Updated from 4:45 p.m. EDT

Biogen Idec

(BIIB) - Get Report

reported first-quarter results that fell below Wall Street estimates, as the company revealed the initial damage caused by its Feb. 28 suspension of its multiple sclerosis drug Tysabri.

But the stock rose 4% in after-hours trading, as the company emphasized that it hopes to get its review of Tysabri data done by this summer.

Biogen Idec earned $43.5 million, or 12 cents a share, on revenue of $587.8 million for the three months ended March 31. For the same period last year, Biogen lost $41.2 million, or 12 cents a share, on revenue of $541.7 million.

Excluding one-time charges, Biogen Idec's first-quarter profit of 30 cents a share was below the Wall Street consensus of 37 cents, according to Thomson First Call.

A few weeks ago, the company withdrew its fiscal 2005 guidance, citing the uncertainty about Tysabri. It didn't offer a new 2005 EPS figure. For the full year, Wall Street predicts a profit of $590 million, or $1.59 a share, on sales of $2.41 billion.

Dr. Burt Adelman, executive vice president for development, told analysts and investors during a telephone conference call that the company and its partner

Elan

(ELN)

continue to review patients' records from clinical trials.

He said the review should be completed by "late summer," at which time Biogen Idec and Elan will discuss with the Food and Drug Administration Tysabri's prospects for returning to the market. Adelman said the companies also remain in contact with health regulators worldwide.

Adelman and other executives said they are hopeful Tysabri will return to the market, but they declined to speculate under what circumstances or restrictions the drug might come back.

Biogen Idec and Elan pulled the promising MS drug on Feb. 28 after disclosing one confirmed case and one suspected case of the rare central nervous system disease. Since then, the second case has been confirmed and a third case has been identified. Two patients have died. Executives declined to comment on the other patient.

All three patients contracted PML, or progressive multifocal leukoencephalopathy, which is often fatal. The first two patients were participating in a clinical trial in which they took both Tysabri and Avonex, another MS drug made by Biogen Idec. They took both drugs for more than two years.

The third patient was involved in a clinical trial to see if Tysabri could treat the severe gastrointestinal ailment Crohn's disease. The patient took Tysabri for 18 months. This patient also took immunosuppressant drugs, which are prescribed for inflammatory diseases such as MS and Crohn's disease as well as for people who have received organ transplants.

The revelations have damaged the companies' stocks, although the much smaller Elan has suffered more than Biogen Idec.

Biogen Idec said the first quarter was affected by one-time charges of $36 million, or 7 cents a share, for the suspension of Tysabri as well as $34 million, or 7 cents a share, in one-time charges for "other impairments and write-downs."

For the year, the company expects to take $140 million, or 25 cents a share, in one-time charges. Of that amount, $90 million to $100 million will be related to Tysabri.

"While we are disappointed with the events surrounding our voluntary suspension of Tysabri, we are working diligently ... to determine the appropriate next steps," said James Mullen, the chairman and CEO, in a prepared statement. Our core business remains healthy and growing, as evidenced by the underlying strength of our top line revenues."

First-quarter revenue was dominated by the MS drug Avonex, whose sales gained 5% to $374 million. The other big contributor was Rituxan, for non-Hodgkins lymphoma, which is being marketed with

Genentech

(DNA)

. Biogen Idec's share was up 20% to $160 million. During the second half of the year, the companies will seek FDA approval of Rituxan as a treatment for rheumatoid arthritis.