LAUSR

BACKGROUND The treatment response to new immunotherapy in advanced melanoma patients remains varied between individuals. Immune related cutaneous side effects may have prognostic value. OBJECTIVE To determine whether developing one or more of the three immune-mediated cutaneous events (eczema, lichenoid reaction or vitiligo-like depigmentation) is associated with improved progression-free survival. METHOD A cohort study of adults with stage IIIC/IV melanoma treated with Pembrolizumab or Nivolumab between May 1, 2012 and Feb 1, 2018 at Westmead Hospital, Sydney, Australia. Treatment response was based on ir-RECIST, version 1.1. RESULTS 82 patients with an average age of 59.9 years were included. Median follow-up was 40.7 months. Thirty-three patients had at least one target skin reaction. One-third of individuals developed their skin reaction by six months. At any given time, the instantaneous risk of disease progression/death is lower for individuals who have developed at least one cutaneous adverse events (CAE) prior to this time. In comparison to individuals with no CAE, the hazard ratio is 0.46 with 95% CI 0.23 - 0.91, p = 0.025, time-dependent Cox proportional hazards model. CONCLUSION This study demonstrates an association between developing at least one of three CAE and improved progression-free survival in this cohort of patients.