Sarepta Reports Encouraging Preliminary Results in DMD Gene Therapy Study

Rare Daily Staff

Sarepta Therapeutics said preliminary results from its phase 1/2a clinical trial of its experimental micro-dystrophin gene therapy showed robust results in three Duchenne muscular dystrophy patients, raising hopes that a gene therapy will be a viable treatment for the rare, progressive, and fatal genetic disease.

Shares of Sarepta rose more than 36 percent on the news to close at $143.93.

During Sarepta’s R&D Day, Jerry Mendell, principal investigator of the study, presented the positive preliminary results from first three patients in the gene therapy clinical trial assessing Sarepta’s AAVrh74.MHCK7.micro-Dystrophin in individuals with DMD.

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

“I have been waiting my entire 49-year career to find a therapy that dramatically reduces CK levels and creates significant levels of dystrophin,” said Mendell. “Although the data are early and preliminary, these results, if they persist and are confirmed in additional patients, will represent an unprecedented advancement in the treatment of DMD.”

All of the patients also showed robust expression of transduced micro-dystrophin, which is properly localized to the cells of the muscle. Post-treatment biopsies showed robust levels of micro-dystrophin as measured by Western blot, with a mean of 38.2 percent compared to normal utilizing Sarepta’s method, or 53.7 percent compared to normal pursuant to Nationwide Children’s quantification of Sarepta’s method that adjusts for fat and fibrotic tissue.

There were no serious adverse events observed in the study.

“Since the discovery of the dystrophin gene in 1986, scientists, clinicians, patient advocates and the biotech ecosystem have tirelessly searched for ways to restore or replace dystrophin and rescue boys with DMD from the damage and early death,” said Doug Ingram, Sarepta’s president and CEO. “Dr. Mendell’s results, if confirmed in additional patients, studies, measures and time points, represent a monumental leap forward in the direction of our goal.”

Parent Project Muscular Dystrophy committed $2.2 million to the trial with support from additional Duchenne foundations and families.

“While these are early days and work remains to fully understand the full potential of gene therapies, these first signals are encouraging,” said Pat Furlong, PPMD founding president and CEO. “We remain hopeful that this will lead to a viable treatment for Duchenne.”

June 19, 2018
Photo: Doug Ingram, president and CEO of Sarepta