Clinical course of patient with iTTP. The clinical course of a 32-year-old woman with iTTP during the first 60 days (A) and at 1 year (B). She presented on day 0 with petechiae, abdominal pain, a platelet count of 18 × 10⁹/L (normal range, 150 × 10⁹/L to 400 × 10⁹/L), a markedly elevated LDH, and schistocytes on the peripheral blood smear (A). ADAMTS13 activity was 3% (normal, ≥67%) with a detectable functional inhibitor, confirming the diagnosis of iTTP. TPE was initiated (light gray bar), along with corticosteroids (dark gray bar) and caplacizumab (medium gray bar). She improved rapidly with resolution of the abdominal pain, reduction in LDH level, and normalization of the platelet count on day 3. This improvement was sustained over the next several days, constituting a clinical response. TPE was discontinued on day 5, the platelet count remained stable, and she was discharged home on day 7 with prescriptions for caplacizumab and a prednisone taper. On day 12, despite a normal platelet count, she had persistent severe ADAMTS13 deficiency (7%). That day, rituximab was prescribed at 375 mg/m² × 1 dose per week for 4 weeks (vertical arrows). By day 19, the ADAMTS13 level had risen to 18%, and by day 26, it had risen to 80%, indicating a complete ADAMTS13 remission and attainment of clinical remission. Based on the demonstration of ADAMTS13 recovery, caplacizumab was discontinued on day 26. The patient completed the planned 4-week course of rituximab. The patient continued to be observed with periodic clinic visits and blood work during remission. At the 52-week visit (B), she remained in clinical remission and complete ADAMTS13 remission with a normal platelet count and an ADAMTS13 level of 79%. Twelve weeks later (week 64), the platelet count remained normal, but the ADAMTS13 level had declined to 47%. She was reclassified as being in clinical remission and partial ADAMTS13 remission and instructed to return for blood work in 4 weeks. At 68 weeks, she remained in clinical remission, but the ADAMTS13 level had declined to 18%, which qualified as an ADAMTS13 relapse. A test for ADAMTS13 level, repeated several days later, showed 15%. Preemptive rituximab was recommended to reduce the risk of clinical relapse. That day, the patient was treated with a single dose of rituximab 375 mg/m² (vertical arrow; B). Rituximab was successful in reinducing ADAMTS13 remission. One week later, the ADAMTS13 level had risen to 38% (partial ADAMTS13 remission) and by 2 weeks, it had risen to 78% (complete ADAMTS13 remission). Two years later, the patient remained in clinical remission and complete ADAMTS13 remission without the need for additional immunosuppression. This case was selected to highlight the updated outcome definitions (Table 2). It is not intended to endorse specific management strategies.