New Aetna Clinical Policy Bulletin Details 'Medical Necessity' Of Sarepta's Exondys 51

After agreeing to cover Sarepta Therapeutics Inc SRPT’s controversial Duchenne muscular dystrophy drug Exondys 51, insurer Aetna Inc AET has released a new clinical policy bulletin describing the conditions under which it deems the drug medically necessary.

Aetna now says:

"[E]teplirsen (Exondys 51) injection is considered medically necessary for the treatment of individuals with a documented diagnosis of Duchenne muscular dystrophy (DMD) when the following criteria are met: 1) member has a confirmed mutation of the DMD gene amenable to exon 51 skipping; 2) eteplirsen has been initiated in childhood (before 14 years of age); 3) member is able to achieve an average distance of at least 180m while walking independently over six minutes; and 4) medication is prescribed by or in consultation with a physician who specializes in treatment of Duchenne muscular dystrophy."

Aetna also clarified its position on the drug's use outside of the conditions described above.

"Aetna considers eteplirsen (Exondys 51) injection experimental and investigational for all other indications."

A number of the FDA’s internal reviewers of Exondys 51 expressed concerns about the efficacy of the drug, yet the FDA approved its use in September.

Insurer Anthem Inc ANTM refused to cover the drug. Its experts noted that the “clinical benefit of treatment for DMD with eteplirsen, including improved motor function, has not been demonstrated.”

Sarepta shares initially spiked more than 130 percent following the FDA approval for Exondys 51. However, the stock has since given up nearly all of those gains.