LAUSR

9094Background: 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 Pval...