BioMarin Pharmaceutical, based in San Rafael, Calif., will acquire Prosensa for $17.75 per share, for a total up-front consideration of approximately $680 million. In addition, two approximately $80 million contingent milestones are payable for the approval of drisapersen in the U.S. no later than May 15, 2016, and Europe no later than Feb. 15, 2017, respectively.

The acquisition will provide BioMarin with worldwide rights to multiple orphan drug candidates, including drisapersen, currently under rolling review as part of an NDA with the FDA. Prosensa's pipeline is comprised of several potential products that leverage their proprietary RNA-modulating technology platform for the treatment of various genotypes of Duchenne muscular dystrophy and other genetic disorders.

Jean-Jacques Bienaime, CEO of BioMarin, said, "We will leverage our experience at developing rare disease therapies to achieve regulatory approvals and bring drisapersen to market as quickly as possible. Further, if we are successful in advancing drisapersen to early regulatory approvals, we believe this transaction would be accretive to operating and GAAP profitability in 2017."

In addition, within five business days of signing the purchase agreement, BioMarin will purchase from Prosensa a $50 million convertible note. If the transaction fails to close for any reason, the note will automatically convert into 4,395,914 shares of Prosensa's stock.

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