---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-193351"
form_type: "8-K"
ticker: "ZYME"
cik: "0001937653"
company_name: "Zymeworks Inc."
filed_at: "2025-09-02T23:59:59+00:00"
generated_at: "2026-05-17T08:59:34.418395+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Zymeworks discontinues ZW171 Phase 1 after dose escalation; benefit-risk profile unfavorable

## Summary
- Decision based on completed dose escalation in ovarian and NSCLC patients; MTD established but benefit-risk not supportive.
- Dose-limiting toxicities consistent with mesothelin-related on-target off-tumor toxicity; CRS was well-managed.
- Ongoing participants may continue at investigator discretion; discontinued patients remain in safety follow-up.
- Pipeline continues: ZW191 Phase 1 ongoing, ZW251 Phase 1 expected 2025, ZW209 IND filing planned H1 2026.

## SEC filing metadata
- accession: 0001193125-25-193351
- form_type: 8-K
- ticker: ZYME
- cik: 0001937653
- company_name: Zymeworks Inc.
- filed_at: 2025-09-02T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1937653/000119312525193351/0001193125-25-193351-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1937653/000119312525193351/d88452d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-193351
- JSON: https://secwatch.observer/filing/0001193125-25-193351.json
- Plain text: https://secwatch.observer/filing/0001193125-25-193351.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.