Duchenne Muscular DystrophyPhase 3NCT04281485
Study to Evaluate the Safety and Efficacy of PF-06939926 for the Treatment of Duchenne Muscular Dystrophy
A Phase 3 study testing PF-06939926 in people with Duchenne Muscular Dystrophy, run by Pfizer at 53 sites in 15 countries.
Trial summary
The study will evaluate the safety and efficacy of gene therapy in boys with DMD. It is a randomized, double-blind, placebo-controlled study with two thirds of participants assigned to gene therapy. Read more about this study
- Who is it for?
- Ages 4 to 7 years, men only
- Conditions the study is for
- Duchenne Muscular Dystrophy
- What is being tested?
- PF-06939926
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 114 participants
- Where
- 53 sitesin 15 countries
- Study dates
- 5 Nov 2020to 15 Apr 2039
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 4 to 7 years
- Men only
- No healthy volunteers
- Child
Who may be able to join
- 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
Who cannot join
- 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:
Show all 9Show fewer
- 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.
Trial locations and contacts
53 sites in 15 countries.
53 sites in 15 countries
United States17 sites
Lenox Baker Children's Hospital
Durham, North Carolina, 27705
KU Clinical Research Center - Clinical and Translational Science Unit (CTSU) - Fairway
Fairway, Kansas, 66205
University of Florida
Gainesville, Florida, 32610
University of Iowa Hospitals and Clinics
Iowa City, Iowa, 52242
KU Clinical Research Center - Clinical and Translational Science Unit (CTSU) - Rainbow
Kansas City, Kansas, 66160
University of Kansas Hospital - Investigational Pharmacy
Kansas City, Kansas, 66160
University of Kansas Hospital - Pediatric and Pediatric ICU - Operating Room
Kansas City, Kansas, 66160
University of Kansas Medical Center
Kansas City, Kansas, 66160
Arkansas Children's Hospital
Little Rock, Arkansas, 72202
Arkansas Children's
Little Rock, Arkansas, 72202
UCLA Medical Center
Los Angeles, California, 90095
The Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, 19104
Pediatric Cardiology
Prairie Village, Kansas, 66208
Primary Childrens Hospital
Salt Lake City, Utah, 84113
University of Utah Clinical Neurosciences Center
Salt Lake City, Utah, 84132
University of Utah Hospital
Salt Lake City, Utah, 84132
Seattle Children's
Seattle, Washington, 98105
Canada4 sites
Alberta Children's Hospital
Calgary, Alberta, T3B 6A8
Children's Hospital - London Health Sciences Centre
London, Ontario, N6A 4G5
Childrens Hospital of Eastern Ontario
Ottawa, Ontario, K1H8L1
The Hospital For Sick Children
Toronto, Ontario, M5G 1X8
Australia3 sites
Perth Children's Hospital
Nedlands, Western Australia, 6009
The Royal Children's Hospital Melbourne
Parkville, Victoria, 3052
The Children's Hospital at Westmead
Westmead, New South Wales, 2145
Japan3 sites
Nagoya City University Hospital
Nagoya, Aichi-ken, 467-8602
Hyogo College of Medicine College Hospital
Nishinomiya, Hyōgo, 663-8501
National Center of Neurology and Psychiatry
Tokyo, 187-8551
South Korea3 sites
Seoul National University Hospital
Seoul, 03080
Samsung Medical Center
Seoul, 06351
Pusan National University Yangsan Hospital
Yangsan, Gyeongsangnam-do, 50612
Spain3 sites
Hospital Universitario Vall d'Hebron
Barcelona, 08035
Hospital Sant Joan de Déu
Esplugues de Llobregat, Barcelona, 08950
Hospital Universitari i Politecnic La Fe de Valencia
Valencia, 46026
Taiwan3 sites
Kaohsiung Medical University Chung-Ho Memorial Hospital
Kaohsiung City, 807
National Taiwan University Hospital
Taipei, 100
Taipei Veterans General Hospital
Taipei, 11217
United Kingdom3 sites
Alder Hey Children's NHS Foundation Trust
Liverpool, Merseyside, L12 2AP
Great Ormond Street Institute of Child Health
London, WCIN 1EH
The Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary
Newcastle upon Tyne, England, NE1 4LP
France2 sites
CHU de Nantes- Hotel Dieu
Nantes, 44093
Hopital Necker
Paris, 75015
Germany2 sites
Charité - Universitätsmedizin Berlin
Berlin, 13353
Universitatsklinikum Essen
Essen, 45147
Israel2 sites
Hadassah University Medical Center, Ein Kerem
Jerusalem, 91120
Schneider Children's Medical Center of Israel
Petach Tikvah, 4920235
Italy2 sites
Fondazione Policlinico Universitario Agostino Gemelli IRCCS
Roma, 00168
IRCCS Ospedale Pediatrico Bambino Gesù
Rome, 00165
Russia2 sites
Saint Petersburg State Paediatric Medical University
Saint Petersburg, 194100
State Autonomous Healthcare Institution of Sverdlovsk Region Children's City Clinical Hospital No 9
Yekaterinburg, 620134
Switzerland2 sites
Inselspital, University Children's Hospital Berne
Bern, 3010
Universitaets-Kinderspital Zuerich
Zurich, 8008
About this study
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
The study will evaluate the safety and efficacy of gene therapy in boys with DMD. It is a randomized, double-blind, placebo-controlled study with two thirds of participants assigned to gene therapy. The one third of participants who are randomized to the placebo arm will have an opportunity for treatment with gene therapy at the beginning of the second year.
Read the detailed description
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 15 years after treatment with gene therapy. Participants who received fordadistrogene movaparvovec in Pfizer studies C3391001 and C3391008 or are currently enrolled in Pfizer study C3391011 will be allowed to roll over into the long-term safety follow-up period of this study and will be considered Cohort 3.
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.
- Conditions
- Duchenne Muscular Dystrophy
- Being tested
- PF-06939926, Placebo
- Keywords
- Clinical trial, Gene therapy, Duchenne muscular dystrophy, fordadistrogene movaparvovec
- Medical subject headings
- Muscular Dystrophy, Duchenne
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PF-06939926Genetic
PF-06939926 will be administered as a single IV infusion at Year 1 for Cohort 1.
PlaceboOther
Placebo will be administered as a single IV infusion at Year 1 for Cohort 2.
PlaceboOther
Placebo will be administered as a single IV infusion at Year 2 for Cohort 1.
PF-06939926Genetic
PF-06939926 will be administered as a single IV infusion at Year 2 for Cohort 2
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 | Other | Approximately two thirds of participants will be randomized to Cohort 1. Receives: Genetic: PF-06939926; Other: Placebo |
| Cohort 2 | Other | Approximately one third of participants will be randomized to Cohort 2. Receives: Other: Placebo; Genetic: PF-06939926 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in North Star Ambulatory Assessment (NSAA) Total Score at Week 52
The NSAA was a 17-item test that graded performance of various functional skills using the following scale: 0 (unable to achieve independently), 1 (modified method but achieves goal independent of physical assistance from another), and 2 ("normal"- no obvious modification of activity). Total score was calculated as the sum of all 17 individual item responses and ranged from 0 (worst) to 34 (fully independent function) with higher scores indicating better function. Baseline NSAA total score is defined as the last non-missing NSAA total score collected prior to Year 1 drug administration.
Measured: Baseline, Week 52
Secondary outcomes (9)
Change From Baseline in Percent Normal Dystrophin Expression Level in Muscle Biopsies by Liquid Chromatography Mass Spectrometry (LC-MS) Based on LLQV Peptide at Week 52
The LC-MS assay measured the LLQVAVEDR (LLQV) peptide that detected full-length endogenous dystrophin as well as the mini-dystrophin transgene protein.
Measured: Baseline, Week 52
Change From Baseline in Percent of Muscle Fibers Expressing Mini-Dystrophin in Muscle Biopsies by Immunofluorescence at Week 52
Muscle fibers expressing mini-dystrophin transgene protein were evaluated by immunofluorescent staining using the mini-dystrophin specific antibody which only recognized the mini-dystrophin transgene protein.
Measured: Baseline, Week 52
Change From Baseline in Serum Creatine Kinase (CK) Concentration at Week 52
The CK results were analyzed by the central laboratory.
Measured: Baseline, Week 52
Least Square Mean of Proportion of Skills Gained Based on the Individual Items of the NSAA at Week 52
Proportion of skills gained at Week 52 were expressed as a proportion of the number of skills at Baseline that could be gained (numerator was number of items on NSAA gained at Week 52, with response 1 or 2 and denominator was number of items on NSAA with score 0 at baseline). The NSAA was a 17-item test that graded performance of various functional skills using the following scale: 0 (unable to achieve independently), 1 (modified method but achieves goal independent of physical assistance from another), and 2 ("normal"- no obvious modification of activity). Total score was calculated as the sum of all 17 individual item responses and ranged from 0 (worst) to 34 (fully independent function) with higher scores indicating better function.
Measured: Baseline, Week 52
Least Square Mean of Proportion of Skills Either Improved or Maintained Based on the Individual Items of the NSAA at Week 52
Proportion of skills either improved or maintained at Week 52 was expressed as a proportion of the number of items at Baseline that could be improved or maintained (numerator was the number of items on NSAA improved or maintained at Week 52 and denominator is number of items on NSAA which is 17). The NSAA was a 17-item test that graded performance of various functional skills using the following scale: 0 (unable to achieve independently), 1 (modified method but achieves goal independent of physical assistance from another), and 2 ("normal"- no obvious modification of activity). Total score was calculated as the sum of all 17 individual item responses and ranged from 0 (worst) to 34 (fully independent function) with higher scores indicating better function.
Measured: Baseline, Week 52
Change From Baseline in 10 Meter Run/Walk Velocity at Week 52
Velocity was calculated based on the time it took to complete the 10-meter run/walk test.
Measured: Baseline, Week 52
Change From Baseline in Rise From Floor Velocity at Week 52
Velocity was calculated based on the time it took to rise from floor.
Measured: Baseline, Week 52
Change From Baseline in Modified Pediatric Outcome Data Collection Instrument (PODCI)- Transfer and Basic Mobility Core Scale at Week 52
Modified PODCI- transfer and basic mobility core scale (parent of pediatric participant) consisted of 11 items that assessed how caregivers of participants evaluated a participant's ability to walk, stand, and perform activities of daily living. The scale produced an independent, standardized score ranging from 0-100, with lower scores representing lower levels of function.
Measured: Baseline, Week 52
Change From Baseline in Modified PODCI- Sports and Physical Functioning Core Scale at Week 52
Modified PODCI- sports and physical functioning core scale (parent of pediatric participant) consisted of 21 items that assessed how caregivers of participants evaluated a participant's ability to perform recreational activities. The scale produced an independent, standardized score ranging from 0-100, with lower scores representing lower levels of function.
Measured: Baseline, Week 52
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Feb 2020
- Study start5 Nov 2020
- Primary completion15 May 2024
- Study completion15 Apr 2039 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Duchenne Muscular DystrophyStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- 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 blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 114 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04281485
- Sponsor's protocol ID
- C3391003
- Other IDs
- 2023-508510-42-00, 2023
- Status last verified
- Jul 2026
- First submitted
- 11 Feb 2020
- Last updated
- 22 Jul 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Publications
Muntoni F, Nascimento A, Shin J, Guglieri M, Stettner GM, Veerapandiyan A, Gallo S, Shi H, Gundapaneni B, Neelakantan S, Lobello K, Shen Q, Levy DI, Mercuri E; CIFFREO Study Group. Safety and efficacy of fordadistrogene movaparvovec in ambulatory participants with Duchenne muscular dystrophy (CIFFREO): a phase 3, double-blind, randomised, placebo-controlled study. Lancet Neurol. 2026 Mar;25(3):245-255. doi: 10.1016/S1474-4422(26)00036-0.
PubMed 41722591
Study at a glance
From the registry record, last updated by the sponsor on 22 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- 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
- ClinicalTrials.gov ID
- NCT04281485
- Acronym / sponsor ID
- C3391003
- Conditions
- Duchenne Muscular Dystrophy
- Keywords
- Clinical trial, Gene therapy, Duchenne muscular dystrophy, fordadistrogene movaparvovec
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 114 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 5 Nov 2020 (actual)
- Primary completion
- 15 May 2024 (actual)
- Study completion
- 15 Apr 2039 (estimated)
- First posted
- 24 Feb 2020 (actual)
- Results
- Posted 8 Jun 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study will evaluate the safety and efficacy of gene therapy in boys with DMD. It is a randomized, double-blind, placebo-controlled study with two thirds of participants assigned to gene therapy. The one third of participants who are randomized to the placebo arm will have an opportunity for treatment with gene therapy at the beginning of the second year.
Detailed description
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 15 years after treatment with gene therapy. Participants who received fordadistrogene movaparvovec in Pfizer studies C3391001 and C3391008 or are currently enrolled in Pfizer study C3391011 will be allowed to roll over into the long-term safety follow-up period of this study and will be considered Cohort 3.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- 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.
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 | Other | Genetic: PF-06939926, Other: PlaceboApproximately two thirds of participants will be randomized to Cohort 1. |
| Cohort 2 | Other | Other: Placebo, Genetic: PF-06939926Approximately one third of participants will be randomized to Cohort 2. |
Who may qualify
- Ages
- 4 to 7 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (3 listed)
- 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 (9 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PF-06939926PF-06939926 will be administered as a single IV infusion at Year 1 for Cohort 1. | Genetic | Cohort 1 |
| PlaceboPlacebo will be administered as a single IV infusion at Year 1 for Cohort 2. | Other | Cohort 2 |
| PlaceboPlacebo will be administered as a single IV infusion at Year 2 for Cohort 1. | Other | Cohort 1 |
| PF-06939926PF-06939926 will be administered as a single IV infusion at Year 2 for Cohort 2 | Genetic | Cohort 2 |
Primary outcome
Change From Baseline in North Star Ambulatory Assessment (NSAA) Total Score at Week 52
Time frame: Baseline, Week 52
The NSAA was a 17-item test that graded performance of various functional skills using the following scale: 0 (unable to achieve independently), 1 (modified method but achieves goal independent of physical assistance from another), and 2 ("normal"- no obvious modification of activity). Total score was calculated as the sum of all 17 individual item responses and ranged from 0 (worst) to 34 (fully independent function) with higher scores indicating better function. Baseline NSAA total score is defined as the last non-missing NSAA total score collected prior to Year 1 drug administration.
9 secondary outcomes
Change From Baseline in Percent Normal Dystrophin Expression Level in Muscle Biopsies by Liquid Chromatography Mass Spectrometry (LC-MS) Based on LLQV Peptide at Week 52
Time frame: Baseline, Week 52
Change From Baseline in Percent of Muscle Fibers Expressing Mini-Dystrophin in Muscle Biopsies by Immunofluorescence at Week 52
Time frame: Baseline, Week 52
Change From Baseline in Serum Creatine Kinase (CK) Concentration at Week 52
Time frame: Baseline, Week 52
Least Square Mean of Proportion of Skills Gained Based on the Individual Items of the NSAA at Week 52
Time frame: Baseline, Week 52
Least Square Mean of Proportion of Skills Either Improved or Maintained Based on the Individual Items of the NSAA at Week 52
Time frame: Baseline, Week 52
Change From Baseline in 10 Meter Run/Walk Velocity at Week 52
Time frame: Baseline, Week 52
Change From Baseline in Rise From Floor Velocity at Week 52
Time frame: Baseline, Week 52
Change From Baseline in Modified Pediatric Outcome Data Collection Instrument (PODCI)- Transfer and Basic Mobility Core Scale at Week 52
Time frame: Baseline, Week 52
Change From Baseline in Modified PODCI- Sports and Physical Functioning Core Scale at Week 52
Time frame: Baseline, Week 52
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jul 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41722591Muntoni F, Nascimento A, Shin J, Guglieri M, Stettner GM, Veerapandiyan A, Gallo S, Shi H, Gundapaneni B, Neelakantan S, Lobello K, Shen Q, Levy DI, Mercuri E; CIFFREO Study Group. Safety and efficacy of fordadistrogene movaparvovec in ambulatory participants with Duchenne muscular dystrophy (CIFFREO): a phase 3, double-blind, randomised, placebo-controlled study. Lancet Neurol. 2026 Mar;25(3):245-255. doi: 10.1016/S1474-4422(26)00036-0.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
53 sites in 15 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing PF-06939926 in people with Duchenne Muscular Dystrophy, run by Pfizer at 53 sites in 15 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 22 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 53 sites in United States, Canada, Australia, Japan, South Korea and 10 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 8 Jun 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change From Baseline in North Star Ambulatory Assessment (NSAA) Total Score at Week 52 (time frame: Baseline, Week 52). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04281485, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jul 2026; AzTrials last refreshed its copy on 7 Nov 2026.