Prosensa Achieves Orphan Drug Status on its Entire

Leiden, The Netherlands – 29 January 2013 – Prosensa, the Dutch biopharmaceutical company focusing on RNA-modulating therapeutics for rare diseases with high unmet need, announced it has achieved orphan drug designation in the EU and the US for all of its compounds for the treatment of Duchenne muscular dystrophy (DMD).

The European Medicines Agency (EMA) assigned orphan drug status to Prosensa’s two preclinical compounds PRO052 and PRO055 and the US Food and Drug Administration (FDA) granted orphan drug status to the company’s four compounds PRO045, PRO052, PRO053 and PRO055. This brings the total number of products in Prosensa’s DMD portfolio with orphan drug status in the EU and the USA to six. Orphan drug designation provides regulatory support in development activities such as protocol assistance, reduced fees, tax incentives and market exclusivity following drug approval.

Commenting on the news, Prosensa CEO Hans Schikan said: “Having orphan drug designation for each compound in our DMD portfolio is of tremendous help in the further development of our personalized medicine candidates. We are committed to finding effective treatments for as many DMD patients as possible, including those affected by very rare mutations. The knowledge and expertise we are gaining from our collaboration with GlaxoSmithKline on our lead compound, drisapersen, in one of the largest clinical programs ever undertaken in this rare and severely debilitating disease, is indispensable in the accelerated development of these additional compounds. Moreover, thanks to these orphan drug designations, the support and assistance of regulatory bodies both in Europe and the USA will be extremely valuable in our further development work.”

Prosensa currently has six exon-skipping compounds in development for treating DMD, of which drisapersen, being developed in collaboration with GlaxoSmithKline, is in a fully enrolled, late stage Phase III clinical trial of 186 patients, in 47 trial sites in 20 countries.