<PAGE>
FILING PURSUANT TO RULE 424(b)(2)
REGISTRATION STATEMENT NO. 333-88051
PROSPECTUS SUPPLEMENT
(TO PROSPECTUS DATED SEPTEMBER 29, 1999)
2,014,036 SHARES
SUPERGEN, INC.
COMMON STOCK
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You should read this prospectus supplement and the accompanying prospectus
carefully before you invest. Both documents contain information you should
consider when making your investment decision.
SEE "RISK FACTORS" BEGINNING ON PAGE 3 OF THE ACCOMPANYING PROSPECTUS TO
READ ABOUT FACTORS YOU SHOULD CONSIDER BEFORE BUYING SHARES OF THE COMMON STOCK.
SELLING STOCKHOLDERS
On December 7, 1999, Dunwoody Brokerage Services, Inc. (Dunwoody)
transferred its warrants to purchase 30,136 shares of common stock to the
following persons, who are all affiliates of Dunwoody:
<TABLE>
<CAPTION>
SHARES OF COMMON
SHARES OF COMMON STOCK TO BE
STOCK BENEFICIALLY BENEFICIALLY OWNED
OWNED BEFORE OFFER AFTER OFFERING UNDER
UNDER THIS PROSPECTUS THIS PROSPECTUS(1)
---------------------- SHARES TO BE ----------------------
NAME NUMBER(2) PERCENTAGE OFFERED NUMBER PERCENTAGE
- ---- --------- ---------- ------------ --------- ----------
<S> <C> <C> <C> <C> <C>
Marc A. Tepper............................. 3,014 * 3,014 0 0%
Andrew V. Riccioni......................... 1,507 * 1,507 0 0%
Michael E. Stough.......................... 603 * 603 0 0%
Glenn R. Archer............................ 2,000 * 2,000 0 0%
Charles M. Whiteman........................ 2,000 * 2,000 0 0%
P. Bradford Hathorn........................ 2,000 * 2,000 0 0%
H. Nelson Logan............................ 500 * 500 0 0%
James D. Mills............................. 500 * 500 0 0%
Carlton M. Johnson, Jr..................... 2,000 * 2,000 0 0%
Robert L. Hopkins.......................... 1,000 * 1,000 0 0%
Dwight B. Bronnum.......................... 1,000 * 1,000 0 0%
Kendrick Family Partnership, L.P........... 7,006 * 7,006 0 0%
Eric S. Swartz............................. 7,006 * 7,006 0 0%
</TABLE>
* Represents less than 1% of the outstanding common stock of the Company
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(1) Assumes the selling stockholders sell all of their shares offered hereby to
unaffiliated third parties pursuant to this Prospectus. The selling
stockholders may sell all or part of their shares.
(2) Represents, in aggregate, 30,136 shares of common stock issuable upon
exercise of immediately exercisable warrants.
S-1
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GENERAL
You should rely only on the information provided or incorporated by
reference in this prospectus supplement and the accompanying prospectus. We have
not authorized anyone else to provide you with different information. You should
not assume that the information in this prospectus supplement is accurate as of
any date other than the date on the front of these documents.
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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.
------------------------
The date of this prospectus supplement is December 23, 1999.
S-2
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TABLE OF CONTENTS
<TABLE>
<CAPTION>
PAGE
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<S> <C>
PROSPECTUS SUPPLEMENT
Selling Stockholders.................. S-1
General............................... S-2
PROSPECTUS
Summary............................... 2
Risk Factors.......................... 3
Recent Developments................... 11
Where You Can Find More Information... 11
Note Regarding Forward-Looking
Statements.......................... 12
Use of Proceeds....................... 13
Dividend Policy....................... 13
Selling Stockholders.................. 13
Plan Of Distribution.................. 15
Legal Matters......................... 15
Experts............................... 15
</TABLE>
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S-3
