Antoni Ribas

Antoni Ribas is a melanoma oncologist and immunologist who has made landmark contributions to understanding the mechanisms of acquired resistance to anti-PD-1 therapy. His laboratory performed comprehensive genomic and transcriptomic analysis of tumor biopsies from pembrolizumab-treated melanoma patients, identifying loss of function mutations in B2M (beta-2-microglobulin) and JAK1/JAK2 IFN-gamma signaling pathway as the dominant acquired resistance mechanisms. This work established that acquired resistance often involves failure of MHC-I antigen presentation (B2M loss) or failure of IFN-gamma response (JAK1/JAK2 loss), providing mechanistic targets to overcome resistance.