First-line nivolumab plus ipilimumab combined with two cycles of chemotherapy in patients with non-small-cell lung cancer (CheckMate 9LA): an international, randomised, open-label, phase 3 trial

First-line nivolumab plus ipilimumab has shown improved overall survival in patients with advanced non-small-cell lung cancer (NSCLC). We aimed to investigate whether the addition of a limited course (two cycles) of chemotherapy to this combination would further enhance the clinical benefit. This randomised, open-label, phase 3 trial was done at 103 hospitals in 19 countries. Eligible patients were aged 18 years or older with treatment-naive, histologically confirmed stage IV or recurrent NSCLC, and an Eastern Cooperative Oncology Group performance status of 0–1. Patients were randomly assigned (1:1) by an interactive web response system via permuted blocks (block size of four) to nivolumab (360 mg intravenously every 3 weeks) plus ipilimumab (1 mg/kg intravenously every 6 weeks) combined with histology-based, platinum doublet chemotherapy (intravenously every 3 weeks for two cycles; experimental group), or chemotherapy alone (every 3 weeks for four cycles; control group). Randomisation was stratified by tumour histology, sex, and PD-L1 expression. The primary endpoint was overall survival in all randomly assigned patients. Safety was analysed in all treated patients. Results reported here are from a pre-planned interim analysis (when the study met its primary endpoint) and an exploratory longer-term follow-up analysis. This study is active but no longer recruiting patients, and is registered with ClinicalTrials.gov, number NCT03215706. Between Aug 24, 2017, and Jan 30, 2019, 1150 patients were enrolled and 719 (62·5%) randomly assigned to nivolumab plus ipilimumab with two cycles of chemotherapy (n=361 [50%]) or four cycles of chemotherapy alone (n=358 [50%]). At the pre-planned interim analysis (median follow-up 9·7 months [IQR 6·4–12·8]), overall survival in all randomly assigned patients was significantly longer in the experimental group than in the control group (median 14·1 months [95% CI 13·2–16·2] vs 10·7 months [9·5–12·4]; hazard ratio [HR] 0·69 [96·71% CI 0·55–0·87]; p=0·00065). With 3·5 months longer median follow-up (median 13·2 months [IQR 6·4–17·0]), median overall survival was 15·6 months (95% CI 13·9–20·0) in the experimental group versus 10·9 months (9·5–12·6) in the control group (HR 0·66 [95% CI 0·55–0·80]). The most common grade 3–4 treatment-related adverse events were neutropenia (in 24 [7%] patients in the experimental group vs 32 [9%] in the control group), anaemia (21 [6%] vs 50 [14%]), diarrhoea (14 [4%] vs two [1%]), increased li