Stephen Willey

Yigal Nochomovitz

Brian Cheng

Derek Archila

Akash Tewari

Jonathan Miller

Amanda Acosta-Ruiz

Charles Zhu

Emily Shutman

Jay Olson

John Miller

Jon Miller

Justin Zelin

Lut Ming Cheng

Manoj Eradath

Mayank Mamtani

Phoebe Tan

Robert Burns

Yaron Werber

Yue-Wen Zhu

- Zymeworks Inc. announced its decision to **voluntarily discontinue clinical development of ZW171**, a mesothelin-directed T cell engager, on **September 2, 2025**.  **[1937653_0001193125-25-193351_d88452dex991.htm:0]** **[1937653_0001193125-25-193351_d88452d8k.htm:1]** **[1937653_0001193125-25-193351_d88452d8k.htm:2]** 
- The decision was made after completing the planned cohorts of the dose escalation portion of the Phase 1 trial, as further dose evaluation was deemed unlikely to support a benefit-risk profile consistent with the desired monotherapy target product profile.  **[1937653_0001193125-25-193351_d88452dex991.htm:0]** **[1937653_0001193125-25-193351_d88452d8k.htm:2]** 
- Dose-limiting toxicities consistent with mesothelin-related on-target off-tumor toxicity were observed in the Phase 1 study.  **[1937653_0001193125-25-193351_d88452dex991.htm:0]** 
- Zymeworks will continue to advance its broader product pipeline, including the ongoing Phase 1 trial of ZW191, the expected initiation of a Phase 1 study for ZW251 in **2025**, and an IND filing for ZW209 planned for the first half of **2026**.  **[1937653_0001193125-25-193351_d88452dex991.htm:0]** **[1937653_0001193125-25-193351_d88452dex991.htm:1]**

Zymeworks Discontinues Clinical Development of ZW171

Zymeworks (ZYME)