Case Report: Early Chinese experience with caplacizumab for plasma-exchange-refractory immune-mediated TTP and a focused review of short-course treatment

Caplacizumab has transformed acute immune-mediated thrombotic thrombocytopenic purpura (iTTP) care, but experience in mainland China remains limited. We report a 53-year-old woman with Sjögren's disease and iTTP complicated by cerebral infarctions. Despite corticosteroids, two early rituximab doses, and more than ten therapeutic plasma exchange (TPE) sessions, her platelet response was not sustained, meeting traditional criteria for TPE-refractory disease. Five daily caplacizumab doses were followed by a rapid platelet increase to 631 × 10 9 /L. Further doses were withheld because of safety concerns about the marked platelet rise, and additional drug supplies were unavailable. TPE was subsequently stopped because of a plasma shortage. ADAMTS13 activity was 72.73% during TPE but remained below 10% after TPE cessation. After two further rituximab doses, ADAMTS13 recovered, and clinical remission persisted through September 2026. A focused review of adult iTTP treated with TPE and immunosuppression found that successful early caplacizumab discontinuation was most consistently associated with serial ADAMTS13 recovery. Treatment preceded another detailed mainland Chinese report, and follow-up extends to 18 months after discharge. Her course is consistent with a rapid platelet effect after caplacizumab was added to standard treatment, but does not establish that a short course is sufficient or that it reduces bleeding risk. In settings with restricted access or reimbursement, shorter courses warrant prospective evaluation alongside standard immunosuppression, serial ADAMTS13 monitoring, close clinical surveillance, and access to rescue therapy.