Sarepta Shares Fall After Anthem Blue Cross Finds Issue With Eteplirsen

Shares of Sarepta Therapeutics Inc SRPT fell about 5 percent Friday after Anthem Blue Cross said the clinical benefit of treatment for DMD (Duchenne Muscular Dystrophy) with the company's eteplirsen (Exondys 51), including improved motor function, has "not been demonstrated."

The health insurance company said the use of Sarepta's therapy is "considered investigational and not medically necessary for all indications," including DMD.

In April, the Peripheral and Central Nervous System Drugs Advisory Committee of the FDA held a meeting and voted against approval of Eteplirsen. The therapy was however approved on September 19 as an orphan drug status.

Related Link: Sarepta's Deal With Summit Could Be More About European Eteplirsen Approval Expectations

According to Anthem, Sarepta secured the FDA's approval based on an increase in dystrophin seen in the sekeltal muscle of some of the boys were were treated with the drug. However, the insurance company added that "uncertainty exists regarding whether the small observed increase in dystrophin will confer a clinically meaningful benefit."

Anthem said the FDA labeled indications include a statement that a clinical benefit has not be established and continued approval is contingent upon verification of a clinical benefit in ongoing confirmatory clinical trials.

"The trial's internal validity was compromised by the use of differing methods of evaluating dystrophin levels (Western blot [percent of normal] and immunofluorescence [percent positive fibers]), variable time points of specimen collection, and from variable muscles," Anthem also stated. "Given that independent methods were used to quantify dystrophin levels, a correlation within individuals was conducted and the correlation was found to be weak. The aforementioned multitude of limitations cast further doubt on the reliability of dystrophin levels as a surrogate endpoint for clinical efficacy in DMD."

The stock traded recently at $58.58, down 5.1 percent.