A Study to Understand the Long-term Safety and Effects of an Experimental Gene Therapy for Duchenne Muscular Dystrophy.

Long-term Follow-up Safety and Efficacy Study in Participants With Duchenne Muscular Dystrophy Who Have Received Fordadistrogene Movaparvovec in a Preceding Clinical Study

The purpose of this study is to understand the safety and effects of an experimental gene therapy called fordadistrogene movaparvovec. We are seeking participants from previous Pfizer interventional studies. We will follow participants' experience in this study for 10 years after the end of their previous study. Participants will have 1 annual onsite visit and a few annual remote visits. The exact number of remote visits will be decided by their study doctor.

Study Overview

• Status: Terminated
• Conditions: Duchenne Muscular Dystrophy
• Intervention / Treatment: Biological: fordadistrogene movaparvovec

• Study Type: Interventional
• Enrollment (Actual): 7
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • California
    • Los Angeles, California, United States, 90095
      • UCLA Medical Center
    • Los Angeles, California, United States, 90095
      • Reed Neurological Research Center
    • Los Angeles, California, United States, 90095
      • UCLA Children's Heart Center
    • Los Angeles, California, United States, 90095
      • UCLA Clinical Lab Services
    • Los Angeles, California, United States, 90095
      • UCLA Kameron Gait and Motion Analysis Laboratory (Westwood Rehabilitation Center)
  • North Carolina
    • Durham, North Carolina, United States, 27705
      • Duke Lenox Baker Children's
    • Durham, North Carolina, United States, 27710
      • Duke Children's Health Center
  • Utah
    • Salt Lake City, Utah, United States, 84113
      • Primary Children's Hospital
    • Salt Lake City, Utah, United States, 84108
      • University of Utah Imaging and Neurosciences Center
    • Salt Lake City, Utah, United States, 84112
      • University of Utah Hospital
    • Salt Lake City, Utah, United States, 84132
      • University of Utah Clinical Neurosciences Center
    • Salt Lake City, Utah, United States, 84132
      • University of Utah Craig H. Neilsen Rehabilitation Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 second and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participants who received fordadistrogene movaparvovec in a previous Pfizer interventional study.

Exclusion Criteria:

• Investigator site staff directly involved in the study and their family members

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: All participants; All participants enrolled in the study.	Biological: fordadistrogene movaparvovec; gene therapy administered in a previous study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Number of participants with serious adverse events	At least annually from 5 through 10 years after dosing in the interventional study.
Percentage of participants with serious adverse events	At least annually from 5 through 10 years after dosing in the interventional study.
Number of participants with adverse events considered related to treatment	At least annually from 5 through 10 years after dosing in the interventional study.
Percentage of particpants with adverse events considered related to treatment	At least annually from 5 through 10 years after dosing in the interventional study
Number of participants with malignancy adverse event	At least annually from 5 through 10 years after dosing in the interventional study
Number of participants with clinically significant findings in electrocardiogram (ECG) assessments	Annually from 5 through 10 years after dosing in the interventional study.
Number of participants with clinically significant findings in cardiac troponin I laboratory examinations	Annually from 5 through 10 years after dosing in the interventional study
Number of participants with clinically significant findings in echocardiogram parameters	Annually from 5 through 10 years after dosing in the interventional study

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from pre-dose in the ability to walk 10 meters unassisted		Annually from 5 through 10 years after dosing in the interventional study.
Change from pre-dose in the ability to climb stairs.		Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in the Performance of Upper Limb (PUL) 2.0 entry score		Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in the North Star Ambulatory Assessment total score	Applicable to a sub-set of participants only	Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in percent of predicted forced vital capacity (%pFVC) and percent predicted peak expiratory flow (%pPEF)		Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in left ventricular ejection fraction (LVEF) on echocardiogram		Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in the Modified Pediatric Outcomes Data Collection Instrument		Annually from 5 through 10 years after dosing in the interventional study
Change from pre-dose in the Upper Limb Function Patient Reported Outcome Measure	Applicable to non-ambulatory participants only	Annually from 5 through 10 years after dosing in the interventional study
Age when percent predicted forced vital capacity <30%		Annually from 5 through 10 years after dosing in the interventional study
Age at loss of ambulation		From 5 through 10 years after dosing in the interventional study
Age at death		From 5 through 10 years after dosing in the interventional study
Cause of death		From 5 through 10 years after dosing in the interventional study
Glucocorticoid use dose and frequency		At least annually from 5 through 10 years after dosing in the interventional study

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): March 13, 2023
• Primary Completion (Actual): September 24, 2025
• Study Completion (Actual): September 24, 2025

Study Registration Dates

• First Submitted: January 9, 2023
• First Submitted That Met QC Criteria: January 9, 2023
• First Posted (Actual): January 19, 2023

Study Record Updates

• Last Update Posted (Estimated): October 21, 2025
• Last Update Submitted That Met QC Criteria: October 18, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Gene Therapy; Duchenne Muscular Dystrophy; Muscular Dystrophy, Duchenne; Genetic Therapy
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Neuromuscular Diseases; Genetic Diseases, Inborn; Genetic Diseases, X-Linked; Muscular Disorders, Atrophic; Muscular Dystrophies; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Muscular Dystrophy, Duchenne
• Other Study ID Numbers: C3391011; NCT05689164 (Registry Identifier: ClinicalTrials.gov)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No