Vancouver, British Columbia, September 28, 2026 ( GLOBE NEWSWIRE ) – Zymeworks Inc. (Nasdaq ticker: ZYME) Today, following the completion of the acquisition of Theravance Biopharma, the company disclosed the final transaction details and updated its financial guidance. Zymeworks is a biotechnology company that manages a portfolio of authorized healthcare assets and is also developing a diversified pipeline of innovative, multi-functional biotherapeutic drugs.

This acquisition will incorporate YUPELRI ® ( revefenacin ) into Zymeworks's asset portfolio, providing the company with stable and continuous cash flow to support its long-term growth strategy. Through the collaboration between Theravance Biopharma and Viatris, Zymeworks is entitled to a 35% share of the net profits in the United States, as well as royalties on net sales outside of the United States. In the first half of 2026, YUPELRI achieved total sales of $133.1 million, generating $38.4 million in collaboration revenue for Theravance Biopharma.

Zymeworks, Chief Commercial Officer, stated: " Zymeworks possesses unique value creation capabilities in this acquisition due to its existing R&D and operational infrastructure. This includes the ability to combine the tax benefits obtained from the acquisition with our ongoing R&D activities in Ireland, opportunities that are not easily accessible to traditional royalty-based buyers. We are delighted to welcome the Theravance Biopharma team to Zymeworks; they will bring differentiated assets and additional meaningful sources of cash flow to our business. As we continue to build a sustainable and diversified business and strive to develop innovative drugs for patients with serious illnesses, we look forward to building on the strengths of the integrated organization."

Business Organizations and Integration

Zymeworks intends to retain the existing commercial team responsible for channel sales at YUPELRI hospitals. This team possesses mature commercial capabilities and customer relationships, and Zymeworks believes that this will help the product continue to grow within the merged organization. The company plans to hire an experienced pharmaceutical executive to oversee the commercial operations of Theravance Biopharma, and this executive is required to have experience in building and leading pharmaceutical commercial organizations.

In addition, Stuart Knight will assume the role of Executive Vice President and Chief Information Officer for Zymeworks, responsible for the company's future technology strategy, including continuing to invest in the company's existing artificial intelligence, machine learning, and data science capabilities. Stuart has extensive experience in biotechnology and pharmaceutical companies operating in the United States and Europe. Jesse Fecker, who holds a Doctorate and a Juris Doctor degree, will also join Zymeworks as Vice President of Intellectual Property.

Zymeworks, Chairman and CEO, Kenneth Galbraith said: "We are very pleased that Stuart and Jesse have joined the leadership team of Zymeworks. They bring additional experience and capabilities, which will help us achieve our long-term strategic goals."

Zymeworks also retains the ownership of the R&D assets of Theravance Biopharma. These assets will be evaluated in conjunction with the company's broader pipeline, strategic priorities, and a prudent capital allocation framework. The company will continue to seek to maximize the value of its comprehensive R&D engine through cooperation, alliances, and other strategic structures, including the possibility of externalizing some projects when appropriate.

Financial Impact of the Theravance Biopharma Acquisition

It is expected that this acquisition will bring significant and immediate incremental revenue and operating cash flow to Zymeworks after the delivery, including:

• Under the baseline scenario, the internal rate of return ( IRR ) is in the mid-teens, primarily driven by the growth in YUPELRI revenue, with VIBATIV ® contributing less significantly. This baseline scenario does not include potential upside from leveraging tax attributes or future research and development opportunities as well as business development prospects.
• In the second quarter of 2026, YUPELRI saw a 25% increase in sales through hospital channels, which supported a continued expansion of profit margins and enhanced operational leverage as net sales continued to grow. The growth in hospital channels remains a key driving factor for the ongoing expansion of this product in community settings.
• Costs related to acquisitions and reorganizations, excluding the capitalized costs of non-recourse financing attributable to OMERS Life Sciences ( OMERS ), amount to approximately 25 million to 30 million US dollars.
• Ireland's tax attributes worth $2.5 billion may provide additional flexibility for future Irish revenue, intellectual property arrangements, as well as potential acquisitions or investments through the company's existing Irish R&D operations. The transaction valuation or baseline scenario IRR does not include the value of these tax attributes; therefore, any future utilization of them will constitute an additional upside.
• If the conditions are met, it is expected that in the first quarter of 2027, a milestone payment of $100 million related to TRELEGY ELLIPTA ® will be received, which can offset the cash expenditure for the purchase price.

Transaction Details

According to the merger agreement terms announced on June 29, 2026, Theravance Biopharma shareholders will receive $17.00 in cash for each ordinary share held at the time of delivery.

The acquisition was completed through $350 million in non-dilutive, non-recourse note financing provided by OMERS. Of this amount, 75% of the profit-sharing cash flow from YUPELRI was allocated to OMERS according to the contract, to be used for repaying related debt obligations. In addition, after utilizing the available cash obtained from Theravance Biopharma, Zymeworks planned to use its own existing cash resources of approximately $217.5 million to fund the remaining acquisition consideration. The company expects that if a milestone payment of $100 million related to TRELEGY ELLIPTA is received in the first quarter of 2027, this net investment will be further reduced.

Within 1 year after the completion of the transaction, the designated party of Theravance Biopharma will seek potential licensing, sale, or other monetization arrangements for ampreloxetine. Zymeworks does not anticipate providing additional resources. Any economic benefits from such transactions will be allocated between the shareholders of Zymeworks and Theravance Biopharma in a 20/80 ratio.

After the transaction was completed, the common shares of Theravance Biopharma are no longer listed for trading on the NASDAQ Global Select Market.

Accounting treatment

It is expected that this transaction will be accounted for as a business combination. The purchase price will be allocated to the fair value of the acquired net assets, which mainly includes rights related to YUPELRI. The remaining amount will be recognized as goodwill. YUPELRI is expected to become a major identifiable intangible asset and will be amortized over its estimated useful life, typically until the period when the exclusive rights are expected to be lost.

Based on the potential milestone payment rights for global net sales of TRELEGY ELLIPTA, it is expected to be recognized as a financial asset at fair value on the settlement date. Assuming that the relevant business sales milestones are achieved before December 31, 2026, the related $100 million milestone payment is expected to be received in the first quarter of 2027.

The company also expects that, as part of the accounting treatment for business combinations, a tax liability arising from uncertain tax positions will be recognized. After the applicable audit period expires in October 2026, this liability may be reversed, and a non-cash income tax benefit will be recognized in the fourth quarter of 2026.

The company expects to treat the $350 million of non-recourse notes issued to OMERS as debt and will measure them using the prospective effective interest rate method. Before the notes are settled, 75% of the profit-sharing cash flow from YUPELRI will be used to pay the principal and interest, with the company retaining the remaining 25%. After the notes are settled, the company will retain 100% of the profit-sharing cash flow from YUPELRI.

The preliminary accounting treatment for this transaction will be reflected in the company's 10-Q quarterly report for the quarter ending September 30, 2026, which is expected to be submitted in November 2026.

2026 Financial Guidance Update

With the completion of the acquisition by Theravance Biopharma, and Ziihera ® ( zanidatamab-hrii ) obtaining approval from the US Food and Drug Administration on August 25, 2026 for use in the first-line treatment of positive advanced gastroesophageal adenocarcinoma, Zymeworks has provided updated financial guidelines and adopted relevant financial indicators that it deems more suitable for assessing business performance.

Zymeworks Chief Financial Officer Kristin Stafford stated: "The company expects total revenue in 2026 to be between $278 million and $292 million, and after adjustments in 2026, EBITDA will be between $114 million and $128 million, excluding the impact of any future transactions. During 2026, we have raised a total of $600 million through non-dilutive financing methods such as notes without recourse, at an attractive cost of capital. These funds will be used to support the Theravance Biopharma acquisition as well as ongoing share repurchases. Our financing strategy and share repurchase program focus on minimizing the dilution of shareholders' equity. We completed our most recent public equity financing in January 2022, and there are currently no plans for additional equity issuance."

After adjustment, EBITDA has been changed to non-GAAP financial indicators. For explanations regarding these indicators, please refer to the section "Explanations on Non-GAAP Financial Information" below. A comparison table of historical performance GAAP with non-GAAP financial information can be found at the end of this press release on performance.

Zymeworks 2026 Stock Repurchase Plan

In May 2026, the board of directors authorized the implementation of a 2026 stock repurchase plan, under which the company was able to repurchase up to $125 million of outstanding common shares with a par value of $0.00001 per share. As of September 28, 2026, the company had utilized approximately $49.3 million of the currently approved repurchase amount to repurchase 1,971,454 shares at an average price of $25.04 per share (excluding commission fees and estimated consumption taxes).

Since the launch of the stock repurchase program in August 2024, the company has cumulatively spent $211.6 million to repurchase 10,571,316 shares at an average repurchase price of $20.02 per share (excluding commission fees and estimated consumption tax). As of September 14, 2026, there are approximately 71.2 million ordinary shares outstanding.

Investor Conference Call Information

Zymeworks will hold a teleconference with investors and the public at 8:30 a.m. Eastern Time today. Details for dialing in and the link to the live webcast can be found at the Zymeworks website at https://ir.zymeworks.com/events-and-presentations. A replay of the live webcast will be available within 24 hours after the teleconference concludes and will be archived for a limited period of time.

Regarding Zymeworks Inc.

Zymeworks is a global biotechnology company dedicated to building a diversified healthcare portfolio to generate sustainable cash flows, while advancing innovative drugs for difficult-to-treat diseases. The asset and royalty integration strategy of Zymeworks combines an expanding portfolio of commercialized and near-commercialized assets, including YUPELRI ® ( revefenacin ), as well as a differentiated in-house R&D engine. The company's portfolio also includes Ziihera ® ( zanidatamab-hrii ), which is a bispecific antibody targeting HER2 discovered and developed by Zymeworks and commercialized through global collaborations with Jazz Pharmaceuticals and BeOne Medicines , as well as pasritamig, which is a multi-specific antibody in the clinical phase developed by Johnson & Johnson using Zymeworks's proprietary antibody engineering technology.

Zymeworks is advancing a diversified pipeline of innovative bi therapeutic drugs, leveraging its proprietary Azymetric ™ platform as well as its expertise in antibody-conjugated drugs, multispecific antibodies, and other next-generation antibody technologies. Combined with its experience in integrated drug development with Zymeworks, the company is able to develop differentiated therapies and create value through internal innovation and strategic collaborations.

For more information about Zymeworks, its asset portfolio, and pipeline, please visit www.zymeworks.com and follow @ZymeworksInc on X.

Warning Regarding Forward-Looking Statements

This press release contains “forward-looking statements” or information as defined under the Securities Act, including sections 27A of the revised Securities Act of 1933 and section 21E of the revised Securities Exchange Act of 1934. The forward-looking statements in this document include, but are not limited to: statements regarding the expected earnings related to the acquisition of Theravance Biopharma; expected earnings from financing related to the completion of the acquisition; expected milestone payments; the ability to take advantage of Irish tax benefits for Zymeworks; the flexibility to invest in the research and development pipeline while returning capital to shareholders and seeking strategic opportunities with Zymeworks; growth in sales and future royalty income for YUPELRI; sales and future royalty income related to VIBATIV ®; contingent milestone payments receivable from the sale of its TRELEGY ELLIPTA ® royalty interests; the repayment of non-recourse notes issued to OMERS Life Sciences; expectations for implementing long-term strategies to maximize value creation for Zymeworks; the clinical development of product candidates by Zymeworks and its partners; the potential safety and therapeutic effects of product candidates; the commercial potential of the technology platform and product candidates; expected benefits from the cooperation agreements; the company’s full-year guidance for 2026; and other non-historical information. The use of words such as “plans”, “believes”, “expects”, “may”, “continue”, “anticipates”, “potential”, “will”, “proceed as planned”, “progress”, “maintain”, “intends”, “can”, and similar expressions is intended to identify these forward-looking statements.In addition, any descriptions involving expectations, beliefs, plans, forecasts, targets, performance, or other aspects of future events or circumstances, including the underlying assumptions, are considered forward-looking information. All forward-looking statements are based on the current expectations and various assumptions of Zymeworks. Zymeworks believes that its expectations and beliefs are reasonably grounded, but there is inherent uncertainty. Zymeworks It is possible that these expectations may not be realized, and the beliefs may also be incorrect.Actual results may vary significantly from those described or implied in such forward-looking statements due to a variety of factors, including but not limited to: risks related to financing for the completion of the acquisition; any product candidates of Zymeworks or its partners may fail in development, may not obtain the required regulatory approvals, or may be delayed to the point where they are no longer commercially viable; uncertainties regarding the commercial success of YUPELRI ®, TRELEGY and VIBATIV ®; the expected benefits from the acquisition may not be realized, or may not be realized within the anticipated time frame; TRELEGY may not achieve the expected sales, resulting in the failure to meet sales milestones; Zymeworks may not be able to achieve milestones or receive additional payments or royalties under the cooperation; regulatory authorities may impose additional requirements or delay the initiation of clinical trials; the impact of new laws, regulations, or changes in regulations; market conditions, including the impact of tariffs; the adverse effects of regulatory delays and recent policy changes, changes in leadership at federal agencies (such as FDA), staff reductions, cuts to institutional projects and research budgets, as well as changes in drug pricing controls; the impact of the pandemic and other health crises on Zymeworks's business, R&D and clinical development plans, timelines, and operating results, including the impact on clinical trial sites, partners, and contractors acting on behalf of Zymeworks; zanidatamab may not be successfully commercialized; Zymeworks business strategies related to expected and potential future milestones, royalty income streams, as well as existing and potential new partnerships, may not be successfully implemented; the evolution of business strategies may not bring meaningful returns to shareholders; Zymeworks may not be able to successfully manage and/or integrate revenue-generating assets outside of active R&D operations; ongoing and future clinical trials may not be able to demonstrate the safety and effectiveness of Zymeworks or its partners' product candidates;The data provided for early validation of the antibody-conjugated drug platform and next-generation pipeline projects may not be reproducible in future research; the assumptions and estimates regarding financial condition, future financial performance, and anticipated cash consumption periods made by Zymeworks may not be accurate; it may be impossible to maintain or establish new collaborations or strategic alliances; Zymeworks may not be able to identify and complete strategic acquisitions; and there are factors mentioned in the "Risk Factors" section of the quarterly and annual reports submitted to the U.S. Securities and Exchange Commission (SEC) (relevant documents can be found at www.sec.gov and www.sedarplus.ca).

Although Zymeworks believes that these forward-looking statements are reasonable, there is no guarantee that they will prove to be correct. Investors should not rely excessively on such forward-looking statements. The aforementioned assumptions, risks, and uncertainties are not exhaustive. These forward-looking statements are as of the date of issuance of this press release. Except as required by law, Zymeworks assumes no obligation to update, republish, or revise any forward-looking statements to reflect new information, future events or circumstances, or to account for unexpected events.

Explanation regarding financial information not related to GAAP

In addition to reporting financial information in accordance with Generally Accepted Accounting Principles (GAAP) in the United States, the company also chooses to disclose non-GAAP financial indicators in a forward-looking manner. The company believes that these indicators help to understand the company's fundamental operating performance and facilitate comparison of operating results across periods. They should be considered as a supplement to GAAP financial indicators, rather than a substitute for them. Other companies may calculate these indicators differently or use other metrics to evaluate performance. Investors and other readers are advised to review the company's financial information comprehensively, rather than relying on a single financial indicator.

The calculation method for Adjusted EBITDA is to adjust the net profit (loss), excluding income or expenses from income tax, interest income and expenses, depreciation and amortization, other non-operating income or expenses, share-based payment expenses, as well as certain other items, including transaction-related costs, restructuring costs, and severance costs. A comparison table of Adjusted EBITDA with the most directly comparable GAAP indicator of net profit (loss) is provided in the table at the end of this press release.

Due to inherent difficulties in predicting and quantifying certain amounts required for this comparison, a comparison between the forward-looking Adjusted EBITDA and the most directly comparable GAAP indicators cannot be provided without unreasonable effort. Therefore, in accordance with the exception provided under item 10(e)(1)(i)(B) of the S-K Regulations, the company has not provided a comparison of the forward-looking Adjusted EBITDA mentioned in this press release. For the same reason, the company is unable to assess the potential significance of the missing information. The company provides the non-financial indicators GAAP that it believes will be achieved; however, it is unable to accurately predict all components of the adjusted calculations, and there may be significant differences between the GAAP indicator and the non-GAAP indicator.

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