Natalizumab was approved in 2004 by the U.S. Food and Drug Administration (FDA) after years of testing.
The FDA has made the "rare" decision to allow a drug to be sold after the product was pulled from the market due to serious health concerns, despite the agency's acknowledgement that there will continue to be deaths related to the drug's use, an official said.
The FDA announced June 5 that it will allow the multiple sclerosis (MS) drug Tysabri to be marketed subject to a restricted distribution program. The announcement comes after Biogen Idec, the drug's manufacturer, voluntarily withdrew Tysabri (natalizumab) early in 2005 following two deaths associated with its use. Two patients involved in clinical trials for the drug died when they developed progressive multifocal leukoencephalopathy (PML).
Tysabri represents "one of the very rare cases" where the agency will allow a drug to return to market after withdrawal, Steven Galson, director of the Center for Drug Evaluation and Research, said in a teleconference with the media. The agency made this decision because it believes that the benefits of using the drug outweigh the 1 in 1,000 chance that patients have of contracting PML. Because MS is such a debilitating condition, the FDA made a "judgment call" to allow Tysabri back on the market, he said. The drug is used as a treatment for patients that cannot tolerate or do not respond to other MS treatments.
While the agency admitted that there "will be deaths" associated with the drug, it believes that the restrictions placed upon Tysabri's sale will limit the risks, Russell Katz, an official with the Office of Drug Evaluation I, Division of Neurology Products, said. The agency is requiring the company to apply a risk management plan for the drug.
Elan took a while but it did come back. It seems AFFY would have filed bk by now if it had no chance. This drug seems important enough so they ca find a way to bring it back. It sure requires patiuence.
It's not as rare as you think. We just saw it this year with ARIAD (ARIA symb). However, the circumstances for both are different. In each case, there were refractory patients who didn't respond to other treatments. While there are other EPO products on the market, the key issue will be whether Takeda can convince an FDA Advisory Committee (hearing) that they have a risk mitigation plan (REMS) in place to minimize the risk of anaphylaxis. Ironically, the gutless FDA officials might prefer to have Omontys come back to the market to insulate them from criticism that they didn't protect the public in the first place (when the drug was initially approved).. There may also be third party issues which will enable the drug to come back to the market. It's a gamble, but I'm long the stock, having done very well with Tysabri/ELN.