Summit Therapeutics (SMMT) Status update summary

HARMONi-6 Phase III Trial Results

• Ivonescimab plus chemotherapy demonstrated a statistically significant overall survival benefit over tislelizumab plus chemotherapy in advanced squamous NSCLC, with a hazard ratio of 0.66 and median OS of 27.89 vs. 23.69 months; 24-month OS rates were 64.7% vs. 48.6%.

• The OS benefit was consistent across all PD-L1 expression subgroups, with hazard ratios of 0.64–0.68, and across age, sex, ECOG PS, disease stage, and metastatic burden.

• Safety profile was manageable, with serious adverse events in 41.4% (ivonescimab) vs. 34.3% (tislelizumab), grade ≥3 TRAEs in 69.2% vs. 58.9%, and discontinuation rates of 5.3% vs. 4.5%; most VEGF-related events were mild.

• This is the first randomized phase III trial to show a significant OS benefit over another PD-1 therapy plus chemotherapy in this setting, suggesting ivonescimab could become a new standard of care.

• Results were presented at ASCO 2026 and published in The Lancet.

Study Design and Patient Characteristics

• Phase III, multicenter, randomized, double-blind trial compared ivonescimab plus chemotherapy to tislelizumab plus chemotherapy in untreated advanced squamous NSCLC (N=532).

• Key eligibility: stage IIIB-IV, ECOG PS 0-1, no prior systemic therapy, no EGFR/ALK alterations.

• Baseline characteristics were well balanced between arms, including age, sex, disease stage, and PD-L1 expression.

Mechanism and Development Program

• Ivonescimab is a first-in-class PD-1/VEGF bispecific antibody designed for higher tumor selectivity and improved efficacy.

• Over 4,000 patients have been treated in clinical studies, and more than 70,000 in commercial settings in China.

• Fifteen Phase III studies are ongoing or completed, including global and China-based trials in NSCLC, CRC, and other cancers.