Fostamatinib for the treatment of immune thrombocytopenia in adults.

PURPOSE: The pharmacology, pharmacokinetics, efficacy, safety, dosing and administration, and place in therapy of fostamatinib, a novel spleen tyrosine kinase inhibitor for the treatment of adult immune thrombocytopenia that has had an insufficient response to a previous treatment are summarized.
SUMMARY: Fostamatinib is an oral inhibitor of spleen tyrosine kinase that is expressed on hematopoietic cells and plays a key role in the accelerated destruction of platelets through Fc-receptor activation. Fostamatinib is indicated for the treatment of adults with immune thrombocytopenia that has had an insufficient response to a previous treatment. In 2 parallel, identically designed, placebo-controlled Phase III trials, patients with persistent and chronic immune thrombocytopenia treated with fostamatinib demonstrated clinically meaningful responses in platelet counts with lower rates of moderate and severe bleeding-related adverse events. Overall, fostamatinib therapy is generally well tolerated; the most common adverse events reported in clinical trials were diarrhea, nausea, hypertension, liver function test elevations, and infection. Being primarily metabolized through the CYP3A4 pathway, fostamatinib is subject to drug-drug interactions and concomitant administration with strong CYP3A4 inhibitors or inducers can affect fostamatinib exposure.
CONCLUSION: Fostamatinib is a first-in-class spleen tyrosine kinase inhibitor approved for the treatment of adults with immune thrombocytopenia that has had an insufficient response to a previous treatment. © American Society of Health-System Pharmacists 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.