secwatch.observer — SEC 8-K summary
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Issuer:     Summit Therapeutics Inc. (SMMT)
CIK:        0001599298
Form:       8-K
Filed at:   2026-06-01T10:57:20+00:00
Accession:  0001599298-26-000043
Event type: other_material
Sentiment:  positive
Materiality: 0.85
Item codes: 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Ivonescimab: 70.8% ORR in mCRC Phase II; HARMONi-6 OS HR 0.66 vs tislelizumab
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- Phase II AK112-206 in 1L mCRC: ORR 70.8%, DCR 100.0% in evaluable patients (n=48); 9-month PFS rate 76.1% for 20 mg/kg arm.
- HARMONi-6 Phase III in squamous NSCLC: OS HR 0.66 (p=0.0017) vs tislelizumab + chemo; 24-month OS rates 64.7% vs 48.6%.
- Ivonescimab + chemo reduced risk of death by 34% vs tislelizumab; first Phase III to show significant OS benefit over anti-PD-1 + chemo in 1L NSCLC.
- Safety profiles manageable; no new safety signals; TRAEs leading to discontinuation in HARMONi-6: 5.3% vs 4.5%.
- Data presented at ASCO 2026; HARMONi-6 results simultaneously published in The Lancet; Summit to host conference call June 1.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1599298/000159929826000043/0001599298-26-000043-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1599298/000159929826000043/smmt-20260530.htm
  HTML page:      https://secwatch.observer/filing/0001599298-26-000043

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer