FDA Gives Fast Track Status to Potential Therapy for Congenital Myotonic Dystrophy

An investigational therapy to treat congenital myotonic dystrophy, AMO-02 (tideglusib), has been granted fast track designation by the U.S. Food and Drug Administration (FDA), AMO Pharma has announced.

Myotonic dystrophy (DM) is the most common form of muscular dystrophy (MD). DM type 1 is the consequence of a dystrophia myotonica protein kinase (DMPK) gene mutation. The condition causes the DMPK gene to have unnecessarily repeated copies.

Patients with mild forms of the mutation generally have 50 to 80 repeat copies; however, up to 2,000 or more copies can be found in children with the severe congenital form of the condition — known as DM1 or Steinert disease.

In cellular and animal models of DM1 and Duchenne muscular dystrophy (DMD), researchers found an increase of the activity of glycogen synthase kinase 3 beta (GSK3ß).

AMO-02 is a GSK3ß inhibitor that has been clinically shown to correct the activity of RNA-binding proteins in animal models of DM1. This was shown to reverse cognitive and behavioral impairments in mouse models of a development disorder (syndromic autism).

AMO-02 is being evaluated in a Phase 2 clinical trial (NCT02858908) in the United Kingdom. The exploratory study, currently recruiting patients, will evaluate the drug candidate in patients with congenital and juvenile onset myotonic dystrophy.

“Our ongoing Phase 2 clinical trial for AMO-02 in the U.K. is the first sponsor-led clinical study in the treatment of congenital myotonic dystrophy and represents a historic milestone in research and a new era of hope for patients and their families affected by this serious condition,” Michael Snape, CEO of AMO Pharma, said in a press release. “In addition to advancing this development program, our research will provide many new insights to help shape the future of new research and to offer the prospect of better health for people living with myotonic dystrophy.”

Fast track designation works to expedite development and review of potential therapies.

AMO Pharma began its investigational new drug (IND) application for AMO-02 in 2016. Both the fast track designation and the outcome of the upcoming Phase 2 clinical trial are important steps in the regulatory process.

“Congenital myotonic dystrophy is a devastating neuromuscular disease where affected patients currently have no treatment options available,” Snape said. “The designation of fast track status for our development program for AMO-02 highlights both the urgent need for a treatment for patients and the potential for this novel therapy to offer a major advance in their care in the years ahead.”