Biogen Idec ( BIIB) and Irish drugmaker Elan ( ELN) said Tuesday they'd seek European regulatory approval for their multiple sclerosis drug Antegren this summer.

In February, the two companies stunned investors by announcing they would seek U.S. regulatory approval a year ahead of schedule after one year of phase III trials produced surprisingly positive test results. The companies, however, said they would continue the testing program despite the decision to apply for early FDA approval, expected sometime in mid-2004. The February announcement triggered a two-day rally in shares of both Elan and Biogen Idec.

In premarket trading Tuesday, Elan shares rose 91 cents, or almost 5%, to $19.31. Biogen Idec shares gained 64 cents, or 1.2% to $52.96.