Fatal Allograft Rejection and Cardiac Allograft Vasculopathy After Treatment With Pembrolizumab for Metastatic Melanoma in a Heart Transplant Recipient: A Case Report

Checkpoint inhibitors decrease the progression of many cancers. However, the experience in immunosuppressed patients is limited, with reports of possible serious adverse events. We present a heart transplant recipient treated with pembrolizumab for metastatic melanoma who developed fatal rejection. The patient was a 29 year-old man who underwent heart transplantation at the age of 10 years for congenital heart disease. Seventeen years after transplant, he was diagnosed with scalp melanoma pT3a, N2a, M0, Stage IIIA, positive for BRAF V600E mutation treated with excision, which metastasized to his lungs and brain a year later. Dabrafenib and trametinib were started with transient response. Additional options and their risks were discussed, and pembrolizumab was started 4 months later due to the incomplete response to previous therapy. Five days after initiation the patient presented with moderate cellular rejection and possible antibody mediated rejection (ISHLT Grade 2R, pAMR 1H). Pembrolizumab was discontinued, and he was treated with steroids. Seven months later he presented in cardiogenic shock and severe coronary allograft vasculopathy. Biopsy was negative for cellular rejection, but suspicious for antibody mediated rejection (ISHLT Grade 0R, pAMR 1H), and he had a new serum alloantibody. Despite steroids and plasmapheresis he remained in refractory cardiogenic shock and died of cardiac arrest.