Elan and its partner Biogen Idec have said they will submit a supplemental licence application for Tysabri "in the coming weeks".
The drugs companies said last night that they will apply to the US Food and Drug Administration for "a supplemental biologics licence" for the drugs use in the treatment of multiple sclerosis.
They added that the safety revaluation of the drug as a treatment of Crohn's disease and rheumatoid arthritis will also be completed shortly.
Shares in Elan closed up very slightly at $8.31 in New York last night ahead of the anticipated update, which came after the market had closed.
The markets are likely to be disappointed that the companies did not set a firm date for the fresh licence application for Tysabri.
Last February Elan's shares collapsed from €30 after the two companies withdrew Tysabri following three case of progressive multifocal leukoencephalopathy (PML) in patients involved in trials of the drug. Two of the case were fatal.
The companies also suspended ongoing clinical trials based on the report of PML, a rare and potentially fatal demyelinating disease of the central nervous system.
Yesterday's announcement followed the completion in early August of a safety evaluation of Tysabri, which resulted in no new confirmed cases of PML.
