Caplacizumab for pediatric immune thrombotic thrombocytopenic Purpura: A scoping review of current evidence

While caplacizumab, a von Willebrand factor inhibitor, has dramatically improved iTTP management in adults, its role in pediatric iTTP remains understudied. This scoping review synthesizes current evidence on the safety and efficacy of caplacizumab in children with iTTP. We conducted a systematic literature search (PubMed, Scopus) up to March 2025, identifying 15 studies (36 patients) meeting inclusion criteria. The cohort (median age 14 years, range 1-17) exhibited female predominance (72 %) and diverse ethnic backgrounds. Neurological symptoms (53 %) and bleeding manifestations (petechiae, purpura, or ecchymoses in 74 %) were common presentations. Caplacizumab was administered at 5 mg (17 %), 10 mg (75 %), or 11 mg (8 %), alongside plasma exchange (22 % received >10 sessions) and immunosuppression (97 % corticosteroids, 92 % rituximab). Key outcomes included rapid platelet recovery (median 3.5 days post-caplacizumab initiation) and relatively short hospitalization (median 14 days). Adverse events were uncommon (11 % minor bleeding), with no major or life-threatening hemorrhagic complications reported. Mortality was 0 %, with all patients surviving to follow-up. During a median follow-up period of 6-12 months, 94 % of patients remained relapse-free. Notably, 22 % of patients were under 12 years of age, underscoring the off-label use of caplacizumab in younger children. These findings suggest caplacizumab is effective and safe in pediatric iTTP, mirroring outcomes observed in adults while demonstrating a favorable bleeding profile. However, variability in dosing and limited data on long-term effects highlight the need for pediatric-specific guidelines and prospective studies. This review supports caplacizumab as a promising adjunct in childhood iTTP but calls for further research to optimize its use in this vulnerable population.