Approval was based on Phase III data from 517 at-risk patients.

The European Commission approved Merck Serono’s drug Rebif (interferon beta-1a) as a treatment for patients with early forms of multiple sclerosis. The drug is already approved for the treatment of relapsing forms of MS. The new indication means Rebif can be used to treat patients who have experienced a single demyelinating event, display an early sign of the disease, and who are at high risk of converting to MS.

The latest approval in Europe was based on data from the two-year international Phase III Reflex study, which involved 517 patients considered at risk of developing MS based on clinical symptoms and brain imaging data. The Reflex study was conducted with the HSA-free formulation of Rebif, which isn’t yet available in the U.S., but which is available in all EU countries and a number of other global markets including Australia, Canada, and Switzerland.

Merck Serono reported that global sales of Rebif rose 4.7% (or 8.4% on an organic basis) to €426 million in the third quarter of 2011. The firm said the increase was largely due to a 20% organic increase in the U.S., which was primarily attributable to price increases in January and June.