BioMarin shares pop on strong pivotal data for rare disease drug

Shares of BioMarin Pharmaceuticals ($BMRN) shot up 28% this morning after the rare disease drug developer excited investors with the news that its experimental therapy GALNS hit the primary endpoint in a pivotal study for a rare enzyme deficiency, setting up plans to seek regulatory approval in early 2013.

Patients on a weekly dose of 2 mg/kg of GALNS improved their walking distance by 22.5 meters compared to a placebo, with benefits showing up in week 12 and continuing through week 24. And results from an extension study indicate that the results continue to get better as dosing continues.

There are only about 3,000 patients diagnosed with the rare lysosomal storage disorder Mucopolysaccharidosis Type IVA, also called Morquio A Syndrome. The condition, the result of an enzyme deficiency, triggers a host of skeletal and bone disorders. But a number of drug developers in the rare disease area have proven time and again that a successful enzyme replacement drug that can control these conditions can earn a significant amount of revenue, with payers of every stripe willing to foot huge bills for these treatments. 

"The GALNS clinical program is currently the highest development priority at BioMarin, and this positive Phase III study serves as a potentially transformative milestone for the company," said Jean-Jacques Bienaimé, the CEO of BioMarin. "We are applying our track record of success in developing novel treatments for orphan diseases and our existing commercial infrastructure for Naglazyme to bring GALNS to patients as rapidly as we can."

The pivotal study also tested the impact of a dose every other week, but investigators concluded that there was no significant benefit. BioMarin has four drugs on the market and may soon have a fifth. Its shares were trading at $48 this morning after the news hit.

- here's the press release