<PAGE>

                                SUPERGEN, INC.

                       1996 DIRECTORS' STOCK OPTION PLAN
                    (AS AMENDED EFFECTIVE FEBRUARY 3, 1997)
                                       

    1.   PURPOSES OF THE PLAN.  The purposes of this 1996 Directors' Stock
Option Plan are to attract and retain the best available personnel for service
as Outside Directors (as defined herein) of the Company, to provide additional
incentive to the Outside Directors of the Company to serve as Directors, and to
encourage their continued service on the Board.

         All options granted hereunder shall be nonstatutory stock options.

    2.   DEFINITIONS.  As used herein, the following definitions shall apply:

         (a)  "BOARD" means the Board of Directors of the Company.

         (b)  "CODE" means the Internal Revenue Code of 1986, as amended.

         (c)  "COMMON STOCK" means the Common Stock of the Company.

         (d)  "COMPANY" means SuperGen, Inc., a California corporation.

         (e)  "DIRECTOR" means a member of the Board.

         (f)  "EMPLOYEE" means any person, including officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company.  The payment
of a Director's fee by the Company shall not be sufficient in and of itself to
constitute "employment" by the Company.

         (g)  "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

         (h)  "FAIR MARKET VALUE" means, as of any date, the value of Common
Stock determined as follows:

              (i)  If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the Nasdaq
National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its
Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
THE WALL STREET JOURNAL or such other source as the Administrator deems
reliable;


<PAGE>

              (ii) If the Common Stock is regularly quoted by a recognized
securities dealer but selling prices are not reported, the Fair Market Value of
a Share of Common Stock shall be the mean between the high bid and low asked
prices for the Common Stock on the date of determination, as reported in THE
WALL STREET JOURNAL or such other source as the Board deems reliable, or;

              (iii) In the absence of an established market for the Common
Stock, the Fair Market Value thereof shall be determined in good faith by the
Board.

         (i)  "INSIDE DIRECTOR" means a Director who is an Employee.

         (j)  "OPTION" means a nonstatutory stock option granted pursuant to
the Plan.

         (k)  "OPTIONED STOCK" means the Common Stock subject to an Option.

         (l)  "OPTIONEE"  means a Director who holds an Option.

         (m)  "OUTSIDE DIRECTOR" means a Director who is not an Employee;
provided, however, that no Director who is a representative of or affiliated
with Israel Chemicals, Ltd. shall be eligible to participate and receive options
under the Plan; provided, further, that neither J. Gregory Swendsen nor David M.
Fineman shall be eligible to participate and receive options under the Plan. 

         (n)  "PARENT" means a "parent corporation," whether now or hereafter
existing, as defined in Section 424(e) of the Code.

         (o)  "PLAN" means this 1996 Directors' Stock Option Plan.

         (p)  "SHARE" means a share of the Common Stock, as adjusted in
accordance with Section 10 of the Plan.

         (q)  "SUBSIDIARY" means a "subsidiary corporation," whether now or
hereafter existing, as defined in Section 424(f) of the Internal Revenue Code of
1986.

    3.   STOCK SUBJECT TO THE PLAN.  Subject to the provisions of Section 10 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 250,000 Shares of Common Stock (the "Pool").  The Shares may
be authorized, but unissued, or reacquired Common Stock.  

         If an Option expires or becomes unexercisable without having been
exercised in full, the unpurchased Shares which were subject thereto shall
become available for future grant or sale under the Plan (unless the Plan has
terminated).  Shares that have actually been issued under the Plan shall not be
returned to the Plan and shall not become available for future distribution
under the Plan.


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<PAGE>

    4.   ADMINISTRATION AND GRANTS OF OPTIONS UNDER THE PLAN.

         (a)  PROCEDURE FOR GRANTS.  All grants of Options to Outside Directors
under this Plan shall be automatic and nondiscretionary and shall be made
strictly in accordance with the following provisions:

              (i)  No person shall have any discretion to select which Outside
Directors shall be granted Options or to determine the number of Shares to be
covered by Options granted to Outside Directors.

              (ii) Each Outside Director shall be automatically granted an
Option to purchase 50,000 Shares on the date on which the later of the following
events occurs:  (A) the effective date of this Plan, as determined in accordance
with Section 6 hereof, or (B) the date on which such person first becomes an
Outside Director, whether through election by the shareholders of the Company or
appointment by the Board to fill a vacancy; provided, however, that an Inside
Director who ceases to be an Inside Director but who remains a Director shall
not receive a Option. 

              (iii) Notwithstanding the provisions of subsection (ii) hereof, 
any exercise of an Option granted before the Company has obtained shareholder 
approval of the Plan in accordance with Section 16 hereof shall be 
conditioned upon obtaining such shareholder approval of the Plan in 
accordance with Section 16 hereof.

              (iv) The terms of each Option granted hereunder shall be as
follows:

                   (A)  the term of the Option shall be ten (10) years.

                   (B)  the Option shall be exercisable only while the Outside
Director remains a Director of the Company, except as set forth in Sections 8
and 10 hereof.

                   (C)  the exercise price per Share shall be 100% of the Fair
Market Value per Share on the date of grant of the Option.  In the event that
the date of grant of the Option is not a trading day, the exercise price per
Share shall be the Fair Market Value on the next trading day immediately
following the date of grant of the Option.

                   (D)  subject to Section 10 hereof, the Option shall become
exercisable as to 20% of the Shares subject to the Option on the date of its
grant and 20% of the Shares subject to the Option on each anniversary of its
date of grant, provided that the Optionee continues to serve as a Director on
such dates.

              (v)  In the event that any Option granted under the Plan would
cause the number of Shares subject to outstanding Options plus the number of
Shares previously purchased under Options to exceed the Pool, then the remaining
Shares available for Option grant shall be granted under Options to the Outside
Directors on a pro rata basis.  No further grants shall be made 


                                  -3-
<PAGE>

until such time, if any, as additional Shares become available for grant 
under the Plan through action of the Board or the shareholders to increase 
the number of Shares which may be issued under the Plan or through 
cancellation or expiration of Options previously granted hereunder.

    5.   ELIGIBILITY.  Options may be granted only to Outside Directors. All
Options shall be automatically granted in accordance with the terms set forth in
Section 4 hereof. 

         The Plan shall not confer upon any Optionee any right with respect to
continuation of service as a Director or nomination to serve as a Director, nor
shall it interfere in any way with any rights which the Director or the Company
may have to terminate the Director's relationship with the Company at any time.

    6.   TERM OF PLAN.  The Plan shall become effective upon the earlier to
occur of its adoption by the Board or its approval by the shareholders of the
Company as described in Section 16 of the Plan.  It shall continue in effect for
a term of ten (10) years unless sooner terminated under Section 11 of the Plan.

    7.   FORM OF CONSIDERATION.  The consideration to be paid for the Shares to
be issued upon exercise of an Option, including the method of payment, shall
consist of (i) cash, (ii) check, (iii) other shares which (x) in the case of
Shares acquired upon exercise of an Option, have been owned by the Optionee for
more than six (6) months on the date of surrender, and (y) have a Fair Market
Value on the date of surrender equal to the aggregate exercise price of the
Shares as to which said Option shall be exercised, (iv) delivery of a properly
executed exercise notice together with such other documentation as the Company
and the broker, if applicable, shall require to effect an exercise of the Option
and delivery to the Company of the sale or loan proceeds required to pay the
exercise price, or (v) any combination of the foregoing methods of payment.

    8.   EXERCISE OF OPTION.

         (a)  PROCEDURE FOR EXERCISE; RIGHTS AS A SHAREHOLDER. Any Option
granted hereunder shall be exercisable at such times as are set forth in
Section 4 hereof; provided, however, that no Options shall be exercisable until
shareholder approval of the Plan in accordance with Section 16 hereof has been
obtained.

         An Option may not be exercised for a fraction of a Share.

         An Option shall be deemed to be exercised when written notice of such
exercise has been given to the Company in accordance with the terms of the
Option by the person entitled to exercise the Option and full payment for the
Shares with respect to which the Option is exercised has been received by the
Company.  Full payment may consist of any consideration and method of payment
allowable under Section 7 of the Plan.  Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the stock certificate evidencing such Shares, no right
to vote or receive dividends or any other rights as a 


                                  -4-
<PAGE>

shareholder shall exist with respect to the Optioned Stock, notwithstanding 
the exercise of the Option. A share certificate for the number of Shares so 
acquired shall be issued to the Optionee as soon as practicable after 
exercise of the Option. No adjustment shall be made for a dividend or other 
right for which the record date is prior to the date the stock certificate is 
issued, except as provided in Section 10 of the Plan.

         Exercise of an Option in any manner shall result in a decrease in the
number of Shares which thereafter may be available, both for purposes of the
Plan and for sale under the Option, by the number of Shares as to which the
Option is exercised.

         (b)  TERMINATION OF CONTINUOUS STATUS AS A DIRECTOR.  Subject to
Section 10 hereof, in the event an Optionee's status as a Director terminates
(other than upon the Optionee's death or total and permanent disability (as
defined in Section 22(e)(3) of the Code)), the Optionee may exercise his or her
Option, but only within three (3) months following the date of such termination,
and only to the extent that the Optionee was entitled to exercise it on the date
of such termination (but in no event later than the expiration of its ten (10)
year term).  To the extent that the Optionee was not entitled to exercise an
Option on the date of such termination, and to the extent that the Optionee does
not exercise such Option (to the extent otherwise so entitled) within the time
specified herein, the Option shall terminate.

         (c)  DISABILITY OF OPTIONEE.  In the event Optionee's status as a
Director terminates as a result of total and permanent disability (as defined in
Section 22(e)(3) of the Code), the Optionee may exercise his or her Option, but
only within twelve (12) months following the date of such termination, and only
to the extent that the Optionee was entitled to exercise it on the date of such
termination (but in no event later than the expiration of its ten (10) year
term).  To the extent that the Optionee was not entitled to exercise an Option
on the date of termination, or if he or she does not exercise such Option (to
the extent otherwise so entitled) within the time specified herein, the Option
shall terminate.

         (d)  DEATH OF OPTIONEE.  In the event of an Optionee's death, the
Optionee's estate or a person who acquired the right to exercise the Option by
bequest or inheritance may exercise the Option, but only within twelve (12)
months following the date of death, and only to the extent that the Optionee was
entitled to exercise it on the date of death (but in no event later than the
expiration of its ten (10) year term).  To the extent that the Optionee was not
entitled to exercise an Option on the date of death, and to the extent that the
Optionee's estate or a person who acquired the right to exercise such Option
does not exercise such Option (to the extent otherwise so entitled) within the
time specified herein, the Option shall terminate.

    9.   NON-TRANSFERABILITY OF OPTIONS.  Unless determined otherwise by the
Board, an  Option may not be sold, pledged, assigned, hypothecated, transferred,
or disposed of in any manner other than by will or by the laws of descent or
distribution and may be exercised, during the lifetime of the Optionee, only by
the Optionee.  If the Administrator makes an Option transferable, such Option
shall contain such additional terms and conditions as the Administrator deems
appropriate.


                                  -5-
<PAGE>

    10.  ADJUSTMENTS UPON CHANGES IN CAPITALIZATION, DISSOLUTION, MERGER OR
         ASSET SALE. 

         (a)  CHANGES IN CAPITALIZATION.  Subject to any required action by the
shareholders of the Company, the number of Shares covered by each outstanding
Option, the number of Shares which have been authorized for issuance under the
Plan but as to which no Options have yet been granted or which have been
returned to the Plan upon cancellation or expiration of an Option, as well as
the price per Share covered by each such outstanding Option, and the number of
Shares issuable pursuant to the automatic grant provisions of Section 4 hereof
shall be proportionately adjusted for any increase or decrease in the number of
issued Shares resulting from a stock split, reverse stock split, stock dividend,
combination or reclassification of the Common Stock, or any other increase or
decrease in the number of issued Shares effected without receipt of
consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration."  Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of Shares
subject to an Option.

         (b)  DISSOLUTION OR LIQUIDATION.  In the event of the proposed
dissolution or liquidation of the Company, to the extent that an Option has not
been previously exercised, it shall terminate immediately prior to the
consummation of such proposed action.

         (c)  MERGER OR ASSET SALE.  In the event of a merger of the Company
with or into another corporation or the sale of substantially all of the assets
of the Company, outstanding Options may be assumed or equivalent options may be
substituted by the successor corporation or a Parent or Subsidiary thereof (the
"Successor Corporation").  If an Option is assumed or substituted for, the
Option or equivalent option shall continue to be exercisable as provided in
Section 4 hereof for so long as the Optionee serves as a Director or a director
of the Successor Corporation.  Following such assumption or substitution, if the
Optionee's status as a Director or director of the Successor Corporation, as
applicable, is terminated other than upon a voluntary resignation by the
Optionee, the Option or option shall become fully vested and exercisable,
including as to Shares for which it would not otherwise be vested or
exercisable.  Thereafter, the Option or option shall remain exercisable in
accordance with Sections 8(c) through (e) above.

    If the Successor Corporation does not assume an outstanding Option or
substitute for it an equivalent option, the Option shall become fully vested and
exercisable, including as to Shares for which it would not otherwise be vested
or exercisable.  In such event the Board shall notify the Optionee that the
Option shall be fully vested and exercisable for a period of thirty (30) days
from the date of such notice, and upon the expiration of such period the Option
shall terminate.  

    For the purposes of this Section 10(c), an Option shall be considered
assumed if, following the merger or sale of assets, the Option confers the right
to purchase or receive, for each Share of Optioned Stock subject to the Option
immediately prior to the merger or sale of assets, the consideration (whether
stock, cash, or other securities or property) received in the merger or sale of


                                  -6-
<PAGE>

assets by holders of Common Stock for each Share held on the effective date of
the transaction (and if holders were offered a choice of consideration, the type
of consideration chosen by the holders of a majority of the outstanding Shares).

    11.  AMENDMENT AND TERMINATION OF THE PLAN.

         (a)  AMENDMENT AND TERMINATION.  Except as set forth in Section 4, the
Board may at any time amend, alter, suspend, or discontinue the Plan, but no
amendment, alteration, suspension, or discontinuation shall be made which would
impair the rights of any Optionee under any grant theretofore made, without his
or her consent.  In addition, to the extent necessary and desirable to comply
with any applicable law or regulation, the Company shall obtain shareholder
approval of any Plan amendment in such a manner and to such a degree as
required.

         (b)  EFFECT OF AMENDMENT OR TERMINATION.  Any such amendment or
termination of the Plan shall not affect Options already granted and such
Options shall remain in full force and effect as if this Plan had not been
amended or terminated.

    12.  TIME OF GRANTING OPTIONS.  The date of grant of an Option shall, for
all purposes, be the date determined in accordance with Section 4 hereof.  

    13.  CONDITIONS UPON ISSUANCE OF SHARES.  Shares shall not be issued
pursuant to the exercise of an Option unless the exercise of such Option and the
issuance and delivery of such Shares pursuant thereto shall comply with all
relevant provisions of law, including, without limitation, the Securities Act of
1933, as amended, the Exchange Act, the rules and regulations promulgated
thereunder, state securities laws, and the requirements of any stock exchange
upon which the Shares may then be listed, and shall be further subject to the
approval of counsel for the Company with respect to such compliance.

         As a condition to the exercise of an Option, the Company may require
the person exercising such Option to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares, if, in the
opinion of counsel for the Company, such a representation is required by any of
the aforementioned relevant provisions of law.

         Inability of the Company to obtain authority from any regulatory body
having jurisdiction, which authority is deemed by the Company's counsel to be
necessary to the lawful issuance and sale of any Shares hereunder, shall relieve
the Company of any liability in respect of the failure to issue or sell such
Shares as to which such requisite authority shall not have been obtained.

    14.  RESERVATION OF SHARES.  The Company, during the term of this Plan,
will at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.


                                  -7-
<PAGE>

    15.  OPTION AGREEMENT.  Options shall be evidenced by written option
agreements in such form as the Board shall approve.

    16.  SHAREHOLDER APPROVAL.  Continuance of the Plan shall be subject to
approval by the shareholders of the Company at or prior to the first annual
meeting of shareholders held subsequent to the granting of an Option hereunder. 
Such shareholder approval shall be obtained in the degree and manner required
under applicable state and federal law.


                                  -8-

<PAGE>

                                SUPERGEN, INC. 

                           DIRECTOR OPTION AGREEMENT



    SuperGen, Inc., a California corporation (the "Company"), has granted to
______________________________________ (the "Optionee"), an option to purchase a
total of [ __________________ (_________)] shares of the Company's Common Stock
(the "Optioned Stock"), at the price determined as provided herein, and in all
respects subject to the terms, definitions and provisions of the Company's 1996
Directors' Stock Option Plan (the "Plan") adopted by the Company which is
incorporated herein by reference.  The terms defined in the Plan shall have the
same defined meanings herein.

    1.   NATURE OF THE OPTION.  This Option is a nonstatutory option and is not
intended to qualify for any special tax benefits to the Optionee.

    2.   EXERCISE PRICE.  The exercise price is $_______ for each share of
Common Stock.

    3.   EXERCISE OF OPTION.  This Option shall be exercisable during its term
in accordance with the provisions of Section 8 of the Plan as follows:

         (i)  RIGHT TO EXERCISE.

              (a)  This Option shall become exercisable in installments
cumulatively with respect to twenty percent (20%) of the Optioned Stock on the
date of grant, and as to an additional twenty percent (20%) of the Optioned
Stock on each anniversary of the date of grant, so that one hundred percent
(100%) of the Optioned Stock shall be exercisable four years after the date of
grant; provided, however, that in no event shall any Option be exercisable prior
to the date the stockholders of the Company approve the Plan.

              (b)  This Option may not be exercised for a fraction of a share.

              (c)  In the event of Optionee's death, disability or other
termination of service as a Director, the exercisability of the Option is
governed by Section 8 of the Plan.

       (ii)   METHOD OF EXERCISE.  This Option shall be exercisable by written
notice which shall state the election to exercise the Option and the number of
Shares in respect of which the Option is being exercised.  Such written notice,
in the form attached hereto as Exhibit A, shall be signed by the Optionee and
shall be delivered in person or by certified mail to the Secretary of the
Company.  The written notice shall be accompanied by payment of the exercise
price.


<PAGE>

    4.   METHOD OF PAYMENT.  Payment of the exercise price shall be by any of
the following, or a combination thereof, at the election of the Optionee:

         (i)  cash;

        (ii)  check; or
 
       (iii)  surrender of other shares which (x) in the case of Shares
acquired upon exercise of an Option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (y) have a Fair Market Value
on the date of surrender equal to the aggregate exercise price of the Shares as
to which said Option shall be exercised; or

        (iv)  delivery of a properly executed exercise notice together with
such other documentation as the Company and the broker, if applicable, shall
require to effect an exercise of the Option and delivery to the Company of the
sale or loan proceeds required to pay the exercise price.

    5.   RESTRICTIONS ON EXERCISE.  This Option may not be exercised if the
issuance of such Shares upon such exercise or the method of payment of
consideration for such shares would constitute a violation of any applicable
federal or state securities or other law or regulations, or if such issuance
would not comply with the requirements of any stock exchange upon which the
Shares may then be listed.  As a condition to the exercise of this Option, the
Company may require Optionee to make any representation and warranty to the
Company as may be required by any applicable law or regulation.

    6.   NON-TRANSFERABILITY OF OPTION.  This Option may not be transferred in
any manner otherwise than by will or by the laws of descent or distribution and
may be exercised during the lifetime of Optionee only by the Optionee.  The
terms of this Option shall be binding upon the executors, administrators, heirs,
successors and assigns of the Optionee.

    7.   TERM OF OPTION.  This Option may not be exercised more than ten (10)
years from the date of grant of this Option, and may be exercised during such
period only in accordance with the Plan and the terms of this Option.

    8.   TAXATION UPON EXERCISE OF OPTION.  Optionee understands that, upon
exercise of this Option, he or she will recognize income for tax purposes in an
amount equal to the excess of the then Fair Market Value of the Shares purchased
over the exercise price paid for such Shares.  Since the Optionee is subject to
Section 16(b) of the Securities Exchange Act of 1934, as amended, under certain
limited circumstances the measurement and timing of such income (and the
commencement of any capital gain holding period) may be deferred, and the
Optionee is advised to contact a tax advisor concerning the application of
Section 83 in general and the availability a Section 83(b) election in
particular in connection with the exercise of the Option.  Upon a resale of such
Shares by the Optionee, any difference between the sale price and the Fair
Market Value of the Shares on the date 


                                  -2-
<PAGE>

of exercise of the Option, to the extent not included in income as described 
above, will be treated as capital gain or loss.

DATE OF GRANT:  ___________________

                                       SUPERGEN, INC., 
                                       a California corporation



                                       By: __________________________________



    Optionee acknowledges receipt of a copy of the Plan, a copy of which is
attached hereto, and represents that he or she is familiar with the terms and
provisions thereof, and hereby accepts this Option subject to all of the terms
and provisions thereof.  Optionee hereby agrees to accept as binding, conclusive
and final all decisions or interpretations of the Board upon any questions
arising under the Plan.


    Dated: _________________

                                       _______________________________________
                                       Optionee



                                  -3-
<PAGE>

                                   EXHIBIT A

                        DIRECTOR OPTION EXERCISE NOTICE



SuperGen, Inc.
Two Annabel Lane, Suite 220
San Ramon, CA  94583

Attention:  Corporate Secretary


    1.   EXERCISE OF OPTION.  The undersigned ("Optionee") hereby elects to
exercise Optionee's option to purchase ______ shares of the Common Stock (the
"Shares") of SuperGen, Inc. (the "Company") under and pursuant to the Company's
1996 Directors' Stock Option Plan and the Director Option Agreement dated
_______________ (the "Agreement").

    2.   REPRESENTATIONS OF OPTIONEE.  Optionee acknowledges that Optionee has
received, read and understood the Agreement.

    3.   FEDERAL RESTRICTIONS ON TRANSFER.  Optionee understands that the
Shares must be held indefinitely unless they are registered under the Securities
Act of 1933, as amended (the "1933 Act"), or unless an exemption from such
registration is available, and that the certificate(s) representing the Shares
may bear a legend to that effect.  Optionee understands that the Company is
under no obligation to register the Shares and that an exemption may not be
available or may not permit Optionee to transfer Shares in the amounts or at the
times proposed by Optionee.  

    4.   TAX CONSEQUENCES.  Optionee understands that Optionee may suffer
adverse tax consequences as a result of Optionee's purchase or disposition of
the Shares.  Optionee represents that Optionee has consulted with any tax
consultant(s) Optionee deems advisable in connection with the purchase or
disposition of the Shares and that Optionee is not relying on the Company for
any tax advice.

    5.   DELIVERY OF PAYMENT.  Optionee herewith delivers to the Company the
aggregate purchase price for the Shares that Optionee has elected to purchase
and has made provision for the payment of any federal or state withholding taxes
required to be paid or withheld by the Company.

    6.   ENTIRE AGREEMENT.  The Agreement is incorporated herein by reference. 
This Exercise Notice and the Agreement constitute the entire agreement of the
parties and supersede in their entirety all prior undertakings and agreements of
the Company and Optionee with respect to the 


<PAGE>

subject matter hereof.  This Exercise Notice and the Agreement are governed 
by California law except for that body of law pertaining to conflict of laws.

Submitted by:                     Accepted by:

OPTIONEE:                         SUPERGEN, INC.

________________________          By: __________________________
         

                                  Its:__________________________

Address:




Dated: _________________          Dated: ________________



                                  -2-