ptc124-duchenne-and-becker-muscular-dystrophy

A phase IIb efficacy and safety study of PTC124 in subjects with nonsense mutation-mediated Duchenne and Becker muscular dystrophy

Background

DMD is an X-linked genetic disorder affecting young boys. The condition is disabling and life-threatening. A small subset of boys is classified as having Becker muscular dystrophy (BMD). This is a phenotypically milder form of the dystrophic muscle disease.

10 to 15% of DMD and BMD are caused by a nonsense mutation in the dystrophin gene. The mutation results in an abnormal production of dystrophin.

PTC124 is a novel, orally bioavailable, small-molecule drug. It has the potential to correct the genetic defect in DMD/BMD boys with a nonsense mutation.

Trial information

This is an international, multi-centre, randomised, double-blind, placebo-controlled, dose-ranging, efficacy and safety study.

Primary objective

To evaluate the effect of PTC124 on patient ambulation.

Ambulation was assessed by the distance walked during a 6-minute walk test.

This work has been completed.

Recruitment:

• 174 participants worldwide
• followed up for 12 months

At the end of this study, all compliant participants were eligible to receive open-label drug (PTC124) in a separate extension study.

Ataluren is now the non-proprietary generic name for PTC124.

Results

The initial study findings did not show significant muscle improvement in the participating patients. The study was thus stopped.

Briefly, analysis showed that efficacy was on average better in patients treated with low-dose ataluren compared to those on high-dose ataluren or placebo. This phenomenon is not unique for ataluren and has been seen with other drugs for other diseases. Further analysis of efficacy data is ongoing.

Antisense oligonucleotide induced exon skipping in Duchenne muscular dystrophy.

This initiative is led by the MDEX consortium. The MDEX consortium led by Professor Muntoni, is a multidisciplinary enterprise to promote translational research into muscular dystrophies. It consists of the clinical groups of:

• Professor F. Muntoni (UCL Institute of Child Health)
• Professor K. Bushby and Professor V.Straub (Newcastle University)

and Scientists from:

• Imperial College London (Professor Dominic Wells)
• UCL Institute of Child Health (Dr Jennifer Morgan)
• Royal Holloway University of London (Professor George Dickson and Dr Ian Graham),
• Oxford University (Dr Matthew Wood)
• University of Western Australia (Prof Steve Wilton)

In addition, the charities also participate in the Consortium

• Muscular Dystrophy Campaign
• Action Duchenne
• Duchenne Family Support Group