TRENTON, N.J. (AP) — U.S. regulators have approved the first drug for an aggressive kind of multiple sclerosis that steadily reduces coordination and the ability to walk.

The Food and Drug Administration approved Ocrevus (OAK'-rave-uss) late Tuesday after a large study found it slowed progression of the neurological disease and reduced symptoms.

While there are treatments for the most common form of MS, there's been nothing specifically for people with the type called primary progressive MS. That type of MS is relatively rare, affecting about 50,000 Americans.

The drug was also approved for less severe forms of MS.

It's given intravenously every six months. The drug was developed by Genentech, part of Swiss drugmaker the Roche Group. The company says the initial list price without insurance will be $65,000 a year.