$SMMT · Summit Therapeutics Inc.

Summit Therapeutics issued an 8-K on September 15, 2026, announcing updated overall survival results from the Phase III HARMONi trial presented at WCLC 2026. The June 2026 data cut showed an improved OS hazard ratio of 0.76 (95% CI: 0.61–0.95; nominal p=0.0151) for ivonescimab plus chemotherapy vs. placebo plus chemotherapy in EGFR-mutated NSCLC. The western patient subgroup HR also reached 0.76 (95% CI: 0.52–1.10) with 23.2 months median follow-up, consistent with the Asian subgroup. Separately, Akeso presented HARMONi-2 data showing ivonescimab monotherapy achieved a statistically superior 0

Stock up +4.96% to $18.42 in regular session following the data presentation. The improving OS trend and western subgroup consistency are being interpreted positively by the market, reinforcing the BLA narrative ahead of the November PDUFA date.

The western subgroup OS HR converging to 0.76 removes a key overhang from the April 2025 primary analysis (HR 0.98), strengthening the BLA package two months before the PDUFA date.

Ivonescimab's bispecific PD-1/VEGF mechanism continues to differentiate from Keytruda in head-to-head China data (HARMONi-2 HR 0.73). Summit is building a global Phase III program across NSCLC, CRC, BTC, and bladder cancer with five positive readouts to date.

The HARMONi primary OS analysis (April 2025) narrowly missed statistical significance (p=0.057). The updated analyses use nominal p-values, and the western subgroup (n=165) remains underpowered with a wide confidence interval (0.52–1.10). FDA approval is not guaranteed.