FDA Approves Hemophilia Treatment Alprolix
First recombinant clotting factor therapy with prolonged circulation in the body
The FDA has approved Alprolix (coagulation factor IX [recombinant], Fc fusion protein), the first recombinant, DNA-derived hemophilia B therapy with prolonged circulation in the body.
Alprolix is indicated for the control and prevention of bleeding episodes, for perioperative management, and for routine prophylaxis in adults and children with hemophilia B. The therapy has been shown to reduce bleeding episodes with prophylactic infusions starting at least a week apart.
According to the product’s developer (Biogen Idec), the approval of Alprolix is the first significant advance in hemophilia B treatment in more than 17 years.
Treatments for hemophilia B can be administered either on a schedule to help prevent or reduce bleeding episodes (prophylaxis), or to help control a bleeding episode when it occurs (on-demand). According to NHF guidelines, traditional therapy for hemophilia B requires prophylactic infusions two or more times a week.
The FDA’s approval of Alprolix is based on results from the phase III B-LONG study, as well as on interim pharmacokinetic and safety data from the ongoing phase III Kids B-LONG study.
B-LONG was a global, open-label, phase III study that evaluated the efficacy, safety, and pharmacokinetics of prevention or reduction of bleeding episodes with prophylactic infusions of in 123 males aged 12 years and older with hemophilia B.
The results from this study showed that adults and adolescents with severe hemophilia B achieved the prevention or reduction of bleeding episodes with prophylactic infusions of Alprolix at least a week apart.
The study included two prophylaxis regimens — the weekly prophylaxis arm and the individualized-interval prophylaxis arm, in which the dosing interval started at once every 10 days. The overall median dosing interval with individualized-interval prophylaxis was 12.5 days; during the last 6 months of the study, the median interval was 13.8 days. More than 90% of all bleeding episodes were controlled by a single infusion of Alprolix.
The overall median annualized bleeding rates reported in the study were 3.0 for the weekly prophylaxis arm, 1.4 for the individualized-interval prophylaxis arm, and 17.7 for the on-demand treatment arm. For 12 study participants undergoing 14 major surgical procedures, treating physicians rated the ability of Alprolix to control bleeding as “excellent” or “good” in all of these surgeries.
No participants in the B-LONG trial developed neutralizing antibodies (inhibitors) to Alprolix. There were no reports of vascular clots or serious allergic reactions.
Across the routine prophylaxis and on-demand therapy arms, adverse reactions were reported in 8.4% of participants. These reactions included headache, oral paresthesia, dizziness, dysgeusia, breath odor, fatigue, infusion-site pain, palpitations, obstructive uropathy, and hypotension. An interim analysis of the ongoing Kids B-LONG trial also found no inhibitors to Alprolix. The increase in half-life seen with Alprolix was consistent with data reported in adults and adolescents.
Alprolix was developed by fusing factor IX to the Fc portion of immunoglobulin G subclass 1 (IgG1). It is believed that this enables Alprolix to use a naturally occurring pathway to prolong the time the therapy remains in the body. While Fc fusion has been used for more than 15 years, Biogen Idec is the only company to apply it in hemophilia.
Source: Biogen Idec; March 28, 2014.