HARMONi-2: Ivonescimab Cuts Death Risk 27% Versus Pembrolizumab in First-Line PD-L1-Positive NSCLC

The phase III HARMONi-2 trial has demonstrated a statistically significant overall survival benefit with ivonescimab查看药品详情, a PD-1 (搜索)搜索该靶点/VEGF (搜索)搜索该靶点 bispecific antibody, compared with pembrolizumab查看药品详情 monotherapy in previously untreated PD-L1 (搜索)搜索该靶点-positive advanced non-small cell lung cancer (搜索)搜索该疾病. The second prespecified interim OS analysis, presented at the 2026 World Conference on Lung Cancer in Seoul, showed a median overall survival of 30.8 months with ivonescimab versus 22.6 months with pembrolizumab, corresponding to a 27% reduction in the risk of death (HR 0.73; 95% CI, 0.57-0.95; P=0.009).

The result is clinically relevant because HARMONi-2 directly compared two chemotherapy-free first-line immunotherapy strategies in patients with a PD-L1 (搜索)搜索该靶点 tumor proportion score of at least 1% and no sensitizing EGFR (搜索)搜索该靶点 or ALK (搜索)搜索该靶点 alterations. Ivonescimab查看药品详情 had already demonstrated a substantial progression-free survival advantage; the new analysis shows that improved disease control translated into longer survival.

Trial Design and Prior Progression-Free Survival Data

HARMONi-2 was a randomized, double-blind phase III trial enrolling 398 patients with previously untreated stage IIIB-IV NSCLC and PD-L1 (搜索)搜索该靶点 TPS of at least 1%. Patients were required to have ECOG performance status 0 or 1 and no EGFR (搜索)搜索该靶点 mutations or ALK (搜索)搜索该靶点 alterations. They were randomized 1:1 to receive ivonescimab查看药品详情 20 mg/kg every three weeks or pembrolizumab查看药品详情 200 mg every three weeks for up to 24 months or until loss of clinical benefit or unacceptable toxicity. Randomization was stratified by disease stage, squamous versus nonsquamous histology, and PD-L1 expression of 1%-49% versus at least 50%.

The primary endpoint was independently assessed PFS, with OS as the key secondary endpoint. The trial had already reported a median PFS of 11.1 months with ivonescimab查看药品详情 versus 5.8 months with pembrolizumab查看药品详情, with an HR of 0.51, representing a 49% reduction in the risk of progression or death.

Survival Separation Persists at Three Years

At the August 20, 2026 cutoff, 234 OS events had occurred and median follow-up was approximately 36 months. The result crossed the prespecified statistical boundary at the second interim analysis. Landmark survival rates showed persistent separation: at 24 months, OS was 57.9% with ivonescimab查看药品详情 versus 48.0% with pembrolizumab查看药品详情, and at 36 months, 45.0% versus 33.1%.

The OS HR of 0.73 is less pronounced than the PFS HR of 0.51, a pattern the investigators noted is common in first-line metastatic trials where subsequent therapies can influence survival. The trial nonetheless provides randomized evidence that simultaneously targeting the PD-1 (搜索)搜索该靶点 and VEGF (搜索)搜索该靶点 pathways improves long-term outcomes compared with PD-1 blockade alone in this population.

PD-L1 Subgroups Show Divergent Signal Strength

Among patients with PD-L1 (搜索)搜索该靶点 TPS of at least 50%, median OS had not been reached with ivonescimab查看药品详情 compared with 23.2 months with pembrolizumab查看药品详情, with an HR for death of 0.58 (95% CI, 0.38-0.89). At 24 months, OS was 63.2% versus 49.7%, and by 36 months the difference had widened to 53.4% versus 31.3%. The investigators cautioned that this subgroup analysis was descriptive and not formally powered, so the magnitude of benefit should not be treated as a definitive independent estimate.

In the PD-L1 (搜索)搜索该靶点 TPS 1%-49% subgroup, median OS was 28.5 months with ivonescimab查看药品详情 versus 22.1 months with pembrolizumab查看药品详情, with an HR of 0.85 (95% CI, 0.61-1.18). The confidence interval crosses 1, meaning this subgroup analysis does not establish a statistically significant survival benefit on its own. At 24 months, survival was 54.1% versus 46.8%, and at 36 months 38.6% versus 34.1%. The distinction is clinically important because pembrolizumab monotherapy is not the dominant first-line strategy for many patients with PD-L1 1%-49% disease in routine international practice, where chemoimmunotherapy is often used for its greater initial disease-control potential.

By histology, the reported OS HR was 0.65 (95% CI, 0.45-0.95) for squamous NSCLC and 0.79 (95% CI, 0.55-1.14) for nonsquamous disease. These subgroup comparisons were not independently powered.

Toxicity Burden Higher With Dual PD-1/VEGF Blockade

Any-grade treatment-related adverse events occurred in 93.4% of patients receiving ivonescimab查看药品详情 compared with 84.9% receiving pembrolizumab查看药品详情. Grade 3 or higher TRAEs were more frequent with ivonescimab at 41.6% versus 21.6%, and serious treatment-related adverse events occurred in 29.9% versus 21.6%. Permanent treatment discontinuation due to TRAEs remained relatively similar at 4.1% with ivonescimab and 5.0% with pembrolizumab, and treatment-related deaths occurred in 0.5% and 1.5%, respectively.

VEGF (搜索)搜索该靶点-related toxicities reflected the drug's mechanism. Proteinuria occurred in 48.2% of patients receiving ivonescimab查看药品详情, including grade 3 or higher events in 8.1%, compared with 13.1% with pembrolizumab查看药品详情. Hypertension occurred in 20.3%, with grade 3 or higher hypertension in 7.1%, compared with 3.0% and 0.5% with pembrolizumab. Bleeding-related events included hematuria, hemoptysis, epistaxis, and gingival bleeding, although most were low grade, and investigators reported no apparent overall increase in clinically significant bleeding risk. The median duration of exposure was longer with ivonescimab at 14 treatment cycles versus 10 with pembrolizumab, a factor to consider when comparing crude adverse-event incidence.

Geographic Limitation and Remaining Questions

All 398 patients were enrolled at centers in China. The investigators stated that this does not diminish the internal validity of the randomized comparison but matters when extrapolating the exact magnitude of benefit to populations in Europe, North America, Latin America, and other regions, given potential differences in patient characteristics, tumor epidemiology, treatment after progression, and supportive care. The presentation compared pembrolizumab查看药品详情 outcomes from HARMONi-2 with historical data from the Chinese KEYNOTE-042 population, showing broadly compatible results, but cross-trial comparisons cannot substitute for international randomized validation.

The biological rationale for the bispecific design extends beyond combining two anticancer pathways. VEGF (搜索)搜索该靶点 promotes angiogenesis and contributes to an immunosuppressive tumor microenvironment by affecting immune-cell trafficking, antigen presentation, vascular architecture, and T-cell function. Simultaneous inhibition of PD-1 (搜索)搜索该靶点 and VEGF may therefore enhance antitumor immunity through complementary mechanisms.

HARMONi-2 answers a specific question: ivonescimab查看药品详情 is superior to pembrolizumab查看药品详情 monotherapy in the studied population. It does not establish superiority over every contemporary first-line NSCLC regimen. The open questions are how the strategy compares with modern chemoimmunotherapy, whether the magnitude of benefit is reproduced internationally, and which patients derive the greatest advantage from combined immune and angiogenic inhibition.