Successful Salvage Treatment With Fostamatinib for an Adolescent Patient With Refractory Chronic Immune Thrombocytopenia.

Fostamatinib (FOS) is a novel drug for chronic immune thrombocytopenia (cITP) that inhibits spleen tyrosine kinase (Syk) signaling. FOS is approved for the treatment of cITP in adults but has not been approved for pediatric and adolescent patients with cITP. We present the first case of refractory cITP in an adolescent patient who was successfully treated with the addition of FOS to prednisolone and thrombopoietin receptor agonists. Although bone dysplasia requires careful monitoring, FOS is effective in the treatment of adolescent cITP refractory to conventional therapies and should be administered on a risk and benefit.