Zymeworks Pulls Plug On Early-Stage Cancer Potential As Therapy Unlikely To Provide Benefit

Core Points - Zymeworks Inc. has decided to voluntarily discontinue the clinical development of ZW171, a T-cell engager targeting gynecological, thoracic, and digestive system cancers [1] - The decision was made after completing the planned cohorts of the dose escalation portion of the Phase 1 trial in patients with ovarian cancer and non-small cell lung cancer [2] - Zymeworks determined that further dose evaluation would unlikely support a benefit-risk profile consistent with the desired monotherapy target product profile [3] - While cytokine release syndrome was well-managed, dose-limiting toxicities were observed, consistent with mesothelin-related on-target off-tumor toxicity [4] - Ongoing participants in the Phase 1 trial will continue treatment at the discretion of their investigator, and those who have discontinued will continue safety follow-up as per the study protocol [4] - The company continues to advance its broader product pipeline, including ongoing trials for ZW191 and ZW251, with an IND filing for ZW209 planned for the first half of 2026 [5] - Following the announcement, ZYME stock decreased by 5%, trading at $14.07 [5]