Abstract
OBJECTIVES: Perioperative pembrolizumab plus neoadjuvant chemotherapy significantly improved outcomes versus neoadjuvant chemotherapy alone in early-stage, resectable, non-small-cell lung cancer (NSCLC) in the phase 3 KEYNOTE-671 study. We report outcomes in participants with baseline clinical stage II disease. METHODS: Participants with untreated, resectable, stage II-IIIB (N2) NSCLC were randomized 1:1 to receive pembrolizumab 200 mg or placebo every 3 weeks plus chemotherapy for 4 cycles, followed by surgery and adjuvant pembrolizumab or placebo for 13 cycles (∼9 months). Exploratory analyses were performed in participants with clinical stage II disease. RESULTS: Of 797 randomized participants, 239 had stage II disease (pembrolizumab plus chemotherapy, n = 118; chemotherapy only, n = 121). Median study follow-up at data cutoff (August 19, 2024) was 49.9 (range, 32.2-75.3) months. Among participants who underwent surgery, 94/99 (94.9%) had R0 resections in the pembrolizumab arm and 89/103 (86.4%) in the neoadjuvant chemotherapy only arm. Event-free survival (hazard ratio [HR], 0.50; 95% CI, 0.34-0.74), overall survival (HR, 0.69; 95% CI, 0.43-1.11), major pathological response (difference, 25.7%; 95% CI, 15.3-35.9), and pathological complete response (difference, 21.3%; 95% CI, 13.2-30.2) were improved in the pembrolizumab arm. Grade 3-4 treatment-related adverse events (AEs) occurred in 50.0% of participants treated with pembrolizumab plus chemotherapy and 40.5% with chemotherapy; no treatment-related AEs led to death. CONCLUSIONS: In participants with stage II NSCLC, perioperative pembrolizumab improved efficacy outcomes with manageable safety versus neoadjuvant chemotherapy alone, consistent with the overall KEYNOTE-671 population. These results support the use of this regimen in patients with stage II disease. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03425643, registered/first posted on February 7, 2018 (https://www.clinicaltrials.gov/study/NCT03425643).