Real-world data on emicizumab prophylaxis in the Milan cohort

Authors: Arcudi, S; Gualtierotti, R; Marino, S; Nicolò, G; Biguzzi, E; Ciavarella, A; Boscarino, M; Siboni, SM; Schiavone, L; Novembrino, C; Valsecchi, C; Peyvandi, F

Affiliations: Università degli Studi di Milano, Department of Pathophysiology and Transplantation, Milan, Italy. Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center and Fondazione Luigi Villa, Milan, Italy.

Publication: Haemophilia: 2022

Abstract: We conducted an observational study enrolling 21 consecutive patients with severe haemophilia A (HA) with and without inhibitors, regularly followed at the Angelo Bianchi Bonomi Hemophilia Center of Milan and switched to emicizumab prophylaxis in the post-licensing period after April 2020. Information regarding age, inhibitor status, previous therapy, annualized bleeding rate (ABR) and information on bleeds were collected at baseline before starting emicizumab, at weeks 1, 5, 10, 20, 50 and in case of breakthrough bleeding episodes. Patients were summoned for medical visits at weeks 0, 1, 5, 10, 20 and 50. In addition, they could call a 24-h phone number to report to the physician on call any suspicion of bleeding. The plasma concentrations of emicizumab were measured at fixed timepoints (weeks 1, 5, 10, 20, 50) and at the time of each bleeding episode by using a modified onestage clotting assay for FVIII calibrated with an emicizumab standard (r2 Diagnostics, USA) and performed on ACL Top with the Synthasil APTT and FVIII-deficient plasma (Werfen, Orangeburg, NY, USA).1 At the same timepoints and baseline, we searched for anti-drug antibodies (ADA) in the total IgG fraction by means of a previously reported Western blot method.