A phase III study of nivolumab (nivo) in previously treated advanced gastric or gastric esophageal junction (G/GEJ) cancer (ATTRACTION-2): Two-years update data

Abstract

Background: Nivo monotherapy has shown superior efficacy with manageable safety for G/GEJ cancer refractory to, or intolerant of standard chemotherapy in a phase 3 study (ATTRACTION-2). Here, we report 2-year updated results of survival. Methods: A total of 493 patients with unresectable advanced or recurrent G/GEJ cancer after failure of two or more previous chemotherapy regimens were randomized in a 2:1 ratio to receive 3 mg/kg Nivo (N=330) or placebo (N=163) until progressive disease or unacceptable toxicity. The primary endpoint was overall survival (OS). Updated results of the efficacy and safety were based on≥ 2-year follow-up after last patient enrollment. As a subgroup analysis, the OS data by BOR was evaluated. Results: As of data cut-off on February 2018, 2 years after last patient enrollment, the median OS (mOS) was 5.3 months with Nivo versus 4.1 months with placebo (hazard ratio [HR] 0.62; 95% confidence interval [CI] 0.51-0.76). The OS rates of Nivo and Placebo were 27.3% and 11.6% at 12 months, and 10.6% and 3.2% at 24 months, respectively. In a OS subgroup analysis stratified by BOR, mOS in PR patients in Nivo arm was not reached. Median OS in SD patients were 9.4 and 7.6 months (HR 0.70, 95%CI 0.44-1.09), and mOS in PD patients were 3.8 and 3.8 months (HR 0.86, 5%CI 0.64-1.16) in Nivo and placebo arm, respectively. In addition, 12-month OS rate in PR patients was 86.7% in Nivo arm. OS rate at 12 months in SD patients were 36.9 and 24.2%, and OS rate at 12 months in PD patients were 12.4 and 6.9% in Nivo and placebo arm, respectively. The safety analysis for 2-year follow-up will be presented. Conclusions: Nivo has significantly improved OS with 2-year follow-up. In PR and SD patients, the subgroup analysis of OS favored Nivo over placebo.