Background: Multicenter studies have shown improved clinical outcomes and favorable safety with pembrolizumab (pembro) in 1L and 2L settings in advanced NSCLC. We present pembro data in Chinese patients (pts) with advanced NSCLC. Method: This open label phase 1 study (NCT02835690) enrolled Chinese pts aged 18 years with histologically/cytologically confirmed advanced, unresectable NSCLC; measurable disease per RECIST v1.1; ECOG PS 0/1; and prior failure/ intolerance/ineligibility for standard therapy. Pts were randomized (stratified by gender) 1:1:1 to IV pembro 2 mg/kg, 10 mg/kg, or 200 mg (each Q3W after initial 28-day cycle). Safety and PK were primary objectives. Responses were assessed centrally per RECIST v1.1. PK was based on noncompartmental analysis. Result: 42 pts received 1 pembro dose (2 pts randomized were not treated thus excluded from analyses; 2 mg/kg, n ¼ 14; 10 mg/kg, n ¼ 13; 200 mg, n ¼ 15): median age 59 (range, 28e71) y, 64% male, 62% adenocarcinoma, and 76% 1e2 prior therapies. Median follow up was 7.9 mo (range, 0.7e13.1). 29 pts (69%) had treatment-related AEs, most commonly fatigue and rash (24% each). 4 pts (10%) had grade 3-4 treatment-related AEs (no grade 5): eyelid ptosis, fatigue, anaphylactic reaction, dermatitis acneiform, and rash (1 each). AEOSIs (predefined list with possible immune etiology) were hypothyroidism (n ¼ 2) and hyperthyroidism, anaphylactic reaction, and rash (n ¼ 1 each). Geometric mean PK values for 2 mg/kg, 10 mg/kg, and 200 mg, respectively, were: t 1/2 (days; CV %), 15 (33), 16 (25), and 12 (41); AUC 0-21d (mg$d/mL; 95% CI), 730.9 (627.4e851.6), 2819.2 (2009.4e3955.4), and 931.0 (724.4e1196.6); and C max (mg/mL; 95% CI), 66.7 (56.9e78.1), 268.6 (217.8e331.2), and 92.2 (81.7e104.2). Anti-drug antibodies did not impact pembro exposure. Overall, ORR was 14.3% (6/42; 95% CI, 5.4e28.5); median DOR was 5.2 mo (range, 2.00 [ongoing]e6.28), PFS was 2.1 mo (range, 2.1e4.2), and OS was not reached. Conclusion: In Chinese pts with advanced NSCLC, pembro had approximately linear serum exposure at the dose range studied (2 to 10 mg/kg), was well tolerated, and showed antitumor activity consistent with the multicohort study KEYNOTE-001. The phase 3 KEYNOTE-033 study (NCT02864394), enrolling mostly Chinese pts, evaluates pembrolizumab versus docetaxel in pts with previously treated NSCLC with PD-L1 TPS 1% and is ongoing.