Advisors to the U.S. Food and Drug Administration (FDA) have recommended the return of a drug called, Tysabri, despite concerns about its safety.

After only four months on the market, manufacturers voluntarily recalled the drug after two patients taking Tysabri died from a brain infection called, progressive multifocal leukoencephalopathy (PML).

Now Biogen Idec Inc. and Elan Corp. PLC want strict controls over who uses the multiple sclerosis (MS) drug, including a mandatory patient registry.

Despite the risk, Dr. Richard Rudick, a neurologist at the Cleveland Clinic appeared before the FDA panel on behalf of the drug, says, "The two-thirds reduction in relapse rate cannot be ignored. It is a striking result."