Caplacizumab for treatment of thrombotic thrombocytopenic purpura in a patient with anaphylaxis to fresh-frozen plasma

BACKGROUND Plasma exchange with plasma replacement has been the mainstay for the treatment of thrombotic thrombocytopenic purpura (TTP) for several decades. Recently an anti-von Willebrand factor (VWF) medication, caplacizumab, has been approved for treatment of TTP when used with plasma exchange. We report a patient with immune-mediated TTP that had an anaphylactic reaction to plasma who was then given caplacizumab daily for 1 week without further plasma exchange therapy with a good clinical and laboratory response. CASE REPORT A 63-year-old woman with acute confusion and multiple ecchymoses after tooth extraction developed TTP with a hemoglobin (Hb) of 6.3 g/dL, white blood cell count 15 x 10(9)/L, platelets (PLTs) 12 x 10(9)/L, lactate dehydrogenase (LDH) 1212 IU/mL, and creatinine 0.9 mg/dL. Her ADAMTS13 level was less than 5% and plasma exchange was started. During the first plasma exchange the patient developed anaphylaxis with hypotension, shortness of breath, angioedema, and urticaria. She recovered from this reaction with treatment and no further plasma exchanges were performed. Instead she was given methylprednisolone, caplacizumab, and later rituximab. The caplacizumab was given daily for 8 days during which her PLT counts and ADAMTS13 levels improved. Her Hb level also increased. She continued to receive oral prednisone and rituximab after discharge was doing well latest follow up (Day 114). CONCLUSION Caplacizumab may be used safely and effectively without concomitant plasma exchange in a patient with anaphylaxis to plasma.