Acquired Thrombotic Thrombocytopenic Purpura Successfully Treated with Caplacizumab through Multidisciplinary Collaboration in the Intensive Care Unit: A Case Report

Thrombotic thrombocytopenic purpura (TTP) is characterized by a severe deficiency of a disintegrin and metalloproteinase with thrombospondin type 1 motifs 13 (ADAMTS13), an enzyme responsible for cleaving hemostatic von Willebrand factor (VWF). This deficiency results in the accumulation of high-molecular-weight VWF multimers and the formation of platelet-rich thrombi in the microvasculature, leading to damage of multiple organs. Recently, caplacizumab, a monoclonal antibody that inhibits the interaction between platelets and VWF, has been approved for insurance coverage. However, due to the rarity of TTP and the challenges in early diagnosis, delays in caplacizumab administration are common, and several aspects must be addressed during initial treatment. Here, we present a case of TTP in a patient who achieved remission through interprofessional collaboration, which facilitated caplacizumab administration and subsequent plasma exchange initiation within 6 h of admission. The patient initially presented with headache and visual disturbances and was later transferred to the intensive care unit due to thrombocytopenia, followed by the onset of neuropsychiatric symptoms. Acquired TTP was suspected, and intravenous caplacizumab along with plasma exchange, was initiated on the day of admission. By day 3 of treatment, the patient’s platelet count had normalized, and plasma exchange was discontinued. On day 15, ADAMTS13 activity improved to 11％, and the patient was subsequently discharged in a stable condition. In conclusion, close multidisciplinary collaboration with pharmacists is important for the timely administration of caplacizumab and plasma exchange.