Pfizer receives FDA fast track designation for DMD gene therapy

Pfizer DMD gene therapy

Pfizer receives FDA fast track designation for Duchenne muscular dystrophy (DMD) investigational gene therapy.

Official press release > NEW YORK–(BUSINESS WIRE)

Pfizer Inc. announced that its investigational gene therapy candidate (PF-06939926) being developed to treat Duchenne muscular dystrophy (DMD) received Fast Track designation from the U.S. Food and Drug Administration (FDA). PF-06939926 is currently being evaluated to determine the safety and efficacy of this gene therapy in boys with DMD.

Fast Track is a process designed to facilitate the development and expedite the review of new drugs that are intended to treat or prevent severe conditions that have the potential to address an unmet medical need. This designation was granted based on data from the Phase 1b study that indicated that the intravenous administration of PF-06939926 was well-tolerated during the infusion period, and dystrophin expression levels were sustained over 12 months.


Brenda Cooperstone, MD, Chief Development Officer, Rare Disease, Pfizer Global Product Development – “The FDA’s decision to grant our investigational gene therapy PF-06939926 Fast Track designation underscores the urgency to address a significant unmet treatment need for Duchenne muscular dystrophy. DMD is a devasting condition and patients, and their parents, are waiting desperately for treatment options. We are working to advance our planned Phase 3 program as quickly as possible.”


DMD is a devastating and life-threatening X-linked disease caused by mutations in the gene encoding dystrophin, which is needed for proper muscle membrane stability and function. Patients present with muscle degeneration that progressively worsens with age to the extent that they require wheelchair assistance when they are in their early teens, and unfortunately, usually succumb to their disease by the time they are in their late twenties. It is estimated that there are ~10-12,000 individuals affected with DMD in the U.S.


About PF-06939926

PF-06939926 is an investigational, recombinant adeno-associated virus serotype 9 (rAAV9) capsid carrying a shortened version of the human dystrophin gene (mini-dystrophin) under the control of a human muscle specific promotor. The rAAV9 capsid was chosen as the delivery vector because of its potential to target muscle tissue. Pfizer initiated the Phase 1b multi-center, open-label, non-randomized, ascending dose study of a single intravenous infusion of PF-06939926 in 2018. The goal of the study is to assess the safety and tolerability of this investigational gene therapy. Other objectives of the clinical study include measurement of dystrophin expression and distribution and assessments of muscle strength, quality and function.

Data from the Phase 1b DMD gene therapy program, including data from an additional nine boys, who were all administered the high dose of the investigational therapy. A total of 15 boys have now been treated with the high dose and 18 boys have been treated overall. > Sources<

  • No Serious Adverse Events (SAE) were observed among the nine additional boys who were treated using a modified immunomodulatory regimen and monitoring regimen. The prophylactic steroid treatment was also changed from 1 mg/kg to an intermediate dose of 2mg/kg.
  • Three of the nine boys were dosed with gene therapy product that was manufactured using the commercial manufacturing process developed at Pfizer’s facility in Sanford, North Carolina.
  • Based on these data, the Company plans to initiate the pivotal study in the next several weeks, with the plan to perform an interim analysis of the clinical data in 2022.

About Pfizer Rare Disease

Rare disease includes some of the most serious of all illnesses and impacts millions of patients worldwide, representing an opportunity to apply their knowledge and expertise to help make a significant impact on addressing unmet medical needs. The Pfizer focus on rare disease builds on more than two decades of experience, a dedicated research unit focusing on rare disease, and a global portfolio of multiple medicines within several disease areas of focus, including rare hematologic, neurologic, cardiac and inherited metabolic disorders.

Pfizer Rare Disease combines pioneering science and a deep understanding of how diseases work with insights from innovative strategic collaborations with academic researchers, patients, and other companies to deliver transformative treatments and solutions. Pfizer innovates every day, leveraging its global footprint to accelerate the development and delivery of groundbreaking medicines and the hope of cures.

Click here to learn more about their Rare Disease portfolio and how Pfizer empowers patients, engage communities in their clinical development programs, and support programs that heighten disease awareness.

Interesting links

La Force DMD talks with Dr. Jeffrey Chamberlain, a geneticist at the University of Washington, Seattle, about adenovirus-associated (AAV) micro-dystrophin gene replacement therapy.

La Force DMD / Press release from Pfizer about gene therapy

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