Hong Kong – September 16, 2026 -- Akeso, Inc. (9926.HK) reported that its bispecific antibody ivonescimab reduced the risk of death by 27% compared with Merck's pembrolizumab in a Phase III trial of PD-L1-positive non-small cell lung cancer (NSCLC), with results presented as a Late-Breaking Abstract at the 2026 World Conference on Lung Cancer (WCLC).
Ivonescimab extends median survival to 30.8 months in head-to-head trial
In the intention-to-treat population of the HARMONi-2 study (AK112-303), patients treated with ivonescimab monotherapy achieved a median overall survival (OS) of 30.8 months versus 22.6 months for pembrolizumab (HR=0.73; 95% CI: 0.57–0.95; P=0.009). The data cutoff was August 20, 2026, with a median follow-up of 36 months and 234 OS events recorded. Professor Caicun Zhou, principal investigator and IASLC President, is scheduled to deliver the full oral presentation on September 15.
Benefit strengthens to 42% risk reduction in high PD-L1 expressers
The survival advantage was consistent across prespecified subgroups but most pronounced in patients with PD-L1 tumor proportion score (TPS) ≥50%, where the hazard ratio reached 0.58 (95% CI: 0.38–0.89), equating to a 42% reduction in death risk. In the TPS 1–49% subgroup, the HR was 0.85 (95% CI: 0.61–1.18), a 15% relative reduction.
Drug shows benefit in squamous patients typically excluded from anti-VEGF therapy
Squamous NSCLC patients made up 45.5% of the trial population, including cohorts with central tumors (72.2%), tumor cavitation or necrosis (10.0%), and tumors encasing major vessels (6.7%) -- profiles traditionally considered contraindicated for anti-VEGF agents due to bleeding risk. Akeso reported no apparent increase in bleeding events in this high-risk group, with squamous patients showing an OS HR of 0.65 (95% CI: 0.45–0.95), a 35% risk reduction. Non-squamous patients recorded an HR of 0.79 (95% CI: 0.55–1.14), a 21% reduction.
Trial becomes first to post dual-positive OS and PFS data against pembrolizumab
An interim analysis in May 2024 had already shown ivonescimab meeting its primary progression-free survival (PFS) endpoint, with median PFS of 11.14 months versus 5.82 months for pembrolizumab (HR=0.51, P0.0001). Akeso said HARMONi-2 is the first randomized, double-blind, controlled Phase III study to report statistically significant positive results for both OS and PFS against pembrolizumab. The indication was approved in China in 2025, and Akeso reported no new safety signals, with safety profiles broadly consistent between treatment arms.
Company advances second Phase III trial targeting PD-L1-high patients globally
Akeso is running an international multicenter Phase III trial, HARMONi-7 (AK112-3007), testing ivonescimab monotherapy against pembrolizumab specifically in PD-L1-high NSCLC patients. The company said the drug has now delivered dual-positive OS and PFS results across multiple Phase III head-to-head trials against PD-1/L1 therapies and is being expanded into additional solid tumor indications beyond lung cancer.