Sarepta’s Gene Therapy Trial Continues Despite Erroneous Event Report

An adverse event report was erroneously submitted for a patient enrolled in Study-102 testing Sarepta Therapeutics’ micro-dystrophin gene therapy, an experimental treatment for Duchenne muscular dystrophy (DMD), the company announced. The board in charge of the study’s safety found no reason to stop the trial.

According to a release from Sarepta, the report described a patient who supposedly developed rhabdomyolysis, a potentially life-threatening syndrome caused by the breakdown of skeletal muscle, also a common risk associated with DMD itself.

The event was submitted to the FDA’s adverse event reporting system (FAERs), a database designed to support the FDA’s post-marketing safety surveillance program for medicines and therapeutic biologic products.

In the release, Sarepta said its investigation so far shows that the notice was not submitted by one of its employees or the study’s principal investigator.

It reported rhabdomyolysis in a participant in Study-102 (NCT03769116) , a double-blind, placebo-controlled Phase 2 trial investigating the use of a micro-dystrophin gene therapy candidate in young boys with DMD.

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The trial, which is still recruiting, is taking place at Nationwide Children’s Hospital in Columbus, Ohio, under the direction of Jerry Mendell, MD. The researchers are looking to enroll 24 boys ages 4–7 with DMD.

The trial will run in two parts: a 48-week, placebo-controlled period where participants will be randomized to receive either a single infusion of the gene therapy SRP-9001d or a placebo; and a 96-week extension study.

The study hopes to confirm the promising safety and efficacy results obtained in a prior trial, Study-101, which showed marked improvements in boys’ functional performance with no signs of adverse effects at about nine months after the treatment.

According to Sarepta, two weeks after receiving the treatment, one of the boys enrolled in the new Study-102 developed dark-colored urine and high blood levels of creatine kinase (CK) — a marker of muscle inflammation — but was free of other symptoms.

CK levels can be slightly elevated in nerve disorders or clearly elevated (3,000 to 3,500 U/L) in DMD or inflammatory myopathies (diseases of the muscle).

During episodes of acute muscle breakdown (rhabdomyolysis), CK levels can temporarily surge, reaching 50,000 to 200,000 U/L.

The patient was hospitalized for observation and discharged the next day, with blood tests returning to CK levels observed at the beginning of the trial (baseline).

Study 102 is a one-to-one blinded study, which means that if an adverse event is noted in a patient, it could have happened either in a participant taking the gene therapy or in the placebo group.

While Sarepta employees and the trial’s principal investigator remained blinded to the study (they could not know in which group the patient was involved), the monitoring board that oversees safety was unblinded and reviewed the issue. The board decided there were no reasons for stopping the trial, recommending that it continue without interruption.