Successful treatment of steroid-refractory immune thrombocytopenia with alemtuzumab

Fig. 1. Platelet count after alemtuzumab treatment. Successful treatment of steroid-refractory immune thrombocytopenia with alemtuzumab TO THE EDITOR: Immune thrombocytopenia (ITP) is an immune-mediated disease characterized by an isolated decrease in platelet count. There are multiple mechanisms underlying this disease, including autoantibodies against platelet membrane proteins and impaired platelet production [1]. In children, ITP is usually acute and the children have a spontaneous recovery, whereas in adults, ITP is chronic and irreversible. First-line therapy for ITP is cortico-steroids, which have response rates of 50%–90%; however, a durable response is observed in only 10–30% of patients. For steroid-refractory ITP, there are several treatments, such as splenectomy, danazol, azathioprine, cyclophosphamide, cyclosporine, rituximab, and thrombopoietin (TPO) receptor agonists [2]. Splenectomy induces a durable complete response in approximately 70% of patients with steroid-refractory ITP. However, it is associated with operative risks and post-operative complications such as encapsulated bacterial infections [3]. Rituximab has a good response rate of approximately 60% and a complete response rate of approximately 40%, though the durability over 5 years is only 15–20% [4]. Recently, the TPO receptor agonists, romiplostim and eltrombopag, demonstrated potent activity and had a response rate of more than 80%. However, However, their mechanism of action require relatively long maintenance period [5]. Other third-line therapies demonstrate minimal efficacy and their response duration is often short. Alemtuzumab, an anti-CD52 humanized monoclonal an-tibody, has shown strong durable immune suppression and has been used for lymphoproliferative disorders and auto-immune diseases such as multiple sclerosis. One study reported the safety and efficacy of alemtuzumab plus low-dose rituximab in patients with steroid-refractory ITP. The overall response rate was 100% and the median response duration was 46 weeks [6]. Another study reported about a patient with ITP and pure red cell aplasia who showed dramatic elevation of platelet count and hemoglobin levels after alem-tuzumab treatment [7]. Since there are few reports assessing the utility of alemtuzumab for treating ITP, this report documents the successful treatment of steroid-refractory ITP with alemtuzumab. We administered alemtuzumab to two patients (patient 1 and patient 2) who were diagnosed with ITP several years ago. Both patients were female, aged 48 and 50 years, respectively. Both had severe steroid-refractory thrombocy-topenia and did not respond to other treatments. Alemtuzu-mab was administered subcutaneously at a dose of 30 mg on days 1, 3, 5, 29, 31, and 33. We administrated 100 mg hydrocortisone intravenously and 650 mg acetaminophen orally 30 minutes …