Drugs firms Elan and Biogen Idec have received European Commission approval to market multiple sclerosis treatment Tysabri.
"The approval was based on a submission that included Tysabri two-year Phase III clinical trial data, findings from the comprehensive safety evaluation, suggested labelling, and a risk management plan," the groups said.
The action follows a recommendation made by the Committee for Medicinal Products for Human Use, the scientific committee of the European Medicines Agency, which in April issued a positive opinion recommending marketing authorisation for Tysabri.
Tysabri was withdrawn from sale last year after three patients taking the drug contracted the rare brain disease multifocal leukoencephalopathy. Two of them died.
US health officials ruled earlier this month Tysabri could return to the market but said patients should try other treatments first. Tysabri's future is key to Elan, which experienced a brush with bankruptcy in 2002.
The company has cut costs and implemented a major restructuring since then, but sales of the drug account for the lion's share of analysts' profit forecasts.