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DOI: 10.1055/s-0039-1680221
Long-term Efficacy and Safety of rVIII-SingleChain in Patients with Severe Hemophilia A: Interim Results of an Extension Study
Publication History
Publication Date:
13 February 2019 (online)
Scientific Research Question: To investigate the long-term efficacy and safety of rVIII-SingleChain in previously treated patients (PTPs) with severe hemophilia A.
Methodology: PTPs with severe hemophilia A (endogenous factor VIII [FVIII] < 1%) and >50 previous exposure days (EDs) to FVIII products were treated either on demand or prophylactically with 15-50 IU/kg rVIII-SingleChain 2- or 3-times weekly, or another regimen at the investigator's discretion (based on the patient's pharmacokinetic profile, FVIII treatment history and bleeding phenotype).
Findings: As of 5 September 2017, 222 PTPs were enrolled. The median (range) age was 20 years (1-64); 77 (34.7%) patients were 0-< 12 years, and 145 (65.3%) were ≥12 to ≤65 years. The majority of patients (n=211; 95%) had achieved ≥100 EDs; the total cumulative EDs in the extension study was 65,522 in 494 treatment years. Of the 211 (95%) patients assigned to prophylaxis, 98 (44.1%) were treated 3-times weekly, and 84 (37.8%) patients were treated 2-times weekly. All prophylaxis regimens resulted in low bleeding rates; median (IQR) annualized spontaneous bleeding rate (AsBR) for all regimens, for patients treated 3-times weekly, and 2-times weekly was 0.35 (0.00, 1.09), 0.35 (0.0, 0.96), and 0.0 (0.0, 1.46), respectively. There were 2273 bleeding events in total, of which 2162 were treated with rVIII-SingleChain. Of these, 2120 were rated for hemostatic efficacy by the investigator with 85.8% rated as either excellent or good and requiring 1 or 2 injections to achieve hemostasis. No PTP developed de novo inhibitors during the study. In addition, there were no thromboembolic events or anaphylactic reactions.
Conclusions: rVIII-SingleChain has a favorable safety profile, and is effective and well tolerated for on-demand and prophylaxis treatment in patients who have severe hemophilia A.
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No conflict of interest has been declared by the author(s).