Biogen-Idec ( BIIB) and Elan ( ELN) suffered a setback Wednesday when the FDA said it wanted another 90 days to review Tysabri, the multiple-sclerosis treatment that was pulled from the market due to concerns it was causing a rare brain disease. The agency enacted the 90-day extension to review the companies' risk-management plan on Tysabri, which remains off the market pending a final FDA decision. Earlier this month, an FDA advisory panel recommended Tysabri be allowed to be sold again following a review of thousands of patients taking the drug. "The companies have been informed by the FDA that the agency requires additional time to review information regarding the Tysabri risk management plan," Biogen and Elan said. "Under this revised timeline, the companies anticipate action from FDA on or before June 28, 2006." Previously, Biogen and Elan hoped for a final decision on Tysabri next week. On March 8, an advisory panel unanimously decided to recommend that the FDA allow the return of Tysabri, which was pulled in February 2005. Committee members voted 7-to-5 to suggest doctors be permitted to prescribe Tysabri as the first treatment choice for MS patients. The panel concluded that additional clinical trials weren't necessary for the drug's return. However, if the FDA were to allow re-entry, the drug should be limited to a certain subgroup of MS patients under strict guidelines, the panel said. Also, according to the advisory committee's suggestions, patients should be tracked by regular surveys given prior to monthly Tysabri infusions. Patients' receipt of the drug would be contingent on Biogen getting the safety reports, which would include any side effects and allergic reactions.