Ivonescimab cut lung cancer death risk 34%. Akeso’s PD-1xVEGF bispecific delivered the first overall survival win over a PD-1 plus chemo regimen in first-line squamous NSCLC, beating out BeOne Medicines’ tislelizumab in the phase 3 HARMONi-6 trial.
The HARMONi-6 interim analysis, selected for the ASCO 2026 plenary session and published in The Lancet, enrolled 532 Chinese patients. Median OS reached 27.9 months versus 23.7 months (HR 0.66, p=0.0017), clearing the prespecified significance boundary of 0.0049. The 24-month survival rate was 64.7% versus 48.6%.
VEGF inhibitors were historically banned in squamous NSCLC because of hemorrhage risk. It’s a restriction that ivonescimab’s bispecific design has changed: grade 3-plus bleeding was 2.6% in the treatment arm versus 0.8% with tislelizumab, and the benefit appeared consistent across both PD-L1-negative and PD-L1-positive patients.
ASCO discussant Julie Brahmer of Johns Hopkins called the data “provocative” rather than globally practice-changing. Harmoni-6 excluded patients older than 75, a serious limitation given the U.S. median lung cancer age approaches 70. In patients 65 and older, Brahmer said ivonescimab’s survival benefit essentially disappeared, with the hazard ratio near 1. She also flagged near-exclusive male enrollment and eligibility criteria for vascular invasion that practicing oncologists can’t easily apply at the bedside.
Summit Therapeutics, Akeso’s global development partner, won’t be able to move on these results with Western regulators until the next wave of global Harmoni studies delivers. Summit holds ex-China rights to ivonescimab, but HARMONi-6’s China-only enrollment means the dataset cannot serve as a standalone basis for a U.S. or European regulatory filing. Brahmer made the requirement plain: “We really do need that next wave of Harmoni studies.”
Sarah Chen