Results of Prosensa's Extended Phase I/II Exon-skipping Trial in Duchenne Muscular Dystrophy Published in the New England Journal of Medicine

 

Leiden, The Netherlands, 24 March 2011

– Prosensa, the Dutch biopharmaceutical company focusing on RNA modulating therapeutics, announces the publication of results from a phase I/II and 12-week extension study of its lead product, PRO051 (GSK2402968) for the treatment of Duchenne Muscular Dystrophy (DMD) in the New England Journal of Medicine (NEJM)[1].

PRO051 (GSK2402968) is an antisense oligonucleotide designed to induce skipping of exon 51 of the dystrophin gene. The published data confirmed the safety and tolerability of the drug in all patients and the 12-week extension study reported a modest improvement in walking distance in the six-minute walk test.

The phase I/II open label study was designed to investigate induction of dystrophin expression and to test the safety and tolerability of the drug. PRO051 (GSK2402968) was given to 12 patients, who received weekly subcutaneous injections at different dose levels. All patients entered an open-label long-term extension study after completion of the initial five weeks of the trial.

The study was conducted under the sponsorship of Prosensa at the University Hospital in Leuven (Belgium) and the Queen Silvia Children’s Hospital in Gothenburg (Sweden) with support from Leiden University Medical Center (The Netherlands). “The publication of the phase I/II clinical trial results in the New England Journal of Medicine is a recognition of Prosensa’s exon skipping approach for the treatment of DMD,� commented Dr Judith van Deutekom, the senior author on the publication and Prosensa’s Head of Drug Discovery.

PRO051 (GSK2402968) induced exon skipping in patients receiving 2 mg/kg or higher doses. Post treatment muscle biopsies confirmed that dystrophin expression ranged between 80% and 100% of muscle fibers in six patients and 60% to 80% in four patients. Results of the 12-week extension study showed an improvement of patients in the six-minute walk test. This was confirmed with 24-week extension data, which was presented at the 15th International Congress of the World Muscle Society in Japan, October 12-16, 2010. Results of the 48-week extension study will be presented at the 2011 Annual Meeting of the American Academy of Neurology in Honolulu, April 9-16. Definitive proof of efficacy and safety is being investigated in ongoing controlled clinical studies. PRO051 (GSK2402968) is currently in phase III clinical trials.

1

Goemans NM et al. Systemic administration of PRO051 in Duchenne’s muscular dystrophy. New England Journal of Medicine. 2011 Mar 23.

--ENDS—


Notes to editors:

About PRO051 (GSK2402968)

 

PRO051 (GSK2402968), 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 PRO051 (GSK2402968), 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.

About Prosensa

Prosensa is an innovative Dutch biopharmaceutical company focused on the discovery, development and commercialization of RNA modulating therapeutics correcting gene expression in diseases with large unmet medical needs, in particular neuromuscular disorders. Prosensa’s focus is on developing a treatment for DMD. In 2009 Prosensa entered into a strategic alliance for part of its DMD exon skipping program with GlaxoSmithKline. Prosensa’s lead compound (GSK2402968/PRO051), being developed by GSK, entered phase III clinical trials in January 2011.

Prosensa is a privately held biopharmaceutical company, backed by a consortium of Abingworth, AGF Private Equity, GIMV, LSP and MedSciences Capital. For more information about Prosensa, please visit www.prosensa.com

For more information please contact:

Prosensa Enquiries:

Luc Dochez +31 71 332 2085

Judith van Deutekom +31 71 332 2100

For Media enquiries:

College Hill Life Sciences

Sue Charles/ Nicole Yost/ Dr Anastasios Koutsos

+44 20 7457 2020

Rebecca Skye Dietrich (US enquiries)

+1 857 241 0795

prosensa@collegehill.com

Posted: March 2011

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