<PAGE>

                                                                     EXHIBIT 4.8

         THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933 AND HAVE BEEN TAKEN FOR INVESTMENT
         PURPOSES ONLY AND NOT WITH A VIEW TO THE DISTRIBUTION THEREOF, AND SUCH
         SECURITIES MAY NOT BE SOLD OR TRANSFERRED UNLESS THERE IS AN EFFECTIVE
         REGISTRATION STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES OR
         SUPERGEN, INC. (THE "COMPANY") RECEIVES AN OPINION OF COUNSEL (WHICH
         MAY BE COUNSEL FOR THE COMPANY) STATING THAT SUCH SALE OR TRANSFER IS
         EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF
         SUCH ACT.

No. Paulson-99                                          Right to Purchase 25,000
October 4, 1999                                           Shares of Common Stock
Void After October 4, 2001


                                 SUPERGEN, INC.

                                     WARRANT

         THIS CERTIFIES THAT, subject to the terms of this agreement, Paulson
Investment Company, Inc. (the "HOLDER") is entitled to subscribe for and
purchase from SuperGen, Inc, a Delaware corporation (the "COMPANY"), at the
Warrant Price defined in Section 2 herein, the number of fully paid and
non-assessable shares of the Company's Common Stock (the "COMMON STOCK")
determined as set forth in Section 3 herein, such price and such number of
shares being subject to adjustment upon occurrence of the contingencies set
forth in this Warrant.

         This Warrant is issued in consideration for the financial advisory
services related to the redemption of the Company's warrants issued in
connection with the Company's Intial Public Offering (the "WARRANT REDEMPTION
SERVICES").

         Upon delivery of this Warrant (with the Notice of Exercise in the form
attached hereto as EXHIBIT A), together with payment of the Warrant Price of the
shares of Common Stock thereby purchased, at the principal office of the Company
or at such other office or agency as the Company may designate by notice in
writing to the holder hereof, the holder of this Warrant shall be entitled to
receive a certificate or certificates for the shares of Common Stock so
purchased. All shares of Common Stock which may be issued upon the exercise of
this Warrant will, upon issuance, be fully paid and non-assessable and free from
all taxes, liens and charges with respect thereto.

         This Warrant is subject to the following terms and conditions:

         1.    TERM OF WARRANT.

               This Warrant may be exercised in whole or in part, at any time,
and from time to time, after issuance and prior to the first to occur of the
following:

<PAGE>

               (a)   5:00 p.m., Pacific Standard Time, October 4, 2001; or

               (b)   The consummation of any transaction or Series of
transactions (collectively, the "TRANSACTION"), including without limitation,
the sale, transfer or disposition of all or substantially all of the Company's
assets or the merger of the Company with or into, or consolidation with, any
other corporation, whereby the holders of the Company's voting securities prior
to the Transaction do not hold more than 50% of the voting securities of the
surviving entity following consummation of the Transaction (a "CHANGE OF
CONTROL").

         2.    WARRANT PRICE. The exercise price of this Warrant (the "WARRANT
PRICE") shall equal $22.125 per share.

         3.    NUMBER OF SHARES.

               All of the 25,000 shares subject to this Warrant shall be
immediately purchasable.

         4.    ADJUSTMENT OF PURCHASE PRICE AND NUMBER OF SHARES; LIMITATION ON
EXERCISE.

               The number and kind of securities purchasable upon the exercise
of this Warrant and the Warrant Price shall be subject to adjustment from time
to time in accordance with the following provisions; provided that, no such
adjustment shall be made if a corresponding adjustment is made pursuant to the
Company's Amended and Restated Certificate of Incorporation.

               (a)   RECLASSIFICATION, CONSOLIDATION OR MERGER. In case of any
reclassification or change of outstanding securities of the class issuable upon
exercise of this Warrant (other than as a result of a subdivision or
combination), or in case of any consolidation or merger of the Company with or
into another corporation (other than a Change of Control as provided in Section
1(b) hereof), the Company, or such successor corporation, as the case may be,
shall execute a new Warrant, providing that the holder of this Warrant shall
have the right to exercise such new Warrant and procure upon such exercise in
lieu of each share of Common Stock theretofore issuable upon exercise of this
Warrant the kind and amount of shares of stock, other securities, money and
property receivable upon such reclassification, change, consolidation or merger
by a holder of one share of Common Stock. Such new Warrant shall provide for
adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 3. The provisions of this subsection
(a) shall similarly apply to successive reclassifications, changes,
consolidations and mergers.

               (b)   SUBDIVISION OR COMBINATION OF SHARES. If at any time on or
after the date of this Warrant the Company shall subdivide its outstanding
shares of Common Stock into a greater number of shares, the Warrant Price in
effect immediately prior to such subdivision shall be proportionately reduced
and the number of shares receivable upon exercise of the Warrant shall be
proportionately increased; and, conversely, if at any time on or after the date
of this Warrant the outstanding number of shares of Common Stock shall be
combined into a smaller number of shares, the Warrant Price in effect
immediately prior to such combination shall be

                                      -2-
<PAGE>

proportionately increased and the number of shares receivable upon exercise
of the Warrant shall be proportionately decreased.

               (c)   ADJUSTMENT OF NUMBER OF SHARES. Upon each adjustment in the
Warrant Price, the number of Shares of Common Stock purchasable hereunder shall
be adjusted, to the nearest whole share, to the product obtained by multiplying
the number of Shares purchasable immediately prior to such adjustment in the
Warrant Price by a fraction, the numerator of which shall be the Warrant Price
immediately prior to such adjustment and the denominator of which shall be the
Warrant Price immediately thereafter.

         5.    NOTICES.

               (a)   Upon any adjustment of the Warrant Price and any increase
or decrease in the number of shares of Common Stock purchasable upon the
exercise of this Warrant, then, and in each such case, the Company, within
thirty (30) days thereafter, shall give written notice thereof to the registered
holder of this Warrant (the "NOTICE"). The Notice shall be mailed to the address
of such holder as shown on the books of the Company, and shall state the Warrant
Price as adjusted and the increased or decreased number of shares purchasable
upon the exercise of this Warrant, setting forth in reasonable detail the method
of calculation of each.

               (b)   In the event that the Company shall propose at any time to
effect a Change of Control, the Company shall send to the Holder at least twenty
(20) days' prior written notice of the date when the same shall take place.

               (c)   Each such written notice shall be given by first class
mail, postage prepaid, addressed to the Holder at the address as shown on the
books of the Company for the Holder.

         6.    INVESTMENT LETTER. Upon exercise or conversion of this Warrant in
accordance with the provisions hereof, the Holder shall either (i) execute and
deliver to the Company an investment letter in the form attached to the Notice
of Exercise on Exhibit A, or (ii) deliver to the Company an opinion of counsel
for the Holder reasonably satisfactory to the Company, stating that such
exercise or conversion is exempt from the registration and prospectus delivery
requirements of the Securities Act of 1933, as amended (the "SECURITIES ACT").

         7.    RESTRICTIONS ON TRANSFER. Certificates representing any of the
Common Stock acquired pursuant to the provisions of this Warrant shall have
endorsed thereon legends substantially in the following form, as appropriate.

               (a)   Unless such shares of Common Stock are received in a
transaction registered under the Securities Act and qualified (if necessary)
under applicable state securities laws:

         "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
         INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
         1933. SUCH SHARES MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH
         REGISTRATION UNLESS THE COMPANY RECEIVES AN OPINION OF COUNSEL
         REASONABLY ACCEPTABLE TO IT STATING

                                      -3-
<PAGE>

         THAT SUCH SALE OR TRANSFER IS EXEMPT FROM THE REGISTRATION AND
         PROSPECTUS DELIVERY REQUIREMENTS OF SAID ACT."

               (b)   Any legend required to be placed thereon by any applicable
state securities laws.

         8.    COMPLIANCE WITH ACT. The Holder, by acceptance hereof, agrees
that this Warrant and the Common Stock to be issued upon the exercise or
conversion hereof are being acquired solely for its own account and not as a
nominee for any other party and not with a view toward the resale or
distribution thereof and that it will not offer, sell or otherwise dispose of
this Warrant or any of the Common Stock to be issued upon the exercise or
conversion hereof except in accordance herewith and under circumstances which
will not result in a violation of the Securities Act or of applicable state
securities laws.

         9.    MISCELLANEOUS.

               (a)   The terms of this Warrant shall be binding upon and shall
inure to the benefit of any successors or assigns of the Company and of the
holder or holders hereof and of the Common Stock issued or issuable upon the
exercise hereof.

               (b)   No holder of this Warrant, as such, shall be entitled to
vote or receive dividends or be deemed to be a stockholder of the Company for
any purpose, nor shall anything contained in this Warrant be construed to confer
upon the holder of this Warrant, as such, any rights of a stockholder of the
Company or any right to vote, give or withhold consent to any corporate action,
receive notice of meetings, receive dividends or subscription rights, or
otherwise.

               (c)   Receipt of this Warrant by the holder hereof shall
constitute acceptance of and agreement to the foregoing terms and conditions.

               (d)   The Company will not, by amendment of its Restated
Certificate of Incorporation or through any other means, avoid or seek to avoid
the observance or performance of any of the terms of this Warrant, but will at
all times in good faith assist in the carrying out of all such terms and in the
taking of all such action as may be necessary or appropriate in order to protect
the rights of the holder of this Warrant against impairment.

               (e)   Upon receipt of evidence reasonably satisfactory to the
Company of the loss, theft, destruction or mutilation of this Warrant and, in
the case of any such loss, theft or distribution, upon delivery of an indemnity
agreement reasonably satisfactory in form and amount to the Company or, in the
case of any such mutilation, upon surrender and cancellation of such Warrant,
the Company at its expense will execute and deliver, in lieu thereof, a new
Warrant of like date and tenor.

               (f)   This Warrant shall be nontransferable, other than pursuant
to (i) a transfer not involving a change in beneficial ownership, (ii) a
distribution without consideration of the Warrant by the Holder to any of its
partners, or retired partners, or to the estate of any of its partners or
retired partners, or if the Holder is a limited liability company, to any of its
members,

                                      -4-
<PAGE>

former members, or to the estate of any of its members or former members, and
(iii) any transfer by any Holder to (A) any individual or entity controlled by,
controlling, or under common control with, such Holder or (B) any individual or
entity with respect to which such Holder (or any person controlled by,
controlling, or under common control with, such Holder) has the power to direct
investment decisions.

               (g)   This Warrant or any provision of this Warrant may be
amended, waived, discharged or terminated by a statement in writing signed by
the either (i) the Company and the holders of warrants representing at least
fifty percent (50%) of the Common Stock issuable upon exercise of all then
outstanding Warrants issued pursuant to the Consulting Agreement, or (ii) the
party against which enforcement of the amendment, waiver, discharge or
termination is sought. A written instrument signed as provided in clause (i)
above shall be effective as to all then outstanding Warrants issued under the
Warrant Agreement.

               (h)   This Warrant shall be governed by the laws of the State of
Delaware.



                            [SIGNATURE PAGE FOLLOWS]



                                      -5-
<PAGE>



         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer.


Dated: October 4, 1999

                                           SUPERGEN, INC.



                                               /s/ Joseph Rubinfeld
                                           ------------------------------------
                                           Dr. Joseph Rubinfeld
                                           President and Chief Executive Officer




                                      -6-
<PAGE>


                                    EXHIBIT A

                               NOTICE OF EXERCISE


TO:      SuperGen, Inc.

         1.    The undersigned hereby elects to purchase ___________ shares of
the Common Stock of SUPERGEN, INC. pursuant to the terms of the attached
Warrant, and tenders herewith payment of the purchase price of such shares in
full, together with all applicable transfer taxes, if any.

         2.    Please issue a certificate or certificates representing said
shares of Common Stock in the name of the undersigned or in such other name as
is specified below:



                  -------------------------------------
                                 (Name)

                  -------------------------------------

                  -------------------------------------
                               (Address)

         3.    The undersigned represents that the aforesaid shares of Common
Stock are being acquired for the account of the undersigned for investment and
not with a view to, or for resale in connection with, the distribution thereof
and that the undersigned has no present intention of distributing or reselling
such shares. In support thereof, the undersigned has executed the Investment
Representation Statement attached hereto as Exhibit A.

                                            Signature of Holder


                                            ------------------------------------

                                            By:
                                               ---------------------------------

                                            Title:
                                                  ------------------------------

                                            Date:
                                                 -------------------------------



                                      -7-
<PAGE>



                         EXHIBIT A TO NOTICE OF EXERCISE

                                 SUPERGEN, INC.

                                WARRANT EXERCISE

                       INVESTMENT REPRESENTATION STATEMENT

PURCHASER                  :

COMPANY                    :   SuperGen, Inc.

SECURITY                   :   Common Stock

NUMBER OF SHARES           :

DATE                       :   ________________, _____

         In connection with the purchase of the above-listed Securities, I, the
Purchaser, represent to the Company the following:

         (a)   I am an accredited investor within the meaning of Rule 501 under
the Securities Act of 1933, as amended (the "Securities Act") and have such
knowledge and experience in financial and business matters that I am capable of
evaluating the merits and risks of the purchase of the Securities.

         (b)   I am aware of the Company's business affairs and financial
condition, and have acquired sufficient information about the Company to reach
an informed and knowledgeable decision to acquire the Securities. In making my
decision to the acquire the Securities, I am not relying on representations of
any officer, director, stockholder or agent of the Company. I am purchasing
these Securities for my own account for investment purposes only and not with a
view to, or for the resale in connection with, any "distribution" thereof for
purposes of the Securities Act.

         (c)   I understand that the Securities have not been registered under
the Securities Act in reliance upon a specific exemption therefrom, and that
reliance by the Company on such an exemption is predicated in part on the
representations set forth in this letter.

         (d)   I further understand that the Securities must be held
indefinitely unless subsequently registered under the Securities Act or unless
an exemption from registration is otherwise available. Moreover, I understand
that the Company is under no obligation to register the Securities. In addition,
I understand that the certificate evidencing the Securities will be imprinted
with a legend which prohibits the transfer of the Securities unless they are
registered or such registration is not required in the opinion of counsel for
the Purchaser satisfactory to the Company or unless the Company receives a
no-action letter from the Securities and Exchange Commission.

         (e)   I am familiar with the provisions of Rule 144, promulgated under
the Securities Act, which, in substance, permits limited public resale of
"restricted securities" acquired, directly

                                      -8-
<PAGE>

or indirectly, from the issuer thereof (or from an affiliate of such issuer), in
a non-public offering subject to the satisfaction of certain conditions,
including, among other things: (1) the resale occurring not less than one year
after the later of the date the securities were sold by the Company or the date
they were sold by an affiliate of the Company, within the meaning of Rule 144;
and, in the case of an affiliate, or of a non-affiliate who has held the
securities less than two years, (2) the availability of certain public
information about the Company, (3) the sale being made through a broker in an
unsolicited "broker's transaction" or in transactions directly with a market
maker (as said term is defined under the Securities Exchange Act of 1934), and
(4) the amount of securities being sold during any three month period not
exceeding the specified limitations stated therein, if applicable.

         (f)   I further understand that at the time I wish to sell the
Securities there may be no public market upon which to make such a sale, and
that, even if such a public market exists, the Company may not be satisfying the
current public information requirements of Rule 144, and that, in such event, I
would be precluded from selling the Securities under Rule 144 even if the
one-year minimum holding period had been satisfied.

         (g)   I further understand that in the event all of the applicable
requirements of Rule 144 are not satisfied, registration under the Securities
Act, compliance with Regulation A, or some other registration exemption will be
required; and that, notwithstanding the fact that Rule 144 is not exclusive, the
Staff of the SEC has expressed its opinion that persons proposing to sell
private placement securities other than in a registered offering and otherwise
than pursuant to Rule 144 will have a substantial burden of proof in
establishing that an exemption from registration is available for such offers or
sales, and that such persons and their respective brokers who participate in
such transactions do so at their own risk.

                                              Signature of Purchaser


                                              ----------------------------------

                                              By:
                                                 -------------------------------

                                              Title:
                                                    ----------------------------

                                              Date:
                                                   -----------------------------
                                      -9-