Elan and its partner Biogen Idec have submitted a supplemental licence application for Tysbari.

The application includes final two-year data from the phase three trial of the drug.

The companies have applied to the US Food and Drug Administration for a "supplemental biologics licence" for the drug's use in the treatment of multiple sclerosis. They have also submitted a similar data package to the European Medicines Agency.

Last February, Elan's shares collapsed from €30 after the two companies withdrew Tysbari following three cases of progressive multifocal leukoencephalopathy (PML) in patients involved in trials of the drug. Two of the cases were fatal.

The companies also suspended clinical trials based on the cases of PML, a rare and potentially fatal demyelinating disease of the central nervous system.

Last night's announcement follows the completion in early August of a safety evaluation of Tysbari, which resulted in no new confirmed cases of PML.

"We are grateful to the MS community for their patience and support over the last several months while we've conducted an extensive safety evaluation of Tysabri in collaboration with leading experts. We look forward to working with regulatory authorities during the review process, and ultimately, we hope to provide Tysabri to people living with MS, a disease with significant unmet need," said Burt Adelmain, executive vice president of development at Biogen.

Lars Ekman, executive vice president of Elan and president of its research and development department, said the company was encouraged by the latest filing.

"We strongly believe in the therapeutic benefit of Tysabri and the difference it could make in the lives of patients with MS," he said.