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Item 1. Business

2026-03-02 compared with 2025-03-05 · 276 added, 178 removed, 475 unchanged (49% of the section changed)

Zymeworks is a clinical-stage biotechnology company developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat diseases such as cancer, autoimmune and inflammatory diseases (“AIID”).

Zymeworks’ complementary therapeutic platforms and fully integrated drug development engine provide the flexibility and compatibility to precisely engineer and develop highly differentiated antibody-based therapeutic candidates from preclinical candidate screening through to registrational clinical trials.

We believe our strategic development priorities position us as thought leaders in our therapeutic areas of interest, driven by a patient-centric approach, scientific innovation, and operational excellence.

Our research and development strategy centers on three key pillars:

• Target Selection:

Our data-driven target strategy is informed by target expression, target biology (including internalization rate), tumor biology, clinical precedence and differentiation to prior therapeutic programs.

For example, mesothelin (“MSLN”), folate receptor-⍺ (“FR⍺”) and sodium-dependent phosphate transporter 2b (“NaPi2b”) are each expressed at higher levels than other targets pursued in ovarian cancer or non-small cell lung cancer (“NSCLC”).

• Therapeutic Modality:

By utilizing our proprietary platforms and in-house expertise, we have the ability to take a modality-agnostic approach to drug development for our selected targets.

We are therefore able to tailor the therapeutic modality – whether antibody drug conjugates (“ADCs”), bispecific T cell engagers (“TCEs”), or trispecific T cell engagers (“TriTCEs”) – with the goal of maximizing efficacy for each target.

• Patient-Centric:

We integrate patient needs and biological diversity into every stage of development, helping to ensure that our therapies have the potential to improve both survival outcomes and quality of life.

As we advance our mission, we aim to deliver life-changing therapies while creating value for all stakeholders.

Our protein engineering expertise and proprietary structure-guided molecular modeling capabilities enable our therapeutic platforms.

Together with our access to both internal and external antibody discovery and generation technologies, we have established a fully integrated drug development engine and toolkit capable of rapidly delivering a steady pipeline of next-generation product candidates in oncology and AIID.

Our first internally developed product candidate, zanidatamab, is a novel bispecific antibody that targets two distinct domains of the human epidermal growth factor receptor 2 (“HER2”).

Through rigorous scientific investigation, innovative protein engineering, and our proprietary Azymetric bispecific platform technology, we developed the unique binding mechanism of zanidatamab which enables it to bind to two extracellular sites on HER2.

Zanidatamab’s unique binding properties result in multiple mechanisms of action that may enable it to address unmet need in patient populations with HER2-expressing cancers.

We have entered into separate agreements with BeiGene, Ltd.

(“BeiGene”) and Jazz Pharmaceuticals Ireland Limited (a subsidiary of Jazz Pharmaceuticals plc, collectively referred to as “Jazz”), granting to each of BeiGene and Jazz exclusive rights to develop and commercialize zanidatamab in different territories.

Zanidatamab is currently being evaluated in multiple global clinical trials as a potential best-in-class treatment for patients with HER2-expressing cancers.

The FDA granted accelerated approval of Ziihera® (zanidatamab-hrii) 50mg/mL for injection for intravenous use for the treatment of adults with previously-treated, unresectable or metastatic HER2-positive (“HER2+”) (IHC 3+) second-line biliary tract cancer (“BTC”).

Ziihera® is the first and only dual HER2-targeted bispecific antibody approved for HER2+ BTC in the U.S.

A Biologics License Application (“BLA”) submitted by our partner, BeiGene, has also been accepted for review by the Center for Drug Evaluation (the “CDE”) of the National Medical Products Administration (the “NMPA”) in China, and the European Medicines Agency (the “EMA”) has validated our partner Jazz’s marketing authorization application for zanidatamab in second-line BTC.

With initial uptake in BTC in the United States, we look forward to reporting on the outcomes of pending regulatory actions in the European Union and China as early as 2Q-2025 with our partners Jazz Pharmaceuticals and BeiGene, as well as the top-line results from the HERIZON-GEA-01 study of Ziihera® expected in 2H-2025.

Zanidatamab is also under development for multiple HER2-expressing indications.

For additional information regarding these agreements with BeiGene and Jazz, see the section titled “Strategic Partnerships and Collaborations” below.

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 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 a nd/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;

• 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:

- $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.

“ Management’s Discussion and Analysis of Financial Condition and Results of Operations ” below.

Wholly-Owned Pipeline

Our wholly-owned programs include novel ADC and multispecific antibody therapeutics (“MSAT”) candidates, such as TCEs, focusing on highly-expressed targets which provide opportunities for benchmarking in preclinical development and expected clinical differentiation.

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 are developed with 2+1 bispecific or trispecific (with co-stimulation or checkpoint inhibition) TCE engineering.

These approaches are 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.

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)

A clinical-stage ADC that targets FRα-expressing tumors including ovarian cancer, endometrial cancer, and NSCLC, is built using our novel, bystander active, TOPO1i payload technology, ZD06519.

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.

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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 optimistic about the prospects of ZW191 and we believe the design features and preclinical profile support the potential of ZW191 to target cancers with lower levels of FRα.

This would allow ZW191 to potentially unlock efficacy for both ovarian cancer patients who are unable to receive Elahere, as it is only approved in FRα-high platinum-resistant ovarian cancer (“PROC”), and other indications including endometrial and NSCLC which typically express lower levels of FRα.

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 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 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.

A potential first-in-class 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.

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.

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.

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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 non-GLP non-human primate studies, ZW251 was tolerated at doses up to 120 mg/kg, suggesting the potential for high doses in humans.

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.

We expect to submit an IND to commence Phase 1 clinical studies for ZW251 by mid-2025, with equivalent non-U.S.

applications to be submitted thereafter.

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.

An ADC that targets NaPi2b-expressing NSCLC and ovarian cancer, is built, like ZW191, using our proprietary bystander active TOPO1i payload technology, ZD06519.

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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.

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.

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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 made the decision to pause the preparations for the commencement of a Phase 1 study of ZW220 to help facilitate the accelerated development of ZW251.

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.

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Multispecific Antibody Therapeutics (MSATs)

A clinical-stage multispecific antibody built using our Azymetric platform, is a novel 2 + 1 format TCE targeting MSLN-expressing cancers.

ZW171 has a unique geometry, with two single-chain fragment variable arms targeting MSLN and one Fab arm targeting the cluster of differentiation 3 protein (“CD3”) component of the T cell receptor, to redirect the body’s natural immune system to fight cancer cells.

Preclinical data demonstrated in vivo anti-tumor activity, with engagement in high-expressing cells but not low-expressing cells, mitigating the risk of on-target, off-tumor toxicities.

MSLN has strong expression in ovarian cancer (~84%), with moderate to strong expression in NSCLC (~36%), making it an appealing target for therapeutic development with our proprietary TCE technology.

In preclinical studies, ZW171 has demonstrated potent preferential killing of tumor cells expressing relatively medium to high thresholds of MSLN while sparing cell line models representative of normal tissue MSLN expression, demonstrating reduced potential for on-target-off tumor toxicity.

Incorporation of a low affinity anti-CD3 binding domain further mitigates the risk of peripheral T cell activation and cytokine release syndrome.

Preclinical data demonstrated that ZW171 exhibits greater anti-tumor activity compared to benchmark in MSLN-expressing tumor models and is well tolerated in cynomolgus monkeys up to 30 mg/kg.

We are actively recruiting patients in the global Phase 1, open-label, multicenter study of ZW171, registered under NCT06523803 on clinicaltrials.gov.

The study aims to enroll 160 adult patients with advanced MSLN-expressing cancers in 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 ZW171.

A novel TriTCE targeting Delta-like ligand 3 (“DLL3”)-expressing tumor cells, is designed using our clinically validated Azymetric and EFECT platforms.

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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 1H-2026, with equivalent non-U.S.

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.

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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 an IND to commence Phase 1 clinical studies for ZW1528 in 2H-2026, with equivalent non-U.S.

applications to be submitted thereafter.

We expect to submit a non-U.S.

regulatory filing to commence Phase 1 clinical studies for ZW1528 in 2026.

Continued Pipeline Development

We continue to develop and advance additional product candidates in multiple different product formats for selected therapeutic indications in solid tumors, hematological cancers, and AIID, with further potential IND applications in 2027 and beyond.

these candidates, 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.

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

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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

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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.

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.

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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 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.

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.

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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.

Thr ough c ollaboration agreements with Jazz and BeiGene relating to our programs for zanidatamab and zanidatamab zovodotin, we have received $446.0 million through December 31, 2024 in the form of non-refundable upfront payments and milestone payments.

In addition, through these partnerships with Jazz and BeiGene with respect to zanidatamab, as of December 31, 2024, we remain eligible to receive up to $1.55 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.

These partnerships have provided us with a significant source of non-dilutive funding and provide for additional future funding for our lead asset, zanidatamab.

These partnerships also leverage our partners’ commercial infrastructure, helping accelerate the development and expanding the potential reach of our lead product candidates.

Thr ough c ollaboration 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.

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

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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’s agreement with BeiGene (“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”).

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

Jazz shall be solely responsible for commercializing the Licensed Products in the Territory and use commercially reasonable efforts to commercialize in each specified major market country each Licensed Product that obtains regulatory approval in such country.

Jazz shall conduct such commercialization at its sole cost and expense.

Under the Jazz Collaboration Agreement, as of December 31, 2024 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 and (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.

As of December 31, 2024, we were also eligible to receive up to an aggregate of $525.0 million in certain regulatory milestones payments and up to an aggregate of $862.5 million in potential commercial milestone payments.

As a result of the FDA’s approval of Ziihera®, $ 25.0 million of regulatory milestone revenue was recognized in November 2024, and we received this $25.0 million milestone payment in the first quarter of 2025.

W e are 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 the licensed 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.

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.

O ur 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 aggre gate of $500.0 million in certain regulatory milestones payments and up to an aggregate of $862.5 million in potential co mmercial milestone payments.

W e 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”).

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and its affiliates in connection with such transactions under the Transfer Agreement.

In November 2018, we entered into agreements with BeiGene whereby we granted BeiGene 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 z anidatamab, as amended, the “Zanidatamab Agreement,” and such agreement relating to zanidatamab zovodotin, the “Zovodotin Agreement”).

In September 2023, Zymeworks BC and BeiGene entered into a termination agreement relating to the Zovodotin Agreement (the “Termination Agreement”).

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 z anidatamab, 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, 2024 we have received milestone payme nts of $31.0 million, including an $8.0 million milestone payment received from BeiGene in July 2024 in relation to the acceptance by the CDE of the NMPA in China of the BLA for zanidatamab for second-line treatment of HER2+ BTC.

As of December 31, 2024, we remain eligible to receive development and commercial milestone payments of u p to $164.0 million, together with tiered royalties of up to 19.5% of net sales in BeiGene 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 million s of dollars.

Under the Zanidatamab Agreement, Zymeworks and BeiGene are collaborating on certain global clinical studies and both Zymeworks and BeiGene will independently conduct other clinical studies in their own respective territories.

Each of Zymeworks and BeiGene are responsible for all of the development and commercialization costs in their own territories.

Under the Zanidatamab Agreement, as of December 31, 2025 we have received milestone payme nts 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 u p 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 million s 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 BeiGene upon prior written notice or by either party upon the other party’s bankruptcy or uncured material breach.

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 BeiGene 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 BeiGene intellectual property with respect to zanidatamab zovodotin.

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 BeiGene relating to zanidatamab and zanidatamab zovodotin, as of December 31, 2024, we have received approximately $183.5 million in the form of non-refundable upfront and milestone payments from platform partnership and collaboration agreements.

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:

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”), Janssen Biotech, Inc.

(“Janssen”), and Merck Sharp & Dohme Research GmbH (“Merck”).

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.

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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.

The table below summarizes the stage of each of our platform partners’ most advanced publicly disclosed program.

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.

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We received an upfront payment of $8.0 million and an expansion fee of $4.0 million .

As of December 31, 2024, BMS had exercised one commercial license option and we received a $7.5 million option payment, but in 2023 BMS stopped development of such program.

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, 2024, BMS remains eligible to exercise its one remaining option, and we remain eligible to receive up to $320.5 million for the two remaining programs (or $164.0 million not including the one program for which BMS stopped development in 2023), comprised of a commercial license option payment of $7.5 million for the one remaining program, development milestone payments of up to $101.5 million per program, and commercial milestone payments of up to $55.0 million per program.

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.

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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.

Under the terms of the agreement, we granted GSK a worldwide, royalty-bearing antibody target-exclusive license to new intellectual property generated to the EFECT platform under this collaboration and a non-exclusive license to the Azymetric platform to research, develop and commercialize future licensed products.

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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.

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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

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.

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Under the expanded agreement, we are eligible to receive up to $1.1 billion in milestone and other payments.

As of December 31, 2024, we have received an upfront technology access fee payment of $6.0 million and a milestone payment of $2.5 million in relation to a sequence pair nomination by GSK.

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.

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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 is from February 28, 2023 until the earlier of (i) the day that we receive written notice from Daiichi Sankyo confirming that Daiichi Sankyo has completed such additional research and (ii) August 27, 2025, unless earlier terminated (including by advance written notice to us from Daiichi Sankyo).

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

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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, 2024, we have received an upfront technology access fee payment of $18.0 million, and we remain eligible to receive development milestone payments totaling up to $63.4 million and commercial milestone payments of up to $170.0 million.

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 shall terminate, with respect to Daiichi Sankyo’s licenses, on a product-by-product basis, with the last payment obligation for the respective product.

In November 2017, we entered into a collaboration and license agreement with Janssen to research, develop and commercialize up to six bispecific antibodies generated through the use of our Azymetric and EFECT platforms.

Under the terms of the agreement, we granted Janssen 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, 2024, we have received an upfront payment of $50.0 million and development milestones totaling $8.0 million in connection with the initiation of clinical trials of two bispecific antibodies.

Janssen has deprioritized the development of one of those two bispecific antibodies, 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 development milestone payments of up to $86.0 million and commercial milestone payments of up to $373.0 million ($43.0 million and $186.5 million, respectively, not including the bispecific antibody that Janssen has deprioritized).

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.

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.

Janssen has the right, prior to the first dosing of a patient in a Phase 3 clinical trial for a product, to buy down the royalty relating to such product by one percentage point with a payment of $10.0 million.

The Company determined that, the events and conditions resulting in payments for research, development and commercial milestones solely depend on Janssen’s performance.

Janssen is solely responsible for the research, development, manufacturing and commercialization of the products.

The agreement contains customary termination rights for Janssen and us, including the right for Janssen to terminate the agreement in its sole discretion with advance notice to us.

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.

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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

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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, 2024, our patent portfolio includes more than 40 patent families related to our therapeutic antibody product (zanidatamab), our preclinical and clinical stage product candidates, and our therapeutic platform technologies.

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.

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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

As of December 31, 2024, we own 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.

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.

As of December 31, 2024, we own patent applications filed in the United States and internationally under the Patent Cooperation Treaty (“PCT”) directed to compositions of matter of ZW171, compositions used in the manufacture of ZW171, and methods of using ZW171.

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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.

ZW171 is also protected by patent families relating to Azymetric Fc.

ZW251 is also protected by a patent family directed to our TOPO1i technology.

L ead Preclinical Product Candidates

As of December 31, 2024, we own patent applications filed internationally under the PCT and in 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.

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.

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

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.

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provisional patent applications directed to compositions of matter of ZW327, compositions used in the manufacture of ZW327, and methods of using ZW327.

If converted to non-provisional applications and granted, these applications are anticipated to expire in 2045, absent any patent term adjustments or extensions.

As of December 31, 2024, we own U.S.

provisional patent applications directed to compositions of matter of ZW1528, compositions used in the manufacture of ZW1528 and methods of using ZW1528.

If converted to non-provisional applications and granted, these applications are anticipated to expire in 2045, absent any patent term adjustments or extensions.

As of December 31, 2024, we own patent applications filed internationally under the PCT and in 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.

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.

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As of December 31, 2025, we own U.S.

and foreign patents and patent applications 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 adjustments or extensions.

and foreign patents and a U.S.

patent application directed to our Azymetric Fc platform.

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 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 adjustments or extensions.

As of December 31, 2024, we own U.S and foreign patents and 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 patents and patent applications, if granted, are expected to expire between 2031 and 2042, absent any adjustments or extensions.

As of December 31, 2024, we own patent applications filed in the United States and 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.

If granted, these patent applications are expected to expire in 2041, absent any adjustments or extensions.

If granted, these patent applications are expected to expire in 2042, absent any patent term adjustments or extensions.

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.

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, 2024, we own U.S and foreign patents and patent applications directed to computational and algorithmic advances incorporated into our ZymeCAD TM platform, including advances in general molecular modeling, conformational dynamics, docking, distal mutations, and molecular packing, as well as parallelization and graphical data analysis.

These patents and patent applications, if granted, are expected to expire between 2026 and 2042, absent any adjustments or extensions.

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

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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 ZW171 and ZW209, using Daiichi Sankyo’s proprietary immune-oncology antibodies.

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.

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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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In February 2016, we entered into a master services and master license agreement with ProBioGen AG ( “ ProBioGen ” ).

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Licensing terms include preclinical, clinical and commercial milestones.

In connection with the first commercial sale of Ziihera®, we expect to pay to ProBioGen €3.95 million for achievement of the first commercial sale milestone.

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.

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For our clinical stage product candidates, we have sufficient cGMP-grade supply to complete our ongoing clinical trials.

For ZW251, our preclinical stage product candidate for which we expect to submit an IND in mid-2025, we expect to have sufficient cGMP-grade supply, through additional manufacturing runs, to commence clinical trials.

The biopharmaceutical industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products.

pharmaceutical and biotechnology companies, academic institutions and governmental agencies, and public and private research institutions.

Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

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 competitors.

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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Smaller or early-stage companies may also prove to be significant competitors, particularly through collaboration arrangements with large and established companies.

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

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.

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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, Alphamab’s anbenitamab, BioNTech’s trastuzumab pamirtecan, Boehringer’s Zongertinib, Bayer’s BAY2927088 and various trastuzumab biosimilars, as well as other candidates in late-stage development.

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 ImmunoGen/AbbVie’s Elahere.

ADCs under development include Sutro’s Luveltamab tazevibulin, Eisai’s Farletuzumab ecteribulin, Coherent Bio’s CBP-1008, Bio-Thera’s BAT8006, ProfoundGenmab’s PRO1184, AstraZeneca’s AZD5335, Eli Lilly’s MBK-103, Multitude’s AMT-151 and ImmunoGen/AbbVie’s IMGN151.

ZW171 is being developed for patients with solid tumors that express MSLN.

TCEs under development include Amgen’s AMG 305, Janssen’s JNJ-79032421, RemeGen’s RC88, and Light Chain Bio’s NI-1801.

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.

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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.

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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.

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 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.

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 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 regulated as biologics by the FDA.

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.

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

requirements or clinical protocols, failure to demonstrate a benefit from using the investigational drug, changes in government regulations or administrative actions.

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.

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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 review 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 review 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.

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 adenocarcinomas (“GEA”) in combination with standard of care chemotherapy and for previously treated or recurrent gene-amplified BTC.

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.

Products designated as a Breakthrough Therapy by the FDA can also be eligible for accelerated approval.

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.

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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 may interpret data differently than the applicant interprets the same data.

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.

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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.

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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 – that is, the agency will continue tying the scope of orphan drug exclusivity to the uses or indications for which a drug is approved, which permits other sponsors to obtain approval of a drug for new uses or indications within the same orphan designated disease or condition that have not yet been approved.

It is unclear how future litigation, legislation, agency decisions, and administrative actions will impact the scope of the orphan drug exclusivity.

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.

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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 compliance with cGMP requirements and other laws.

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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.

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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 Canada relating to their labeling and distribution.

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.

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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.

On December 17, 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.

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.

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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 are still in draft form.

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.

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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 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.

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.

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The CTR harmonizes the processes for assessment and supervision of clinical trials throughout the EU.

From January 2023 onwards, clinical trial sponsors must apply to start a new clinical trial via the Clinical Trials Information System (CTIS), and beginning January 2025, 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.

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.

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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 for particular procedures or drug treatments.

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.

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for particular procedures or drug treatments.

Additionally, coverage and reimbursement for drug products can differ significantly from payor to payor.

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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 to sell our products profitably.

Healthcare Reform

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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.

For 2026, the first year in which negotiated prices become effective, the Centers for Medicare & Medicaid Services (“CMS”) selected ten high-cost Medicare Part D drugs in 2023, negotiations began in 2024, and the negotiated maximum fair price for each drug has been announced.

CMS has selected 15 additional Medicare Part D drugs for negotiated maximum fair pricing in 2027.

For 2028, up to an additional 15 drugs, which may be covered under either Medicare Part B or Part D, will be selected, and for 2029 and subsequent years, up to 20 additional Part B or Part D drugs will be selected.

The impact of these legislative, executive, and administrative actions and any future healthcare measures and agency rules implemented by the Trump administration on us and the pharmaceutical industry as a whole is unclear.

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.

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.

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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 BeiGene whereby BeiGene 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, 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.

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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 market size and complexity, access to pre-commercial and commercial infrastructure and our resource availability for developing a commercial organization.

For product candidates targeting patient populations that can be serviced by a small, specialized commercial effort, we may seek out co-development and co-promotion agreements granting commercialization rights to an established commercial partner in some jurisdictions while allowing us to build these capabilities in other jurisdictions.

We also evaluate opportunities to retain rights further into development for certain drug candidates, providing flexibility around future commercialization strategies.

This approach includes the potential to retain commercial rights in one or more geographic jurisdictions, allowing us the option to independently commercialize and launch product(s) in the future.

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, 2024, we had 286 employees, including 280 full-time employees, 203 of whom were primarily engaged in research and development activities and 53 of whom hold an M.D.

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.

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.

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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.

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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.

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Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1. Business