Abstract
Immune thrombotic thrombocytopenic purpura (iTTP) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular occlusion secondary to acquired ADAMTS13 deficiency. Contemporary data regarding iTTP treatment practices in the US, including the use of caplacizumab, are lacking. We aimed to characterize the demographics and therapies, including medications and apheresis practices, in patients with iTTP in the US. We retrospectively analyzed iTTP cases at 15 sites in the US that provide comprehensive care for patients with iTTP. The time-period assessed was from January 1, 2017 to December 31, 2021. Our primary objective was to analyze data by iTTP episode, inclusive of initial episodes and relapses. A total of 390 iTTP episodes were reported for 280 unique individuals (187 females, 93 males). Thirty-day mortality was 3.7% (14/374), and 6-month mortality was 7.4% (27/367). TPE details were reported for 343 episodes, among which 261 underwent at least one procedure (median 6, IQR 3-11). Among the 261 episodes with at least one therapeutic plasma exchange (TPE) performed, 82.0% (214/261) used only plasma. Caplacizumab was used either alone or in combination with other agents in 43 (11.0%) episodes. Management strategies for iTTP remain varied across centers in the US, with a variety of combinations for TPE replacement fluids and therapeutic agents, as well as limited use of caplacizumab. Further research and standardization of treatment regimens may further reduce mortality in this condition.