination rights for GSK and us, including the right for GSK to terminate the agreement in its sole discretion with advance notice to us. The agreement will terminate on the earlier of (i) the end of the research period if GSK does not elect to advance one or more products incorporating intellectual property generated under the research period for further research and development or (ii) on a product-by-product and country-by-country basis upon the latter of the product being no longer covered by a patent related to the GSK licensed product, or ten years after the first commercial sale of the GSK licensed product in such a country.

In April 2016, we entered into a platform technology transfer and license agreement with GSK to research, develop and commercialize up to six bispecific antibodies generated through the use of our Azymetric platform. This may include bispecific antibodies incorporating new engineered Fc regions generated under the 2015 GSK agreement. Under the terms of this 2016 agreement, we granted GSK a worldwide, royalty-bearing antibody sequence pair-specific exclusive license to research, develop and commercialize licensed products. In May 2019, this agreement was expanded to provide GSK access to Zymeworks’ unique heavy-light chain pairing technology under the Azymetric platform. Under the expanded agreement, we are eligible to receive up to $1.1 billion in milestone and other payments. As of December 31, 2025, we have received an upfront technology access fee payment of $6.0 million and $16.5 million of milestones in total. As of December 31, 2025, we remain eligible to receive research milestone payments of up to $35.0 million, development milestone payments of up to $168.5 million and commercial milestone payments of up to $867.0 million. In addition, we are eligible to receive tiered royalties in the low to mid-single digits on product sales. GSK bears all responsibility and costs associated with research, development and commercialization of products generated using the Azymetric platform. The agreement contains customary termination rights for GSK and us, including the right for GSK to terminate the agreement in its sole discretion with advance notice to us. Termination provisions allow for GSK to terminate the agreement or specific antibody sequence pairs due to an incurable material breach by us, and under specific conditions, GSK shall have certain rights to continue the research, development, and commercialization of products with their license payment, milestone, and royalty obligations reduced by 50%.

Daiichi Sankyo

2016 Agreement

In September 2016, we entered into a collaboration and cross-license agreement (“Collaboration and Cross License Agreement”) with Daiichi Sankyo to research, develop and commercialize one bispecific antibody generated through the use of our Azymetric and EFECT platforms. Under this agreement, we received an upfront technology access fee payment of $2.0 million and research and commercial option related payments totaling $4.5 million. Under this agreement, we also gained non-exclusive rights to develop and commercialize up to three products (revised to up to six products pursuant to a June 2022 amendment) using Daiichi Sankyo’s proprietary immune-oncology antibodies, with royalties in the low single digits to be paid to Daiichi Sankyo on sales of such products.

In March 2023, we entered into a termination and license agreement (the “Termination and License Agreement”) relating to the Collaboration and Cross License Agreement. Pursuant to the Termination and License Agreement, the Collaboration and Cross License Agreement is terminated and is no longer in effect, except that the termination does not relieve the parties from obligations under the Collaboration and Cross License Agreement that accrued prior to the termination or were expressly intended to survive. Among the rights to survive the termination of the Collaboration and Cross License Agreement are Zymeworks’ non-exclusive royalty-bearing rights to develop and commercialize products using Daiichi Sankyo’s proprietary immune-oncology antibodies. Under the Termination and License Agreement, we granted to Daiichi Sankyo a non-exclusive, worldwide, royalty-free right and license, with the right to sublicense, to certain intellectual property to perform additional research in accordance with the terms of the Termination and License Agreement during the term of the Termination and License Agreement, which expired in August 2025. The Termination and License Agreement has no impact on our separate license agreement with Daiichi Sankyo, which we entered into in 2018, as described below.

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2018 Agreement

In May 2018, we entered into a license agreement with Daiichi Sankyo to research, develop and commercialize two bispecific antibodies generated through the use of our Azymetric and EFECT platforms. This agreement did not alter or amend the initial 2016 agreement. Under the terms of this 2018 agreement, we granted Daiichi Sankyo a worldwide, royalty-bearing, antibody sequence pair-specific, exclusive license to research, develop and commercialize certain products, and we were eligible to receive up to $484.7 million in various milestone and other payments. As of December 31, 2025, we have received an upfront technology access fee payment of $18.0 million, and $3.1 million in development milestone payments. We remain eligible to receive development milestone payments totaling up to $60.3 million and commercial milestone payments of up to $170.0 million. In addition, we are eligible to receive tiered royalties ranging from the low single digits up to 10% on product sales. Daiichi Sankyo is solely responsible for the research, development, manufacturing and commercialization of the products. The agreement contains customary termination rights for Daiichi Sankyo and us, including the right for Daiichi Sankyo to terminate the rights to our therapeutic platforms in its sole discretion with advance notice to us. The agreement will terminate, with respect to Daiichi Sankyo’s licenses, on a product-by-product basis, with the last payment obligation for the respective product.

J&J

In November 2017, we entered into a collaboration and license agreement with J&J to research, develop and commercialize up to six bispecific antibodies generated through our Azymetric and EFECT platforms. Under the terms of the agreement, we granted J&J a worldwide, royalty-bearing, antibody sequence group-specific exclusive license to research, develop and commercialize certain products, and we were eligible to receive up to $1.45 billion in various license and milestone payments.

As of December 31, 2025, we have received an upfront payment of $50.0 million and development milestones totaling $33.0 million, which included $8.0 million in connection with the initiation of clinical trials of two bispecific antibodies and $25.0 million related to clinical progress of pasritamig entering into a Phase 3 trial in metastatic castration-resistant prostate cancer. Pasritamig (JNJ-78278343) is a first-in-class, bispecific T-cell engager targeting human kallikrein 2 (KLK2), engineered using Zymeworks’ Azymetric platform. J&J has deprioritized the development of the other bispecific antibody, and in 2023 the research program term under the agreement ended with respect to the remaining four bispecific antibodies.

As a result, we remain eligible to receive up to $18.0 million in additional development milestone payments and up to $186.5 million in commercial milestone payments relating to pasritamig. We remain eligible to receive up to $43.0 million in additional development milestone payments and up to $186.5 million in commercial milestone payments with respect to the other bispecific antibody which has been deprioritized by J&J.

In addition, we are eligible to receive tiered royalties in the mid-single digits on product sales, with the royalty term being, on a product-by-product and country-by-country basis, either (i) for as long as there is Zymeworks platform patent coverage on products, or (ii) for 10 years, beginning from the first commercial sale, whichever period is longer. If there is no Zymeworks patent coverage on products, royalty rates may be potentially reduced. The Company determined that, the events and conditions resulting in payments for research, development and commercial milestones solely depend on J&J’s performance. J&J is solely responsible for the research, development, manufacturing and commercialization of the products. The agreement contains customary termination rights for J&J and us, including the right for J&J to terminate the agreement in its sole discretion with advance notice to us. The agreement will terminate, on a product-by-product basis, on the expiry of the royalty term for the product.

Other Collaborations - Merck

We have collaborated with Merck since 2011. In July 2020, we entered into a new licensing agreement with Merck granting Merck a worldwide, royalty-bearing license to research, develop and commercialize up to three new multispecific antibodies toward Merck’s therapeutic targets in the human health field and up to three new multispecific antibodies toward Merck’s therapeutic targets in the animal health field using our Azymetric and EFECT platforms. We are eligible to receive up to $419.3 million in option exercise fees and clinical development and regulatory approval milestone payments and up to $502.5 million in commercial milestone payments, as well as tiered royalties on worldwide sales.

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Intellectual Property

Our business success will depend significantly on our ability to:

•secure, maintain and enforce patent and other proprietary protection for our core technologies, inventions and know-how;

•obtain and maintain licenses to key third-party intellectual property owned by such third parties;

•preserve the confidentiality of our trade secrets; and

•operate without infringing upon valid, enforceable third-party patents and other rights.

We seek to secure and maintain patent protection for the composition of matter, manufacturing processes and methods of use for our drug candidates and for our underlying protein engineering capabilities and therapeutic platforms including Azymetric, EFECT, ZymeCAD and ProTECT. We also utilize trade secrets, careful monitoring and limited disclosure of our proprietary information where patent protection is not appropriate. We also protect our proprietary information by ensuring that our employees, consultants, contractors and other advisors execute agreements requiring non-disclosure and assignment of inventions prior to their engagement. We intend to continue to expand our intellectual property holdings by seeking patent protection for new compositions of matter, new features and applications of our core therapeutic platforms, and innovative new therapeutic platforms, in the United States and other jurisdictions. We also intend to supplement internal innovation through in-licensing of new technologies and compositions of matter as appropriate. We intend to take advantage of any available data exclusivity, market exclusivity, patent term adjustment and patent term extensions.

We routinely monitor the status of existing and emerging intellectual property disclosed by third parties that may impact our business, and to the extent we identify any such disclosures, evaluate them and take appropriate courses of action.

As of December 31, 2025, our patent portfolio includes more than 30 patent families related to our therapeutic antibody product (zanidatamab), our preclinical, clinical stage, and additional product candidates, and our therapeutic platform technologies. As of December 31, 2025, from these patent families we have more than 275 issued patents, 29 of which are U.S. patents. Additional patent families in our patent portfolio relate to other earlier stage potential product candidates or platforms that we do not consider material to our business at this time.

Therapeutic Antibody Portfolio

Our therapeutic antibody patent portfolio is directed to specific compositions of matter, methods of using and compositions used in manufacturing our approved products and product candidates.

Approved Product

Zanidatamab: As of December 31, 2025, we own U.S. and foreign patents and patent applications directed to compositions of matter of zanidatamab, compositions used in the manufacture of zanidatamab, and methods of using zanidatamab. Issued patents and patent applications, if granted, directed to compositions of matter of zanidatamab are anticipated to expire in 2034, absent any patent term adjustments or extensions. Issued patents and patent applications, if granted, directed to compositions used in the manufacture of zanidatamab are anticipated to expire in 2034, absent any patent term adjustments or extensions. Issued patents and patent applications, if granted, directed to methods of using zanidatamab are anticipated to expire between 2034 and 2042, absent any patent term adjustments or extensions. In January 2025, an application was submitted to the USPTO for the extension of the patent term of U.S. patent number 10,000,576 directed to compositions of matter of zanidatamab. This application is currently under review by the USPTO and FDA.

Zanidatamab is also protected by our patent families directed to Azymetric Fc, as described below.

Clinical Stage Product Candidates

ZW191: As of December 31, 2025, we own a U.S. patent and patent applications filed in the United States and foreign jurisdictions directed to compositions of matter of ZW191, compositions used in the manufacture of ZW191, and methods of using ZW191. If granted, these patent applications are anticipated to expire in 2043, absent any patent term adjustments or extensions. We also own U.S. provisional patent applications directed to additional methods of using ZW191. If converted to non-provisional patent applications and granted, these applications are anticipated to expire in 2046, absent any patent term adjustments or extensions. ZW191 is also protected by a patent family directed to our TOPO1i technology.

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ZW251: As of December 31, 2025, we own patent applications filed in the United States and foreign jurisdictions directed to compositions of matter of ZW251 and methods of using ZW251. If granted, these patent applications are anticipated to expire in 2043, absent any patent term adjustments or extensions. ZW251 is also protected by a patent family directed to our TOPO1i technology.

Lead Preclinical Product Candidates

ZW209: As of December 31, 2025, we own patent applications filed internationally under the Patent Cooperation Treaty (“PCT”) and in foreign jurisdictions directed to compositions of matter of ZW209, compositions used in the manufacture of ZW209, and methods of using ZW209. If granted, these applications are anticipated to expire in 2045, absent any patent term adjustments or extensions. ZW209 is also protected by patent families relating to Azymetric Fc and Azymetric Fab.

ZW1528: As of December 31, 2025, we own patent applications filed internationally under the PCT and in foreign jurisdictions directed to compositions of matter of ZW1528, compositions used in the manufacture of ZW1528 and methods of using ZW1528. If granted, these applications are anticipated to expire in 2045, absent any patent term adjustments or extensions. ZW1528 is also protected by patent families relating to Azymetric Fc and Azymetric Fab.

Additional Product Candidates

ZW220: As of December 31, 2025, we own patent applications filed internationally under the PCT, and in the United States and foreign jurisdictions, directed to compositions of matter of ZW220, compositions used in the manufacture of ZW220, and methods of using ZW220. If granted, these patent applications are anticipated to expire between 2043 and 2044, absent any patent term adjustments or extensions. ZW220 is also protected by a patent family directed to our TOPO1i technology.

ZW327: As of December 31, 2025, we own U.S. provisional patent applications directed to compositions of matter of ZW327, compositions used in the manufacture of ZW327, and methods of using ZW327. If converted and granted, these applications are anticipated to expire in 2046, absent any patent term adjustments or extensions. ZW327 is also protected by a patent family directed to our TOPO1i technology.

Therapeutic Platform Technology Portfolio

Our therapeutic platform technology portfolio includes biological formats and variants thereof, including the Azymetric platform, our drug conjugate platforms (including our TOPO1i technology), the EFECT platform, and specific applications, manufacturing methods and assays related to the platform constructs and underlying computational chemistry.

Azymetric

We own patents and patent applications relating to the Azymetric platform for engineering Fc and Fab constructs for the development of bispecific antibodies.

Azymetric Fc: As of December 31, 2025, we own U.S. and foreign patents and a U.S. patent application directed to our Azymetric Fc platform. Patents and patent applications, if granted, directed to compositions of matter of engineered antibody Fc regions, methods of engineering antibody Fc regions to preferentially form heterodimers, and methods of making heterodimers comprising engineered Fc regions are expected to expire between 2031 and 2033, absent any patent term adjustments or extensions.

Azymetric Fab: As of December 31, 2025, we own U.S and foreign patents and patent applications directed to our Azymetric Fab platform. Patents and patent applications, if granted, directed to compositions of matter, methods of engineering antibody Fabs to preferentially form heterodimers, and methods of making heterodimers comprising engineered Fabs are expected to expire between 2033 and 2036 absent any patent term adjustments or extensions.

Drug Conjugate Platforms

Our drug conjugate platforms are a suite of proprietary cytotoxins (including TOPO1i), stable linkers, and conjugation technologies that are compatible with and complementary to our antibody product candidates and enable delivery of cytotoxins directly to target cells.

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TOPO1i Platform: As of December 31, 2025, we own patent applications filed in the United States and foreign jurisdictions directed to novel TOPO1i compounds (including ZD06519), TOPO1i-linker compositions and antibody-TOPO1i conjugates. If granted, these patent applications are expected to expire in 2042, absent any patent term adjustments or extensions.

EFECT

As of December 31, 2025, we own U.S and foreign patent applications directed to engineering Fc constructs with modulated FcγR-binding and Fc effector function, including compositions of matter and methods of making Fc constructs with altered FcγR-binding and Fc effector function, and compositions of matter and methods of making Fc constructs that lack FcγR-binding. These patent applications, if granted, are expected to expire between 2041 and 2042, absent any patent term adjustments or extensions.

ProTECT

As of December 31, 2025, we own patent applications filed in the United States and foreign jurisdictions and patents in foreign jurisdictions directed to compositions of matter, methods of making and methods of using conditionally active antibody constructs comprising immunomodulatory ligands and their cognate receptors derived from the immunoglobulin superfamily (such as PDL1 and PD1) fused to the antibody variable heavy and light chain region termini. These patents and, if granted, patent applications are expected to expire in 2041, absent any patent term adjustments or extensions.

Computational Chemistry

As of December 31, 2025, we own U.S and foreign patents and patent applications directed to computational and algorithmic advances incorporated into our ZymeCAD platform, including advances in general molecular modeling, conformational dynamics, and computational workflows. These patents and patent applications, if granted, are expected to expire between 2034 and 2042, absent any patent term adjustments or extensions.

Technology Licensing and In-Licensed Intellectual Property

Daiichi Sankyo

As noted above under “Strategic Partnerships and Collaborations – Platform Partnerships – Daiichi Sankyo – 2016 Agreement,” in September 2016, we entered into the Collaboration and Cross License Agreement with Daiichi Sankyo under which we gained non-exclusive rights to develop and commercialize up to three products (up to six products pursuant to a June 2022 amendment) using Daiichi Sankyo’s proprietary immune-oncology antibodies. In March 2023, we entered into the Termination and License Agreement relating to the Collaboration and Cross License Agreement. Pursuant to the Termination and License Agreement, the Collaboration and Cross License Agreement is terminated and is no longer in effect, except that the termination does not relieve the parties from obligations under the Collaboration and Cross License Agreement that accrued prior to the termination or were expressly intended to survive. Among the rights to survive the termination of the Collaboration and Cross License Agreement are Zymeworks’ non-exclusive royalty-bearing rights to develop and commercialize products, such as ZW209, using Daiichi Sankyo’s proprietary immune-oncology antibodies. Under the surviving terms of the Collaboration and Cross License Agreement, pending receipt of regulatory approval, we may be required to make future low single-digit royalty payments on the net sales of such products.

Phanes

In November 2021, we entered into a license agreement with Phanes Therapeutics, Inc. (“Phanes”). Phanes granted Zymeworks an exclusive, worldwide, non-transferable (except in connection with an assignment of the agreement), sublicensable, royalty-bearing license to research, develop, commercialize, and otherwise exploit certain antibody products incorporating proprietary Phanes binders in the field of oncology. In December 2023, this license agreement was partially terminated only with respect to a specific set of such products. All other rights and obligations under this license agreement remain in full force and effect.

Under the license agreement, we may be required to make future payments to Phanes upon the direct achievement of certain clinical development milestones for products, such as ZW251, that incorporate certain Phanes intellectual property. In addition, subject to receipt of regulatory approval, we may be required to make future payments to Phanes upon direct achievement of certain commercial milestones and certain sales milestones, as well as up to low single-digit royalty payments on net sales of such products.

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ProBioGen

In February 2016, we entered into a master services and master license agreement with ProBioGen AG (“ProBioGen”). ProBioGen provided certain development and manufacturing services and granted us a non-exclusive, worldwide, sublicensable license to research, develop, manufacture and commercialize our product candidates (which include Ziihera (zanidatamab-hrii)) using ProBioGen’s platforms, including their proprietary GlymaxX technology for generating afucosylated antibodies. This license includes certain additional non-exclusive patent rights sub-licensed by ProBioGen. Licensing terms include preclinical, clinical and commercial milestones. In connection with the first commercial sale of Ziihera, we paid to ProBioGen €3.95 million for achievement of the first commercial sale milestone, which amount was reimbursed by Jazz. In addition, subject to achievement of certain commercial sales thresholds of Ziihera, we are required to make additional future payments to ProBioGen.

Chugai

In June 2020, we entered into a patent license agreement with Chugai Pharmaceuticals Co., Ltd (“Chugai”). Chugai granted Zymeworks a non-exclusive, worldwide, non-transferable (except in connection with an assignment of the agreement), sublicensable license under certain patents to research, develop, manufacture and commercialize certain antibody products covered by such patents. Under the license agreement, we are required to pay an immaterial annual fee for so long as there is a valid claim within the licensed patents covering certain antibody products.

Manufacturing

We rely on third-party contract manufacturing organizations to provide manufacturing, linker-toxin conjugation, and fill-finish services in order to generate all of the therapeutic antibody supply required for our clinical studies and other research and development activities. To retain focus on our expertise in developing new product candidates, we do not currently plan to develop or operate in-house manufacturing capacity. Our multispecific therapeutic antibody and ADC candidates require standard chemistry, manufacturing and control (“CMC”) processes typical of those required for monoclonal antibody manufacturing. We therefore expect to continue to be able to develop product candidates that can be manufactured in a cost-effective fashion by our network of qualified third-party contract manufacturing organizations.

Through our contract manufacturing organizations, we currently have sufficient supply of our product candidates to carry out ongoing and planned preclinical studies. For zanidatamab, we also have sufficient current good manufacturing practices (“cGMP”)-grade supply to continue ongoing clinical trials. Our strategic partners are responsible for the commercial manufacture of zanidatamab. For our clinical stage product candidates, we have sufficient cGMP-grade supply to complete our ongoing clinical trials.

Competition

The biopharmaceutical industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technology, knowledge, experience and scientific resources provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions and governmental agencies, and public and private research institutions. Any product candidates that we or our strategic partners successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

With respect to our healthcare asset aggregation strategy, we face competition from other companies, funds and other investment vehicles seeking to aggregate royalties or provide alternative financing to biotechnology companies. These competitors may have a lower cost of capital or access to greater amounts of capital and thereby may be able to successfully acquire assets that we are also targeting for acquisitions. There is a limited number of suitable and attractive acquisition or partnering opportunities available in the market, and competition to acquire such assets may be intense.

With respect to target discovery activities, competitors and other third parties, including academic and clinical researchers, may be able to access rare families and identify targets before we do.

Many of the companies against which we compete or against which we may compete in the future have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our

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competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaboration arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites, recruiting patients for clinical trials, and by acquiring technologies complementary to, or necessary for, our programs.

The key competitive factors affecting the success of all of our product candidates, if approved, are likely to be their efficacy, safety, convenience and price, the effectiveness of alternative products, the level of competition and the availability of coverage, and adequate reimbursement from government and other third-party payors.

Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products or therapies that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain FDA, EMA or other regulatory approval for their products more rapidly than we or our strategic partners may obtain approval, which could result in our competitors establishing a strong market position before we or our partnered product candidates are able to enter the market. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic or biosimilar products.

Zanidatamab is being developed for patients with solid tumors that express HER2, including patients with tumors expressing low levels of HER2. Competing approved HER2-targeted therapies include F. Hoffmann-La Roche Ltd.’s Herceptin, Perjeta, Phesgo, and Kadcyla as well as Novartis Pharmaceuticals Corporation’s Tykerb, Puma Biotechnology, Inc.’s Nerlynx, AstraZeneca PLC / Daiichi Sankyo’s Enhertu, Seagen Inc.’s Tukysa, MacroGenics, Inc.’s Margenza, Jiangsu HengRui Medicine Co., Ltd.’s pyrotinib, Pfizer’s disitamab vedotin, Alphamab’s anbenitamab and anbenitamab repodetecan, BioNTech’s trastuzumab pamirtecan, Boehringer’s zongertinib, Bayer’s sevabertinib and various trastuzumab biosimilars, as well as other candidates in late-stage development.

ZW191 is being developed for patients with solid tumors that express FRα. Competing approved FRα -targeted therapies include AbbVie’s Elahere. Key FRα-targeted ADCs under development include Genmab’s Rina-S, AstraZeneca’s AZD5335, Eli Lilly’s sofetabart mipitecan (LY4170156) and AbbVie’s IMGN151 and ABBV901.

ZW251 is being developed for patients with solid tumors that express GPC3. Competing GPC3-targeted ADCs include Lepu/Miracogen’s MRG006 and BioCity’s BC2027. Alternative approaches targeting GPC3 include cell therapies, TCEs, radioconjugates and monoclonal antibodies exemplified by AstraZeneca’s AZD5851 (C-CAR031), Legend Biotech’s LB2101, Sotio’s BOXR1030, Eureka Therapeutics’ ECT204, CARsgen’s CT011; AstraZeneca’s AZD9793 & Keymed’s CM350; BMS’ RYZ801; and Roche’s codrituzumab.

ZW1528 is being developed for patients with respiratory inflammation, targeting IL-4R⍺ and IL-33 receptors. Competing development-stage therapies with a similar profile include AK139, the IL-4Ra/ST2 bispecific from Akeso Bio.

ZW209 is being developed for patients with solid tumors that express DLL3. Competing approved DLL3-targeted therapies include Amgen’s IMDELLTRA (tarlatamab). Key DLL3-targeted TCEs under development include Boehringer Ingelheim’s BI 764532, Merck’s gocatamig (MK-6070, formerly HPN328), Chugai/Roche’s ALPS12 (RG6524), Qilu’s QLS31904 and Zelgen’s alveltamig (ZG006). Alternative approaches targeting DLL3 include ADCs, radioconjugates and bispecific antibodies, such as Zai Labs’ zocilurtatug (ZL-1310), Roche/Innovent’s IBI3009, IDEAYA Biosciences’ IDE849, Phanes Therapeutics’ Peluntamig (PT217) and Abdera’s ABD-147.

The FDA and corresponding regulatory authorities will ultimately review our clinical results and determine whether our product candidates are effective. No regulatory agency has made any such determination that any of our product candidates are effective for use by the general public for any indication.

Government Regulation

Government authorities in the United States, at the federal, state and local level, and in other countries extensively regulate, among other things, the research, development, testing, manufacturing, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, marketing and export and import of products such as those we are developing. Our ADC product candidates are comprised of both a drug product and a biologic product, and will therefore be subject to regulation in the United States as combination products. If marketed individually, each component would be subject to different regulatory pathways and would require approval of independent marketing applications by the FDA. A combination product, however, is assigned to an FDA center that will have primary jurisdiction

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over its regulation based on a determination of the combination product’s primary mode of action, which is the single mode of action that provides the most important therapeutic action. In the case of our ADCs, we believe that the primary mode of action is attributable to the biologic component of the product. Thus, our ADC product candidates are regulated as therapeutic biologics, with the FDA’s Center for Drug Evaluation and Research having primary jurisdiction over premarket development. Our antibody therapeutics, including MSATs, are also regulated as therapeutic biologics by the FDA’s Center for Drug Evaluation and Research.

Biological products are subject to regulation under the Federal Food, Drug, and Cosmetic Act, the Public Health Service Act, and other federal, state, local and foreign statutes and regulations. Our product candidates must be approved by the FDA before they may be legally marketed in the United States and by the appropriate foreign regulatory agency before they may be legally marketed in foreign countries.

U.S. Biological Products Development Process

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

•completion of extensive nonclinical, sometimes referred to as preclinical, laboratory tests and preclinical animal trials and applicable requirements for the humane use of laboratory animals and formulation studies in accordance with applicable regulations, including GLP;

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

•performance of adequate and well-controlled human clinical trials according to the FDA’s regulations commonly referred to as current good clinical practice (“cGCP”) regulations and any additional requirements for the protection of human research subjects and their health information, to establish the safety and efficacy of the proposed biological product for its intended use. The FDA may also impose clinical holds on a biological product candidate at any time before or during clinical trials due to safety concerns or noncompliance. If the FDA imposes a clinical hold, trials may not recommence without FDA authorization and then only under terms authorized by the FDA.

•submission to the FDA of a BLA for marketing approval that includes substantive evidence of safety, purity, and potency from results of nonclinical testing and clinical trials;

•satisfactory completion of an FDA inspection of the manufacturing facility or facilities where the biological product is produced to assess compliance with cGMP requirements to assure that the facilities, methods and controls are adequate to preserve the biological product’s identity, strength, quality and purity;

•potential FDA audit of the nonclinical and clinical study sites that generated the data in support of the BLA; and

•FDA review and approval, or licensure, of the BLA.

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

•Phase 1. The biological product candidate is initially introduced into healthy human volunteers and tested for safety. In the case of some products for severe or life-threatening diseases, especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted in patients.

•Phase 2. The biological product candidate is evaluated in a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance, optimal dosage and dosing schedule.

•Phase 3. Clinical trials are undertaken to further evaluate dosage, clinical efficacy, potency, and safety in an expanded patient population at geographically dispersed clinical study sites. These clinical trials are intended to establish the overall risk/benefit ratio of the product and provide an adequate basis for product labelling.

During all phases of clinical development, regulatory agencies require extensive reporting, monitoring and auditing of all clinical activities, clinical data, and clinical study investigators.

A sponsor, an institutional review board (“IRB”) or independent ethics committee, the FDA or other regulatory or monitoring authorities may suspend a clinical study at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk, failure to conduct the clinical trial in accordance with regulatory requirements or clinical protocols, failure to demonstrate a benefit from using the investigational drug, changes in government regulations or administrative actions.

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Sponsors of clinical trials of FDA-regulated products, including biologics, are required to register and disclose certain clinical trial information, which is publicly available at www.clinicaltrials.gov. Information related to the product, patient population, phase of investigation, study sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are also obligated to submit a summary of the results of their clinical trials after completion of a trial, unless an extension or a certification permitting delayed submission is obtained from the government.

U.S. Review and Approval Processes

After the completion of clinical trials of a biological product candidate, FDA approval of a BLA must be obtained before commercial marketing of the biological product. When a BLA is submitted, the FDA conducts a preliminary review to determine whether the application is sufficiently complete to be accepted for filing. If it is not, the FDA may refuse to file the application and request additional information, in which case the application must be resubmitted with the supplemental information, and review of the application is delayed. Upon accepting the BLA for filing, the FDA will conduct an in-depth review of the BLA and may hold a public hearing where an independent advisory committee of expert advisors considers key questions regarding the product candidate. This advisory committee makes a recommendation to the FDA, which is not binding on the FDA, but is generally followed.

The FDA is authorized to designate certain products for expedited programs if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. In particular, the FDA may designate a product for Fast Track designation if it is intended, whether alone or in combination with one or more other drugs, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track designated products, sponsors may have a higher number of interactions with the FDA and may be eligible for “rolling review” where review of sections of a Fast Track product’s New Drug Application or BLA is initiated before the full New Drug Application or BLA application is complete. The FDA has granted two Fast Track designations to zanidatamab for the first-line treatment of patients with HER2-overexpressing gastroesophageal adenocarcinoma in combination with standard of care chemotherapy and for previously treated or recurrent gene-amplified BTC.

The FDA also may designate a product as a Breakthrough Therapy if it is intended, alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically important endpoints, such as substantial treatment effects observed early in clinical development. For products that have been designated as a Breakthrough Therapy, interaction and communication between the FDA and the sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. The FDA has granted Breakthrough Therapy designation for zanidatamab in HER2 gene-amplified BTC patients who have received prior systemic chemotherapy. Products designated as a Breakthrough Therapy by the FDA can also be eligible for accelerated approval. In December 2022, the Consolidated Appropriations Act, 2023, including the Food and Drug Omnibus Reform Act (“FDORA”), was signed into law. FDORA made several changes to the FDA’s authorities and its regulatory framework, including, among other changes, reforms to the accelerated approval pathway, such as requiring the FDA to specify conditions for post-approval study requirements and setting forth procedures for the FDA to withdraw a product on an expedited basis for non-compliance with post-approval requirements.

Under the Pediatric Research Equity Act, certain applications for approval must include an assessment, generally based on clinical study data, of the safety and effectiveness of the subject drug in relevant pediatric populations. The FDA may waive or defer the requirement for a pediatric assessment, either at a company’s request or by the FDA’s initiative. The FDA may determine that a Risk Evaluation and Mitigation Strategy (“REMS”) is necessary to ensure that the benefits of a new product outweigh its risks. A REMS may include various elements, ranging from a medication guide or patient package insert to limitations on who may prescribe or dispense the drug or other elements to assure safe use, depending on what the FDA considers necessary for the safe use of the drug.

Before approving a BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure that the clinical trials were conducted in compliance with IND study requirements and cGCP requirements.

Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the BLA does not satisfy its regulatory criteria for approval and deny approval. Data obtained from clinical trials are not always conclusive and the FDA

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may interpret data differently than the applicant interprets the same data. If the FDA decides not to approve the BLA in its present form, the FDA will issue a complete response letter that usually describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies identified may be minor (for example, requiring labeling changes) or major (for example, requiring additional clinical trials). Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application. The FDA’s “real time” release of newly issued Complete Response Letters associated with withdrawn or abandoned applications, if applicable to any of our product candidates, can materially impact our competitive advantage and intellectual property.

If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form of a REMS, or otherwise limit the scope of any approval. In addition, the FDA may require post-marketing clinical trials, sometimes referred to as Phase 4 clinical trials, designed to further assess a biological product’s safety and effectiveness, and testing and surveillance programs to monitor the safety of approved products that have been commercialized.

Orphan Drug Designation

The Orphan Drug Act established incentives for the development of drugs intended to treat rare diseases or conditions, which generally are diseases or conditions affecting less than 200,000 individuals in the United States at the time of the request for orphan designation. If a sponsor demonstrates that a drug is intended to treat a rare disease or condition and meets other applicable requirements, the FDA grants Orphan Drug Designation to the product for that use. The FDA has granted zanidatamab Orphan Drug Designation for the treatment of BTC and GEA.

The benefits of Orphan Drug Designation include tax credits for clinical testing expenses and exemption from user fees. A drug candidate that is approved for the orphan drug designated use typically is granted seven years of orphan drug exclusivity. During that period, the FDA generally may not approve any other application for the same product for the same indication, although there are exceptions, most notably when the later product is shown to be clinically superior to the product with exclusivity. However, the FDA Reauthorization Act, which was enacted in 2017, requires, among other things, that certain orphan drugs for cancer be tested for children. The government has also increased focus on the potential misuse of the orphan drug approval process to increase the price of orphan drugs.

In Catalyst Pharms., Inc. v. Becerra, 14 F.4th 1299 (11th Cir. 2021), the court disagreed with the FDA’s longstanding position that the orphan drug exclusivity only applies to the approved use or indication within an eligible disease, and not to all uses or indications within the entire disease or condition. In January 2023, the FDA published a notice in the Federal Register to clarify that while the agency complies with the court’s order in Catalyst, the FDA intends to continue to apply its longstanding interpretation of the regulations to matters outside of the scope of the Catalyst order. The Consolidated Appropriations Act of 2026, signed into law in February 2026, codified this longstanding FDA interpretation of the Orphan Drug Act, allowing the FDA to approve multiple versions of the same orphan drug for different subindications and subpopulations.

Further, in June 2024, the U.S. Supreme Court overruled the Chevron doctrine, which gives deference to regulatory agencies’ statutory interpretations in litigation against federal government agencies, such as the FDA, where the law is ambiguous. This Supreme Court decision may invite various stakeholders to bring lawsuits against the FDA to challenge longstanding decisions and policies, which could lead to uncertainties in the industry. Changes in the leadership of the FDA and other federal agencies under the new Presidential administration may lead to new policies and changes in the regulations that may impact our clinical development plans.

Post-Approval Requirements

Even if regulatory approval is granted, a marketed product is subject to continuing comprehensive requirements under federal, state and foreign laws and regulations, including requirements and restrictions regarding adverse event reporting, recordkeeping, marketing, and compliance with cGMP. Adverse events reported after approval of a drug can result in additional restrictions on the use of a marketed product or requirements for additional post-marketing studies or clinical trials.

Maintaining substantial compliance with applicable federal, state and local statutes and regulations requires the expenditure of substantial time and financial resources. Rigorous and extensive FDA regulation of biological products continues after approval, particularly with respect to cGMP requirements. Biological product manufacturers and other entities involved in the manufacture and distribution of approved biological products 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

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compliance with cGMP requirements and other laws. We will rely, and expect to continue to rely, on third parties for the production of clinical and commercial quantities of any products that we may commercialize. Manufacturers of our products are required to comply with applicable requirements in the cGMP regulations, including quality control and quality assurance and maintenance of records and documentation. Other post-approval requirements applicable to biological products include record-keeping requirements, reporting of adverse effects and reporting updated safety and efficacy information. Discovery of previously unknown problems or the failure to comply with the applicable regulatory requirements relating to the manufacture or promotion of an approved product may result in restrictions on the marketing of a product or withdrawal of the product from the market as well as significant administrative, civil or criminal sanctions.

Biosimilars and Exclusivity

The 2010 Patient Protection and Affordable Care Act (“PPACA”) includes a subtitle called the Biologics Price Competition and Innovation Act of 2009 (“BPCIA”), which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product.

Under the BPCIA, 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 the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product. The BPCIA also created certain exclusivity periods for biosimilars approved as the first interchangeable for biologic products.

Canadian Review and Approval Process

In Canada, our biologic product candidates and our research and development activities are primarily regulated by the Food and Drugs Act and the rules and regulations thereunder, which are enforced by Health Canada. Health Canada regulates, among other things, the research, development, testing, manufacture, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, post-approval monitoring, marketing and import and export of pharmaceutical products. Drug approval laws require licensing of manufacturing facilities, carefully controlled research and testing of products, and government review and approval of experimental results prior to giving approval to sell drug products, including biologic drug products. Regulators also typically require that rigorous and specific standards such as cGMP, GLP and cGCP are followed in the manufacture, testing and clinical development, respectively, of any drug product. The processes for obtaining regulatory approvals in Canada, along with subsequent compliance with applicable statutes and regulations, require the expenditure of substantial time and financial resources.

The principal steps required for drug approval in Canada are as follows:

Preclinical Toxicology Studies and Clinical Trials

Non-clinical studies are conducted in vitro and in animals to evaluate pharmacokinetics, metabolism and possible toxic effects to provide evidence of the safety of the drug candidate prior to its administration to humans in clinical studies and throughout development. Such studies are conducted in accordance with applicable laws and GLP.

In Canada, the process of conducting clinical trials with a new drug cannot begin until a Clinical Trial Application (“CTA”) is submitted and the required number of days has lapsed without objection from Health Canada. Biological drugs carry additional risks, as compared to traditional small-molecule drugs, associated with complexity and variability in manufacturing that can contribute to increased lot-to-lot variation of the final product, and with the potential for adventitious agents. Therefore, the content requirements for the quality information for biological drugs to be used in clinical trials are different from those for standard small-molecule pharmaceutical drugs (for example, the inclusion of information on manufacturing facilities is required for biological drugs). In addition, it is necessary to have more stringent controls on the release of biologic drug lots used in authorized clinical trials.

Similar regulations apply in Canada regarding clinical trials as in the United States. In Canada, Research Ethics Boards (“REBs”), instead of IRBs, are used to review and approve clinical trial plans. Human clinical trials are typically conducted in three sequential phases, as discussed above in the context of government regulation in the United States.

The manufacture of investigational drugs for the conduct of human clinical trials is subject to cGMP requirements. Investigational drugs and active pharmaceutical ingredients imported into Canada are also subject to regulation by Health

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Canada relating to their labeling and distribution. Progress reports detailing the results of the clinical trials must generally be submitted at least annually to Health Canada and/or the applicable REBs, and more frequently if serious adverse events occur.

New Drug Submission

Upon successful completion of Phase 3 clinical trials, the company sponsoring a new drug then assembles all the preclinical and clinical data and other testing relating to the product’s pharmacology, chemistry, manufacture, and controls, and submits it to Health Canada as part of a New Drug Submission (“NDS”). The NDS is then reviewed by Health Canada for approval to market the drug.

The testing and approval process for an NDS requires substantial time, effort and financial resources, and may take several years to complete. Biologic drugs, such as our candidates, differ from standard small-molecule drugs in that applicants must include more detailed chemistry and manufacturing information. This is necessary to help ensure the purity and quality of the product, for example to help ensure that it is not contaminated by an undesired microorganism. Data obtained from preclinical and clinical testing are not always conclusive and may be susceptible to varying interpretations, which could delay, limit or prevent regulatory approval. Health Canada may not grant approval of an NDS on a timely basis, or at all.

Even if Health Canada approves a product candidate, it may limit the approved indications for use of the product candidate, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies be conducted to further assess a drug’s safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms.

Biologic products in particular are monitored post-approval by being placed on a lot-release schedule tailored to their potential risk, manufacturing, testing and inspection history as of the date of this report. With higher-risk biologics, each lot is tested before being released for sale in Canada. Moderate-risk biologics are periodically tested at the discretion of Health Canada while manufacturers of low-risk biologics usually only need to contact Health Canada regarding lots being sold or for providing certification of complete and satisfactory testing. Products are carefully scrutinized before they are placed in any level of the lot-release process, and the testing regime for a biologic may be altered at any time. In December 2022, the Minister of Health in Canada published proposed amendments to the Food and Drug Regulations, and several of the amendments relate to biologic drugs. The purpose of the amendments is to modernize the biologics regulatory regime by repealing outdated requirements and replacing them with those that reflect current safety practices. Proposed amendments include enabling Health Canada to require certain labelling statements for safety reasons on a case-by-case basis, and clarifying the Minister’s authority to consider information or material obtained during on-site evaluations. Other proposed amendments include clarifying the record retention expectations for market authorization holders, and providing a general framework to minimize the potential for contamination of drugs, active ingredients and biological source material between processes. The proposed amendments were finalized in 2024, and the provisions relating to biologic drugs were brought into force on July 1, 2025. In June 2025, Health Canada opened a consultation for stakeholders and interested parties to submit comments on new draft biosimilar submission guidance. The consultation closed in September 2025, and the timeline for implementation or further revisions to this new guidance is unknown.

Health Canada may prevent or limit further marketing of a product based on the results of post-marketing studies or surveillance programs. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes, and additional labeling claims, are subject to further testing requirements, notification, and regulatory authority review and approval. Further, should new safety information arise, additional testing, product labeling or regulatory notification may be required.

Canadian Biosimilars and Exclusivity

The term biosimilar is used by Health Canada to describe a biologic drug that enters the market subsequent to a version previously authorized in Canada and with demonstrated similarity to a reference biologic drug. Accordingly, a biosimilar (previously known in Canada as a subsequent entry biologic or SEB) will in all instances be a subsequent entrant onto the Canadian market.

Based on Health Canada guidance documents, a biosimilar can rely in part on prior information regarding safety and efficacy that is deemed relevant due to the demonstration of similarity to the reference biologic drug and which influences the amount and type of original data required. Generic drugs are chemically derived products that are pharmaceutically equivalent to innovative drugs, whereas biosimilars are products of a biologic nature that are similar to innovative biologics. According to Health Canada, it is not currently possible to demonstrate that two biologic drugs are pharmaceutically equivalent, and therefore the regulatory approval process for generics and biosimilars is different: biosimilars are approved using the standard NDS

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pathway with some allowances made for reduced safety and efficacy information set out in guidance documents, while generic drugs are approved using an abbreviated new drug submission pathway set out in guidance and law. In part because it continues to be set out only in guidance and not law, the pathway for receiving biosimilar approval is somewhat in flux and subject to some uncertainty.

As discussed above, all biosimilars enter the market subsequent to a biologic drug product previously approved in Canada and to which the biosimilar is considered similar. As such, biosimilars are subject to existing laws and regulations outlined in the Patented Medicines (Notice of Compliance) Regulations and the Food and Drug Regulations, and related guidance documents.

Similar to the Hatch-Waxman Amendments in the United States, Canada has the Patented Medicines (Notice of Compliance) Regulations, which require a company that files a drug submission that references a patented product to address any relevant patents listed on the Patent Register prior to being able to receive approval from Health Canada. The Canadian regime is similar to the U.S. regime, but a number of distinctions do exist.

Like the United States, Canada also has data protection in addition to patent protection, but again differences exist between the two jurisdictions. For example, Canada’s data protection applies to “innovative drugs” (i.e., a drug that contains a medicinal ingredient not previously approved in a drug by the Minister of Health and that is not a variation of a previously approved medicinal ingredient such as a salt, ester, enantiomer, solvate or polymorph) and, where it exists, lasts for eight years in most (but not all) circumstances. In general biologics can be considered innovative drugs but biosimilars are not.

Additional Regulation

In addition to the foregoing, provincial, state and federal U.S. and Canadian laws regarding environmental protection and hazardous substances affect our business. These and other laws govern our use, handling and disposal of various biological, chemical and radioactive substances used in, and wastes generated by, our operations. If our operations result in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued compliance therewith will not have a material adverse effect on our business. We cannot predict, however, how changes in these laws may affect our future operations.

Government Regulation Outside of the United States and Canada

In addition to regulations in the United States, we will be subject to a variety of regulations in other jurisdictions governing, among other things, clinical studies and any commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of clinical studies or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the submission of a clinical study application much like the IND prior to the commencement of human clinical studies. In the EU, in January 2022, the Clinical Trials Regulation (CTR) repealed the Clinical Trials Directive (EC) No. 2001/20/EC and national implementing legislation in the EU Member States. The CTR harmonizes the processes for assessment and supervision of clinical trials throughout the EU. Clinical trial sponsors must apply to start a new clinical trial via the Clinical Trials Information System (CTIS), and any trials approved under the Clinical Trials Directive that continue running need to comply with the CTR and their sponsors must have recorded information on them in CTIS. National regulators in the EU Member States and EU/EEA countries use the CTIS.

The requirements and process governing the conduct of clinical studies, product licensing, coverage, pricing and reimbursement vary from country to country. In all cases, the clinical studies are conducted in accordance with cGCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

Pharmaceutical Coverage, Pricing and Reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we may obtain regulatory approval. In the United States and markets in other countries, sales of any products for which we receive regulatory approval for commercial sale will depend, in part, on pricing and the availability of coverage and adequate reimbursement from third-party payors. These third-party payors may deny coverage or reimbursement for a product or therapy in whole or in part if they determine that the product or therapy was not medically appropriate or necessary. Third-party payors may attempt to control costs by limiting coverage to specific drug products on an approved list, or formulary, which might not include all of the FDA-approved drug products for a particular indication, requiring pre-approval of coverage for new or innovative drug therapies before they will reimburse healthcare providers who use such therapies, and by limiting the amount of reimbursement

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for particular procedures or drug treatments. Additionally, coverage and reimbursement for drug products can differ significantly from payor to payor. The Medicare and Medicaid programs are often used as models by private payors and other governmental payors to develop their coverage and reimbursement policies for drugs and biologics. However, one third-party payor’s decision to cover a particular drug product does not ensure that other payors will also provide coverage for the product, or will provide coverage at an adequate reimbursement rate.

The cost of pharmaceuticals continues to generate substantial governmental and third-party payor interest. We expect that the pharmaceutical industry will experience pricing pressures due to the trend toward managed healthcare, the increasing influence of managed care organizations and additional legislative proposals. Third-party payors are increasingly challenging the price and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. We may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of our products to obtain third-party payor coverage, in addition to the costs required to obtain the FDA approvals. Our product candidates may not be considered medically necessary or cost effective. A payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Adequate third-party reimbursement may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development.

While we cannot predict whether any proposed cost-containment measures will be adopted or otherwise implemented in the future, these requirements or any announcement or adoption of such proposals could have a material adverse effect on our ability to obtain adequate prices for our product candidates and to operate profitably.

In international markets, pricing, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies. There can be no assurance that our products will be considered medically reasonable and necessary for a specific indication, that our products will be considered cost effective by third-party payors, that coverage or an adequate level of reimbursement will be available or that third-party payors’ reimbursement policies will not adversely affect our ability or our partners’ ability to sell our products profitably.

Healthcare Reform

The United States and some other jurisdictions are considering or have enacted a number of legislative and regulatory proposals to change the healthcare system in ways that could affect our ability to sell our future products profitably. 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 or expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives. For example, in August 2022, Congress passed the Inflation Reduction Act of 2022, which includes prescription drug provisions that have significant implications for the pharmaceutical industry and Medicare beneficiaries, including allowing the federal government to negotiate a maximum fair price for certain high-priced single-source Medicare drugs, imposing penalties and excise tax for manufacturers that fail to comply with the drug price negotiation requirements, requiring inflation rebates for all Medicare Part B and Part D drugs, with limited exceptions, if their drug prices increase faster than inflation, and redesigning Medicare Part D to reduce out-of-pocket prescription drug costs for beneficiaries, among other changes. Only high-expenditure single-source drugs that have been approved for at least seven years (11 years for single-source biologics) can qualify for negotiation, with the negotiated price taking effect two years after the selection year. Various industry stakeholders have initiated lawsuits against the federal government asserting that the price negotiation provisions of the Inflation Reduction Act are unconstitutional. Further, the current administration has issued executive orders focused on decreasing prescription drug prices, including directing the Secretary of HHS to establish a mechanism through which U.S. patients can buy drugs directly from manufacturers who sell at a most-favored-nation price and directing the U.S. Trade Representative and Secretary of Commerce to take action to ensure foreign countries are not engaged in practices that purposefully and unfairly undercut market prices and drive price hikes in the United States. In November 2025, the Centers for Medicare & Medicaid Services announced a voluntary initiative called the GENEROUS Model to introduce the option of most-favored-nation pricing to the Medicaid program, whereby a drug manufacturer may voluntarily offer supplemental rebates to participating state Medicaid programs for a manufacturer’s covered outpatient drugs. Government agreements with pharmaceutical companies and other measures that use most-favored-nation pricing targets for prescription drugs or that increase generic and biosimilar drug entry sooner than expected can have a material adverse effect on our industry, ability to set adequate pricing for new drugs to recover research and development costs, ability to attract potential investors and potential buyers in the future, or the pricing of our approved product in the United States and in foreign countries. The impact of these and future legislative, executive, and administrative actions implemented by the government on us and the pharmaceutical industry as a whole is unclear.

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We expect that the PPACA, as well as reform measures that may be adopted in the future, may result in more rigorous coverage criteria and lower reimbursement, and in additional downward pressure on the price that we receive for any approved product. Any reduction in reimbursement from Medicare or other government-funded programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our drugs, once regulatory approval is obtained.

Other Healthcare Laws and Compliance Requirements

In the United States, the research, manufacturing, distribution, sale and promotion of drug products are subject to regulation by various federal, state and local authorities in addition to the FDA, including the Centers for Medicare & Medicaid Services, other divisions of the U.S. Department of Health and Human Services (e.g., the Office of Inspector General), the U.S. Department of Justice, state attorneys general, and other state and local government agencies.

If our operations are found to be in violation of any of the U.S. federal and state laws described above or any other governmental regulations that apply to us, we may be subject to penalties, including criminal and significant civil monetary penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government healthcare programs, injunctions, recall or seizure of products, total or partial suspension of production, denial or withdrawal of pre-marketing product approvals, private qui tam actions brought by individual whistleblowers in the name of the government or refusal to allow us to enter into supply contracts, including government contracts, and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations. We may also be subject to additional reporting requirements and oversight if we become subject to a corporate integrity agreement or similar agreement with a governmental entity to resolve allegations that we have violated these laws. To the extent that any of our product candidates, once approved, are sold in a foreign country, we may be subject to similar foreign laws and regulations, which may include, for instance, applicable post-approval requirements, including safety surveillance, anti-fraud and abuse laws, and implementation of corporate compliance programs and reporting of payments or transfers of value to healthcare professionals.

Sales and Marketing

As a clinical-stage biopharmaceutical company, we do not currently possess the commercial infrastructure required to launch and market our product candidates. For zanidatamab, we have entered into a development and commercialization agreement with BeOne whereby BeOne is responsible for certain clinical development activities and all commercial activities in Asia (excluding Japan but including the People’s Republic of China, South Korea and other countries), Australia and New Zealand. For zanidatamab, under the Amended Jazz Collaboration Agreement, Jazz is responsible for all development and commercial activities with respect to the Licensed Products in the Territory. There are no other agreements granting commercialization rights to zanidatamab or any of our other product candidates.

To access the sales, marketing and distribution capacity required to market our drug candidates, we plan to selectively establish additional partnerships with biotechnology and pharmaceutical companies having established commercial capabilities in relevant indications. The timing and nature of such agreements will be determined by many factors, including market size and complexity, as well as access to pre-commercial and commercial infrastructure. In addition, as part of our revised corporate strategy, we do not currently intend to commercialize any of our product candidates on our own, though we retain the flexibility to reevaluate this intention if we believe doing so is in our and our stockholders’ best interests.

Human Capital Resources

As of December 31, 2025, we had 264 full-time employees, 204 of whom were primarily engaged in research and development activities and 60 of whom hold an M.D. or Ph.D. degree. 184 of our full-time employees were based in Canada, 66 were based in the United States, and 14 were based in Singapore, Ireland and United Kingdom (the “UK”) combined.

Our ability to achieve our mission is dependent upon attracting and retaining the right talent. We seek to provide what we consider to be a competitive mix of compensation and benefits for all our employees, including participation in our equity programs.

We believe everyone belongs at Zymeworks and we are committed to providing equal opportunities for our employees. This means ensuring we have good representation in our workforce from within the communities in which we operate, conducting training to remove biases in our processes and activities, and respecting all employees’ rights, cultures, diversity, and dignity.

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We consider our employees to be an essential driver of our business and key to our future prospects and believe that we have a good relationship with our employees. None of our employees are represented by a labor organization or covered by a collective bargaining arrangement.

Corporate History

Effective October 13, 2022, we became a Delaware corporation, following receipt of necessary shareholder, stock exchange, and court approvals (the “Redomicile Transactions”). Zymeworks Inc. was incorporated under the laws of the State of Delaware in June 2022. Our principal executive offices are located at 108 Patriot Drive, Suite A, Middletown, Delaware 19709, and our telephone number is (302) 274-8744. Our predecessor, now named Zymeworks BC Inc., was originally incorporated on September 8, 2003 under the Canada Business Corporations Act under the name “Zymeworks Inc.” On October 22, 2003, our predecessor was registered as an extra-provincial company under the Company Act (British Columbia), the predecessor to the Business Corporations Act (British Columbia) (“BCBCA”). Our predecessor continued to British Columbia under the BCBCA on May 2, 2017.

Available Information

This Annual Report on Form 10-K, our quarterly reports on Form 10-Q, our current reports on Form 8-K, and any amendments to these reports are filed, or will be filed, as appropriate, with the SEC and the Canadian Securities Administrators (“CSA”). These reports are available free of charge on our website, www.zymeworks.com, as soon as reasonably practicable after we electronically file such reports with or furnish such reports to the SEC and the Canadian regulatory authorities. Information contained on, or accessible through, our website is not a part of this Annual Report on Form 10-K, and the inclusion of our website address in this document is an inactive textual reference.

Additionally, our filings with the SEC may be accessed through the SEC’s website at www.sec.gov and our filings with the CSA may be accessed through the Canadian System for Electronic Document Analysis and Retrieval (“SEDAR+”) at www.sedarplus.ca.