Elan said last night that the US drug regulator designated its suspended Tysabri drug for priority review.
The fast-tracking of the review process will mean a decision from the Federal Drug Administration (FDA) by the end of March 2006, and the drug could be back on the market by April.
The granting of priority review status implies that the FDA still assumes that despite PML concerns, Tysabri is a drug that is a significant advance over existing therapies that address an unmet medical need.
Elan and its partner company Biogen Iodec were required to submit data on their drug trials of Tysabri which was tested on 3,000 patients.
Tysabri was hailed as a blockbuster drug for the treatmnet of MS before it was suspended following the death of a number of patients from complications during trials.