<PAGE> 1
Filed Pursuant to Rule 424(b)(3) and (c)
File Number 333-93219
PROSPECTUS SUPPLEMENT DATED FEBRUARY 24, 2000
TO
PROSPECTUS DATED JANUARY 4, 2000
1,194,600 SHARES
ILEX ONCOLOGY, INC.
COMMON STOCK
---------------
This Prospectus Supplement supplements the Prospectus dated January 4,
2000 (the "Prospectus") of ILEX Oncology, Inc. (the "Company") relating to the
public offering, which is not being underwritten, and sale by certain
stockholders of the Company or by pledgees, donees, transferees or other
successors in interest that receive such shares as a gift, partnership
distribution or other non-sale related transfer (the "Selling Stockholders") of
1,194,600 shares of Common Stock, $0.01 par value, of the Company ("Common
Stock"), who received such shares pursuant to a Stock Purchase Agreement dated
July 16, 1999 among the Company and Alta BioPharma Partners, L.P., Alta
Embarcadero BioPharma, L.L.C., ILEX Chase Partners (Alta Bio), L.L.C., Chase
Venture Capital Associates, L.P., B. J. McCombs, Advent Health Care and Life
Sciences II Limited Partnership, Advent Health Care and Life Sciences II
Beteiligung GmbH & Co. KG, Advent Partners HLSII Limited Partnership and Advent
Partners Limited Partnership. This Prospectus Supplement should be read in
conjunction with the Prospectus, and this Prospectus Supplement is qualified by
reference to the information contained in the Prospectus except to the extent
that the information herein contained supersedes the information contained in
the Prospectus. Capitalized terms used in this Prospectus Summary and not
otherwise defined herein have the meanings specified in the Prospectus.
Alta BioPharma Partners, L.P., ILEX Chase Partners (Alta Bio), L.L.C.
and Alta Embarcadero BioPharma Partners, L.L.C., each listed as a Selling
Stockholder of the Company, is distributing all of their respective shares of
Common Stock. The following table sets forth the number of shares of Common
Stock owned by a stockholder of the Company who was not specifically identified
in the Prospectus as a Selling Stockholder and the number of shares of Common
Stock now owned by Chase Venture Capital Associates, L.P., who was identified as
a Selling Stockholder in the Prospectus but received additional shares of Common
Stock in the distribution by ILEX Chase Partners (Alta Bio), L.L.C. The table of
Selling Stockholders in the Prospectus is hereby amended to include the
following stockholder as a Selling Stockholder.
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SELLING STOCKHOLDERS
The table below presents the following information about the number of
shares of the Common Stock of the Company which is owned by the Selling
Stockholders: (i) the number of shares each Selling Stockholder beneficially
owns as of the date of this prospectus, (ii) the percentage of the Company's
outstanding shares of Common Stock that each Selling Stockholder beneficially
owns prior to the offering, (iii) the number of shares that each Selling
Stockholder is offering under this prospectus, (iv) the number of shares that
each Selling Stockholder will beneficially own after the completion of this
offering and (v) the percentage of the Company's outstanding shares of Common
Stock that each Selling Stockholder will beneficially own after the completion
of the offering.
<TABLE>
<CAPTION>
BENEFICIAL OWNERSHIP BENEFICIAL OWNERSHIP
BEFORE THE OFFERING AFTER THE OFFERING(1)
---------------------- ----------------------
NUMBER PERCENTAGE SHARES TO NUMBER PERCENTAGE
NAME OF SHARES OF CLASS(2) BE SOLD OF SHARES OF CLASS
---- --------- ----------- --------- --------- ----------
<S> <C> <C> <C> <C> <C>
Chase Venture Capital Associates,
L.P.(3) 591,028 2.7 591,028 0 0
California Public Employees'
Retirement System 293,877 1.4 293,877 0 0
Financiere et Industrielle Gaz et
Eaux 88,163 * 88,163 0 0
Rhode Island Employees'
Retirement System 58,775 * 58,775 0 0
Daniel Janney 38,108 * 38,108 0 0
Alix Marduel 38,108 * 38,108 0 0
Garrett Gruener 28,295 * 28,295 0 0
Guy Nohra 27,945 * 27,945 0 0
Marino Polestra 27,945 * 27,945 0 0
Jean Deleage 17,340 * 17,340 0 0
Deleage Children's Trust FBO
Andre Deleage 5,716 * 57,16 0 0
Deleage Children's Trust FBO
Emmanuel Deleage 5,716 * 5,716 0 0
Deleage Children's Trust FBO
Phillippe Deleage 5,716 * 5,716 0 0
Deleage Children's Trust FBO
Michel Deleage 5,716 * 5,716 0 0
Eileen McCarthy 5,187 * 5,187 0 0
An additional 37 Selling
Stockholders, who in the
aggregate own less than 1% of
the Outstanding Common Stock
of the Company as of the date
hereof 195,885 * 195,885 0 0
--------- --- --------- --- ---
TOTAL 1,194,600 6.0 1,194,600 0 0
</TABLE>
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* represents less than 1%
(1) Assumes all shares of Common Stock offered hereby are sold.
(2) Based on 21,588,599 shares of Common Stock outstanding as of December 31,
1999.
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