Carboplatin-paclitaxel/nab-paclitaxel with or without pembrolizumab in first-line metastatic squamous NSCLC: Results from the KEYNOTE-407 east Asia subgroup

Abstract

Background: Primary results from the global, randomized, double-blind, phase 3 KEYNOTE- 407 study (NCT02775435) demonstrated superior OS, PFS, and ORR with pembrolizumab plus carboplatin and paclitaxel or nab-paclitaxel (chemo) in patients with previously untreated squamous NSCLC. Here we report results from the East Asia subgroup of Methods: In KEYNOTE-407, patients with untreated metastatic squamous NSCLC were randomized 1:1 to carboplatin 6 mg/mL/min and paclitaxel 200 mg/m2Q3W or nab-paclitaxel 100 mg/m2weekly (investigator's choice) plus pembrolizumab or saline placebo Q3W for 4 cycles followed by pembrolizumab or placebo Q3W for a total of 35 treatment cycles. Randomization was stratified by taxane (paclitaxel vs nab-paclitaxel), PD-L1 (tumor proportion score [TPS] <1% vs ≥ 1%), and region (East Asia vs other). Primary endpoints were OS and PFS (by blinded independent central review [BICR]); ORR by BICR was a secondary endpoint. For the East Asia subgroup, OS and PFS HRs were estimated using an unstratified Cox regression model; between-group difference in ORR was estimated using an unstratified Miettinen & Nurminen method. Results: Of 559 patients randomized globally, 106 (19.0%) with largely similar baseline characteristics were enrolled from East Asia (pembrolizumab plus chemo, n = 54; placebo plus chemo, n = 52). After median follow-up of 6.7 (range, 0.5-18.9) mo among patients from East-Asia, median (95% CI) OS (16.6 [16.6-NR] mo vs 9.5 [7.5-NR] mo) and PFS (6.3 [5.3-10.2] mo vs 4.1 [3.5-5.2] mo) were longer in those who received pembrolizumab plus chemo vs placebo plus chemo, with HRs of 0.44 [95% CI, 0.22-0.89] and 0.49 [95% CI, 0.30-0.82], respectively. ORR was 63.0% vs 34.6%, respectively (ORR difference, 28.3% [95% CI, 9.3-45.4]). Grade ≥3 AEs occurred in 83.3% of patients in the pembrolizumab plus chemo arm vs 80.8% of those in the placebo plus chemo arm. Conclusions: Consistent with overall results from KEYNOTE-407, pembrolizumab plus chemo extended OS and PFS, and almost doubled ORR vs placebo plus chemo in patients from East Asia with previously untreated metastatic squamous NSCLC. No new safety signals were observed.