First-line carboplatin and pemetrexed (CP) with or without pembrolizumab (pembro) for advanced nonsquamous NSCLC: Updated results of KEYNOTE-021 cohort G.

Abstract

9094 Background: Data from the randomized, phase 2 cohort G of KEYNOTE-021 (NCT02039674) showed that adding pembro to first-line CP in patients (pts) with advanced nonsquamous NSCLC significantly improved the primary end point of ORR (55% vs 29%, P = 0.0016) and the key secondary end point of PFS (HR 0.53, P= 0.0102) compared with CP alone and had a manageable safety profile (grade 3-4 treatment-related AEs, 39% vs 26%; treatment-related AEs leading to discontinuation, 10% vs 13%). We present updated efficacy for cohort G based on 5 mo additional follow-up. Methods: 123 pts with stage IIIB/IV, chemotherapy-naive, nonsquamous NSCLC and no EGFR mutation or ALK translocation were randomized to 4 cycles of carboplatin AUC 5 + pemetrexed 500 mg/m2 Q3W ± 24 mo of pembro 200 mg Q3W; maintenance pemetrexed was permitted in both arms. Eligible pts in the CP arm who had radiologic progression could crossover to pembro monotherapy. Response was assessed per RECIST v1.1 by blinded, independent central review. All Pvalues are nominal. Results: As of Dec 31, 2016, median follow-up was 14.5 mo (range, 0.8-24.0). 36 of 48 pts (75.0%) in the CP arm who discontinued CP received subsequent anti–PD-1 or PD-L1 therapy. There was 1 additional response in each arm, and ORR was 56.7% (95% CI 43.2%-69.4%) with pembro + CP vs 30.2% (95% CI 19.2%-43.0%) with CP ( P = 0.0016). Median DOR was not reached for pembro + CP (range, 1.4+ to 18.6+ mo) and was 16.2 mo (range, 2.8 to 20.7+) for CP alone. PFS remained longer with pembro + CP (HR 0.49, 95% CI 0.29-0.83, P = 0.0035; median [95% CI] NR [9.7 mo-NR] vs 8.9 mo [6.2-10.3]; 12-mo estimate, 56% vs 34%). With 16 deaths in the pembro + CP arm and 23 deaths in the CP arm, HR for OS was 0.69 (95% CI 0.36-1.31, P= 0.13). Median OS was not reached in either arm; at 12 mo, estimated OS was 76% in the pembro + CP arm and 69% in the CP alone arm. Conclusions: With 5 mo additional follow-up, first-line pembro + CP continues to provide a substantial, clinically relevant improvement in efficacy over CP alone in pts with advanced nonquamous NSCLC, including an almost doubled ORR, halved risk of progression or death, and a trend toward improved OS despite a 75.0% crossover rate in the CP arm. Clinical trial information: NCT02039674.