Thrombotic Thrombocytopenic Purpura Induced by Combined Toripalimab and Pazopanib Therapy in a Patient with Renal Cell Carcinoma and Vertebral Metastasis: A Case Report

Abstract

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening form of thrombotic microangiopathy, primarily caused by a deficiency of ADAMTS-13 activity. Immune-related adverse events (irAEs) are autoimmune toxicities mediated by the use of immune checkpoint inhibitors (ICIs).  Here, the study reports a case of thrombotic thrombocytopenic purpura that developed in a patient with renal cell carcinoma and vertebral metastasis following combined treatment with Toripalimab and Pazopanib. The patient received Toripalimab in combination with Pazopanib after undergoing radical nephrectomy for right renal cell carcinoma. Five days later, a generalized erythematous rash appeared, partly confluent, accompanied by congestion and swelling of both palpebral and bulbar conjunctiva. Based on the clinical presentation and laboratory results showing thrombocytopenia and hemolytic anemia, the diagnosis of TTP was established. The condition was considered an adverse effect associated with the combination therapy of Toripalimab and Pazopanib. Plasma exchange and high-dose intravenous immunoglobulin therapy were promptly initiated. The treatment regimen was subsequently modified to Axitinib combined with radiotherapy, leading to a gradual recovery of platelet counts. This report highlights the potential risk of TTP associated with combined ICI and TKI therapy, and underscores the importance of early recognition and timely management of this potentially fatal complication.