Real-World Use of Fostamatinib in Patients with Immune Thrombocytopenia and Thrombotic Risk.

Patients with immune thrombocytopenia (ITP) are at increased risk for bleeding and are paradoxically at increased risk for thrombosis. Many patients with ITP have underlying cardiovascular (CV) disease and/or other thrombotic risk factors for which considerable attention to selecting a therapeutic agent to manage ITP is needed. Fostamatinib, a spleen tyrosine kinase inhibitor, may reduce the risk of thrombosis while not interfering with hemostasis. We present a case series of 5 patients with ITP who had significant CV histories; each had at least 2 thrombotic risk factors. After unsuccessful management of ITP with other treatments, fostamatinib was initiated, was observed to be tolerable, and provided a durable platelet response without associated thromboembolic events. Fostamatinib may be the treatment of choice for patients with ITP in whom use of prothrombotic treatments should be avoided and/or continued use of antiplatelet or anticoagulant medication is needed.

Transitioning From Thrombopoietin Agonists to the Novel SYK Inhibitor Fostamatinib: A Multicenter, Real-World Case Series.

Fostamatinib is an oral spleen tyrosine kinase (SYK) inhibitor used for the treatment of adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment. Clinical and operational barriers may exist that warrant bridging or switching from thrombopoietin receptor agonists (TPO-RAs), such as volatility or unpredictability of platelets, adverse events, and quality of life or patient preference. While fostamatinib demonstrated durable platelet responses, the safety and efficacy in combination, bridging, and/or switching with TPO-RAs is not well documented. The objective of this article is to provide guidance from real-world case studies for a safe and effective strategy for the transitioning of patients from TPO-RAs to fostamatinib, with some degree of overlap between the two agents. Currently, the evidence does not exist to guide the safe and effective use of combination therapy or transition between therapies in ITP. This case series highlights the importance to further understand the complexities of managing this disease, as well as successfully combining, bridging, and/or switching patients over to fostamatinib without the need for rescue therapy or increase in adverse events. The need for real-world evidence that guides providers on the safety and efficacy of short- and long-term combination therapy of fostamatinib and TPO-RAs is crucial. The rationale for combination therapy is to target different pathways, platelet destruction, and production without added toxicities. Additionally, gradual tapering off of TPO-RAs may provide a more favorable clinical outcome when switching to fostamatinib. The need for additional data is necessary to provide clinicians with guidance when managing patients with ITP.