BIOGEN REPORTS SECOND QUARTER 2000 RESULTS

Record Revenues and Number of AVONEX Patients Reported

Biogen, Inc. (NASDAQ/BGEN) today reported financial results for the second quarter of 2000. For the three months ended June 30, 2000, the Company reported net income of $72,060,000, or $0.47 per share. Revenues for the quarter were $230,514,000. For the second quarter of last year, the Company reported net income of $43,388,000, or $0.28 per share, based on revenues of $188,929,000. Net income and diluted earnings per share for the second quarter of 2000 included gains from sales of certain securities of approximately
$8,681,000 (on a pre-tax basis), or $0.04 per diluted share (net of tax).

James C. Mullen, Biogen´s President and Chief Executive Officer, said, “The market for MS treatments continues to expand, led by AVONEX®, with its unsurpassed convenience and efficacy. AVONEX remains the leader both in terms of number of patients and sales volume. More than 90,000 patients are on therapy worldwide. Total AVONEX sales in the second quarter 2000 were $190,009,000, up from $145,852,000 in second quarter 1999, an increase of more than 30 percent.

“We believe this growth will be reinforced by the CHAMPS data, which again proved the importance of AVONEX by showing that it significantly delayed the onset of clinically definite MS in people at risk for MS. There is a very clear message behind the continuing strength of this drug: AVONEX is the best choice for people with MS who want to maintain their daily functioning.

“During the quarter, we continued to make good progress on our clinical pipeline. Patient accrual for two Phase III trials with AMEVIVEô, both involving patients with chronic plaque psoriasis, is well ahead of schedule. Other accomplishments included the topping off of a large-scale manufacturing facility in Research Triangle Park, North Carolina, and the opening of Biogen´s first European manufacturing operation, a packaging facility in The Netherlands. This expansion reinforces our leadership position in the biopharmaceutical industry in terms of manufacturing capability and our confidence in the future.”

In addition to historical facts, this press release contains forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those reflected in the forward-looking statements. Reference is made in particular to statements regarding the anticipated growth in AVONEX sales and outlook for AVONEX and the anticipated effect of new data related to AVONEX. Factors which could cause actual results related to AVONEX growth and outlook to differ from the Company´s current expectations include, without limitation, the impact of competitive products on AVONEX sales, any slowdown or failure in obtaining or maintaining market acceptance for AVONEX in key markets worldwide, any unexpected negative results from clinical trials, any failure of the FDA to approve labeling changes related to new data and the other risks and uncertainties associated with drug development and commercialization described in the Company´s periodic reports filed with the Securities and Exchange Commission. Reference is made in particular to the “Outlook” section of Management´s Discussion and Analysis of Financial Condition and Results of Operation in the Company´s 1999 Annual Report on Form 10-K and in quarterly reports on Form 10-Q.

Biogen, Inc., winner of the 1998 U.S. National Medal of Technology, is a biopharmaceutical company principally engaged in discovering and developing drugs for human healthcare through genetic engineering. Headquartered in Cambridge, MA, the Company´s revenues are generated from worldwide sales of AVONEX® for treatment of relapsing forms of multiple sclerosis, and from the worldwide sales by licensees of a number of products, including alpha interferon and hepatitis B vaccines and diagnostic products ( Prescribing Information ). Biogen´s research and development activities are focused on novel products for multiple sclerosis, inflammatory, respiratory, kidney and cardiovascular diseases and in developmental biology and gene therapy. For copies of press releases and additional information about the Company, please consult Biogen´s Homepage on the World Wide Web at http://www.biogen.com.

Financial Results For The Second Quarter of 2000

Condensed Consolidated Statements Of Income
(in thousands, except per share amounts)

Three Months Ended Six Months Ended
June 30, June 30,
2000 1999 2000 1999

REVENUES
Product $190,009 $145,852 $364,605 $277,172
Royalties 40,505 43,077 82,757 83,477
Total Revenues 230,514 188,929 447,362 360,649

COST AND EXPENSES

Cost of revenues 30,795 26,961 59,418 51,831

Research and
development 71,701 50,941 134,707 101,928

Selling, general and
administrative 40,921 36,999 82,104 70,860

Total Cost and
Expenses 143,417 114,901 276,229 224,619

Income from
Operations 87,097 74,028 171,133 136,030

Other income (expense),
net 16,737 (9,270) 115,761 (3,086)

INCOME BEFORE
INCOME TAXES 103,834 64,758 286,894 132,944

Income Taxes 31,774 21,370 93,468 43,872

NET INCOME $72,060 $43,388 $193,426 $89,072

BASIC EARNINGS
PER SHARE $0.48 $0.29 $1.29 $0.59

DILUTED EARNINGS
PER SHARE $0.47 $0.28 $1.24 $0.57

SHARES USED IN CALCULATING:

BASIC EARNINGS
PER SHARE 148,643 150,047 149,501 149,722

DILUTED EARNINGS
PER SHARE 154,150 157,575 155,931 157,553


Condensed Consolidated Balance Sheets
(in thousands)

Jun. 30, 2000 Dec. 31, 1999
ASSETS
Current Assets

Cash and marketable securities $652,188 $654,539

Accounts receivable, net 154,301 137,363

Other current assets 139,647 118,324

Total current assets 946,136 910,226

Property and equipment, net 302,799 239,777

Other assets 76,630 127,970
$1,325,565 $1,277,973

LIABILITIES AND SHAREHOLDERS' EQUITY

Current liabilities $216,463 $190,270

Long term debt & liabilities 105,909 108,173

Shareholders' equity 1,003,193 979,530
$1,325,565 $1,277,973