The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has recommended that albutrepenonacog alfa (Idelvion) receive marketing authorization to treat patients with hemophilia B.
Albutrepenonacog alfa is a recombinant fusion protein linking coagulation factor IX with albumin.
The CHMP’s recommendation will be reviewed by the European Commission, which usually follows the CHMP’s advice.
In 2010, the European Commission granted albutrepenonacog alfa orphan designation as a treatment for hemophilia B.
Albutrepenonacog alfa is being developed by CSL Behring. The product is approved for use in Canada. Regulatory agencies in the US, Australia, Switzerland, and Japan are reviewing applications for the drug.
Phase 3 trial
The CHMP’s recommendation to approve albutrepenonacog alfa is based on the PROLONG-9FP clinical development program. PROLONG-9FP includes phase 1, 2, and 3 studies evaluating the safety and efficacy of albutrepenonacog alfa in adults and children (ages 1 to 61) with hemophilia B.
Data from the phase 3 study were recently published in Blood. This study included 63 previously treated male patients with severe hemophilia B. They had a mean age of 33 (range, 12 to 61).
The patients were divided into 2 groups. Group 1 (n=40) received routine prophylaxis with albutrepenonacog alfa once every 7 days for 26 weeks, followed by a 7-, 10- or 14-day prophylaxis regimen for a mean of 50, 38, or 51 weeks, respectively.
Group 2 received on-demand treatment with albutrepenonacog alfa for bleeding episodes for 26 weeks (n=23) and then switched to a 7-day prophylaxis regimen for a mean of 45 weeks (n=19).
The median annualized bleeding rate (ABR) was 2.0 in the prophylaxis arm (group 1) and 23.5 in the on-demand treatment arm (group 2). The median spontaneous ABRs were 0.0 and 17.0, respectively.
For patients in group 2, there was a significant reduction in median ABRs when patients switched from on-demand treatment to prophylaxis—19.22 and 1.58, respectively (P<0.0001). And there was a significant reduction in median spontaneous ABRs—15.43 and 0.00, respectively (P<0.0001).
Overall, 98.6% of bleeding episodes were treated successfully, including 93.6% that were treated with a single injection of albutrepenonacog alfa.
None of the patients developed inhibitors or experienced thromboembolic events, anaphylaxis, or life-threatening adverse events (AEs).
There were 347 treatment-emergent AEs reported in 54 (85.7%) patients. The most common were nasopharyngitis (25.4%), headache (23.8%), arthralgia (4.3%), and influenza (11.1%).
Eleven mild/moderate AEs in 5 patients (7.9%) were considered possibly related to albutrepenonacog alfa. Two patients discontinued treatment due to AEs—1 with hypersensitivity and 1 with headache.
