BioMarin Pharmaceuticals is acquiring Dutch group Prosensa in a deal valued at up to around $840 million.

The group said it will offer to buy all of Prosensa’s outstanding ordinary stock for $17.75 per share, for a total upfront consideration of around $680 million, as well as two $80-million milestones contingent on the approval of drisapersen for Duchenne Muscular Dystrophy (DMD) in the US (no later than May 15, 2016) and Europe (before February 15, 2017).

The move buys BioMarin access to multiple orphan-drug candidates - such as drisapersen, which has a shot at becoming first approved treatment for the rare genetic disease, albeit for about just 13% of patients (who carry a particular mutation) - leveraging the firm’s proprietary RNA-modulating technology platform for the treatment of various genotypes of DMD and other genetic disorders.      

The transaction is expected to be accounted for as a business combination, BioMarin said, also noting that it plans to maintain operations at Prosensa's headquarters, based in Leiden, The Netherlands and integrate personnel from that office. 

"BioMarin is dedicated to the rare disease community, and the acquisition of Prosensa fits strategically with our mission of delivering therapies that address serious unmet medical needs," said its chief Jean-Jacques Bienaimé, while Prosensa’s head said the move while help his firm’s mission by “bringing innovative therapies to patients across the world as quickly and efficiently as possible”.