---
schema_version: "secwatch.filing_event.v1"
accession: "0001599298-26-000078"
form_type: "8-K"
ticker: "SMMT"
cik: "0001599298"
company_name: "Summit Therapeutics Inc."
filed_at: "2026-09-14T12:37:42+00:00"
generated_at: "2026-09-14T12:40:25.014726+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Ivonescimab HARMONi-2 shows OS benefit: HR 0.73, median OS 30.8 vs 22.6 months vs pembrolizumab

## Summary
- HARMONi-2 OS HR 0.73 (95% CI 0.57-0.95; p=0.009); median OS 30.8 vs 22.6 months.
- PD-L1 high subgroup HR 0.58; PD-L1 low HR 0.85; squamous HR 0.65; non-squamous HR 0.79.
- Serious TRAEs: 29.9% (ivonescimab) vs 21.6% (pembrolizumab); discontinuation 4.1% vs 5.0%.
- Summit's global Phase III HARMONi-7 (NCT06767514) targets 780 patients with PD-L1 high-expressing NSCLC.

## SEC filing metadata
- accession: 0001599298-26-000078
- form_type: 8-K
- ticker: SMMT
- cik: 0001599298
- company_name: Summit Therapeutics Inc.
- filed_at: 2026-09-14T12:37:42+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1599298/000159929826000078/0001599298-26-000078-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1599298/000159929826000078/smmt-20260913.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001599298-26-000078
- JSON: https://secwatch.observer/filing/0001599298-26-000078.json
- Plain text: https://secwatch.observer/filing/0001599298-26-000078.txt

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