Abstract Number: PB0623
Meeting: ISTH 2021 Congress
Background: Emicizumab is a recombinant monoclonal antibody that bridges FIXa and FX, replacing the function of FVIIIa. Emicizumab has demonstrated efficacy and a favorable safety profile in PwHA with/without FVIII inhibitors. For all PwHA developing persistent FVIII inhibitors (PwHAwI), ITI therapy for inhibitor eradication is recommended. However, since PwHAwI on ITI therapy were excluded from the emicizumab clinical development program, there are currently limited safety data for emicizumab treatment under/immediately after ITI therapy in PwHAwI. Accordingly, there is a need to collect safety/efficacy data on this concomitant treatment strategy in a clinical setting. The present study was planned as no such study has been conducted in Japan.
Aims: To evaluate the safety of emicizumab under/immediately after ITI therapy in PwHAwI. Here we report details of the study protocol.
Methods: This open-label, non-randomized, interventional, multicenter study in Japan (jRCTS041200037) of emicizumab in PwHAwI receiving ITI therapy (Figure) aims to enroll 20 participants; informed consent and approvals will be obtained prior to study start. The primary endpoint is to comprehensively evaluate safety (adverse events [mainly thromboembolic events] and abnormal laboratory values) over time. Secondary endpoints are the number of bleeds requiring coagulation factor treatment, the number of participants achieving a partially successful ITI therapy response, FVIII inhibitor titers under/immediately after ITI therapy, quality of life, and time to achieve negative FVIII inhibitor titers and partial success in PwHAwI starting ITI therapy after study enrollment. Partial success is defined as a negative FVIII inhibitor titer plus normal FVIII recovery; for success, a normal FVIII half-life is required, but due to the participants’ burden, half-life assessment based on full pharmacokinetic analysis is not mandatory (Table).
Results: This registered study is ongoing.
Conclusions: This study will evaluate the safety of emicizumab prophylaxis administered under/immediately after ITI therapy in PwHAwI, providing reference data to inform treatment strategies in this study population.
To cite this abstract in AMA style:Matsushita T, Suzuki N, Nagao A, Nagae C, Yamaguchi-Suita H, Kyogoku Y, Ioka A, Nogami K. AKATSUKI Study: A Prospective, Multicenter, Phase IV Study to Evaluate the Safety of Emicizumab Under and Immediately After Immune Tolerance Induction (ITI) Therapy in Persons with Congenital Hemophilia A (PwHA) with Factor (F) VIII Inhibitors [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/akatsuki-study-a-prospective-multicenter-phase-iv-study-to-evaluate-the-safety-of-emicizumab-under-and-immediately-after-immune-tolerance-induction-iti-therapy-in-persons-with-congenital-hemophil/. Accessed December 8, 2021.
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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/akatsuki-study-a-prospective-multicenter-phase-iv-study-to-evaluate-the-safety-of-emicizumab-under-and-immediately-after-immune-tolerance-induction-iti-therapy-in-persons-with-congenital-hemophil/