P73-2 A retrospective study of advanced gastric cancer patients treated with nivolumab monotherapy: 4 years of experience

An anti PD-1 antibody drug nivolumab has been approved for advanced gastric cancer and has been available in daily practice. With regard to the efficacy and safety profiles of nivolumab in gastric cancer patients, there are a few year update data only from clinical trials. We examined the efficacy and safety profiles of nivolumab in clinical practice based on the experience of advanced gastric cancer patients in our hospital. We retrospectively studied 76 advanced gastric cancer patients whose safety profiles of nivolumab could be evaluated for at least one month from September 2017 to August 2021. We excluded patients who participated in clinical trials of nivolumab. The median age was 66 years (35 to 84 years) and 57% of cases were male. There were 54% of cases with prior history of ramucirumab use. At the start of the nivolumab treatment, PS was 0 in 8 cases, 1 in 47 cases, 2 or more in 21 cases. There were 63% of cases with peritoneal metastasis. The median PFS is 50.5 days. The best overall response (RECIST 1.1) were 5 CR+PR and 6 SD, with a 12.2% response rate. There were patients who experienced durable efficacy beyond first PD events. The 1-year survival rate was 20%, and the 2-year survival rate was 5.3%. We experienced immune related adverse events (irAEs) in 43% of cases, Grade3 or higher irAEs in 13% of cases. There were more progressed cases than trial-qualified cases, such as cases with poor PS and with peritoneal metastasis. Responded and durable cases have also been identified. We consider the treatment is an important option in later line therapy of advanced gastric cancer.