Zymeworks Inc. Common Stock

Zymeworks shares climbed nearly 4.0% in pre-market trading as investors positioned themselves ahead of an important U.S. regulatory decision on zanidatamab, expected the following day. The FDA's PDUFA target action date for zanidatamab, a bispecific HER2-targeting antibody developed alongside Jazz Pharmaceuticals, is August 25, 2026, with the regulator reviewing the treatment for first-line HER2-positive locally advanced or metastatic gastroesophageal adenocarcinoma. Approval would immediately trigger a $250 million U.S. regulatory milestone payment, with up to an additional $190 million possible through regulatory milestones in other markets. Citi placed the stock on an upside 90-day catalyst watch earlier in August, while Truist and Wells Fargo have increased their price targets ahead of the PDUFA date. Zymeworks is also pursuing a roughly $929 million all-cash acquisition of Theravance Biopharma, expected to close in the second half of 2026, which would add commercial cash flows from the COPD treatment YUPELRI.

Truist Securities initiated coverage of Zymeworks with a Buy rating and a $28 price target, down from $40. The firm highlighted Zymeworks as a balanced investment opportunity, supported by its royalty-based business model and expanding oncology pipeline that could provide long-term growth potential. Truist also pointed to pipeline assets, including Pasritamig in metastatic castration-resistant prostate cancer, as potential contributors due to upcoming clinical milestones. Separately, Zymeworks presented updated clinical findings from the dose-escalation phase of its ongoing Phase 1 trial assessing ZW191, an antibody-drug conjugate targeting folate receptor alpha, at the European Society for Medical Oncology Gynaecological Cancers Congress 2026. Results showed a confirmed objective response rate of 78.6% in FRalpha-positive patients and 47.4% in FRalpha-negative patients across evaluated dose levels, with median progression-free survival of 7.6 months across ovarian and endometrial cancer groups.

Theravance Biopharma shares fell about 3% on June 29, 2026, after the company announced a definitive agreement to be acquired by Zymeworks in an all-cash deal valued at approximately $929 million. Theravance shareholders will receive $17.00 per share in cash, a 22% premium to the closing price on March 3, 2026, the day the company reported failed phase III results for its lead candidate ampreloxetine, plus a contingent value right for 80% of any future net proceeds from licensing or monetizing ampreloxetine over 10 years. The acquisition, expected to close in the second half of 2026, follows a strategic review launched after the CYPRESS study missed primary and secondary endpoints, leading Theravance to wind down the program and restructure. The company had relied heavily on collaboration revenues from its 35% share of U.S. profits on Viatris' COPD therapy Yupelri. Management stated the Zymeworks deal is the most value-maximizing option for shareholders.

Zymeworks has agreed to acquire Theravance Biopharma in a cash deal valued at approximately $929 million. Theravance shareholders will receive $17 per share plus a contingent value right entitling them to 80% of net proceeds from any future monetization of ampreloxetine within ten years. The boards of both companies have unanimously approved the transaction, which is expected to close in the second half of 2026, subject to shareholder and regulatory approvals. Financing includes a $350 million note from OMERS Life Sciences and cash from both companies' expected balances at closing.