Ivonescimab plus chemotherapy versus tislelizumab plus chemotherapy as first-line treatment for advanced squamous non-small-cell lung cancer (HARMONi-6): a randomised, double-blind, phase 3 trial

Background: Squamous non-small-cell lung cancer (NSCLC) is associated with worse clinical outcomes than non-squamous NSCLC, but treatment options are scarce. We aimed to evaluate the efficacy and safety of ivonescimab plus chemotherapy versus tislelizumab plus chemotherapy as a first-line therapy for patients with advanced squamous NSCLC.

Methods: We conducted a randomised, double-blind, phase 3 trial at 50 sites across China (HARMONi-6). Patients aged 18-75 years with previously untreated, pathologically confirmed, unresectable stage IIIB, IIIC, or stage IV squamous NSCLC and an Eastern Cooperative Oncology Group performance status score of 0 or 1 were eligible for inclusion. Patients were randomly assigned (1:1) to receive intravenous ivonescimab (20 mg/kg) or tislelizumab (200 mg), plus intravenous paclitaxel (175 mg/m 2) and carboplatin (area under the curve 5 mg/mL per min) once every 3 weeks for four cycles, followed by ivonescimab (20 mg/kg) or tislelizumab (200 mg) monotherapy as maintenance treatment for up to 24 months. Randomisation was stratified by disease stage (IIIB or IIIC vs IV) and PD-L1 tumour proportion score (≥1% vs <1%). The primary endpoint was progression-free survival assessed by the independent radiographic review committee as per Response Evaluation Criteria in Solid Tumours guidelines (version 1.1) in all randomly assigned patients. Safety, defined as adverse events and serious adverse events related to treatment, as well as adverse events related to immunity or VEGF blockade, were analysed in all randomly assigned patients who received at least one dose of the assigned study treatment. This study is registered at ClinicalTrial.gov (NCT05840016), has completed enrolment, and is ongoing for treatment and follow-up.

Findings: From Aug 17, 2023, to Jan 21, 2025, 761 patients were screened for eligibility, among whom 532 (70%) patients were enrolled and randomly assigned to receive ivonescimab plus chemotherapy (266 [50%] patients) or tislelizumab plus chemotherapy (266 [50%] patients). at Feb 28, 2025, median follow-up time was 10·3 months (95% CI 9·5-11·0). Median progression-free survival was 11·1 months (95% CI 9·9-not evaluable) in the ivonescimab group and 6·9 months (5·8-8·6) in the tislelizumab group (hazard ratio 0·60 [95% CI 0·46-0·78]; one-sided p<0·0001). The progression-free survival benefit with ivonescimab plus chemotherapy was consistent regardless of PD-L1 status. 170 (64%) patients in the ivonescimab group and 144 (54%) patients in the tislelizumab group had grade 3 or higher treatment-related adverse events, with grade 3 or higher immune-related adverse events occurring in 24 (9%) patients in the ivonescimab group and in 27 (10%) patients in the tislelizumab group. Grade 3 or higher treatment-related haemorrhage occurred in five (2%) patients in the ivonescimab group and in two (1%) patients in the tislelizumab group.

Interpretation: In patients with untreated advanced squamous NSCLC, ivonescimab plus chemotherapy showed significantly improved progression-free survival compared with tislelizumab plus chemotherapy, regardless of PD-L1 status, as well as a manageable safety profile. This regimen could be used as a novel first-line treatment in this patient group.

Funding: Akeso Biopharma.

Indexed on Europe PMC as PubMed record 41125109 (DOI 10.1016/s0140-6736(25)01848-3). Its abstract cites the registry id NCT05840016, which is how it was matched to this trial; no figure has been checked by an editor.