1444P Real-world nivolumab safety data from 650 patients with unresectable advanced or recurrent gastric cancer that had progressed after cancer chemotherapy: Summary of post-marketing surveillance in Japan

Nivolumab, an anti-PD-1 antibody, was approved in 2017 as a treatment for unresectable advanced or recurrent gastric cancer that had progressed following ≥2 lines of chemotherapy. Subsequently, post-marketing surveillance was implemented to collect real-world safety and efficacy data. This is the first real-world data on immune checkpoint inhibitors from >600 gastric cancer patients. This surveillance comprised a multi-centered, open-labeled, non-interventional, observational cohort study. Patients with unresectable advanced or recurrent gastric cancer that had progressed after ≥2 lines of chemotherapy were enrolled in the study from November 1st, 2017 to October 31st, 2018. The data were collected using a case report form. The observation period was 6 months. In total, 654 patients were enrolled in this surveillance study. The safety and efficacy analysis sets included 650 and 636 patients, respectively. The background characteristics of the patients were as follows: 73% were male, the median age was 69 years, 90% had an ECOG performance-status score of 0 or 1, the median number of previous treatment regiments was 2.0, and 18% had large amounts of ascites before starting nivolumab treatment. The incidence of adverse drug reactions (ADRs) was 32%. The four most frequent ADRs (>2%) were diarrhea (3.7%), decreased appetite (2.9%), rash (2.5%), and malaise (2.3%). The incidence of ADRs that were grade 3 or above was 11%, and the most frequent ADRs were decreased appetite and diarrhea (0.92% each). In addition, 0.9%, 9.3%, 23%, and 55% of patients showed complete response, partial response, stable disease, and progressive disease, respectively. The overall survival rate at 6 months was 43% (95% CI: 39.5%-47.4%). The real world data of Japanese patients with unresectable advanced or recurrent gastric cancer showed safety profile and efficacy of nivolumab consistent to those reported in the ATTRACTION-2 study.