General Information

Alprolix is specifically indicated in adults and children with hemophilia B for control and prevention of bleeding episodes, perioperative management and routine prophylaxis to prevent or reduce the frequency of bleeding episodes.

Alprolix is supplied as a powder for reconstitution into a solution for intravenous injection. The recommended dosing is as follows:
Control and prevention of bleeding episodes and perioperative management:
Minor and Moderate bleeding: 30-60 Circulating FIX (IU/dL), repeat every 48 hours as needed
Major bleeding: 80-100 Circulating FIX (IU/dL), Consider repeat dose after 6-10 hours, then every 24 hours for 3 days, then every 48 hours until healing achieved
Routine prophylaxis:
50 IU/kg once weekly or 100 IU/kg once every 10 days. Adjust dosing regimen based on individual response.

Clinical Results

FDA Approval
The FDA approval of Alprolix was based on a multi center open label trial that compared each of two prophylactic treatment regimens (fixed weekly and individualized interval) to episodic (on-demand) treatment; determined hemostatic efficacy in the treatment of bleeding episodes; and determined hemostatic efficacy during perioperative management of subjects undergoing major surgical procedures. A total of 123 previously treated patients (PTPs) with severe hemophilia B (= 2% endogenous FIX activity), ages 12-71, were followed for up to 77 weeks. Sixty three subjects in the fixed weekly interval arm received Alprolix for routine prophylaxis starting at an initial dose of 50 IU/kg. The dose was adjusted to maintain FIX trough level between 1% and 3% above baseline or higher, as clinically indicated to prevent bleeding. Twenty nine subjects in the individualized interval arm received Alprolix for routine prophylaxis at a dose of 100 IU/kg every 10 days, with the interval adjusted to maintain FIX trough level between 1% and 3% above baseline or higher, as clinically indicated to prevent bleeding. Twenty seven subjects received Alprolix as needed for the treatment of bleeding episodes in the episodic (on-demand) treatment arm. Twelve subjects received Alprolix for perioperative management in 14 major surgical procedures. The overall median annualized bleeding rates (including spontaneous and traumatic bleeds) were 2.95 in the weekly prophylaxis arm, 1.38 in the individualized interval prophylaxis arm, and 17.69 in the episodic treatment arm. In the individualized interval prophylaxis arm, the median dosing interval during the last 6 months on study was 14 days. Overall, 90.4% of bleeding episodes were controlled by a single injection of rFIXFc. Routine Prophylaxis: Using a negative binomial model, a reduction in annualized bleeding rate (ABR) of 83% (76-89%) for subjects in the fixed weekly interval arm and a reduction of 87% (80-92%) for subjects in the individualized interval arm compared to the episodic (on-demand) treatment arm was observed.

Mechanism of Action

Alprolix Coagulation Factor IX (Recombinant), Fc Fusion Protein, is a recombinant DNA derived, coagulation Factor IX concentrate. It temporarily replaces the missing coagulation Factor IX needed for effective hemostasis. Alprolix contains the Fc region of human IgG1, which binds to the neonatal Fc receptor (FcRn). FcRn is part of a naturally occurring pathway that delays lysosomal degradation of immunoglobulins by cycling them back into circulation, and prolonging their plasma half-life.