Summit's ivonescimab misses the early squamous PFS bar in HARMONi-3; final readout still due in 2026

Summit Therapeutics/Ivonescimab

Summit Therapeutics reported an interim progression-free survival analysis from the squamous lung cancer cohort of its Phase 3 HARMONi-3 trial, which compares ivonescimab plus chemotherapy with Keytruda. The result did not clear the statistical bar set for an earlier regulatory filing, and Summit's shares fell about 26%. An independent data monitoring committee recommended the trial continue unchanged.

• The interim analysis was meant to open talks with regulators ahead of a possible early filing; it did not meet the threshold for that.
• The independent data monitoring committee recommended the study continue as planned, and the trial remains double-blinded.
• Summit says it remains on track for the pre-planned final progression-free survival readout in the second half of 2026.
• Summit shares closed nearly 26% lower at $16.12 after the release.