RESUMEN
Immune thrombocytopenia (ITP) refractory to multiple therapies may require a combination of drugs targeting different mechanisms and targets. In this retrospective, multicentre, international study, we report the safety and effectiveness of avatrombopag and fostamatininb in combination administered to 18 patients with multirefractory ITP. Overall, the combination response was achieved in 15 patients (83.3%), with a median time from combination start to best response of 15 days (IQR: 8-35 days). After a median follow-up of 256 days (IQR: 142.8-319), 5 patients relapsed (26.7%), all during tapering or stopping one drug. Adverse events were described in 6 of 18 patients (33%).
RESUMEN
Immune thrombocytopenia (ITP) is characterized by low platelet counts (PLTs) and an increased risk of bleeding. Fostamatinib, a spleen tyrosine kinase inhibitor, has been approved as a second-line treatment for ITP. Real-world data on fostamatinib are lacking. This observational, retrospective, multicentre study, conducted in the Andalusia region of Spain, evaluated 44 adult primary ITP patients (47.7% female; median age 58 years; newly diagnosed ITP 6.8%; persistent 13.6%; chronic 79.5%; median four prior treatments) after ≥ 4 weeks of fostamatinib therapy. The median PLT at the initiation of fostamatinib was 15 × 109/L. Common reasons for starting fostamatinib were refractoriness or intolerance to prior therapy, oral medication preference, history of thrombosis and cardiovascular risk. Dosing was individualized based on efficacy and tolerance. After 2 weeks, global response rate was 56.8% (response and complete response). Response rates were 70.5%, 62.5% and 64% at 4 weeks, 12 weeks and at the end of the study respectively. Adverse events were mild, and no patients discontinued as a result. This real-world study demonstrated a response rate similar to fostamatinib as seen in the pivotal clinical trials while including newly diagnosed patients and allowing for individualized dosing.