Population pharmacokinetics analysis of nivolumab in Asian and non-Asian patients with gastric and gastro-esophageal junction cancers.

Nivolumab monotherapy provided clinically meaningful antitumor activity in Asian and non-Asian patients with chemotherapy-refractory gastric cancer (GC) or gastro-esophageal junction cancer (GEJC) in the ATTRACTION-2 and CheckMate 032 studies, respectively. This analysis assessed the population pharmacokinetics (PopPK) of nivolumab, the impact of covariates on pharmacokinetics (PK), and the PK of nivolumab flat dosing in GC/GEJC using samples from these studies. PopPK analyses were conducted using data from 1302 patients with solid tumors, including 387 patients with GC/GEJC who had received nivolumab 3 mg/kg once every 2 weeks (Q2W). The impact of covariates on nivolumab PK was assessed in the full model. Nivolumab exposures following a flat dose of 240 mg Q2W in patients with GC/GEJC were simulated and compared with those of 3 mg/kg Q2W. Nivolumab PK was described using a 2-compartment, zero-order intravenous infusion and time-varying clearance (CL) model. Baseline CL in patients with GC/GEJC was ~ 33% greater than in patients with non-small cell lung cancer (NSCLC) in second line or subsequent lines of treatment (2L+). The effect of race was not clinically relevant (< 20% difference). Nivolumab exposures following 240 mg Q2W were similar to 3 mg/kg Q2W in non-Asian patients and 46% higher in Asian patients due to lower body weight. Nivolumab CL was increased in GC/GEJC relative to NSCLC 2L+. Higher nivolumab exposures achieved with 240 mg Q2W in Asian patients are predicted to be below the acceptable safety margin, supporting the use of a flat dose in both patient populations.