Safety and efficacy of irinotecan administered after nivolumab for advanced gastric cancer

Abstract

Abstract Background Nivolumab (NIVO) showed a survival benefit compared to placebo in patients (pts) with advanced gastric cancer (AGC) after two or more previous lines of chemotherapy. It has been reported that prior treatment with immune check point inhibitors might improve responses to salvage chemotherapy without unexpected safety signals in non-small cell lung cancer. However, safety and efficacy of irinotecan (IRI) administered after NIVO in pts with AGC remains unclear. Methods Pts with AGC treated with IRI after NIVO (cohort A) or IRI before NIVO (cohort B) from September 2017 to December 2018 were analyzed in this study. Clinical outcomes after IRI were compared between two groups. Results A total of 44 pts (14 in cohort A and 31 in cohort B) were included in this study. Common grade 3 or worse adverse events in cohort A were leukocytopenia (21%), neutropenia (14%), thrombocytopenia (7%) and diarrhea (7%), which were not significantly different in cohort B. No immune related adverse events occurred in cohort A. The ORR-IRI was 21% in cohort A and 16% in cohort B (p = 0.48), and the median PFS-IRI was 2.67 and 2.37 months (HR = 0.87, p = 0.68), respectively. In cohort A, the PFS of IRI was longer than that of NIVO in 9 of 14 pts (64%). Conclusions IRI administered after NIVO was manageable without unexpected adverse events. Although prior NIVO did not seem to improve responses to IRI, it was notable that IRI showed a longer PFS than that of prior NIVO in a substantial number of pts.