Use and Positioning of Fostamatinib in the Management of Primary Chronic Immune Thrombocytopenia: an Italian Expert Opinion

Fostamatinib, a spleen tyrosine kinase (Syk) inhibitor, represents a new therapeutic opportunity for patients with immune thrombocytopenia (ITP) in Europe and Italy. However, the positioning of this drug in patient's therapeutic sequence is undefined within the most recent international guidelines. The conclusions from a consensus meeting between Italian experts, whose task was to outline the profile of the ideal candidate to receive fostamatinib, are reported here. A modified Delphi methodology was used to achieve shared statements, which were reported in a narrative form. In particular, the panelists examined the strengths and weaknesses of the registration studies in terms of clinical outcomes, the safety profile of fostamatinib, the drug's impact on the quality of life of patients with chronic ITP, and the potential benefits of its use in the pandemic era. Although the experience with thrombopoietin receptor agonists (TPO-RAs) and the amount of data from real-world studies suggest the preferential use of these drugs as a second-line treatment in most patients, the absence of an increased thrombotic risk in the clinical trials could make fostamatinib a reasonable choice in patients with an increased risk of vascular events. An unstable platelet count during TPO-RAs might also justify a switch to the Syk inhibitor, which is more likely to stabilize the platelet count in responders. Fostamatinib may be preferred to immunosuppressors during the SARS-CoV-2 pandemic, in patients at infectious risk, or in case of contraindication to splenectomy. Finally, the novel mechanism of action makes it an attractive drug in multi-refractory patient.