Akeso’s ivonescimab cut the risk of death by 34% versus tislelizumab plus chemotherapy in first-line squamous NSCLC, posting an overall survival hazard ratio of 0.66 in the 532-patient HARMONi-6 trial. Median OS landed at 27.9 months against 23.7 months for the comparator arm; the four-month gap is what one KOL told Truist would be “clinically meaningful and practice changing.” Results hit the plenary session at ASCO on Sunday.
The number cleared every bar analysts set. Leerink pegged the OS HR “trending towards 0.80” before the read; 0.70 to 0.72 would have been called very good. A separate expert said 0.75 or lower would be “a complete game changer” and doubted ivonescimab could reach 0.6. It didn’t just approach 0.6 — it landed there.
For US partner Summit Therapeutics, the data matters beyond the China story. Summit already filed a biologics license application for ivonescimab in EGFR-mutated non-squamous NSCLC; FDA’s PDUFA date is November 14. A strong HARMONi-6 read relieves pressure from HARMONi-3, whose early interim PFS analysis didn’t reach statistical significance in May, killing Summit’s plans for an earlier regulatory filing in squamous NSCLC.
The harder question is whether HR 0.66 holds in a Western population. HARMONi-6 enrolled about 90% male smokers, a population that may derive more benefit from immuno-oncology agents than HARMONi-3’s more heterogeneous global cohort. If the HR degrades materially from China to global, the narrative shifts from “ivonescimab beats Keytruda” to “ivonescimab beats Keytruda in Chinese male smokers.” Final PFS and interim OS from HARMONi-3 are due in the second half of 2026.
HARMONi-3 non-squamous cohort data arrives in the first half of 2027.
— Sarah Chen