G. Moulis, Matthieu Mahévas, Jean‐François Viallard, Stéphane Cheze, L. Terriou, S. Audia, T. Moulinet, Mikael Ebbo, D. Gobert, Ailsa Robbins, C. Gourguechon, Julie Graveleau, Thibault Comont, A. Saunier, Jehanne Faldlallah, Miguel Carreiro, P. Guilpain, Helder Gil, M. Ruivard, N. Magy‐Bertrand, Antoine Dossier, Y. Leveneur, Xavier Delbrel, Bernard Anthony, François Lifermann, Mikaël Martin, Marie‐Pierre Ledoux, Frédérique Roy‐Péaud, Laurie Chabbert, Maryse Lapeyre‐mestre, A. Sommet, Yoann Zadro, Bernard Bonnotte, Marc Michel, B. Godeau, et le groupe des investigateurs de CARMEN‐France
ABSTRACT Fostamatinib is available in France since October 2021 for the treatment of adult chronic immune thrombocytopenia (ITP). French health authorities requested a 3‐year, prospective, multicenter registry to provide real‐world evidence about the effectiveness and safety of fostamatinib. Patients' characteristics, treatment response (ongoing exposure to fostamatinib and a platelet count ≥ 30 × 10 9 /L with no rescue in the previous 4 weeks) after 3, 6, 12, and 24 months (M); bleeding; fostamatinib discontinuation; adverse drug reactions (ADRs) and other events of interest have been analyzed. In total, 164 patients were included (median age: 59 years; 55.5% women; 84.1% had previous bleeding; 30 had secondary ITP; 89.0% had chronic ITP). The median ITP duration was 7.2 years and the median number of previous ITP treatments was 6. The response rate was 44.0% (70/159) at M3, 41.9% (62/148) at M6, 32.4% (44/136) at M12 and 20.0% (21/105) at M24. Concomitant treatment (mostly TPO‐RA) was used in > 60.0% of responders at each endpoint. The cumulative discontinuation rate at each endpoint was, respectively, 27.0%, 44.6%, 55.9%, and 76.2%. Seventy‐one (43.3%) patients experienced at least one bleeding during fostamatinib exposure; none was fatal. One hundred adverse drug reactions (8 serious) were observed in 61 (36.7%) patients, including diarrhea in 28 (17.1%) patients, arterial hypertension in 17 (10.4%). Seven thrombosis (4.3%) and 40 infections (12 serious) were reported in 25 patients (15.2%), mostly in patients with known risk factors. In conclusion, fostamatinib in combination with TPO‐RA should be considered in difficult‐to‐treat ITP patients. No new safety signal was observed.