Filed Pursuant to Rule 424(b)(3)
REGISTRATION NO. 333-42887
PROSPECTUS SUPPLEMENT NO. 1 DATED FEBRUARY 5, 1999 TO THE
PROSPECTUS DATED FEBRUARY 2, 1999 OF
BIOGEN, INC.
This Prospectus Supplement No. 1 amends the information contained in the table
under the caption "Selling Stockholders" in the Prospectus dated February 2,
1999 by deleting the information as to James L. Vincent in the body of the table
and footnote (2) thereto, and substituting therefor the following information:
<TABLE>
<CAPTION>
Number of Shares to be
Shares Number of Beneficially
Beneficially Shares to Owned After
Name Owned be Offered Offering
<S> <C> <C> <C> <C>
Number Percent
James L. Vincent(1) 860,499(2) 634,300 226,199(3) *
------------------------------------
<FN>
(2) Includes (i) 6,800 shares of common stock acquired by the selling
stockholder through the exercise of options granted under the Plan, (ii) 852,500
Shares of common stock which the selling stockholder has the right to acquire
through the exercise of options granted under the Plan, all of which are
currently exercisable and (iii) an estimated 1,199 shares of common stock
representing the selling stockholder's beneficial interest in a Biogen 401(k)
plan.
</FN>
</TABLE>
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This Prospectus Supplement No. 1 forms a part of and should be read in
conjunction with the Prospectus dated February 2, 1999.
