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Filed Pursuant to Rule 424(b)(3) and (c)
File Number 333-85339
PROSPECTUS SUPPLEMENT DATED DECEMBER 15, 1999
to
Prospectus Dated November 12, 1999
$345,000,000
IDEC PHARMACEUTICALS CORPORATION
LIQUID YIELD OPTION(TM) NOTES DUE 2019
(ZERO COUPON - SUBORDINATED)
AND
COMMON STOCK ISSUABLE UPON
CONVERSION OF THE LYONS
This prospectus supplement supplements the prospectus dated
November 12, 1999 (the "prospectus") of IDEC Pharmaceuticals Corporation ("IDEC
Pharmaceuticals" or the "Company" or "we," "our" or "us") relating to the sale
by certain of our securityholders or by their pledgees, donees, transferees or
other successors in interest that receive any of these securities as a gift,
partnership distribution or other non-sale related transfer (the "Selling
Securityholders") of up to $345,000,000 principal amount of Liquid Yield
Option(TM) Notes due 2019 (the "LYONs") and up to 2,323,230 shares of common
stock to be issued upon conversion of the LYONs. You should read this prospectus
supplement in conjunction with the prospectus, and this prospectus supplement is
qualified by reference to the prospectus except to the extent that the
information in this prospectus supplement supersedes the information contained
in the prospectus. Capitalized terms used in this prospectus supplement and not
otherwise defined herein have the meanings specified in the prospectus.
SELLING SECURITYHOLDERS
The following table provides certain information with respect to
the principal amount of LYONs at maturity beneficially owned by (a) entities who
were not identified in the prospectus as Selling Securityholders, and (b)
entities who were identified in the prospectus as Selling Securityholders and
have increased the principal amount of LYONs that may be offered by such Selling
Securityholders pursuant to the prospectus; the percentage of outstanding LYONs
this represents; and the number of shares of common stock issuable upon
conversion of such LYONs to be registered for sale hereby. Distributions may be
made by certain of the Selling Securityholders listed below to individuals other
than those listed in the prospectus. The table of Selling Securityholders in the
prospectus is hereby amended to include the entities who are named below as
Selling Securityholders and to amend the information provided for "SoundShore
Holdings Ltd.," "SoundShore Opportunity Holding Fund Ltd.," and "All other
Holders of LYONs or future transferee, pledgee, donee or successor of any such
Holders" in the table of Selling Securityholders in the prospectus.
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<TABLE>
<CAPTION>
Aggregate Number of
Principal Amount Shares of
of LYONs at Percentage Common
Maturity That of LYONs Stock That
Name of Selling Securityholder May be Sold Outstanding May be Sold(1)
- ------------------------------ ----------- ----------- --------------
<S> <C> <C> <C>
ABN AMRO Incorporated 328,000 * 2,208
Allstate Insurance Company 350,000 * 2,356
SoundShore Holdings Ltd 19,119,000 5.5% 128,747
SoundShore Opportunity Holding Fund Ltd. 4,971,000 1.4% 33,474
All other Holders of LYONs or
future transferee, pledgee, donee,
or successor of any such Holders 27,227,000 7.9% 183,346
</TABLE>
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* less than one percent.
(1) This prospectus supplement shall also cover any additional shares of
common stock which become issuable in connection with the shares registered for
sale hereby by reason of any stock dividend, stock split, recapitalization or
other similar transaction effected without the receipt of consideration which
results in an increase in the number of the Selling Securityholders' outstanding
shares of common stock.
(TM) Trademark of Merrill Lynch & Co.
