---
schema_version: "secwatch.filing_event.v1"
accession: "0001599298-25-000099"
form_type: "8-K"
ticker: "SMMT"
cik: "0001599298"
company_name: "Summit Therapeutics Inc."
filed_at: "2025-05-30T23:59:59+00:00"
generated_at: "2026-05-20T04:27:51.065153+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Summit's ivonescimab meets PFS endpoint in global Phase III HARMONi; OS trend positive

## Summary
- Ivonescimab + chemo reduced risk of progression or death by 48% vs chemo alone (HR 0.52; p<0.00001).
- Overall survival showed positive trend (HR 0.79; p=0.057), not statistically significant.
- No new safety signals; Grade 3+ TEAEs 56.9% ivonescimab arm vs 50.0% control.
- Summit plans to file BLA with FDA but notes FDA requires statistically significant OS benefit.
- Consistent PFS benefit observed across Asia and ex-Asia (including North America) sub-populations.

## SEC filing metadata
- accession: 0001599298-25-000099
- form_type: 8-K
- ticker: SMMT
- cik: 0001599298
- company_name: Summit Therapeutics Inc.
- filed_at: 2025-05-30T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1599298/000159929825000099/0001599298-25-000099-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1599298/000159929825000099/smmt-20250530.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001599298-25-000099
- JSON: https://secwatch.observer/filing/0001599298-25-000099.json
- Plain text: https://secwatch.observer/filing/0001599298-25-000099.txt

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