Benzinga | May 18, 2021 08:51AM EDT

Sarepta Therapeutics Reports Its Duchenne Muscular Dystrophy Treatment Showed Expression, Consistent Profile Using Co.'s Commercial Process Material

* Results from the first 11 participants enrolled in Study 9001-103 ENDEAVOR showed robust transduction, delivering mean vector genome copies of 3.87 per nucleus

* Treated patients achieved mean micro-dystrophin expression levels of 55.4% of normal as measured by western blot

* Micro-dystrophin was properly localized to the muscle sarcolemma, with patients achieving mean percentage of dystrophin positive fibers of 70.5% and intensity of micro-dystrophin expression of 116.9% of normal control, as measured by immunofluorescence (IF)

* Safety profile consistent with prior studies and no new safety signals identified

CAMBRIDGE, Mass., May 18, 2021 (GLOBE NEWSWIRE) -- Sarepta Therapeutics, Inc. (NASDAQ:SRPT), the leader in precision genetic medicine for rare diseases, today announced positive 12-week expression and safety results from the first 11 participants enrolled in Study SRP-9001-103, an open-label study known as ENDEAVOR being conducted in partnership with Roche. In results from the first clinical study using commercially representative material, SRP-9001 (rAAVrh74.MHCK7.micro-dystrophin) demonstrated robust expression of micro-dystrophin and no new safety signals from prior studies, supporting its potentially differentiated profile for the treatment of Duchenne muscular dystrophy. SRP-9001 is an investigational gene transfer therapy intended to deliver its micro-dystrophin-encoding gene to muscle tissue for the targeted production of the micro-dystrophin protein.

"We are delighted by these seminal results from the ENDEAVOR Study, our first trial results with SRP-9001 made by our commercial-scale manufacturing process. These data show strong transduction of the micro-dystrophin gene, resulting in robust expression of the properly localized micro-dystrophin protein, and did so with no new or unexpected safety signals," said Doug Ingram, president and chief executive officer, Sarepta. "In addition to characterizing and differentiating SRP-9001, these results confirm the extraordinary work done over the last two and a half years to build an at-scale gene therapy manufacturing process and corresponding analytics sufficient to meet the needs of the Duchenne population with what we believe will be a potentially life-changing therapy. Armed with these data, we will seek a meeting with the FDA with the goal of rapidly starting our registrational study."

In the open-label study, 20 participants between the ages of four and seven were treated with a single infusion of SRP-9001 at a dose of 1.33x1014 vg/kg. In muscle biopsies from the first 11 patients taken 12 weeks after treatment, the following results were observed:

* All patients demonstrated robust transduction, with mean micro-dystrophin expression of 55.4% of normal, as measured by western blot.

* Muscle dystrophin levels demonstrated a mean of 70.5% (baseline 12.8%) muscle fibers expressing micro-dystrophin at 12 weeks with a mean intensity at the sarcolemma of 116.9% (baseline 41.0%) compared to normal biopsies, as measured by immunofluorescence. Comparisons between baseline and post-treatment measures were statistically significant (p=0.001 for positive fibers, and p=0.002 for intensity).

* Mean vector genome copies per nucleus reached 3.87.

The safety profile of SRP-9001 observed in the first 11 participants in ENDEAVOR is consistent with the safety seen in earlier studies using clinical manufacturing process material. In line with previously reported clinical data, no clinically relevant complement activation was observed in these 11 patients. Two patients experienced serious adverse events (transaminase elevation in one patient and nausea and vomiting in a second patient) that fully resolved.