DUBLIN--
Elan shares have lost 85 percent of their value since Feb. 28, when Tysabri -- the multiple sclerosis-fighting drug Elan is developing in partnership with Biogen Idec Inc. of Cambridge -- was linked to a potentially fatal disease of the central nervous system. Three patients using the drug have contracted the disease, two fatally.
Elan spokeswoman Anita Kawatra characterized the Securities and Exchange Commission's probe as ''routine information gathering" that wasn't linked to a specific sale of shares.
Analysts said an SEC probe was expected given the drop in Elan shares, which rose 5 cents yesterday to close at $3.81 on the Irish Stock Exchange. Elan shares were worth $26.40 before Tysabri's withdrawal.
Ian Hunter, an analyst for Goodbody Stockbrokers in Dublin, said the SEC ''will always look to see if there's anything untoward" when a company's shares fall so much so quickly.
The SEC also is investigating stock trades by Biogen Idec executives in the days leading up to the companies' Feb. 28 Tysabri disclosure, including trades by Thomas Bucknum, who resigned March 9 as Biogen Idec's vice president and general counsel.