GSK’s drisapersen to receive FDA breakthrough therapy designation for potential treatment of patients with DMD

GlaxoSmithKline plc (GSK) received verbal notification yesterday that its investigational compound drisapersen (previously GSK2402968/PRO051) has been granted Breakthrough Therapy designation by the United States Food and Drug Administration (FDA) for the potential treatment of patients with Duchenne Muscular Dystrophy.

The Breakthrough Therapy designation is one of several programmes created by the FDA to expedite the development and review of drugs for serious or life-threatening conditions and was enacted in 2012 as part of the Food and Drug Administration Safety and Innovation Act (FDASIA).

Duchenne Muscular Dystrophy (DMD) is a severely debilitating childhood neuromuscular disease that affects 1 in 3,500 live male births. This rare disease is caused by mutations in the dystrophin gene, resulting in the absence or defect of the dystrophin protein.

GSK’s clinical development plan evaluates the effect of drisapersen in ambulant (Phases II and III) and non-ambulant boys (Phase I) with DMD who have dystrophin gene mutations amenable to an exon 51 skip. Up to 13% of boys with DMD have dystrophin gene mutations/deletions amenable to an exon 51 skip.

The Breakthrough Therapy designation was based on results from the Phase II Study (DMD114117), presented in April at Cold Spring Harbor.

GSK is developing drisapersen under an exclusive, worldwide license from the Dutch company, Prosensa Holding BV.

About drisapersen

Drisapersen, (previously GSK2402968/PRO051) an antisense oligonucleotide, which induces exon skipping of exon 51, is currently in late stage development for DMD. It has been designated orphan drug status in the EU and US, and is being developed as part of an alliance between GlaxoSmithKline and Prosensa.

For more information regarding the ongoing clinical studies involving GSK968 (including study protocols) visit www.clinicaltrials.gov

About DMD

Duchenne Muscular Dystrophy (DMD) is a severely debilitating childhood neuromuscular disease that affects 1 in 3,500 live male births. This rare disease is caused by mutations in the dystrophin gene, resulting in the absence or defect of the dystrophin protein.

Patients suffer from progressive loss of muscle strength due to the absence or defect of the dystrophin protein, often making them wheelchair bound before the age of 12. Respiratory and cardiac muscle can also be affected by the disease and most patients die in early adulthood due to respiratory and cardiac failure.

About exon skipping

The dystrophin gene is the largest gene in the body, consisting of 79 exons. Exons are small sequences of genetic code which lead to the manufacture of sections of protein. In DMD, when certain exons are mutated/deleted, the RNA cannot read past the fault. This prevents the rest of the exons being read, resulting in a non-functional dystrophin protein and the severe symptoms of DMD.

RNA-based therapeutics, specifically antisense oligonucleotides inducing exon skipping, are currently in development for DMD. This technology uses small pieces of DNA called antisense oligonucleotides to skip a defective exon and thereby correct the reading frame, enabling the production of a novel dystrophin protein. Up to 13% of boys with DMD have dystrophin gene mutation/deletions amenable to an exon 51 skip.