The FDA has requested that Sarepta Therapeutics provide dystrophin data, as measured by western blot, from biopsies already obtained from the ongoing confirmatory study of eteplirsen (Promovi) as part of its evaluation of the eteplirsen new drug application (NDA). The company plans to submit data from 13 patient biopsy samples, at baseline and week 48, to the FDA during the coming weeks to facilitate a prompt decision on the NDA by the agency.
Eteplirsen is designed to address the underlying cause of Duchenne muscular dystrophy (DMD) by restoring the dystrophin messenger RNA (mRNA) reading frame, thereby enabling the production of a shorter, functional form of the dystrophin protein. Eteplirsen uses a proprietary phosphorodiamidate morpholino oligomer (PMO) chemistry and exon-skipping technology to skip exon 51 of the dystrophin gene. Approximately 13% of the DMD population is amenable to exon 51 skipping. Promoting the synthesis of a shorter dystrophin protein is intended to slow the decline of ambulation and mobility seen in DMD patients.
There is no approved treatment in the United States for DMD. Eteplirsen has not been approved by the FDA or any regulatory authority for treatment of the disease.
DMD is a rare X-linked degenerative neuromuscular disorder causing severe progressive muscle loss and premature death. One of the most common fatal genetic disorders, DMD affects approximately one in every 3,500 to 5,000 males worldwide. An incurable muscle-wasting disease, DMD is associated with specific errors in the gene that codes for dystrophin, a protein that plays a key structural role in muscle fiber function. Progressive muscle weakness in the lower limbs spreads to the arms, neck, and other areas. Eventually, increasing difficulty in breathing due to respiratory-muscle dysfunction requires ventilation support, and cardiac dysfunction can lead to heart failure. The condition is universally fatal, and death usually occurs before the age of 30.
Source: Sarepta Therapeutics; June 6, 2016.