Marathon Pharmaceuticals, a biopharmaceutical company that develops new treatments for rare diseases, announced that the company will begin the New Drug Application (NDA) process for deflazacort as a potential treatment for patients with Duchenne muscular dystrophy (DMD) following a positive pre-NDA meeting with the US Food and Drug Administration (FDA).

DMD is a recessive X-linked form of muscular dystrophy, which results in muscle degeneration, difficulty walking, breathing and ultimately death. Diagnosis typically occurs between the ages of 2 and 5 with progressive weakness leading to a loss of ambulation in the pre-teen to teenage years. Though DMD affects approximately 15,000 boys in the United States, there are currently no approved therapies for the disease in the U.S.

The deflazacort NDA is expected to be submitted in the first quarter of 2016 and will be subject to review by the FDA. If approved, deflazacort is expected to be made commercially available in the US in the first quarter of 2017. The FDA previously granted Fast Track status and Orphan Drug designation for deflazacort for the treatment of patients with DMD.

Marathon has requested authorisation from the FDA to provide deflazacort as an investigational drug to qualified patients with DMD at no cost, through an expanded access program (EAP). FDA indicated that it may formally authorise this programme pending a full review of the EAP protocol. If the programme is authorised by FDA, doctors will be able to enroll qualified patients to receive this investigational medication beginning in September 2015.

The development of deflazacort is part of a broader effort by Marathon to provide new treatment options for patients with DMD and other rare diseases. Additionally, Marathon is developing a national precision medicine program in partnership with leading patient advocacy, research and commercial organisations to accelerate research on treatments for DMD. This effort will launch in the first quarter of 2016.

Deflazacort is a glucocorticoid with anti-inflammatory and immunosuppressant properties. Based on published clinical studies, it appears that deflazacort may be an important new treatment option for patients with DMD. Side effects reported to date include cushingoid appearance, hirsutism, weight gain, erythema, nasopharyngitis, irritability and cataract formation.

Deflazacort is currently not approved in the US but is available outside the US for many approved uses not including DMD. The FDA previously granted Fast Track status and Orphan Drug designation for deflazacort for the treatment of patients with DMD.

DMD occurs as a result of mutations (mainly deletions) in the dystrophin gene. These mutations lead to an absence of or defect in the protein dystrophin, which results in progressive muscle degeneration. The incidence is approximately 1 in 3,500 live male births. There is currently no cure for DMD. Treatment is generally aimed at controlling symptoms to maximise the quality of life.