Roche has agreed to license Zymeworks’ ZW209 program worldwide in a deal that could yield up to $813 million before royalties, subject to U.S. antitrust clearance and other closing conditions.
The companies signed the agreement Oct. 22, according to a securities filing. Its exclusive license extends beyond ZW209 to specified related DLL3-targeting trispecifics, derivatives and backup compounds, as well as companion diagnostics. It takes effect on the first business day after clearance under the Hart-Scott-Rodino Antitrust Improvements Act.
Zymeworks is due a nonrefundable $55 million after clearance and $40 million when the first product’s Phase 1b trial starts. The company may also receive up to $718 million in research, development, commercial and sales milestones. Milestone payments are contingent. Royalties would range from high single digits to the mid-teens on annual net sales, subject to customary reductions.
Zymeworks will conduct the Phase 1a monotherapy dose-escalation trial, with Roche covering its costs. Roche will fund and lead subsequent development, including Phase 1b, and will be responsible for commercialization. The filing sets Roche’s development obligation for one product and one U.S. indication under a commercially reasonable efforts standard.
The U.S. Food and Drug Administration (FDA) cleared ZW209’s investigational new drug application, Zymeworks said, and a global, open-label Phase 1 study had been initiated. The study is designed to assess safety, drug levels in the body and early antitumor activity in selected advanced solid tumors, including small-cell lung cancer and other DLL3-expressing neuroendocrine tumors. Reuters reported that Zymeworks CEO Kenneth Galbraith expected the first participant to enroll by the end of 2026.
ZW209 is designed to connect DLL3-expressing tumor cells with T cells by engaging DLL3, CD3 and CD28. Zymeworks reported preclinical in vitro findings, including increased T-cell proliferation and survival; these were laboratory findings, not patient results. Adam Schayowitz, the company’s executive vice president and head of research and development, described the agreement as a way to share development risk while preserving potential participation in the drug’s future success.
Zymeworks retains its existing patents and know-how for ZW209 and its multispecific-antibody platforms. Roche will own specified product-specific intellectual property created through the collaboration. The FDA granted traditional approval to tarlatamab-dlle (Imdelltra), a DLL3-directed bispecific T-cell engager, for adults with extensive-stage small-cell lung cancer on Nov. 19, 2025.
Zymeworks said it plans additional regulatory applications to support clinical sites outside the United States. Its next announced update is an investor webcast scheduled for Oct. 27 at 8:30 a.m. ET.
