Study to Evaluate the Safety and Efficacy of PF-06939926 for the Treatment of Duchenne Muscular Dystrophy
![]() |
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT04281485 |
Recruitment Status :
Recruiting
First Posted : February 24, 2020
Last Update Posted : March 20, 2023
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Duchenne Muscular Dystrophy | Genetic: PF-06939926 Other: Placebo | Phase 3 |
The study will assess the efficacy of PF-06939926 gene therapy on ambulatory function while also monitoring its safety. Approximately 99 boys with DMD will be enrolled and randomly assigned to one of two groups: approximately two thirds will be in Cohort 1 and receive gene therapy at the start of the study; approximately one third will be in Cohort 2 and receive placebo at the start of the study and receive gene therapy after one year, as long as it remains safe to do so. The treatment (PF-06939926 gene therapy or placebo) will be given as an intravenous infusion lasting up to 2 hours.
The study includes boys who are at least 4 years old and less than 8 years old (including 7 year olds up until their 8th birthday). All boys will need to be on a daily dose of glucocorticoids (prednisone, prednisolone, or deflazacort) for at least 3 months prior to enrolling and to stay on daily glucocorticoids for the first 2 years of the study. All boys will need to be negative for neutralizing antibodies against AAV9, as measured by the test done for the study as part of screening.
The primary outcome of the study will be assessed at 52 weeks. All participants will be followed in the study for 5 years after treatment with gene therapy.
The study medication, all medical tests associated with the study, and the visits to the study sites are free of charge. Participants will also be supported for travel costs associated with study visits.
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 99 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Parallel up to the measurement of the primary outcome at Week 52. At the beginning of study Year 2 participants who were originally assigned to placebo will have the opportunity to receive PF-06939926. All participants will be followed for 5 years following treatment with PF-06939926. |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Masking Description: | The study will be quadruple blind. |
Primary Purpose: | Treatment |
Official Title: | A PHASE 3, MULTICENTER, RANDOMIZED, DOUBLE-BLIND, PLACEBO CONTROLLED STUDY TO EVALUATE THE SAFETY AND EFFICACY OF PF 06939926 FOR THE TREATMENT OF DUCHENNE MUSCULAR DYSTROPHY |
Actual Study Start Date : | November 5, 2020 |
Estimated Primary Completion Date : | April 26, 2024 |
Estimated Study Completion Date : | April 26, 2029 |

Arm | Intervention/treatment |
---|---|
Cohort 1
Approximately two thirds of participants will be randomized to Cohort 1.
|
Genetic: PF-06939926
PF-06939926 will be administered as a single IV infusion at Year 1 for Cohort 1. Other: Placebo Placebo will be administered as a single IV infusion at Year 2 for Cohort 1. |
Cohort 2
Approximately one third of participants will be randomized to Cohort 2.
|
Other: Placebo
Placebo will be administered as a single IV infusion at Year 1 for Cohort 2. Genetic: PF-06939926 PF-06939926 will be administered as a single IV infusion at Year 2 for Cohort 2 |
- Change from Baseline in North Star Ambulatory Assessment (NSAA) [ Time Frame: Week 52 ]The NSAA is a 17-item test that measures gross motor function in children with Duchenne.
- Change from Baseline in mini-dystrophin expression level in muscle [ Time Frame: Week 52 ]Mini-dystrophin expression level from a muscle biopsy will be assessed by liquid chromatography mass spectrometry (LC-MS).
- Change from Baseline in distribution of mini-dystrophin expression in the muscle [ Time Frame: Week 52 ]Mini-dystrophin distribution from a muscle biopsy will be assessed by immunofluorescence.
- Change from Baseline in serum creatine kinase (CK) [ Time Frame: Week 52 ]Changes in the circulating levels of CK.
- Number of skills gained based on the individual items of the NSAA. [ Time Frame: Week 52 ]To count the skills that each child gained, based on the individual items of the NSAA.
- Number of skills improved or maintained based on the individual items of the NSAA [ Time Frame: Week 52 ]To count the skills that each child improved or maintained, based on the individual items of the NSAA.
- Change from Baseline in the 10-meter run/walk test velocity [ Time Frame: Week 52 ]Velocity is calculated based on the time that it takes to complete the 10-meter run/walk test.
- Change from Baseline in the rise from floor velocity [ Time Frame: Week 52 ]Velocity is calculated based on the time that it takes to the rise from floor.
- Change from Baseline in the Modified Pediatric Outcomes Data Collection Instrument (PODCI): Transfer and Basic Mobility Core Scale [ Time Frame: Week 52 ]The PODCI contains a list of questions to assess how each caregiver/child evaluates the child´s ability to to walk, stand, and perform activities of daily living.
- Change from Baseline in the Modified Pediatric Outcomes Data Collection Instrucment (PODCI): Sports and Physical Functioning Core Scale [ Time Frame: Week 52 ]The PODCI contains a list of questions to assess how each caregiver/child evaluates the child´s ability to perform recreational activities.

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 4 Years to 7 Years (Child) |
Sexes Eligible for Study: | Male |
Gender Based Eligibility: | Yes |
Gender Eligibility Description: | Male |
Accepts Healthy Volunteers: | No |
Key inclusion criteria:
- Confirmed diagnosis of Duchenne muscular dystrophy by prior genetic testing
- Receiving a stable daily dose (at least 0.5 mg/kg/day prednisone or prednisolone, or at least 0.75 mg/kg/day deflazacort) for at least 3 months prior to Screening
- Ambulatory, as assessed by protocol-specified criteria
Key exclusion criteria:
- Positive test performed by Pfizer for neutralizing antibodies to AAV9
- Any treatment designed to increase dystrophin expression within 6 months prior to screening (e.g., Translarna™, EXONDYS 51™, VYONDYS 53™)
- Any prior treatment with gene therapy
- Any non-healed injury that may impact functional testing (eg NSAA)
- Abnormality in specified laboratory tests, including blood counts, liver and kidney function
-
Any of the following genetic abnormalities in the dystrophin gene:
- Any mutation (exon deletion, exon duplication, insertion, or point mutation) affecting any exon between exon 9 and exon 13, inclusive; OR
- A deletion that affects both exon 29 and exon 30;OR
- A deletion that affects any exons between 56-71, inclusive.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04281485
Contact: Pfizer CT.gov Call Center | 1-800-718-1021 | ClinicalTrials.gov_Inquiries@pfizer.com |

Study Director: | Pfizer CT.gov Call Center | Pfizer |
Responsible Party: | Pfizer |
ClinicalTrials.gov Identifier: | NCT04281485 |
Other Study ID Numbers: |
C3391003 2019-002921-31 ( EudraCT Number ) |
First Posted: | February 24, 2020 Key Record Dates |
Last Update Posted: | March 20, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests. |
URL: | https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Clinical trial Gene therapy Duchenne muscular dystrophy fordadistrogene movaparvovec |
Muscular Dystrophies Muscular Dystrophy, Duchenne Muscular Disorders, Atrophic Muscular Diseases Musculoskeletal Diseases |
Neuromuscular Diseases Nervous System Diseases Genetic Diseases, Inborn Genetic Diseases, X-Linked |