Department of Paediatric Haematology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, United Kingdom.
Department of Haematology, University College London Hospitals National Health Service Foundation Trust, London, United Kingdom.
Blood Adv. 2024 Sep 10;8(17):4563-4567. doi: 10.1182/bloodadvances.2024013488.
Pediatric thrombotic thrombocytopenic purpura (TTP) is an ultrarare disease. Immune TTP (iTTP) is driven by anti-ADAMTS13 autoantibodies causing an imbalanced von Willebrand factor (VWF):ADAMTS13 axis, and rarer still in children, but potentially life-threatening. Caplacizumab is licensed for iTTP treatment in adults and adolescents aged ≥12 years who weigh ≥40 kg. There is a need to clarify whether caplacizumab can be used in younger children. We retrospectively described caplacizumab use in 16 patients under 18 years of age from the UK TTP Registry, including 4 children aged <12 years. For patients weighing <40 kg (n = 3), caplacizumab was dosed at 5 mg once dailyThe youngest patient was 33 months old at diagnosis. Plasma exchange (PEX) was used in 15 patients, with a median of 5 exchanges required before platelet count normalization (range, 2-9). One patient was managed without PEX. All patients achieved normalization of platelet count (median, 5.5 days; range, 3-28) and ADAMTS13 activity (median, 35 days; range, 8-149), with a median hospital admission of 11 days (range, 5-26). There were no refractory patients. One patient relapsed 9 months after presentation. Bleeding requiring VWF supplementation and reduction of caplacizumab use occurred in 1 patient with severe epistaxis, with no significant intracranial or gastrointestinal bleeding. We demonstrated the efficacy and safety of caplacizumab in the pediatric population, which is synonymous with the adult trial data: primarily, reduction of PEX compared with the precaplacizumab era. This has implications for the intensification and duration of admission, particularly relevant in pediatric care.
儿童血栓性血小板减少性紫癜（TTP）是一种极罕见的疾病。免疫性 TTP（iTTP）由抗 ADAMTS13 自身抗体驱动，导致血管性血友病因子（VWF）：ADAMTS13 轴失衡，在儿童中更为罕见，但仍有潜在的生命威胁。卡普拉珠单抗已获准用于治疗成人和 12 岁及以上体重≥40kg 的青少年 iTTP。需要明确卡普拉珠单抗是否可用于年龄较小的儿童。我们回顾性描述了来自英国 TTP 登记处的 16 名年龄<18 岁的患者使用卡普拉珠单抗的情况，包括 4 名<12 岁的儿童。对于体重<40kg（n=3）的患者，卡普拉珠单抗的剂量为 5mg 每日一次。年龄最小的患者在诊断时为 33 个月。15 名患者使用了血浆置换（PEX），血小板计数恢复正常前需要进行中位数为 5 次 PEX（范围，2-9 次）。1 名患者未进行 PEX 治疗。所有患者的血小板计数（中位数，5.5 天；范围，3-28）和 ADAMTS13 活性（中位数，35 天；范围，8-149）均恢复正常，中位住院时间为 11 天（范围，5-26）。无难治性患者。1 例患者在发病后 9 个月复发。1 例严重鼻出血患者需要补充 VWF 和减少卡普拉珠单抗使用，出现出血情况，但无明显颅内或胃肠道出血。我们在儿科人群中证明了卡普拉珠单抗的疗效和安全性，与成人试验数据一致：主要是与卡普拉珠单抗治疗前相比，减少了 PEX 的使用。这对入院的强化和持续时间有影响，在儿科护理中尤为重要。
