True Refractoriness to Caplacizumab in iTTP Is Rare

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening microangiopathy driven by severe ADAMTS13 deficiency, where prompt treatment is critical to avert high mortality [1, 2, 3]. While standard care includes therapeutic plasma exchange and immunosuppression, the addition of caplacizumab, an anti-von Willebrand factor nanobody, has become a key therapeutic component, shortening time to platelet normalization and reducing exacerbations [4, 5, 6, 7]. Despite this, some patients exhibit delayed platelet count recovery, creating a clinical dilemma regarding potential treatment refractoriness [8]. This uncertainty can prompt difficult decisions about treatment intensification, such as adding immunosuppressants or considering splenectomy, making it essential to understand the factors that truly drive persistent thrombocytopenia [9, 10].