The U.S. FDA has conditionally approved Sarepta Therapeutics' Amondys 45 injection for the treatment of Duchenne muscular dystrophy (DMD) in patients with certain mutations.
The injection is an antisense oligonucleotide indicated for the treatment of DMD in patients with a confirmed mutation amenable to exon 45 skipping. This is the first FDA-approved targeted treatment for the eight percent of DMD patients with this type of mutation.
Consistent with the accelerated approval pathway, the continued approval of Amondys 45 is contingent on confirmation of a clinical benefit in further trials. A placebo-controlled trial to support the approval is ongoing and expected to end in 2024.
Amondys 45 is Sarepta’s third marketed treatment for the rare, inherited disease. Similar to the two previous approvals — Exondys 51 and Voyndys 53 — Amondys 45 won the FDA nod based on its ability to produce the muscle protein dystrophin missing in DMD patients. Yet, without established proof that more dystrophin improves muscle function or slows disease progression, the approvals have proven to be controversial and have previously been a point of contention with scientists and FDA officials.
In 2016, Sarepta’s Exondys 51 won FDA approval based on dystrophin data without showing actual clinical benefits. Internal disagreements between the then FDA Commissioner, Dr. Robert Califf and Janet Woodcock, who is now acting commission, were made public. In Dec. 2019, the agency granted accelerated approval to Vyondys 53 after having previously rejected it just months before, having cited infection risk tied to the drug's delivery as well as preclinical signs of kidney toxicity.
Read the press release