Irish pharmaceutical company Elan is likely to see its breakthrough multiple sclerosis treatment Tysabri return to the market as soon as next month after winning support from a crucial drug review group.
A body of 12 outside experts convened by the US Food and Drug Administration (FDA) voted unanimously to recommend the drug's return to shelves just over 12 months after it was withdrawn amid safety fears.
The decision is a major boost for Elan which had staked its future success in part on the breakthrough MS treatment, which has been determined to be significantly more effective in treating MS patients than existing medicines.
If confirmed by the FDA, which must rule on this recommendation by March 29th, Tysabri would be only the second prescription drug ever returned to market in the United States following its withdrawal for safety concerns.
The FDA, as a rule, does not go against decisions of its expert advisory committees.
Dr Orla Hardiman, consultant neurologist at Beaumont Hospital, Dublin, said last night that the FDA decision on Tysabri was a positive step.
"The FDA would have been exhaustive in terms of its safety tests and the fact that they voted 12-0 to reintroduce it is a good sign," she said.
But Irish patients will have to await a decision, expected in the next few months, by the European Agency for the Evaluation of Medicinal Products.
The FDA advisory committee said the drug should be used on its own rather than with other immune modulating drugs that had been implicated in the three cases of a rare and generally fatal brain disease that were diagnosed among Tysabri clinical trial patients.
It also ruled that there should be compulsory patient monitoring, something to which the manufacturers had agreed ahead of the two-day meeting.
Tysabri was withdrawn in February last year after the first two cases of the disease, progressive multifocal encephalopathy (PML), were diagnosed.
Elan and its US partner Biogen Idec subsequently carried out a safety evaluation of 3,000 patients who had taken the drug in clinical trials - a study Elan vice-president for global R&D Dr Lars Ekman described as "the most extensive ever undertaken".
The advisory committee also voted by a narrow majority to recommend that Tysabri not be restricted to patients who had failed to respond to older and less effective MS drugs.
Any patients who do not find relief with current MS drugs should have Tysabri as an option, advisory committee members said. "Most people in [ Tysabri] studies did not have a relapse and did not have disability progression," said Dr Karl Kieburtz, the panel chairman.
Dozens of MS patients, some in tears, appealed to the panel on Tuesday to let them decide for themselves whether Tysabri's risks were worth taking.
They said Tysabri produced dramatic improvements in motor function and should be available as long as patients are told of the risks.
Elan and Biogen based their case to the FDA on the clinical efficacy of the drug and the fact that there was a large group of MS patients who do not respond to existing treatments.
Shares in Elan jumped by almost a quarter as trading reopened briefly in New York last night following the announcement.
Before it was withdrawn last year, Tysabri had been seen as a blockbuster drug that could reach sales of $1 billion a year. Sanford Bernstein analyst Geoff Porges said yesterday that sales of the drug could reach $700 million a year by 2010.
Dr Hardiman said it was unlikely, however, to be used as a first option for patients newly diagnosed with the condition.
"Most neurologists will be cautious about reintroducing it once it is licensed.
"It will probably be used as a second-line treatment and then may well become a first-line treatment over time," she said.
"There will be a close monitoring process for patients who are prescribed the drug."
Biogen Idec and Elan said last night that they would continue to work closely with the FDA in the weeks ahead with the goal of making Tysabri available soon. - (Additional reporting, Reuters)