Prosensa Enrolls 100th Patient to its Natural History Study of Duchenne Muscular Dystrophy

Prosensa Holding B.V. Logo

Leiden, The Netherlands, Nov. 7, 2013 (GLOBE NEWSWIRE) -- Prosensa Holding N.V. (NASDAQ: RNA), the Dutch biopharmaceutical company focusing on RNA-modulating therapeutics for rare diseases with high unmet need, today announced the successful enrollment of the 100th patient into the Natural History Study of Duchenne muscular dystrophy (DMD).

The goal of this observational study is to characterize DMD at various stages of progression using the same measures used in ongoing clinical studies, such as the "six minute walk test." No medication is being tested in this study.

"The enrollment of the 100th patient for the Natural History Study reinforces our commitment to developing innovative treatment options for DMD," said Dr. Giles Campion, Prosensa's Chief Medical Officer. "This study will foster greater understanding of the progression of this debilitating disease and will help explore new endpoints that could be used to expedite drug development."

Dr. Brenda Wong, Director of the Comprehensive Neuromuscular Center at Cincinnati Children's and one of the study's lead investigators, adds "this critical work on the natural history of DMD represents an impactful milestone for patients and their families. Our findings may enable more efficient trial design for follow-on programs and improved outcomes for patients."

Patients in the study are assessed every six months for a period of three years to measure their muscle strength and function, in addition to how the disease affects their quality of life as the condition evolves over time. Investigators are observing the patients as they perform various physical tests, and assess their quality of life through survey questions. Furthermore, certain biomarkers are measured through blood and urine samples to investigate a possible correlation to disease progression.

Prosensa and GlaxoSmithKline (GSK), who are both funding the study, expect to enroll up to 250 DMD patients into the study with any type of mutation in the DMD gene between the ages of three and 18. The study is being conducted in 16 hospitals across 10 countries with 14 sites already open in the U.S. and Europe. Further information on the study can be found here: - Study ID: NCT01753804

Notes to editors

About Prosensa Holding N.V.

Prosensa (NASDAQ: RNA) is a Dutch biotechnology company engaged in the discovery and development of RNA-modulating therapeutics for the treatment of genetic disorders. Its primary focus is on rare neuromuscular and neurodegenerative disorders with a large unmet medical need, including Duchenne muscular dystrophy, myotonic dystrophy and Huntington's disease.

Prosensa's current portfolio includes six compounds for the treatment of DMD, all of which have received orphan drug status in the United States and the European Union. The compounds use an innovative technique called exon-skipping to provide a personalized medicine approach to treat different populations of DMD patients. The company's lead investigational drug candidate, drisapersen, which is exclusively licensed to GlaxoSmithKline, is in Phase III clinical trials.

About DMD

Duchenne muscular dystrophy (DMD) is a severely debilitating childhood neuromuscular disease that affects up to 1 in 3,500 boys. This rare disease is caused by mutations in the dystrophin gene, resulting in the absence or defect of the dystrophin protein. As a result, patients suffer from progressive loss of muscle strength, often rendering them wheelchair-bound before the age of 12. Few patients survive the age of 30.

Forward Looking Statements

This press release contains certain forward-looking statements. All statements, other than statements of historical facts, contained in this press release, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. The words "anticipate," "believe," "estimate," "expect," "intend," "may," "plan," "predict," "project," "target," "potential," "will," "would," "could," "should," "continue," and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Forward-looking statements in this press release include statements around our exon -skipping drug candidates and our collaboration with GlaxoSmithKline (GSK). Actual results may differ materially from those projected or implied in such forward-looking statements. Such forward-looking information involves risks and uncertainties that could significantly affect expected results. These risks and uncertainties are discussed in the Company's SEC filings, including, but not limited to, the Company's Form 6-K containing this press release and certain sections of the Company's Registration Statement on Form F-1. In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. While we may elect to update these forward-looking statements at some point in the future, we specifically disclaim any obligation to do so, even if our views change.

CONTACT: Prosensa Holding N.V. Celia Economides, Director IR & Corporate Communications Phone: +1 917 941 9059 Email:

Source:Prosensa Holding N.V.