1287PExcess weight and efficacy of anti-PD-1 antibodies in advanced cancer patients

Abstract Background Immunotherapy is a new and effective form of therapy in several types of cancer, although molecular predictors of response are limited. Recently, we have described that immune-related adverse-events (irAEs) are significantly associated with immunotherapy efficacy, and it has been suggested that body mass index (BMI) might be a favourable factor. We have studied whether excess weight influences the efficacy outcomes of immunotherapy and whether it is associated with immune-related adverse events. We have also evaluated the combined effect of overweight and irAEs. Methods We calculated BMI in patients treated with single-agent anti-PD-1 antibodies for advanced cancer. Efficacy of anti-PD-1 treatment was evaluated with both objective response (OR) rate, and progression-free survival (PFS), and toxicity with irAEs. We established the association between overweight and OR, PFS and irAEs. Results One hundred and thirty-two patients were included in the study. Primary malignancies were lung cancer (n = 93), melanoma (n = 12), head and neck carcinoma (n = 9), renal carcinoma (n = 6), urothelial carcinoma (n = 4), Hodgkin’s lymphoma (n = 3), and other cancers (n = 5). Median BMI was 24.9 kg/m2, and 64 patients (48.4%) were excess weight (BMI≥25 kg/m2). An OR was achieved in 50 patients (38.0%), and median PFS was 6 months. IrAEs occurred in 44 patients (33.3%). OR was significantly higher in excess weight patients that in patients with BMI Conclusions Excess weight patients with advanced cancer that receive single-agent anti-PD-1 antibody therapy exhibit a significantly improved clinical outcome compared with patients with normal BMI. This association was especially marked when BMI and irAEs were considered combined. Legal entity responsible for the study Instituto Investigacion Sanitaria Princesa. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.