Prosensa To Provide Corporate Update To Key Stakeholders

Leiden, The Netherlands, Jan. 13, 2014 (GLOBE NEWSWIRE) -- Prosensa Holding N.V. (NASDAQ: RNA), the Dutch biopharmaceuticalcompany focusing on RNA-modulating therapeutics for rare diseaseswith high unmet medical need, will be providing updates to both thefinancial and patient communities regarding drisapersen.

As previously announced, the company will be providing a fullcorporate update, which will now also include additional analysesof the drisapersen dataset, at the 32 nd Annual J.P.Morgan Healthcare Conference on Thursday, January 16, 2014 at 10:00AM Pacific Time. Furthermore, the company will be providing aseparate update to the patient community on Tuesday, January 21,2014 at 8:00 AM Eastern Time.  A live webcast of thesepresentations can be accessed through the Investors & Mediasection of the Prosensa corporate website at and will bearchived for 90 days.

About drisapersen and the clinicaldevelopment program

Drisapersen, (previously GSK2402968/PRO051), anantisense oligonucleotide which induces exon skipping of exon 51,is currently in-late stage development for DMD. Drisapersen hasorphan drug status in the EU, US, Japan and Australia. In June2013, drisapersen was granted Breakthrough Therapy designation bythe US Food and Drug Administration.

The overall drisapersen clinical registrationprogram comprises three double-blind, placebo-controlled studies(DMD114117, DMD114876 and DMD114044) and two long term open-labelextension studies (DMD114673 and DMD114349).

About DMD

Duchenne Muscular Dystrophy (DMD) is a severelydebilitating childhood neuromuscular disease that affects up to 1in 3,500 live male births. This rare disease is caused by mutationsin the dystrophin gene, resulting in the absence or defect of thedystrophin protein. Patients suffer from progressive loss of musclefunction, often making them wheelchair bound before the age of 12.Respiratory and cardiac muscle can also be affected by the disease.Few patients survive the age of 30.

About exon skipping

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

RNA-based therapeutics, specifically antisenseoligonucleotides inducing exon skipping, are currently indevelopment for DMD. This technology uses synthetic antisenseoligonucleotides to skip an exon next to a deletion and therebycorrect the reading frame, enabling the production of a noveldystrophin protein. Up to 13% of boys with DMD have dystrophin genemutation/deletions amenable to an exon 51 skip.

About Prosensa Holding N.V.

Prosensa (NASDAQ: RNA) is a Dutch biotechnology company engagedin the discovery and development of RNA-modulating therapeutics forthe treatment of genetic disorders. Its primary focus is on rareneuromuscular and neurodegenerative disorders with a large unmetmedical need, including Duchenne muscular dystrophy, myotonicdystrophy and Huntington's disease.

Forward Looking Statements

This press release contains certainforward-looking statements.  All statements, other thanstatements 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-lookingstatements. The words "anticipate," "believe," "estimate,""expect," "intend," "may," "plan," "predict," "project," "target,""potential," "will," "would," "could," "should," "continue," andsimilar expressions are intended to identify forward-lookingstatements, although not all forward-looking statements containthese identifying words. Forward-looking statements in this pressrelease include statements around our exon -skipping drugcandidates. Actual results may differ materially from thoseprojected or implied in such forward-looking statements.  Suchforward-looking information involves risks and uncertainties thatcould significantly affect expected results.  These risks anduncertainties are discussed in the Company's SEC filings,including, but not limited to, the Company's Form 6-K containingthis press release and certain sections of the Company'sRegistration Statement on Form F-1. In addition, anyforward-looking statements represent our views only as of today andshould not be relied upon as representing our views as of anysubsequent date. While we may elect to update these forward-lookingstatements at some point in the future, we specifically disclaimany obligation to do so, even if our views change.
CONTACT: Celia Economides, Senior Director IR & Corporate Communications         Phone: +1 917 941 9059         Email:

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