Sarepta/Roche's Closely Watched Duchenne Gene Therapy Faces More FDA Scrutiny - Stock Tanks

Sarepta Therapeutics Inc SRPT released topline results from EMBARK (Study SRP-9001-301) Phase 3 study of Elevidys (delandistrogene moxeparvovec-rokl) in ambulatory boys (those who can walk) with Duchenne muscular dystrophy aged 4-7 years.

In June, the FDA granted accelerated approval to gene therapy, Elevidys, for Duchenne muscular dystrophy in ambulatory pediatric patients aged 4 through 5 years with a confirmed mutation in the DMD gene.

Elevidys-treated patients improved by 2.6 points on their North Star Ambulatory Assessment (NSAA), a measure of motor function 52 weeks after treatment, compared to 1.9 points in placebo-treated patients. 

The difference of 0.65 points between the treated and placebo groups did not reach statistical significance (n=125; p=0.24).

In all pre-specified, timed functional key secondary endpoints, time to rise from the floor, and 10-meter walk test, clinically meaningful and statistically significant improvements were observed. 

On the time to rise from the floor, Elevidys-treated patients experienced a 0.64-second improvement versus placebo. On the 10-meter distance test, the drug was associated with a 0.42-second improvement versus placebo.

Additionally, a clinically meaningful and statistically significant improvement was also observed for the pre-specified secondary endpoint stride velocity 95th centile. 

The time to ascend the 4-step secondary endpoint also demonstrated consistent treatment benefit favoring Elevidys.

There were no new safety signals in the EMBARK study. As part of a collaboration agreement signed in 2019, Roche Holdings AG RHHBY is working with Sarepta. 

Sarepta is responsible for regulatory approval and commercialization of Elevidys in the U.S., as well as manufacturing. Roche is responsible for regulatory approvals across the rest of the world. 

Price Action: SRPT shares are down 43.8% at $60.50 premarket on the last check Tuesday.