Drug initiation, mortality, and disease recurrence in relation to ADAMTS13 activity. (A) Time taken from initiation of PEX therapy to the first dose of caplacizumab (days). <1 day refers to the first administration of caplacizumab <24 hours following initiation of PEX. (B) Mortality according to caplacizumab initiation (≤48 hours vs >48 hours). Eighty percent of those who died had caplacizumab initiated >48 hours after the first PEX. (C) Recurrence status according to ADAMTS13 activity at completion of PEX. (i) Individual patient data with regard to exacerbation status. ADAMST13 activity after the end of daily PEX was available for 76 patients. Of these, 37 (48.7%) had ADAMST13 activity <10.0% (range, <1.0 to 5.2); 2 patients experienced exacerbations. The other 39 patients (51.3%) had ADAMST13 ≥10.0% (range, 10.2-107.2), without any exacerbations. (ii) Individual patient data with regard to relapse status. No patient with ADAMST13 activity ≥10.0% relapsed, whereas 3 of the 37 patients with ADAMST13 activity <10.0% did. Recurrences are termed exacerbations if they occur within 30 days of last PEX and are classified as relapses if they occur >30 days after last PEX.