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

Abstract

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.

Perspectives of vitamin C upregulating regulatory T cells in the era of thrombopoietin receptor agonists for immune thrombocytopenia

“…However, its low stable response rate may render it unlikely to replace rituximab, TPO‐RA or splenectomy. Despite this lower efficiency in multi‐treated and refractory patients, fostamatinib would still be a viable option for refractory ITP 55 . Other potentially useful agents may include rapamycin (that blocks the mTOR pathway) and low‐dose decitabine which may have immunomodulating effects.…”

“…Despite this lower efficiency in multitreated and refractory patients, fostamatinib would still be a viable option for refractory ITP. 55 Other potentially useful agents may include rapamycin (that blocks the mTOR pathway) and low-dose decitabine which may have immunomodulating effects. However, as these have not yet been approved for ITP, better documentation of the longterm effects may be advisable.…”

Eltrombopag plus cyclosporine in refractory immune thrombocytopenia: a single-center study

“…However, the prognostic indicators for patients who fail to respond to initial treatment or experience relapse during treatment with eltrombopag are yet to be confirmed. As there is still no consensus on how to manage eltrombopag-resistant ITP, other TPO-RAs, fostamatinib [ 9 ] (syk inhibitor), efgartigimod [ 10 ] (FcRn antagonist), and other immune suppressive therapies, alone or in combination, may be considered.…”

“…The total response to eltrombopag combined with azathioprine for patients with refractory ITP was significantly higher than that to azathioprine alone (90.32% vs 73.33%, respectively); however, the incidence of side effects was also significantly increased [ [12] , [13] , [14] ], particularly related to hepatotoxicity (∼25%). Thus far, only a limited number of studies have focused on improving the efficacy of eltrombopag-resistant ITP, achieving a response of about 40% to 50% [ 9 , 10 ]. Consequently, a combination treatment with a safe and rapid response should be explored, especially for eltrombopag-resistant ITP.…”