Design of a prospective observational study on the effectiveness and real-world usage of recombinant factor VIII Fc (rFVIIIFc) compared with conventional products in haemophilia A: The A-SURE study

Introduction: Haemophilia A is a rare bleeding disorder caused by coagulation factor VIII (FVIII) deficiency. This is treated with factor VIII, conventionally using products with a half-life of 8-12 hours typically administered every 2-3 days. Recombinant FVIII Fc (rFVIIIFc) represents a new generation of products with an extended half-life allowing higher FVIII levels and longer dosing interval. The efficacy and safety of rFVIIIFc have been established in clinical studies and several years of postmarketing use. However, there remains a need to compare treatment outcome with conventional products in routine clinical use. Methods and analysis: A-SURE is an ongoing, non-interventional European study with the primary objective to compare the clinical effectiveness of rFVIIIFc with conventional factor products used for haemophilia A prophylaxis. Data covering a 24-month prospective period and a 12-month retrospective period will be collected. Three primary endpoints: bleeding rate, injection frequency and factor consumption will be used to evaluate treatment outcomes. Enrolment of 175 patients on rFVIIIFc and 175 on conventional products is planned. All eligible patients from participating centres will be invited to participate. Visits and treatments follow routine clinical practice. Bias will be reduced by patient matching for age at baseline and the last weekly prophylaxis dose of a conventional product prior to baseline. Propensity scores will be calculated based on prognostic factors and potential confounders assessed at baseline and adjusted for in the estimation of the treatment effect. Ethics and dissemination: Study approval was obtained by local independent ethics committees and/or authorities, and informed consent from patients or their legal representative is a requirement for participation. Names of ethical committees and approval numbers are provided as supplementary information. The study results will be submitted for publication in a peer-reviewed scientific journal and presented at scientific conferences.This work was fully funded by Swedish Orphan Biovitrum AB (publ