---
schema_version: "secwatch.filing_event.v1"
accession: "0001599298-25-000166"
form_type: "8-K"
ticker: "SMMT"
cik: "0001599298"
company_name: "Summit Therapeutics Inc."
filed_at: "2025-11-07T23:59:59+00:00"
generated_at: "2026-05-16T23:04:43.869042+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Ivonescimab + chemo shows OS benefit in EGFRm NSCLC; HR 0.74 in HARMONi-A final analysis

## Summary
- Final OS analysis: ivonescimab+chemo vs chemo achieved HR 0.74 (95% CI: 0.58-0.95, p=0.019); median OS 16.8 vs 14.1 months.
- First Phase III study of ivonescimab to show statistically significant OS benefit; prior HARMONi showed PFS benefit.
- Over 40,000 patients treated with ivonescimab in China in clinical/commercial settings.
- Safety manageable: TRAE discontinuation 11.2% vs 6.2%; no additional TRAE deaths vs chemo alone.
- Global HARMONi study subsequent OS analysis: HR 0.78 (nominal p=0.0332) consistent with primary HR 0.79.

## SEC filing metadata
- accession: 0001599298-25-000166
- form_type: 8-K
- ticker: SMMT
- cik: 0001599298
- company_name: Summit Therapeutics Inc.
- filed_at: 2025-11-07T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1599298/000159929825000166/0001599298-25-000166-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1599298/000159929825000166/smmt-20251107.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001599298-25-000166
- JSON: https://secwatch.observer/filing/0001599298-25-000166.json
- Plain text: https://secwatch.observer/filing/0001599298-25-000166.txt

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