Long-term sustained response to fostamatinib in two patients with chronic refractory immune thrombocytopenia (ITP).

Care of patients with chronic immune thrombocytopenia (ITP) who are refractory to available treatments can be quite challenging. Fostamatinib, an oral Syk inhibitor, is the newest FDA-approved agent for ITP. Phase 3 clinical trials demonstrated an overall response in 43% of patients treated with fostamatinib and use for two years has been reported. Herein, we report two patients with long histories of ITP without lasting responses to numerous first-, second- and third-line therapies with prolonged responses to ongoing fostamatinib. This shows that patients unresponsive to other agents may respond to fostamatinib and can have sustained benefit.