Treatment with fostamatinib in patients with immune thrombocytopenia: Experience from the Andalusian region in Spain-The Fostasur Study.

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.

Treatment characteristics, efficacy and safety of thrombopoietin analogues in routine management of primary immune thrombocytopenia.

: Thrombopoietin receptor agonist (TPO-RAs) have demonstrated good efficacy and tolerance in clinical trials in refractory chronic primary immune thrombocytopenia (ITP) or chronic ITP with contraindication for splenectomy. No head-to-head study is available, and differences in trials design do not allow comparisons. Information on the use of TPO-RAs in nonchronic ITP is scant. We described our experience with TPO-RAs in ITP (chronic, persistent and newly diagnosed ITP) in routine clinical practice. Retrospective series of 100 adult ITP patients was analysed; 41 treated with eltrombopag, 37 with romiplostim and 22 with both. Response-related and safety variables were evaluated. With a median follow-up of 86.5 weeks (interquartile range, 34.3-128 weeks), no differences were found in response rate, time to response, stability of response or response duration based on the type of TPO-RA used. Of all, 25% of patients with newly diagnosed or persistent ITP and 7.2% with chronic responded and maintained their response when TPO-RAs were stopped. Regarding safety, two developed bone marrow fibrosis grade 3, with loss of response to both drugs. Incidence of vascular events was 7%. Both TPO-RAs may be useful in all types of ITP, not only chronic but also persistent and newly diagnosed. Similar results were noted in efficacy and safety variables for both drugs.