Another gene therapy for Hemophilia B is now approved by the FDA

After the approval of Etranacogene dezaparvovec in November 2022, the FDA has now approved another gene therapy- Fidanacogene elaparvovec for haemophilia B (deficiency in clotting factor IX due to a faulty gene occurring typically in men).

Patients can receive a one-time infusion of this recently approved gene therapy if they are currently on clotting factor IX prophylaxis therapy, have a history of or are currently suffering life-threatening haemorrhages, or have recurrent severe spontaneous bleeding episodes.

Currently priced at $3.5 million, Fidanacogene elaparvovec claims to provide a cure and be more cost-effective than lifelong factor IX infusions, though uptake has been slow due to cost, durability, and safety concerns.

Clinical trial associated with the approval of this gene therapy:

BENEGENE-2 trial comprised 45 males with moderate to severe haemophilia B who were on factor IX prophylaxis for about 6 months along with a negative test for antibodies against the viral delivery vector. As observed, the bleeding rate per annum lowered from 4.5 events (average) during the 6-month pre-treatment phase to 2.5 events (average) between week 12 and the data cut-off. Compared to 29% of patients on factor IX therapy, 60% of patients who received the one-time infusion experienced complete elimination of bleeding events.

This gene therapy was well-tolerated with increased transaminases reported as the most commonly occurring adverse event. There were no reported cases of death, serious reactions, thrombotic occurrences, or factor IX antibodies.

Continuous monitoring of patients aimed to assess the long-term safety and durability of gene treatment over 15 years is ensured.