Overall survival of metastatic melanoma (mM) treated with high dose IL-2 (HD IL-2) followed by anti-CTLA4 (IPI) and/or anti-PD-1/PDL1 (aPD1) therapy: Analysis of the prospective cohort of the PROCLAIM national registry.

e20071 Background: PROCLAIMSM (www.proclaimregistry.com) is an IL-2 observational registry with over 40 participating sites consisting of a retrospective (n = 170, locked) and prospective cohort (n > 343 on-going). Previously, we reported a median overall survival (mOS) of 20 months (mo) with a median follow-up of 37 mo in mM patients treated with HD IL-2 between 2007 and 2012 from a retrospective cohort (ASCO 2014). We report for the first time, analysis of 240 prospective patients. Methods: Patients must have received at least one dose of HD IL-2 prior to 2014 for this analysis. Response rates are reported per standard RECIST criteria and mOS by the method of Kaplan-Meier. All patients provided informed consent. Survival is current to January 2015. Results: For the 240 prospective patients, the mOS is 17.9 mo and the ORR is 15.2% at a median follow-up of 20.1 mo. The 1 year survival rate of patients receiving aPD1 or IPI after HD IL-2 is 100% and 68% respectively, compared to 58% in the IL-2 only group....