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 100 th 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 100 th 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: www.ClinicalTrials.gov - 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.