A Real-World Analysis of Immune Thrombotic Thrombocytopenic Purpura: Comparing Clinical Outcomes of Conventional Treatment Vs Addition of Caplacizumab, a Single-Center Experience

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.2634-2634
• Main Authors: Delgado Pinos, Valeria Estefania, Lancho Lavilla, Pilar, Moreno Carbonell, Marta, Pérez Corral, Ana, Pascual Izquierdo, Cristina
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-190922

Introduction Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening thrombotic microangiopathy that causes systemic platelet-rich microthrombi with multiorgan damage. Caplacizumab is an anti-von Willebrand factor humanized nano-antibody, thereby blocking platelet binding and it is the first targeted therapy approved for the treatment of iTTP, in conjunction with plasma exchange (PLEX) and immunosuppression. Two pivotal randomized controlled trials have provided positive results where the use of Caplacizumab is associated with faster platelet count recovery, decrease relapse rates significantly and reduce mortality and recurrence rates compared with placebo. Likewise, published real-life studies support the positive results; however, today the controversy continues to exist whether Caplacizumab should be used first line or in refractory or relapsed disease. Methods We performed a single-center retrospective, observational analysis of clinic-biological and survival outcomes of conventional treatment alone vs addition of Caplacizumab in adult patients (≥18 years old) with confirmed diagnosis by ADAMTS13 activity of acquired iTTP (first or relapsed episode) who were treated at our institution between April 2008 and June 2023. Baseline demographic and clinical data and laboratory values were collected at the time of diagnosis. The PLASMIC score was determined retrospectively. Day 0 was defined as the day of diagnosis as indicated by the treating physician, beginning of iTTP-specific therapy, or a reported ADAMTS13 activity measurement of less than 10%. Time to normalization of platelet count after the start of iTTP-specific treatment was defined as the first day with a count ≥150×10 9/L (clinical response). Clinical remission, exacerbation, refractory disease, and relapse were defined according to the criteria published by Cuker et al in 2021 for the International Working Group for TTP. Results Patient characteristics, initial disease presentation, treatment modalities, individual courses, and outcome data are shown in Tables 1 and 2. Thirty-three patients were included, 24 received conventional treatment and 9 additional Caplacizumab. In 39.4% of the cases (13 of 33 episodes), iTTP was presented with a disease relapse. An initial ADAMTS13 activity of