<PAGE>
PROSPECTUS SUPPLEMENT FILED PURSUANT TO RULE 424(b)(3)
(TO PROSPECTUS DATED APRIL 27, 2000) REGISTRATION NO. 333-31344
MILLENNIUM PHARMACEUTICALS, INC.
$400,000,000 Principal Amount 5.50% Convertible Subordinated Notes
Due January 15, 2007
4,753,920 Shares of Common Stock issuable upon conversion of the Notes
211,554 Shares of Common Stock issuable upon exercise of outstanding
warrants to purchase common stock
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This prospectus supplement relates to resales by selling holders of:
- - our 5.50% Convertible Subordinated Notes due January 15, 2007;
- - our common stock into which the notes are convertible; and
- - our common stock issuable upon exercise of warrants to purchase our common
stock held by GATX Capital Corporation and MM Ventures
This prospectus supplement should be read in conjunction with the
prospectus dated April 27, 2000, which is to be delivered with this prospectus
supplement.
SEE "RISK FACTORS" BEGINNING ON PAGE 6 OF THE PROSPECTUS TO READ ABOUT
FACTORS YOU SHOULD CONSIDER BEFORE BUYING THE NOTES OR OUR COMMON STOCK.
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Neither the Securities and Exchange Commission nor any other regulatory
body has approved or disapproved of these securities or passed upon the accuracy
or adequacy of this prospectus. Any representation to the contrary is a criminal
offense.
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The information in the table appearing in the prospectus under the heading
"Selling Holders" is superseded in part by the information appearing in the
following table:
<TABLE>
<CAPTION>
Number of
Notes Percentage Shares of
Notes Beneficially of the Common Number of Number of Percentage
Beneficially Notes Owned Notes Stock Shares of Shares of of Shares of
Owned Offered After Beneficially Beneficially Common Common Stock Common Stock
Prior to Hereby Offering Owned Owned Stock Beneficially Beneficially
Selling Offering (in (1) After the Prior to Offered Owned After Owned After
Securityholder (in $1,000) $1,000) (in $1,000) Offering Offering Hereby Offering(1) Offering(1)
<S> <C> <C> <C> <C> <C> <C> <C> <C>
Arkansas 2,132 2,132 0 0 25,338 25,338 0 0
Teachers
Retirement
System
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Number of
Notes Percentage Shares of
Notes Beneficially of the Common Number of Number of Percentage
Beneficially Notes Owned Notes Stock Shares of Shares of of Shares of
Owned Offered After Beneficially Beneficially Common Common Stock Common Stock
Prior to Hereby Offering Owned Owned Stock Beneficially Beneficially
Selling Offering (in (1) After the Prior to Offered Owned After Owned After
Securityholder (in $1,000) $1,000) (in $1,000) Offering Offering Hereby Offering(1) Offering(1)
<S> <C> <C> <C> <C> <C> <C> <C> <C>
Associated 450 450 0 0 5,348 5,348 0 0
Electric & Gas
Insurance
Services Limited
Baptist Health 103 103 0 0 1,224 1,224 0 0
of South Florida
Boston Museum 83 83 0 0 986 986 0 0
of Fine Arts
Champion 393 393 0 0 4,670 4,670 0 0
International
Corp.
Engineers Joint 289 289 0 0 3,434 3,434 0 0
Pension Fund
Goldman Sachs 14,000 14,000 0 0 166,387 166,387 0 0
and Company
HBK Master Fund 2,500 2,500 0 0 29,712 29,712 0 0
L.P.
Jeffries & Co. 550 550 0 0 6,536 6,536 0 0
Inc.
Nicholas-Applegate 738 738 0 0 8,770 8,770 0 0
Convertible Fund
Physicians Life 226 226 0 0 2,685 2,685 0 0
Pilgrim 2,765 2,765 0 0 32,861 32,861 0 0
Convertible Fund
Sagemore Hill 6,250 6,250 0 0 74,280 74,280 0 0
Hub Fund Ltd.
San Diego City 580 580 0 0 6,893 6,893 0 0
Retirement
San Diego 1,408 1,408 0 0 16,733 16,733 0 0
County
Convertible
Wake Forest 692 692 0 0 8,224 8,224 0 0
University
Writers 179 179 0 0 2,127 2,127 0 0
Guild-Industry
Health Fund
</TABLE>
(1) We do not know if, when or in what amounts a selling securityholder
may offer securities for sale and we do not know that the selling
securityholders will sell any or all of the securities offered
2
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hereby. Because the selling securityholders may offer all or some of the
securities pursuant to this prospectus, and because there are currently no
other agreements, arrangements or understandings with respect to the sale of
any of the securities that will be held by the selling securityholders, no
estimate can be given as to the amount of the securities that will be held by
the selling securityholders after completion of the offering made by this
prospectus. However, for purposes of this table, we have assumed that, after
completion of the offering, no securities will be held by the selling
securityholders.
The date of this prospectus supplement is May 18, 2000.
