Clinical Data -- Biopsies performed at Day 90 showed robust micro-dystrophin expression in muscle measured by all methods and observed in all three patients ---- Significant decrease in levels of serum creatine kinase (CK), an enzyme biomarker strongly associated with muscle damage caused by Duchenne muscular dystrophy --

All patients showed robust expression of transduced micro-dystrophin, which is properly localized to the muscle sarcolemma, as measured by immunohistochemistry. Mean gene expression, as measured by percentage of micro-dystrophin positive fibers was 76.2% and the mean intensity of the fibers was 74.5% compared to normal control.

All post-treatment biopsies showed robust levels of micro-dystrophin as measured by Western blot, with a mean of 38.2% compared to normal utilizing Sarepta’s method, or 53.7% compared to normal pursuant to Nationwide Children’s quantification of Sarepta’s method that adjusts for fat and fibrotic tissue.

A mean of 1.6 vector copies per cell nucleus was measured in patients, consistent with the high micro-dystrophin expression levels observed.

All patients showed significant decreases of serum creatine kinase (CK) levels, with a mean reduction of CK of over 87% at Day 60. CK is an enzyme associated with muscle damage and patients with DMD uniformly exhibit high levels of CK. Indeed, significantly elevated CK is often used as a preliminary diagnosis tool for DMD, which is then followed by confirmatory genetic testing.

No serious adverse events (SAEs) were observed in the study. Two patients had elevated gamma-glutamyl transferase (GGT) that resolved with increased steroids within a week and returned to baseline levels. There were no other significant laboratory findings. Patients had transient nausea generally during the first week of therapy coincident with increased steroid dosing.