The proposed phase I clinical trial is a pilot study to evaluate safety and biological activity of the rAAVrh74.MCK.micro-Dystrophin vector administered by an intramuscular route. This study will evaluated the micro-Dystrophin vector as a potential dystrophin replacement mechanism for Duchenne Muscular Dystrophy. Two cohorts will undergo gene transfer in a standard three-six dose escalation scheme to establish maximum tolerated dose (MTD) using toxicity. A minimum of three subjects will be enrolled into each cohort. The first cohort will receive a total dose of 3E11 vg. The second cohort will receive 1E12 vg total dose.

The primary objective of this study is the assessment of the safety of an intramuscular administration of rAAVrh74.MCK.micro-Dystrophin to the Extensor Digitorum Brevis (EDB) muscle of patients with Duchenne Muscular Dystrophy (DMD). Safety will be assessed by changes in hematology, serum chemistry, urinalysis, immunologic response to rAAVrh74 and micro-Dystrophin protein, and reported history and observations of symptoms. Subjects will be evaluated at baseline, injection visit (days 0-2), and return for follow up visits on days 7, 14, 30,60, 90, and 180 and at the end of 1st and 2nd years. On Day 180, subjects will undergo a muscle biopsy on the injected muscles in one foot compared with placebo-treatment in the opposite foot to establish transgene expression and any potential toxicity from gene transfer.

Inclusion Criteria:

• Age 7 or older; must be wheelchair-dependent
• Confirmed Dystrophin mutations based on mutation compatibility with micro-dys cDNA based on previously published methods.
• Males of any ethnic group will be eligible.
• Ability to cooperate with muscle testing.
• Willingness of sexually active subjects with reproductive capacity to practice reliable method of contraception (If appropriate).

Exclusion Criteria:

• Active viral infection based on clinical observations.

• Symptoms or signs of cardiomyopathy, including:

  • Dyspnea on exertion, pedal edema, shortness of breath upon lying flat, or rales at the base of the lungs
  • Echocardiogram with ejection fraction below 40%

• Serological evidence of HIV infection, or Hepatitis A, B or C infection

• Diagnosis of (or ongoing treatment for) an autoimmune disease

• Concomitant illness or requirement for chronic drug treatment that in the opinion of the PI creates unnecessary risks for gene transfer.

• Subjects with AAVrh74 binding antibody titers ≥ 1:50 as determined by ELISA immunoassay.

• Abnormal laboratory values in the clinically significant range as defined in protocol or based upon normal values in the Nationwide Children's Hospital Laboratory.