This week in Thrombosis and Haemastasis
, Pasi et al report on the long term safety and efficacy of Alprolix [Coagulation Factor IX (Recombinant), Fc Fusion Protein] in patients with severe hemophilia B.
Aprolix was approved in 2014 based on the B-LONG and kids B-LONG clinical trials showing the drugs to be effective in patients with Hemophilia B.
Those patients were allowed to enter an extension study, called the B-YOND study, and 2 - 3 year data from that study was published this week. At the time of the interim data cut, 116 male subjects (93 from B-LONG and 23 from Kids B-LONG) were enrolled in the study. The primary outcome measure was development of inhibitors (neutralizing antibodies that can interfere with activity of the therapy) and the study found no patients treated with Alprolix in the study developed inhibitors.
At the data cut off point, the mean treatment duration was 39.5 months in the adults and 21.9 months in the children.
In addition to no inhibitors being present in any of the patients, the analysis showed that median annualized bleeding rates (ABR) remained low in these patients. For children under 6 years of age, mean ABR was 0.0 per week. For children 7-12 years of age, mean ABR was 2.7 per week. For patients over 12 years of age, mean ABR was 2.3 per week.
The study also noted that 1 or 2 infusions of Alprolix were sufficient to control 95-97% of patients’ bleeding episodes.
In a news release
, John Pasi, MD, PhD, principal investigator of the study, Professor of Haemostasis and Thrombosis at The Royal London Hospital, Barts and the London School of Medicine and Dentistry, London said, “The interim data from B-YOND confirm the safety profile of Alprolix, and show that adult, adolescent and pediatric subjects maintained low annual bleed rates with prophylactic dosing of ALPROLIX every 1-2 weeks.”
The most common adverse events were headache (12.1%) and common cold (11.2%), and the majority of adverse events were considered by the investigator to be unrelated to Alprolix treatment.
About Hemophilia B
Hemophilia B is a rare, inherited disorder in which the ability of a person’s blood to clot is impaired due to reduced or no factor IX activity. Hemophilia B affects approximately 3,300 people in the United States. Patients with hemophilia B experience prolonged bleeding episodes that can cause pain, irreversible joint damage and life-threatening hemorrhages.
Currently, there are several treatment options for hemophilia B.