Pfizer Drops Approved Hemophilia B Gene Therapy

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Pfizer has announced that it is discontinuing development and commercialization of fidanacogene elaparvovec an adeno-associated virus (AAV) vector-based gene therapy for the treatment of hemophilia B.¹ The therapy was approved by the FDA under the name Beqvez less than a year ago, in April 2024.²

Reuters reported the news on February 21, stating that Pfizer cited limited interest in gene therapies for hemophilia as a reason for discontinuation.¹ No patients had been dosed yet in the commercial setting with the therapy, which was priced at a whopping $3.5 million.²

The last data Pfizer reported on fidanacogene elaparvovec were presented at December’s American Society of Hematology meeting by Ben Samelson-Jones, MD, PhD, assistant professor pediatric hematology, Perelman School of Medicine, University of Pennsylvania and Associate Director, Clinical In Vivo Gene Therapy, Children’s Hospital of Philadelphia.³

The data demonstrated favorable safety 5 years out from administration but a slight and continuous degradation in factor IX levels that reflects concerns patients and clinicians in the field have about the long-term durability and efficacy of gene therapy for hemophilia, especially considering that gene therapies are currently a one-and-done, not redosable treatment strategy.³

“It should be very reassuring that there's nothing unexpected," Samelson-Jones told HCPLive® during the meeting. “I think the story of AAV-based gene therapy for hemophilia over the last 3 decades has been surprises. And I think what this is should be reassuring, that there's nothing has popped up that it that is of concern.”

The news follows Pfizer’s shift away from gene therapy development, after it discontinued development of fordadistrogene movaparvovec, an investigational AAV gene therapy for the potential treatment of Duchenne muscular dystrophy in July, and more recently, terminated its deal with Sangamo Therapeutics to develop and commercialize giroctocogene fitelparvovec gene therapy, which was also in development for treating hemophilia A.^4,5

Other players in the field of hemophilia gene therapy have likely felt similar sentiments toward the treatment strategy since entering the market. Namely, BioMarin has scaled back its efforts with regard to valoctocogene roxaparvovec (Roctavian) hemophilia A gene therapy to center on distribution in the United States, Germany, and Italy, the 3 countries in which it has been approved for use by relevant regulatory authorities and is reimbursed,⁶ while both val-rox and UniQure and CSL Behring’s hemophilia B gene therapy, etranacogene dezaparvovec (Hemgenix), have reportedly been slow to be embraced in the commerical field.

REFERENCES

1. Santhosh C. Pfizer stops commercialization of hemophilia gene therapy Beqvez. Reuters. February 21, 2025. https://www.reuters.com/business/healthcare-pharmaceuticals/pfizer-says-it-will-end-global-development-gene-therapy-beqvez-nikkei-reports-2025-02-20/

2. U.S. FDA Approves Pfizer’s BEQVEZ™ (fidanacogene elaparvovec-dzkt), a One-Time Gene Therapy for Adults with Hemophilia B. News release. Pfizer. April 26, 2024. Accessed April 26, 2024. https://www.businesswire.com/news/home/20240425269649/en/U.S.-FDA-Approves-Pfizer%E2%80%99s-BEQVEZ%E2%84%A2-fidanacogene-elaparvovec-dzkt-a-One-Time-Gene-Therapy-for-Adults-with-Hemophilia-B

3. Samelson-Jones B, Frenzel L, Kavakli K, et al. Use of Fidanacogene Elaparvovec, a Gene Therapy Vector, to Deliver a Stable, Fully Functional Human Factor IX Transgene for the Treatment of Hemophilia B: A Combined Analysis of Safety. Presented at: ASH Annual meeting; December 7-10; San Diego, California. Abstract 3577

4. Pfizer officially calls it quits on DMD gene therapy, lays off staff at Sanford site. News article. Elizabeth S. Eaton. FirstWordPharma. July 29, 2024. https://firstwordpharma.com/story/5880030

5. Sangamo Therapeutics to Regain Full Rights to Hemophilia A Gene Therapy Program Following Pfizer’s Decision to Cease Development of Giroctocogene Fitelparvovec. News release. Sangamo Therapeutics. December 30, 2024.

6. BioMarin Announces Updated Strategy for ROCTAVIAN® to Focus on U.S., Germany and Ital. News release. BioMarin Pharmaceutical Inc. August 5, 2024. Accessed August 15, 2024. https://investors.biomarin.com/news/news-details/2024/BioMarin-Announces-Updated-Strategy-for-ROCTAVIAN-to-Focus-on-U.S.-Germany-and-Italy/default.aspx