e14600 Background: Nivolumab (NIVO), a PD-1 inhibitor, is used in various advanced malignancies with meaningful and durable outcomes. However, its use can be limited by severe immune-related adverse events (irAEs). We analyzed our large single institution patient cohort who have been treated with NIVO to risk stratify and identify clinical factors associated with continued benefit after irAEs. Methods: 125 patients with advanced malignancies, treated with NIVO during 2011-2016 at the University of New Mexico Comprehensive Cancer Center, were evaluated. Inclusion criteria included a minimum of 1 completed treatment of NIVO (1 or 3mg/kg). Stratifying factors including age, gender, BMI, ethnicity, co-morbidities, pretreatment WBC and albumin, number of treatments received, type of malignancy, number of metastatic sites, overall tumor response rate (ORR), irAEs, and tumor response rates after irAE were identified. Results: Primary sites of cancer for the 125 patients who received NIVO were lung (44, 35%), melanoma (43, 34%), head-neck (8, 6%), renal (14, 11%), Hodgkin’s (16, 13%), 2 patients with more than one malignancy (1 with lung and head-neck, and 1 with lung and melanoma), and other non-approved indications (16, 13%). The overall tumor response rate was 34.4%. Total All CTCAE v4 grades irAEs experienced were 32% (40/125), and 33% (13/40) were severe (grade > 3). Eighteen (18/40, 45%) patients continued to have tumor response after experiencing any grade irAE. The mean age of those experiencing an irAE with subsequent tumor control (CR, PR, or SD) was 72.3 years, mean BMI 28.2 kg/m2, 38.9% were female, 11.1% were non-Caucasian, 61.1% had > 2 co-morbidities, 72.2% with > 2 metastatic sites and the mean albumin was 3.4 g/dl. Conclusions: Patients who had a tumor response after being re-challenged with NIVO, despite experiencing an irAE, were found to be older, had a higher BMI, an increased number of co-morbidities, higher tumor burden, and mean albumin > 3.0g/dl. Risk stratifying these patients prior to starting treatment is possible and can be helpful in anticipating which patients should be re-challenged or will have continued benefit with NIVO after experiencing an irAE.