FDA Approves Larger Idelvion Vial Size for Hemophilia B Patients Requiring Higher Doses

The U.S. Food and Drug Administration has approved a larger vial size — 3,500 IU — of CSL Behring’s Idelvion (albutrepenonacog alfa) for the treatment of hemophilia B patients.

Idelvion is supplied as a powder for intravenous use and must be reconstituted, or mixed with a liquid (called a diluent), before it is injected. While the current vial and dose sizes are adequate for most patients, some require higher doses, which involves reconstituting several smaller vials of the therapy. The larger vial size will be more convenient for these patients who require higher doses.

“Having a variety of vial sizes available for patients, particularly larger vials, increases convenience for patients in optimizing their administration regimen,” Craig Kessler, MD, director of the Division of Coagulation and director of the Hemophilia and Thrombosis Comprehensive Care Center at Georgetown University Medical Center, said in a press release. “The 3500 IU vial can be helpful for patients currently on IDELVION or those who might have been waiting until more convenient vial sizes were available in order to begin treatment with IDELVION.”

Currently, Idelvion is available in 250 IU, 500 IU, 1,000 IU, and 2,000 IU. The 3,500-IU vial is expected to be available for order in the coming weeks.

“We believe a good portion of the community will benefit from the addition of this fifth, larger vial to the IDELVION family,” said Jerry Powell, MD, coagulation medical director of CSL Behring’s North America division. “Reconstituting the same amount of factor from a single vial will require less diluent than reconstituting multiple vial sizes, saving patients time and ancillary supplies.”

Hemophilia B is a bleeding disorder characterized by deficient or defective clotting factor IX. Idevlion, a recombinant human factor IX fused to a protein called albumin, can be used for the treatment or prevention of bleeds. The fusion to albumin allows Idevlion to have a longer half-life, enabling the recombinant factor IX to stay in circulation longer.

Clinical trial results have shown that Idelvion use led to factor IX levels of 21% at steady state with preventive use and 5% over 14 days with a single dose.

Idelvion is the only FDA-approved factor IX treatment that delivers a zero median annual spontaneous bleeding rate. The 3,500-IU vial is also already approved in Canada.

The European Medicines Agency’s Committee for Medicinal Products for Human Use has recommended marketing authorization approval for the 3,500-IU vial of Idelvion in the European Union. Additionally, marketing applications for this larger vial size in Australia, Switzerland, and Japan are currently under review by regulatory agencies.