<PAGE> 1
Filed Pursuant to Rule 424(b)(3) and (c)
File Number 333-85339
PROSPECTUS SUPPLEMENT DATED FEBRUARY 11, 2000
to
Prospectus Dated November 12, 1999
and supplemented December 15, 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 and supplemented December 15, 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
4,646,460 shares of common stock to be issued upon conversion of the LYON, as
adjusted to reflect the two-for-one stock split of the Company's common stock
effected in December, 1999. 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) an entity
who was not identified in the prospectus as a Selling Securityholder, and (b) an
entity who was identified in the prospectus as a Selling Securityholder and has
increased the principal amount of LYONs that may be offered by such Selling
Securityholder 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 entity who is named below as a
Selling Securityholder, and to amend the information provided for "Merrill Lynch
Pierce Fenner & Smith, Inc." 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.
<PAGE> 2
<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>
Capital Market Transactions, Inc. $ 4,172,000 1.2% 56,188
Merrill Lynch Pierce Fenner & Smith, Inc. $ 11,440,000 3.3% 154,072
All other Holders of LYONs or $ 15,055,000 4.4% 202,760
future transferee, pledgee, donee,
or successor of any such Holders.
</TABLE>
- ----------
(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. The number of shares of common stock listed in this
table have been adjusted to reflect the two-for-one stock split of the Company's
common stock effected in December, 1999.
(TM) Trademark of Merrill Lynch & Co.
