A case for consideration by apheresis practitioners: Melanoma and PD-1 inhibitor treatment in a patient with multiple relapses of immune thrombotic thrombocytopenic purpura

Abstract

Thrombotic Thrombocytopenic Purpura (TTP) is a rare life-threatening disease caused by ADAMTS-13 deficiency. Up to forty percent of patients with TTP relapse, and most relapse within eight years of their first presentation. This case report describes a patient with an aggressive course of TTP who subsequently developed metastatic melanoma while receiving prophylactic rituximab. Limited data exists regarding the potential for malignancy in patients receiving Rituximab for benign conditions. This is the first published case of melanoma in a TTP patient treated with rituximab. Melanoma treatment with PD-1 inhibitors is also associated with worsening of pre-existing autoimmune conditions. In this case, a splenectomy resulted in a durable remission despite treatment with PD-1 inhibitor.