FDA Staff Raises Issues For Sarepta's Duchenne Gene Therapy Data, Analyst Says Issues Known, Expects Positive Vote

The FDA's Cellular, Tissue and Gene Therapies Advisory Committee is meeting this Friday to discuss Sarepta Therapeutics Inc's SRPT to review SRP-9001 (delandistrogene moxeparvovec), investigational gene therapy for Duchenne muscular dystrophy.

In briefing documents, the FDA said the data does not provide unambiguous evidence that SRP-9001 is likely beneficial for ambulatory patients with Duchenne muscular dystrophy (DMD). 

The FDA took a U-turn when it announced to hold an advisory committee meeting related to Sarepta's SRP-9001 marketing application.

The FDA staff says it is challenging to conclude with reasonable certainty from the data that SRP-9001 is likely effective for younger patients or is likely ineffective for older patients or those with somewhat poorer functional status. 

Additionally, FDA has safety concerns related to the possibility of administering an ineffective gene therapy.

William Blair noted that while the briefing documents highlight several limitations in the data, most of these issues are known and will be answered in confirmatory studies, including the placebo-controlled EMBARK study, which is fully enrolled and set to read out by year-end. 

The analyst is also bullish for the investigational gene therapy, noting Peter Marks is listed as a participant in the AdCom, which can be positive given reports that he has supported the program.

Pooled data from Sarepta's randomized and single-arm studies suggest that micro-dystrophin expression 12 weeks after the therapy is administered is associated with a change in performance on a motor function test for Duchenne patients after one year.

"However, the persuasiveness of such associations is uncertain," the FDA wrote, noting that two-thirds of patients in the analysis were from open-label studies as opposed to blinded and randomized studies, meaning that data could be biased to favor improvement on motor function test.

Price Action: SRPT shares are down 2.78% at $121.76 on the last check Wednesday.