---
schema_version: "secwatch.filing_event.v1"
accession: "0001599298-23-000092"
form_type: "8-K"
ticker: "SMMT"
cik: "0001599298"
company_name: "Summit Therapeutics Inc."
filed_at: "2023-10-31T23:59:59+00:00"
generated_at: "2026-06-09T04:43:37.065023+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Ivonescimab shows 18-fold increased PD-1 binding affinity in presence of VEGF at SITC

## Summary
- Poster at SITC 2023 details cooperative binding: 18x higher PD-1 affinity with VEGF present in vitro.
- Tetravalent bispecific antibody designed for higher avidity in tumor microenvironment vs. healthy tissue.
- Ongoing Phase III trials HARMONi (EGFR-mutated NSCLC) and HARMONi-3 (squamous NSCLC).
- Over 950 patients treated with ivonescimab across studies in China, Australia, and Summit territories.

## SEC filing metadata
- accession: 0001599298-23-000092
- form_type: 8-K
- ticker: SMMT
- cik: 0001599298
- company_name: Summit Therapeutics Inc.
- filed_at: 2023-10-31T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1599298/000159929823000092/0001599298-23-000092-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1599298/000159929823000092/smmt-20231031.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001599298-23-000092
- JSON: https://secwatch.observer/filing/0001599298-23-000092.json
- Plain text: https://secwatch.observer/filing/0001599298-23-000092.txt

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