Caplacizumab compared to noncaplacizumab patients in acute TTP. (A) Duration of caplacizumab use after completion of PEX, ADAMTS13 activity at point of stopping caplacizumab and clinical outcomes. Failure to achieve an ADAMTS13 activity >30 IU/dL was 6 times more likely in patients treated with caplacizumab (odds ratio, 6.3; 95% confidence interval, 2.15-17.94; P = .0006). This was calculated based on the 18 patients with an ADAMTS13 activity ≤30 IU/dL in those who received extended caplacizumab, and additionally 5 patients who continued to receive capalcizumab after 30 + 28 days owing to ongoing ADAMTS13 activity <30 IU/dL. This was compared with the 33 patients who received ≤30 days of caplacizumab and had an ADAMTS13 activity >30 IU/dL at time of stopping caplacizumab, in addition to the 6 patients with an ADAMTS13 activity >30 IU/dL in those who received extended caplacizumab. The 2 patients with early caplacizumab cessation were not included in this analysis. (B) ADAMTS13 activity at time of stopping caplacizumab and duration of caplacizumab used after completion of PEX. (C) ADAMTS13 activity at 30 days and 30 + 28 days in noncaplacizumab cohort and clinical outcomes.