BIOGEN REPORTS SECOND QUARTER 2001 RESULTS

Sales Showing Strong Accelerated Growth Rate

Biogen, Inc. (Nasdaq: BGEN)
today reported financial results for the second quarter of 2001. For the
three months ended June 30, 2001, the Company reported net income of
$72 million, resulting in $0.47 per share. Product revenues for the quarter
were $243 million, representing a 28 percent increase in AVONEX(R) (Interferon
beta-1a) sales over the second quarter of last year. Including royalties,
total revenues for the quarter were $261 million, a 13 percent increase over
the same period in 2000. Second quarter earnings per share growth over the
operating results of the comparable period in the prior year was eight
percent, excluding $8.7 million in gains on sales of securities in the prior
year period.
James C. Mullen, Biogen's President and Chief Executive Officer, said
"AVONEX sales growth rate has been accelerating on a consecutive quarter over
quarter basis. This year, total revenue for the Company is expected to top
$1 billion, a landmark event for Biogen as we become a global, multi-product
biopharmaceutical company."
Commenting on AVONEX sales performance, Mullen said, "AVONEX is the world
leader in MS therapies. We are competing successfully throughout the world
and, in particular, we have turned in a great performance in Europe.
International product sales are up 37 percent over the comparable period last
year and 20 percent over last quarter. U.S. sales grew faster than the market
in the first half of the year.
"We have completed Phase III trials for AMEVIVE(TM) (alefacept) and we now
have six products in the clinic, representing enormous progress from just a
year ago. Biogen continues to execute on its strategy of multiple offerings
for key therapeutic areas, drawing from our own research efforts and through
collaborations such as Elan and ICOS."

Other events highlighted by the Company include:

Regulatory filings with the FDA and EMEA for AMEVIVE in chronic plaque
psoriasis are expected to be completed in the second half of this year.

ANTEGREN(R) (natalizumab) provides another significant opportunity for
Biogen. Being developed in collaboration with Elan Pharmaceuticals,
ANTEGREN is expected to move into Phase III trials in the second half of
the year in both MS and Crohn's disease. Details of the Phase II results
in MS will be presented at ECTRIMS in Dublin this September.

An agreement with ICOS Corporation was finalized to collaborate worldwide
on the development and commercialization of orally active, small molecule
LFA-1 antagonists for the treatment of immuno-inflammatory conditions.

Biogen expects earnings for 2001 in the range of $1.90 to $1.92 diluted
earnings per share, which includes the balance of 2001 development costs for
the partnered ICOS program announced yesterday. This guidance excludes the
$8 million up-front payment related to the formation of the ICOS
collaboration. Earnings per share for the third quarter of 2001 are expected
to fall within the $0.42 to $0.44 range due to significant milestone payments
related to the advancement of various clinical programs. Earnings per share
for the fourth quarter of 2001 are expected to increase to $0.53 to $0.55.
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 revenues and range of earnings per share for the third and
fourth quarter and the year, the Company's expectations regarding the
commencement of clinical trials of its development-stage products and the
anticipated worldwide regulatory filings for AMEVIVE. Factors which could
cause actual financial results to differ from the Company's current
expectations include, without limitation, the impact of competitive products
on AVONEX(R) (Interferon beta-1a) sales, any change in market acceptance for
AVONEX in key markets worldwide, any unexpected negative results related to
AVONEX, any unanticipated increase in expenses including in the areas of
research and development, the impact of litigation and in-licensing
opportunities 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.
Factors which could cause actual results regarding clinical trials to
differ from the Company's current expectations include the risk that the
Company will encounter one or more technical hurdles associated with new drug
development or that problems or delays may arise during preparations for or
the conduct of clinical trials, as well as the other risks and uncertainties
associated with drug development described in the Company's periodic reports
filed with the Securities and Exchange Commission. Factors which could cause
actual results related to AMEVIVE regulatory filings to differ materially from
the Company's current expectations include the risk that unexpected concerns
may arise from additional data analysis or from additional data or that
obstacles may arise or issues be identified in connection with review of data
with regulatory authorities or that regulatory authorities may disagree with
the Company's view of the data or may require additional data or information
or additional studies. Drug development involves a high degree of risk.
Success in early stage clinical trials or preclinical work does not ensure
that later stage or larger scale clinical trials will be successful.
Biogen, Inc., winner of the 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 international sales
of AVONEX(R) (Interferon beta-1a) 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 to treat inflammatory and autoimmune diseases,
neurological diseases, cancer, fibrosis and congestive heart failure. The
Company maintains active clinical research programs in protein therapeutics,
small molecules, genomics 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
AVONEX(R) (Interferon beta-1a) is a registered trademark of Biogen, Inc.
AMEVIVE(TM) (alefacept) is a trademark of Biogen, Inc. ANTEGREN(R)
(natalizumab) is a registered trademark of Elan Corporation.
NOTE: The Company's earnings conference call for the second quarter will
be broadcast via the Internet at 8:30 a.m. EST on Tuesday, July 17, 2001, and
will be accessible through the investor relations section of Biogen's
homepage, http://www.biogen.com.



Financial Results For The First Quarter of 2001
Condensed Consolidated Statements Of Income
(in thousands, except per share amounts)

Three Months Ended Six Months Ended
June 30, June 30,
2001 2000 2001 2000
REVENUES

Product $243,217 $190,009 $463,214 $364,605

Royalties 17,445 40,505 34,495 82,757

Total Revenues 260,662 230,514 497,709 447,362

COST AND EXPENSES

Cost of revenues 35,202 30,795 64,348 59,418

Research and development 79,118 71,701 151,888 134,707

Selling, general and
administrative 55,266 40,921 103,826 82,104

Total Cost and Expenses 169,586 143,417 320,062 276,229

Income from Operations 91,076 87,097 177,647 171,133

Other income, net 11,533 16,737 27,996 115,761

INCOME BEFORE INCOME TAXES 102,609 103,834 205,643 286,894

Income Taxes 30,757 31,774 61,668 93,468

NET INCOME $71,852 $72,060 $143,975 $193,426

BASIC EARNINGS PER SHARE $0.48 $0.48 $0.97 $1.29

DILUTED EARNINGS PER SHARE $0.47 $0.47 $0.94 $1.24

SHARES USED IN CALCULATING:

BASIC EARNINGS PER SHARE 148,602 148,643 148,395 149,501

DILUTED EARNINGS PER SHARE 153,337 154,150 153,414 155,931




Condensed Consolidated Balance Sheets
(in thousands)


Jun. 30, 2001 Dec. 31, 2000

ASSETS
Current Assets

Cash and marketable securities $759,996 $682,412

Accounts receivable, net 166,457 143,178

Other current assets 100,680 102,681

Total current assets 1,027,133 928,271

Property and equipment, net 474,104 400,429

Other assets 92,659 103,156

$1,593,896 $1,431,856


LIABILITIES AND SHAREHOLDERS' EQUITY

Current liabilities $234,982 $221,021

Long term debt & liabilities 98,171 104,433

Shareholders' equity 1,260,743 1,106,402

$1,593,896 $1,431,856