AOZORA: long-term safety and joint health in paediatric persons with haemophilia A without factor VIII inhibitors receiving emicizumab - protocol for a multicentre, open-label, phase IV clinical study

INTRODUCTION

Persons with haemophilia A (PwHA) commonly experience regular bleeding into joints, which may result in joint damage and complications such as degenerative arthritis. Emicizumab has previously demonstrated efficacy in reducing the occurrence of joint bleeds and target joints, along with having a favourable safety profile; however, data on the long-term effects on joint health are lacking. The AOZORA study will evaluate the long-term safety and joint health of paediatric PwHA without factor (F)VIII inhibitors taking emicizumab; here, we report the details of the study protocol and baseline data.

METHODS AND ANALYSIS

AOZORA is a multicentre, open-label, phase IV clinical study in Japan that aims to enrol approximately 30 PwHA aged <12 years without FVIII inhibitors. The primary endpoints include a long-term safety evaluation of adverse events, laboratory test abnormalities and FVIII inhibitor development; and a long-term joint health assessment using MRI and the Hemophilia Joint Health Score. Exploratory endpoints include characterising participants' physical activities and the number of activity-related bleeds requiring coagulation factor treatment. Currently, 30 participants have been enrolled, including 20 emicizumab-naïve participants and 10 who transferred from HOHOEMI, a previous study in paediatric PwHA.

ETHICS AND DISSEMINATION

The AOZORA study was approved by the Institutional Review Boards of Nara Medical University and the St Marianna University Group. The study will be conducted in compliance with the Declaration of Helsinki, the standards stipulated in paragraph 3 of Article 14 and Article 80-2 of the Pharmaceuticals, Medical Devices and Other Therapeutic Products Act, the Ministerial Ordinance on Good Clinical Practice and the Ministerial Ordinance on Good Post-marketing Study Practice. Data will be published in peer-reviewed journals and presented at Global congresses.

TRIAL REGISTRATION NUMBER

JapicCTI-194701.

AKATSUKI study: a prospective, multicentre, phase IV study evaluating the safety of emicizumab under and immediately after immune tolerance induction therapy in persons with congenital haemophilia A with factor VIII inhibitors

INTRODUCTION

For persons with haemophilia A with factor (F) VIII inhibitors (PwHAwI), immune tolerance induction (ITI) therapy is indicated for inhibitor eradication; however, since PwHAwI on ITI were excluded from the emicizumab clinical development programme, there are limited safety data for emicizumab treatment under/immediately after ITI in PwHAwI. Accordingly, there is a need to collect safety and efficacy data on this concomitant treatment strategy. The AKATSUKI study aims to evaluate the safety of emicizumab under/immediately after ITI in PwHAwI; here we report details of the study protocol.

METHODS AND ANALYSIS

AKATSUKI is an open-label, non-randomised, interventional, multicentre study. Twenty participants with congenital HA with FVIII inhibitors will be enrolled from 17 sites across Japan. Emicizumab will be administered subcutaneously, with an initial loading dose of 3 mg/kg once per week (QW) for the first 4 weeks, followed by a maintenance dose of 1.5 mg/kg QW, 3 mg/kg once every 2 weeks or 6 mg/kg once every 4 weeks. For ITI therapy, 50 IU/kg FVIII will be administered three times per week. For extended half-life FVIII, a dosing frequency of twice per week will be permitted. The primary endpoint is a comprehensive safety evaluation of 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 response, FVIII inhibitor titres under/immediately after ITI, quality of life and time to achieve a negative FVIII inhibitor result (<0.6 BU/mL) and partial success in PwHAwI starting ITI after study enrolment.

CONCLUSIONS

AKATSUKI will evaluate the safety of emicizumab administered under/immediately after ITI, providing reference data to inform treatment strategies in PwHAwI.

ETHICS AND DISSEMINATION

The results of this study will be published in a peer-reviewed international journal and presented at national and/or international medical scientific conferences; the major findings of this study will be published on the jRCT registry website (https://jrct.niph.go.jp).

TRIAL REGISTRATION NUMBER

jRCTs041200037.