Pfizer to Discontinue Its Hemophilia B Gene Therapy

Less than a year after approval, Pfizer said it plans to discontinue its hemophilia B gene therapy fidanacogene elaparvovec (Beqvez) across all global markets, citing weak demand.

“Pfizer has made the decision to cease further development and commercialization activities with respect to Beqvez for several reasons, including the limited interest patients and their doctors have demonstrated in hemophilia gene therapies to date,” the company said in an email statement to MedPage Today.

The company went on to say it will focus its efforts on treatments such as marstacimab (Hympavzi) — a non-factor treatment option — “that we believe will have the greatest impact on patients.” That drug, an IgG1 monoclonal antibody that helps promote clotting, was approved by the FDA in October for hemophilia A and B in adults and adolescents.

The move comes after Pfizer terminated a global collaboration and license agreement with Sangamo Therapeutics to develop giroctocogene fitelparvovec, an investigational gene therapy for the treatment of adults with moderately severe to severe hemophilia A.

Fidanacogene elaparvovec was approved by the FDA last year for adult men with moderate to severe hemophilia B currently treated with prophylactic factor IX, who have a history of life-threatening hemorrhage or repeated serious spontaneous bleeding episodes, and who do not have neutralizing antibodies to the adeno-associated virus serotype Rh74var capsid.

The gene therapy had a list price of $3.5 million per dose at launch.

Support for the approval came from the phase III, single-arm, open-label BENEGENE-2 trial involving 45 men with moderate or severe hemophilia B (factor IX circulating activity ≤2%).

From week 12 to data cutoff after 1.8 years of follow-up, the annualized bleeding rate decreased from 4.5 during the lead-in period to 2.5 following a single administration of the gene therapy. Bleeds were eliminated in 60% of patients with fidanacogene elaparvovec as compared with 29% with prophylactic factor IX.

The withdrawal of fidanacogene elaparvovec leaves one gene therapy — etranacogene dezaparvovec (Hemgenix) — approved for treatment of hemophilia B. It was approved in 2022 for adults who currently use factor IX prophylaxis therapy for blood clotting, those who have or have had life-threatening hemorrhage, and those who have repeated serious spontaneous bleeding episodes.

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