Elan and Biogen Idec got the go-ahead to bring their multiple sclerosis drug Tysabri to the market in Europe, just over a year after it was removed from sale in the USA on safety concerns.

Tysabri (natalizumab) is also due to make its comeback in the USA next month after its return to market was cleared by the Food and Drug Administration on June 5. It was never launched in Europe.

As in the USA, the drug comes to the European market with slightly more restrictive labelling than before, as it will be reserved for patients who have not responded adequately to, or cannot tolerate, other treatments for MS, notably interferon beta, or those with “rapidly evolving, severe relapsing/remitting MS.”

Tysabri was taken off the market in February 2005 after being linked to a rare and usually fatal brain disease called progressive multifocal leukoencephalopathy (PML), dealing a massive blow to both Elan and Biogen Idec which had expected the product to be a blockbuster. Three cases of PML were uncovered, with two fatalities, but regulators ruled that Tysabri could return with appropriate safeguards and monitoring after no additional cases were found among several thousand patients who had receive the drug in clinical trials.

Elan said it would launch Tysabri in Ireland next month, but neither company has provided any additional details on their plans for a European roll-out.

There has been considerable debate about the market potential for Tysabri in the wake of the marketing suspension, with a poll of neurologists conducted by Piper Jaffray indicating in March that the majority would be reluctant to prescribe the drug if it returned to the market.

Biogen Idec and Elan are carrying out a major, open-label study of Tysabri to try to generate long-term safety data and rebuild confidence in the drug’s safety.

The product has returned to the US market with premium pricing, 20% more than when it was first available at $28,400 per patient per year. The companies said the move was a result of inflation and the additional cost of safety studies.