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                                SUPERGEN, INC.
                            1993 STOCK OPTION PLAN

               (AMENDED AND RESTATED EFFECTIVE FEBRUARY 3, 1997)
                                       


    1.   PURPOSES OF THE PLAN.  The purposes of this Stock Plan are:

         -    to attract and retain the best available personnel for positions
              of substantial responsibility, 

         -    to provide additional incentive to Employees, Directors and
              Consultants, and 

         -    to promote the success of the Company's business.  

    Options granted under the Plan may be Incentive Stock Options or
Nonstatutory Stock Options, as determined by the Administrator at the time of
grant.  Stock Purchase Rights may also be granted under the Plan.

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

         (a)  "ADMINISTRATOR" means the Board or any of its Committees as shall
be administering the Plan, in accordance with Section 4 of the Plan.

         (b)  "APPLICABLE LAWS" means the requirements relating to the
administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of
any foreign country or jurisdiction where Options or Stock Purchase Rights are,
or will be, granted under the Plan.

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

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

         (e)  "COMMITTEE"  means a Committee appointed by the Board in
accordance with Section 4 of the Plan.

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

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

         (h)  "CONSULTANT" means any person, including an advisor, engaged by
the Company or a Parent or Subsidiary to render services and who is compensated
for such services.


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         (i)  "CONTINUOUS STATUS AS A DIRECTOR OR CONSULTANT" means that the 
employment relationship, directorship or consulting relationship with the 
Company, any Parent, or Subsidiary, is not interrupted or terminated. 
Continuous Status as a Director or Consultant shall not be considered 
interrupted in the case of (i) any leave of absence approved by the Company 
or (ii) transfers between locations of the Company or between the Company, 
its Parent, any Subsidiary, or any successor.  A leave of absence approved by 
the Company shall include sick leave, military leave, or any other personal 
leave approved by an authorized representative of the Company.  For purposes 
of Incentive Stock Options, no such leave may exceed ninety days, unless 
reemployment upon expiration of such leave is guaranteed by statute or 
contract. If reemployment upon expiration of a leave of absence approved by 
the Company is not so guaranteed, on the 181st day of such leave any 
Incentive Stock Option held by the Optionee shall cease to be treated as an 
Incentive Stock Option and shall be treated for tax purposes as a 
Nonstatutory Stock Option.

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

         (k)  "DISABILITY" means total and permanent disability as defined in
Section 22(e)(3) of the Code.

         (l)  "EMPLOYEE" means any person, including Officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company.  Neither
service as a Director nor payment of a director's fee by the Company shall be
sufficient to constitute "employment" by the Company.

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

         (n)  "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;

              (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 last market trading day prior to the day of
determination, as reported in THE WALL STREET JOURNAL or such other source as
the Administrator deems reliable;

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

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         (o)  "INCENTIVE STOCK OPTION" means an Option intended to qualify as
an incentive stock option within the meaning of Section 422 of the Code and the
regulations promulgated thereunder.

         (p)  "NONSTATUTORY STOCK OPTION" means an Option not intended to
qualify as an Incentive Stock Option.

         (q)  "NOTICE OF GRANT" means a written notice evidencing certain terms
and conditions of an individual Option or Stock Purchase Right grant.  The
Notice of Grant is part of the Option Agreement.

         (r)  "OFFICER" means a person who is an officer of the Company within
the meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

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

         (t)  "OPTION AGREEMENT" means a written agreement between the Company
and an Optionee evidencing the terms and conditions of an individual Option
grant.  The Option Agreement is subject to the terms and conditions of the Plan.

         (u)  "OPTION EXCHANGE PROGRAM" means a program whereby outstanding
options are surrendered in exchange for options with a lower exercise price.

         (v)  "OPTIONED STOCK" means the Common Stock subject to an Option or
Stock Purchase Right.

         (w)  "OPTIONEE" means an Employee, Director or Consultant who holds an
outstanding Option or Stock Purchase Right.

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

         (y)  "PLAN" means this SuperGen, Inc. 1993 Stock Plan.

         (z)  "RESTRICTED STOCK" means shares of Common Stock acquired pursuant
to a grant of Stock Purchase Rights under Section 11 below.

         (aa) "RESTRICTED STOCK PURCHASE AGREEMENT" means a written agreement
between the Company and the Optionee evidencing the terms and restrictions
applying to stock purchased under a Stock Purchase Right.  The Restricted Stock
Purchase Agreement is subject to the terms and conditions of the Plan and the
Notice of Grant.

         (bb) "RULE 16B-3" means Rule 16b-3 of the Exchange Act or any
successor to Rule 16b-3, as in effect when discretion is being exercised with
respect to the Plan.


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         (cc) "SECTION 16(b)" means Section 16(b) of the Securities Exchange
Act of 1934, as amended.

         (dd) "SHARE" means a share of the Common Stock, as adjusted in
accordance with Section 13 of the Plan.

         (ee) "STOCK PURCHASE RIGHT" means the right to purchase Common Stock
pursuant to Section 11 of the Plan, as evidenced by a Notice of Grant.

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

    3.   STOCK SUBJECT TO THE PLAN.  Subject to the provisions of Section 13 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 2,500,000 Shares.  The Shares may be authorized, but unissued,
or reacquired Common Stock.  

         If an Option or Stock Purchase Right expires or becomes unexercisable
without having been exercised in full, or is surrendered pursuant to an Option
Exchange Program, the unpurchased Shares which were subject thereto shall become
available for future grant or sale under the Plan (unless the Plan has
terminated); PROVIDED, however, that Shares that have actually been issued under
the Plan, whether upon exercise of an Option or Right, shall not be returned to
the Plan and shall not become available for future distribution under the Plan,
except that if Shares of Restricted Stock are repurchased by the Company at
their original purchase price, such Shares shall become available for future
grant under the Plan.  For purposes of the preceding sentence, voting rights
shall not be considered a benefit of Share ownership.

    4.   ADMINISTRATION OF THE PLAN.

         (a)  PROCEDURE.

              (i)   MULTIPLE ADMINISTRATIVE BODIES.  The Plan may be 
administered by different Committees with respect to different groups of 
Service Providers.

              (ii)  SECTION 162(M). To the extent that the Administrator 
determines it to be desirable to qualify Options granted hereunder as 
"performance-based compensation" within the meaning of Section 162(m) of the 
Code, the Plan shall be administered by a Committee of two or more "outside 
directors" within the meaning of Section 162(m) of the Code.

              (iii) RULE 16B-3.  To the extent desirable to qualify 
transactions hereunder as exempt under Rule 16b-3, the transactions 
contemplated hereunder shall be structured to satisfy the requirements for 
exemption under Rule 16b-3.


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              (iv)  OTHER ADMINISTRATION.  Other than as provided above, the 
Plan shall be administered by (A) the Board or (B) a Committee, which 
committee shall be constituted to satisfy Applicable Laws. 

         (b)  POWERS OF THE ADMINISTRATOR.  Subject to the provisions of the
Plan, and in the case of a Committee, subject to the specific duties delegated
by the Board to such Committee, the Administrator shall have the authority, in
its discretion:

              (i)   to determine the Fair Market Value of the Common Stock, 
in accordance with Section 2(n) of the Plan;

              (ii)  to select the Employees, Directors and Consultants to 
whom Options and Stock Purchase Rights may be granted hereunder;

              (iii) to determine whether and to what extent Options and Stock 
Purchase Rights or any combination thereof, are granted hereunder;

              (iv)  to determine the number of shares of Common Stock to be 
covered by each Option and Stock Purchase Right granted hereunder;

              (v)   to approve forms of agreement for use under the Plan;

              (vi)  to determine the terms and conditions, not inconsistent 
with the terms of the Plan, of any award granted hereunder.  Such terms and 
conditions include, but are not limited to, the exercise price, the time or 
times when Options or Stock Purchase Rights may be exercised (which may be 
based on performance criteria), any vesting acceleration or waiver of 
forfeiture restrictions, and any restriction or limitation regarding any 
Option or Stock Purchase Right or the shares of Common Stock relating 
thereto, based in each case on such factors as the Administrator, in its sole 
discretion, shall determine;

              (vii) to reduce the exercise price of any Option or Stock 
Purchase Right to the then current Fair Market Value if the Fair Market Value 
of the Common Stock covered by such Option or Stock Purchase Right shall have 
declined since the date the Option or Stock Purchase Right was granted;

              (viii) to construe and interpret the terms of the Plan and
awards granted pursuant to the Plan;

              (ix)  to prescribe, amend and rescind rules and regulations 
relating to the Plan, including rules and regulations relating to sub-plans 
established for the purpose of qualifying for preferred tax treatment under 
foreign tax laws;


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              (x)    to modify or amend each Option or Stock Purchase Right 
(subject to Section 15(c) of the Plan), including the discretionary authority 
to extend the post-termination exercisability period of Options longer than 
is otherwise provided for in the Plan;

              (xi)   to authorize any person to execute on behalf of the 
Company any instrument required to effect the grant of an Option or Stock 
Purchase Right previously granted by the Administrator;

              (xii)  to institute an Option Exchange Program;

              (xiii) to allow Optionees to satisfy withholding tax 
obligations by electing to have the Company withhold from the Shares to be 
issued upon exercise of an Option or Stock Purchase Right that number of 
Shares having a Fair Market Value equal to the amount required to be 
withheld.  The Fair Market Value of the Shares to be withheld shall be 
determined on the date that the amount of tax to be withheld is to be 
determined.  All elections by an Optionee to have Shares withheld for this 
purpose shall be made in such form and under such conditions as the 
Administrator may deem necessary or advisable;

              (xiv)  to make all other determinations deemed necessary or 
advisable for administering the Plan.

         (c)  EFFECT OF ADMINISTRATOR'S DECISION.  The Administrator's
decisions, determinations and interpretations shall be final and binding on all
Optionees and any other holders of Options or Stock Purchase Rights.

    5.   ELIGIBILITY.  Nonstatutory Stock Options and Stock Purchase Rights may
be granted to Employees, Directors and Consultants.  Incentive Stock Options may
be granted only to Employees.  

    6.   LIMITATIONS.

         (a)  Each Option shall be designated in the written option agreement
as either an Incentive Stock Option or a Nonstatutory Stock Option.  However,
notwithstanding such designation, to the extent that the aggregate Fair Market
Value of the Shares with respect to which Incentive Stock Options are
exercisable for the first time by the Optionee during any calendar year (under
all plans of the Company and any Parent or Subsidiary) exceeds $100,000, such
Options shall be treated as Nonstatutory Stock Options.  For purposes of this
Section 6(a), Incentive Stock Options shall be taken into account in the order
in which they were granted.  The Fair Market Value of the Shares shall be
determined as of the time the Option with respect to such Shares is granted.

         (b)  Neither the Plan nor any Option or Stock Purchase Right shall
confer upon an Optionee any right with respect to continuing the Optionee's
employment relationship, directorship or consulting relationship with the
Company, nor shall they interfere in any way with the Optionee's right or the
Company's right to terminate such employment relationship, directorship or
consulting relationship at any time, with or without cause.


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         (c)  The following limitations shall apply to grants of Options and
Stock Purchase Rights to Employees, Directors and Consultants:

              (i)   No Employee, Director or Consultant shall be granted, in 
any fiscal year of the Company, Options and Stock Purchase Rights to purchase 
more than 500,000 Shares.

              (ii)  In connection with his or her initial service with the 
Company, an Employee, Director or Consultant may be granted Options and Stock 
Purchase Rights to purchase up to an additional 200,000 Shares which shall 
not count against the limit set forth in subsection (i) above.

              (iii) The foregoing limitations shall be adjusted 
proportionately in connection with any change in the Company's capitalization 
as described in Section 13. 

              (iv)  If an Option or Stock Purchase Right is cancelled in the 
same fiscal year of the Company in which it was granted (other than in 
connection with a transaction described in Section 13), the cancelled Option 
or Stock Purchase Right will be counted against the limits set forth in 
subsections (i) and (ii) above.  For this purpose, if the exercise price of 
an Option or Stock Purchase Right is reduced, the transaction will be treated 
as a cancellation of the Option or Stock Purchase Right and the grant of a 
new Option or Stock Purchase Right.

    7.   TERM OF PLAN.  Subject to Section 19 of the 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 19 of the
Plan.  It shall continue in effect for a term of ten (10) years unless
terminated earlier under Section 15 of the Plan.

    8.   TERM OF OPTION.  The term of each Option shall be stated in the Notice
of Grant; provided, however, that in the case of an Incentive Stock Option, the
term shall be ten (10) years from the date of grant or such shorter term as may
be provided in the Notice of Grant.  Moreover, in the case of an Incentive Stock
Option granted to an Optionee who, at the time the Incentive Stock Option is
granted, owns stock representing more than ten percent (10%) of the voting power
of all classes of stock of the Company or any Parent or Subsidiary, the term of
the Incentive Stock Option shall be five (5) years from the date of grant or
such shorter term as may be provided in the Notice of Grant.

    9.   OPTION EXERCISE PRICE AND CONSIDERATION.

         (a)  EXERCISE PRICE.  The per share exercise price for the Shares to
be issued pursuant to exercise of an Option shall be determined by the
Administrator, subject to the following:

              (i)  In the case of an Incentive Stock Option

                   (A)  granted to an Employee who, at the time the Incentive
Stock Option is granted, owns stock representing more than ten percent (10%) of
the voting power of all classes of 


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stock of the Company or any Parent or Subsidiary, the per Share exercise 
price shall be no less than 110% of the Fair Market Value per Share on the 
date of grant.

                   (B)  granted to any Employee other than an Employee
described in paragraph (A) immediately above, the per Share exercise price shall
be no less than 100% of the Fair Market Value per Share on the date of grant.

              (ii)  In the case of a Nonstatutory Stock Option, the per Share 
exercise price shall be determined by the Administrator.  In the case of a 
Nonstatutory Stock Option intended to qualify as "performance-based 
compensation" within the meaning of Section 162(m) of the Code, the per Share 
exercise price shall be no less than 100% of the Fair Market Value per Share 
on the date of grant.

              (iii) Notwithstanding the foregoing, Options may be granted 
with a per Share exercise price of less than 100% of the Fair Market Value 
per Share on the date of grant pursuant to a merger or other corporate 
transaction.

         (b)  WAITING PERIOD AND EXERCISE DATES.  At the time an Option is
granted, the Administrator shall fix the period within which the Option may be
exercised and shall determine any conditions which must be satisfied before the
Option may be exercised.  In so doing, the Administrator may specify that an
Option may not be exercised until the completion of a service period.

         (c)  FORM OF CONSIDERATION.  The Administrator shall determine the
acceptable form of consideration for exercising an Option, including the method
of payment.  In the case of an Incentive Stock Option, the Administrator shall
determine the acceptable form of consideration at the time of grant.  Such
consideration may consist entirely of:

              (i)   cash;

              (ii)  check;

              (iii) promissory note;

              (iv)  other Shares which (A) in the case of Shares acquired 
upon exercise of an option, have been owned by the Optionee for more than six 
months on the date of surrender, and (B) 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;

              (v)   delivery of a properly executed exercise notice together 
with such other documentation as the Administrator 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;


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              (vi)   a reduction in the amount of any Company liability to 
the Optionee, including any liability attributable to the Optionee's 
participation in any Company-sponsored deferred compensation program or 
arrangement;

              (vii)  any combination of the foregoing methods of payment; or

              (viii) such other consideration and method of payment for the 
issuance of Shares to the extent permitted by Applicable Laws.

    10.  EXERCISE OF OPTION.

         (a)  PROCEDURE FOR EXERCISE; RIGHTS AS A SHAREHOLDER. Any Option
granted hereunder shall be exercisable according to the terms of the Plan and at
such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement.

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

              An Option shall be deemed exercised when the Company receives:
(i) written notice of exercise (in accordance with the Option Agreement) from
the person entitled to exercise the Option, and (ii) full payment for the Shares
with respect to which the Option is exercised.  Full payment may consist of any
consideration and method of payment authorized by the Administrator and
permitted by the Option Agreement and the Plan.  Shares issued upon exercise of
an Option shall be issued in the name of the Optionee or, if requested by the
Optionee, in the name of the Optionee and his or her spouse.  Until the stock
certificate evidencing such Shares is issued (as evidenced by the appropriate
entry on the books of the Company or of a duly authorized transfer agent of the
Company), no right to vote or receive dividends or any other rights as a
shareholder shall exist with respect to the Optioned Stock, notwithstanding the
exercise of the Option.  The Company shall issue (or cause to be issued) such
stock certificate promptly after the Option is exercised.  No adjustment will 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 13 of the
Plan.

              Exercising an Option in any manner shall decrease the number of
Shares thereafter 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 EMPLOYMENT, CONSULTING RELATIONSHIP OR
DIRECTORSHIP.  Upon termination of an Optionee's Continuous Status as an
Employee, Director or Consultant, other than upon the Optionee's death or
Disability, the Optionee may exercise his or her Option, but only within such
period of time as is specified in the Notice of Grant, and only to the extent
that the Optionee was entitled to exercise it at the date of termination (but in
no event later than the expiration of the term of such Option as set forth in
the Notice of Grant).  In the absence of a specified time in the Notice of
Grant, the Option shall remain exercisable for three (3) months following the
Optionee's termination.  In the case of an Incentive Stock Option, such period
of time for exercise shall not exceed three (3) months from the date of
termination.  If, on the date of termination, the Optionee is not entitled to


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exercise the Optionee's entire Option, the Shares covered by the unexercisable
portion of the Option shall revert to the Plan.  If, after termination, the
Optionee does not exercise his or her Option within the time specified by the
Administrator, the Option shall terminate, and the Shares covered by such Option
shall revert to the Plan.

         Notwithstanding the above, in the event of an Optionee's change in
status from Consultant or Director to Employee or Employee or Director to
Consultant, an Optionee's Continuous Status as a Director or Consultant shall
not automatically terminate solely as a result of such change in status. 
However, in such event, an Incentive Stock Option held by the Optionee shall
cease to be treated as an Incentive Stock Option and shall be treated for tax
purposes as a Nonstatutory Stock Option three months and one day following such
change of status from an Employee to a Consultant.  

         (c)  DISABILITY OF OPTIONEE.  In the event that an Optionee's
Continuous Status as an Employee, Director or Consultant terminates as a result
of the Optionee's Disability, the Optionee may exercise his or her Option at any
time within twelve (12) months from the date of such termination, but only to
the extent that the Optionee was entitled to exercise it at the date of such
termination (but in no event later than the expiration of the term of such
Option as set forth in the Notice of Grant).  If, at the date of termination,
the Optionee is not entitled to exercise his or her entire Option, the Shares
covered by the unexercisable portion of the Option shall revert to the Plan. 
If, after termination, the Optionee does not exercise his or her Option within
the time specified herein, the Option shall terminate, and the Shares covered by
such Option shall revert to the Plan.

         (d)  DEATH OF OPTIONEE.  In the event of the death of an Optionee, the
Option may be exercised at any time within twelve (12) months following the date
of death (but in no event later than the expiration of the term of such Option
as set forth in the Notice of Grant), by the Optionee's estate or by a person
who acquired the right to exercise the Option by bequest or inheritance, but
only to the extent that the Optionee was entitled to exercise the Option at the
date of death.  If, at the time of death, the Optionee was not entitled to
exercise his or her entire Option, the Shares covered by the unexercisable
portion of the Option shall immediately revert to the Plan.  If, after death,
the Optionee's estate or a person who acquired the right to exercise the Option
by bequest or inheritance does not exercise the Option within the time specified
herein, the Option shall terminate, and the Shares covered by such Option shall
revert to the Plan.

         (e)  BUYOUT PROVISIONS.  The Administrator may at any time offer to
buy out for a payment in cash or Shares, an Option previously granted based on
such terms and conditions as the Administrator shall establish and communicate
to the Optionee at the time that such offer is made.

    11.  STOCK PURCHASE RIGHTS.

         (a)  RIGHTS TO PURCHASE.  Stock Purchase Rights may be issued either
alone, in addition to, or in tandem with other awards granted under the Plan
and/or cash awards made outside of the Plan.  After the Administrator determines
that it will offer Stock Purchase Rights under the Plan, it shall advise the
offeree in writing, by means of a Notice of Grant, of the terms, conditions and


                                  -10-
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restrictions related to the offer, including the number of Shares that the
offeree shall be entitled to purchase, the price to be paid, and the time within
which the offeree must accept such offer, which shall in no event exceed six (6)
months from the date upon which the Administrator made the determination to
grant the Stock Purchase Right.  The offer shall be accepted by execution of a
Restricted Stock Purchase Agreement in the form determined by the Administrator.

         (b)  REPURCHASE OPTION.  Unless the Administrator determines
otherwise, the Restricted Stock Purchase Agreement shall grant the Company a
repurchase option exercisable upon the voluntary or involuntary termination of
the purchaser's employment with the Company for any reason (including death or
Disability).  The purchase price for Shares repurchased pursuant to the
Restricted Stock purchase agreement shall be the original price paid by the
purchaser and may be paid by cancellation of any indebtedness of the purchaser
to the Company.  The repurchase option shall lapse at a rate determined by the
Administrator.

         (c)  OTHER PROVISIONS.  The Restricted Stock Purchase Agreement shall
contain such other terms, provisions and conditions not inconsistent with the
Plan as may be determined by the Administrator in its sole discretion.  In
addition, the provisions of Restricted Stock Purchase Agreements need not be the
same with respect to each purchaser.

         (d)  RIGHTS AS A SHAREHOLDER.  Once the Stock Purchase Right is
exercised, the purchaser shall have the rights equivalent to those of a
shareholder, and shall be a shareholder when his or her purchase is entered upon
the records of the duly authorized transfer agent of the Company.  No adjustment
will be made for a dividend or other right for which the record date is prior to
the date the Stock Purchase Right is exercised, except as provided in Section 13
of the Plan.

    12.  NON-TRANSFERABILITY OF OPTIONS AND STOCK PURCHASE RIGHTS.  Unless
determined otherwise by the Administrator, an Option or Stock Purchase Right 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 or Stock Purchase Right transferable, such Option
or Stock Purchase Right shall contain such additional terms and conditions as
the Administrator deems appropriate.

    13.  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 of Common Stock covered by
each outstanding Option and Stock Purchase Right, and the number of shares of
Common Stock which have been authorized for issuance under the Plan but as to
which no Options or Stock Purchase Rights have yet been granted or which have
been returned to the Plan upon cancellation or expiration of an Option or Stock
Purchase Right, as well as the price per share of Common Stock covered by each
such outstanding Option or Stock Purchase Right, shall be proportionately
adjusted for any increase or decrease in the number of issued shares of Common
Stock 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 of Common Stock effected without receipt
of consideration by the Company; provided, 


                                  -11-
<PAGE>

however, that conversion of any convertible securities of the Company shall 
not be deemed to have been "effected without receipt of consideration."  Such 
adjustment shall be made by the Board, whose determination in that respect 
shall be final, binding and conclusive. 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 of Common Stock subject to an Option or Stock Purchase Right.

         (b)  DISSOLUTION OR LIQUIDATION.  In the event of the proposed
dissolution or liquidation of the Company, the Administrator shall notify each
Optionee as soon as practicable prior to the effective date of such proposed
transaction.  The Administrator in its discretion may provide for an Optionee to
have the right to exercise his or her Option until ten (10) days prior to such
transaction as to all of the Optioned Stock covered thereby, including Shares as
to which the Option would not otherwise be exercisable.  In addition, the
Administrator may provide that any Company repurchase option applicable to any
Shares purchased upon exercise of an Option shall lapse as to all such Shares,
provided the proposed dissolution or liquidation takes place at the time and in
the manner contemplated.  To the extent it has not been previously exercised, an
Option will 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, each outstanding Option and Stock Purchase Right shall be
assumed or an equivalent option or right substituted by the successor
corporation or a Parent or Subsidiary of the successor corporation.  In the
event that the successor corporation refuses to assume or substitute for the
Option or Stock Purchase Right, the Optionee shall have the right to exercise
the Option or Stock Purchase Right as to all of the Optioned Stock, including
Shares as to which it would not otherwise be exercisable.  If an Option or Stock
Purchase Right is exercisable in lieu of assumption or substitution in the event
of a merger or sale of assets, the Administrator shall notify the Optionee that
the Option or Stock Purchase Right shall be fully exercisable for a period of
fifteen (15) days from the date of such notice, and the Option or Stock Purchase
Right shall terminate upon the expiration of such period.  For the purposes of
this paragraph, the Option or Stock Purchase Right shall be considered assumed
if, following the merger or sale of assets, the option or right confers the
right to purchase or receive, for each Share of Optioned Stock subject to the
Option or Stock Purchase Right 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 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); provided, however, that if such
consideration received in the merger or sale of assets was not solely common
stock of the successor corporation or its Parent, the Administrator may, with
the consent of the successor corporation, provide for the consideration to be
received upon the exercise of the Option or Stock Purchase Right, for each Share
of Optioned Stock subject to the Option or Stock Purchase Right, to be solely
common stock of the successor corporation or its Parent equal in fair market
value to the per share consideration received by holders of Common Stock in the
merger or sale of assets.


                                  -12-
<PAGE>

    14.  DATE OF GRANT.  The date of grant of an Option or Stock Purchase Right
shall be, for all purposes, the date on which the Administrator makes the
determination granting such Option or Stock Purchase Right, or such other later
date as is determined by the Administrator.  Notice of the determination shall
be provided to each Optionee within a reasonable time after the date of such
grant.

    15.  AMENDMENT AND TERMINATION OF THE PLAN.

         (a)  AMENDMENT AND TERMINATION.  The Board may at any time amend,
alter, suspend or terminate the Plan.  

         (b)  SHAREHOLDER APPROVAL.  The Company shall obtain shareholder
approval of any Plan amendment to the extent necessary and desirable to comply
with Sections 162(m) or 422 of the Code (or any successor rule or statute or
other applicable law, rule or regulation, including the requirements of any
exchange or quotation system on which the Common Stock is listed or quoted). 
Such shareholder approval, if required, shall be obtained in such a manner and
to such a degree as is required by the applicable law, rule or regulation.

         (c)  EFFECT OF AMENDMENT OR TERMINATION.  No amendment, alteration,
suspension or termination of the Plan shall impair the rights of any Optionee,
unless mutually agreed otherwise between the Optionee and the Administrator,
which agreement must be in writing and signed by the Optionee and the Company.

    16.  CONDITIONS UPON ISSUANCE OF SHARES.  

         (a)  LEGAL COMPLIANCE.  Shares shall not be issued pursuant to the
exercise of an Option or Stock Purchase Right unless the exercise of such Option
or Stock Purchase Right and the issuance and delivery of such Shares 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, Applicable Laws, and the requirements of any stock
exchange or quotation system upon which the Shares may then be listed or quoted,
and shall be further subject to the approval of counsel for the Company with
respect to such compliance.

         (b)  INVESTMENT REPRESENTATIONS.  As a condition to the exercise of an
Option or Stock Purchase Right, the Company may require the person exercising
such Option or Stock Purchase Right 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.

    17.  LIABILITY OF COMPANY.

         (a)  INABILITY TO OBTAIN AUTHORITY.  The 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 


                                  -13-
<PAGE>

any liability in respect of the failure to issue or sell such Shares as to 
which such requisite authority shall not have been obtained.

         (b)  GRANTS EXCEEDING ALLOTTED SHARES.  If the Optioned Stock covered
by an Option or Stock Purchase Right exceeds, as of the date of grant, the
number of Shares which may be issued under the Plan without additional
shareholder approval, such Option or Stock Purchase Right shall be void with
respect to such excess Optioned Stock, unless shareholder approval of an
amendment sufficiently increasing the number of Shares subject to the Plan is
timely obtained in accordance with Section 15(b) of the Plan.

    18.  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.

    19.  SHAREHOLDER APPROVAL.  Continuance of the Plan shall be subject to 
approval by the shareholders of the Company within twelve (12) months before 
or after the date the Plan is adopted.  Such shareholder approval shall be 
obtained in the manner and to the degree required under applicable federal 
and state law.

                                  -14-
<PAGE>
                                1993 STOCK OPTION PLAN

                                STOCK OPTION AGREEMENT


    Unless otherwise defined herein, the terms defined in the Plan shall have
the same defined meanings in this Option Agreement.

I.  NOTICE OF STOCK OPTION GRANT




    You have been granted an option to purchase Common Stock of the Company,
subject to the terms and conditions of the Plan and this Option Agreement, as
follows:

    Grant Number                  

    Date of Grant                 

    Vesting Commencement Date          

    Exercise Price per Share           

    Total Number of Shares Granted     

    Total Exercise Price               
    
    Type of Option:                    __ Incentive Stock Option

                                       __ Nonstatutory Stock Option

    Term/Expiration Date:              

    VESTING SCHEDULE:

    This Option may be exercised, in whole or in part, in accordance with the
following schedule:

    
<PAGE>

    TERMINATION PERIOD:

    This Option may be exercised for six months after termination of the
Optionee's employment relationship, directorship or consulting relationship with
the Company.  Upon the death or Disability of the Optionee, this Option may be
exercised for such longer period as provided in the Plan.  In the event of the
Optionee's change in status from Employee or Director to Consultant or
Consultant or Director to Employee, this Option Agreement shall remain in
effect.  In no event shall this Option be exercised later than the
Term/Expiration Date as provided above.

II.  AGREEMENT

    1.   GRANT OF OPTION.  The Plan Administrator of the Company hereby grants
to the Optionee named in the Notice of Grant attached as Part I of this
Agreement (the "Optionee") an option (the "Option") to purchase the number of
Shares, as set forth in the Notice of Grant, at the exercise price per share set
forth in the Notice of Grant (the "Exercise Price"), subject to the terms and
conditions of the Plan, which is incorporated herein by reference.  Subject to
Section 15(c) of the Plan, in the event of a conflict between the terms and
conditions of the Plan and the terms and conditions of this Option Agreement,
the terms and conditions of the Plan shall prevail.

         If designated in the Notice of Grant as an Incentive Stock Option
("ISO"), this Option is intended to qualify as an Incentive Stock Option under
Section 422 of the Code.  However, if this Option is intended to be an Incentive
Stock Option, to the extent that it exceeds the $100,000 rule of Code Section
422(d) it shall be treated as a Nonstatutory Stock Option ("NSO").

    2.   EXERCISE OF OPTION.

         (a)  RIGHT TO EXERCISE.  This Option is exercisable during its term in
accordance with the Vesting Schedule set out in the Notice of Grant and the
applicable provisions of the Plan and this Option Agreement.  In the event of
Optionee's death, Disability or other termination of Optionee's employment or
consulting relationship, the exercisability of the Option is governed by the
applicable provisions of the Plan and this Option Agreement.

         (b)  METHOD OF EXERCISE.  This Option is exercisable by delivery of an
exercise notice, in the form attached as Exhibit A (the "Exercise Notice"),
which shall state the election to exercise the Option, the number of Shares in
respect of which the Option is being exercised (the "Exercised Shares"), and
such other representations and agreements as may be required by the Company
pursuant to the provisions of the Plan.  The Exercise Notice shall be signed by
the Optionee and shall be delivered in person or by certified mail to the
Secretary of the Company.  The Exercise Notice shall be accompanied by payment
of the aggregate Exercise Price as to all Exercised Shares.  This Option shall
be deemed to be exercised upon receipt by the Company of such fully executed
Exercise Notice accompanied by such aggregate Exercise Price.

         No Shares shall be issued pursuant to the exercise of this Option
unless such issuance and exercise complies with all relevant provisions of law
and the requirements of any stock exchange 


                                  -2-
<PAGE>

or quotation service upon which the Shares are then listed.  Assuming such 
compliance, for income tax purposes the Exercised Shares shall be considered 
transferred to the Optionee on the date the Option is exercised with respect 
to such Exercised Shares.

    3.   METHOD OF PAYMENT.  Payment of the aggregate Exercise Price shall be
by any of the following, or a combination thereof, at the election of the
Optionee:

         (a)  cash;

         (b)  check;

         (c)  delivery of a properly executed exercise notice together with
such other documentation as the Administrator 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;

         (d)  surrender of other Shares which (i) 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 (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares; or

         (e)  delivery of Optionee's promissory note (the "Note") in the form
attached hereto as Exhibit C, in the amount of the aggregate Exercise Price of
the Exercised Shares together with the execution and delivery by the Optionee of
the Security Agreement attached hereto as Exhibit B.  The Note shall bear
interest at a rate no less than the "applicable federal rate" prescribed under
the Code and its regulations at time of purchase, and shall be secured by a
pledge of the Shares purchased by the Note pursuant to the Security Agreement.

    4.   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 the Plan and this Option Agreement shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.

    5.   TERM OF OPTION.  This Option may be exercised only within the term set
out in the Notice of Grant, and may be exercised during such term only in
accordance with the Plan and the terms of this Option Agreement.

    6.   TAX CONSEQUENCES.  Some of the federal and California tax consequences
relating to this Option, as of the date of this Option, are set forth below. 
THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE
SUBJECT TO CHANGE.  THE OPTIONEE SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING
THIS OPTION OR DISPOSING OF THE SHARES.


                                  -3-
<PAGE>

         (a)  EXERCISING THE OPTION.

              (i)  NONSTATUTORY STOCK OPTION.  The Optionee may incur regular
federal income tax and California income tax liability upon exercise of a NSO. 
The Optionee will be treated as having received compensation income (taxable at
ordinary income tax rates) equal to the excess, if any, of the Fair Market Value
of the Exercised Shares on the date of exercise over their aggregate Exercise
Price.  If the Optionee is an Employee or a former Employee, the Company will be
required to withhold from his or her compensation or collect from Optionee and
pay to the applicable taxing authorities an amount in cash equal to a percentage
of this compensation income at the time of exercise, and may refuse to honor the
exercise and refuse to deliver Shares if such withholding amounts are not
delivered at the time of exercise.

              (ii) INCENTIVE STOCK OPTION.  If this Option qualifies as an ISO,
the Optionee will have no regular federal income tax or California income tax
liability upon its exercise, although the excess, if any, of the Fair Market
Value of the Exercised Shares on the date of exercise over their aggregate
Exercise Price will be treated as an adjustment to alternative minimum taxable
income for federal tax purposes and may subject the Optionee to alternative
minimum tax in the year of exercise.  In the event that the Optionee undergoes a
change of status from Employee to Consultant, any Incentive Stock Option of the
Optionee that remains unexercised shall cease to qualify as an Incentive Stock
Option and will be treated for tax purposes as a Nonstatutory Stock Option on
the ninety-first (91st) day following such change of status.

         (b)  DISPOSITION OF SHARES.  

              (i)  NSO.  If the Optionee holds NSO Shares for at least one 
year, any gain realized on disposition of the Shares will be treated as 
long-term capital gain for federal income tax purposes.

              (ii) ISO.  If the Optionee holds ISO Shares for at least one 
year after exercise and two years after the grant date, any gain realized on 
disposition of the Shares will be treated as long-term capital gain for 
federal income tax purposes.  If the Optionee disposes of ISO Shares within 
one year after exercise or two years after the grant date, any gain realized 
on such disposition will be treated as compensation income (taxable at 
ordinary income rates) to the extent of the excess, if any, of the lesser of 
(A) the difference between the Fair Market Value of the Shares acquired on 
the date of exercise and the aggregate Exercise Price, or (B) the difference 
between the sale price of such Shares and the aggregate Exercise Price.

         (c)  NOTICE OF DISQUALIFYING DISPOSITION OF ISO SHARES.  If the 
Optionee sells or otherwise disposes of any of the Shares acquired pursuant 
to an ISO on or before the later of (i) two years after the grant date, or 
(ii) one year after the exercise date, the Optionee shall immediately notify 
the Company in writing of such disposition.  The Optionee agrees that he or 
she may be subject to income tax withholding by the Company on the 
compensation income recognized from such early disposition of ISO Shares by 
payment in cash or out of the current earnings paid to the Optionee.


                                  -4-
<PAGE>

    7.   ENTIRE AGREEMENT; GOVERNING LAW.  The Plan is incorporated herein by 
reference.  The Plan and this Option Agreement constitute the entire 
agreement of the parties with respect to the subject matter hereof and 
supersede in their entirety all prior undertakings and agreements of the 
Company and Optionee with respect to the subject matter hereof, and may not 
be modified adversely to the Optionee's interest except by means of a writing 
signed by the Company and Optionee.  This agreement is governed by California 
law except for that body of law pertaining to conflict of laws.

    By your signature and the signature of the Company's representative 
below, you and the Company agree that this Option is granted under and 
governed by the terms and conditions of the Plan and this Option Agreement.  
Optionee has reviewed the Plan and this Option Agreement in their entirety, 
has had an opportunity to obtain the advice of counsel prior to executing 
this Option Agreement and fully understands all provisions of the Plan and 
Option Agreement. Optionee hereby agrees to accept as binding, conclusive and 
final all decisions or interpretations of the Administrator upon any 
questions relating to the Plan and Option Agreement.  Optionee further agrees 
to notify the Company upon any change in the residence address indicated 
below.

OPTIONEE:                              SUPERGEN, INC.



____________________________________   By:____________________________________
Signature

____________________________________   Title:_________________________________
Print Name

____________________________________
Residence Address

____________________________________



                                  -5-
<PAGE>

                                  CONSENT OF SPOUSE

    The undersigned spouse of Optionee has read and hereby approves the terms
and conditions of the Plan and this Option Agreement.  In consideration of the
Company's granting his or her spouse the right to purchase Shares as set forth
in the Plan and this Option Agreement, the undersigned hereby agrees to be
irrevocably bound by the terms and conditions of the Plan and this Option
Agreement and further agrees that any community property interest shall be
similarly bound.  The undersigned hereby appoints the undersigned's spouse as
attorney-in-fact for the undersigned with respect to any amendment or exercise
of rights under the Plan or this Option Agreement.


              
                                  _______________________________________
                                  Spouse of Optionee


                                  -6-
<PAGE>

                                      EXHIBIT A

                                1993 STOCK OPTION PLAN

                                   EXERCISE NOTICE


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

Attention:  Secretary  

    1.   EXERCISE OF OPTION.  Effective as of today, ________________, 199__, 
the undersigned ("Purchaser") hereby elects to purchase ______________ shares 
(the "Shares") of the Common Stock of SuperGen, Inc. (the "Company") under 
and pursuant to the 1993 Stock Option Plan (the "Plan") and the Stock Option 
Agreement dated ____________, 19___ (the "Option Agreement").  The purchase 
price for the Shares shall be $___________, as required by the Option 
Agreement.

    2.   DELIVERY OF PAYMENT.  Purchaser herewith delivers to the Company the
full purchase price for the Shares.

    3.   REPRESENTATIONS OF PURCHASER.  Purchaser acknowledges that Purchaser
has received, read and understood the Plan and the Option Agreement and agrees
to abide by and be bound by their terms and conditions.

    4.   RIGHTS AS SHAREHOLDER.  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 
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 will 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 13 of the Plan.

    5.   TAX CONSULTATION.  Purchaser understands that Purchaser may suffer 
adverse tax consequences as a result of Purchaser's purchase or disposition 
of the Shares.  Purchaser represents that Purchaser has consulted with any 
tax consultants Purchaser deems advisable in connection with the purchase or 
disposition of the Shares and that Purchaser is not relying on the Company 
for any tax advice.


<PAGE>

    6.   ENTIRE AGREEMENT; GOVERNING LAW.  The Plan and Option Agreement are
incorporated herein by reference.  This Agreement, the Plan and the Option
Agreement constitute the entire agreement of the parties with respect to the
subject matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and Purchaser with respect to the subject matter
hereof, and may not be modified adversely to the Purchaser's interest except by
means of a writing signed by the Company and Purchaser.  This agreement is
governed by California law except for that body of law pertaining to conflict of
laws.


Submitted by:                     Accepted by:

PURCHASER:                        SUPERGEN, INC.


__________________________________     By: _________________________________
Signature

__________________________________     Its: ________________________________
Print Name


ADDRESS:                               ADDRESS:

___________________________            Two Annabel Lane, Suite 220
___________________________            San Ramon, California  94583


                                  -2-
<PAGE>

                                      EXHIBIT B


                                  SECURITY AGREEMENT



    This Security Agreement is made as of __________, 19___ between SuperGen,
Inc., a California corporation ("Pledgee"), and _________________________
("Pledgor").


                                       RECITALS

    Pursuant to Pledgor's election to purchase Shares under the Option 
Agreement dated ________ (the "Option"), between Pledgor and Pledgee under 
Pledgee's 1993 Stock Option Plan, and Pledgor's election under the terms of 
the Option to pay for such shares with his promissory note (the "Note"), 
Pledgor has purchased _________ shares of Pledgee's Common Stock (the 
"Shares") at a price of $________ per share, for a total purchase price of 
$__________.  The Note and the obligations thereunder are as set forth in 
Exhibit C to the Option.

    NOW, THEREFORE, it is agreed as follows:

    1.   CREATION AND DESCRIPTION OF SECURITY INTEREST.  In consideration of 
the transfer of the Shares to Pledgor under the Option Agreement, Pledgor, 
pursuant to the California Commercial Code, hereby pledges all of such Shares 
(herein sometimes referred to as the "Collateral") represented by certificate 
number ______, duly endorsed in blank or with executed stock powers, and 
herewith delivers said certificate to the Secretary of Pledgee 
("Pledgeholder"), who shall hold said certificate subject to the terms and 
conditions of this Security Agreement.

    The pledged stock (together with an executed blank stock assignment for 
use in transferring all or a portion of the Shares to Pledgee if, as and when 
required pursuant to this Security Agreement) shall be held by the 
Pledgeholder as security for the repayment of the Note, and any extensions or 
renewals thereof, to be executed by Pledgor pursuant to the terms of the 
Option, and the Pledgeholder shall not encumber or dispose of such Shares 
except in accordance with the provisions of this Security Agreement.

    2.   PLEDGOR'S REPRESENTATIONS AND COVENANTS.  To induce Pledgee to enter 
into this Security Agreement, Pledgor represents and covenants to Pledgee, 
its successors and assigns, as follows:

         a.   PAYMENT OF INDEBTEDNESS.  Pledgor will pay the principal sum of 
the Note secured hereby, together with interest thereon, at the time and in 
the manner provided in the Note.

         b.   ENCUMBRANCES.  The Shares are free of all other encumbrances, 
defenses and liens, and Pledgor will not further encumber the Shares without 
the prior written consent of Pledgee.


<PAGE>

         c.   MARGIN REGULATIONS.  In the event that Pledgee's Common Stock 
is now or later becomes margin-listed by the Federal Reserve Board and 
Pledgee is classified as a "lender" within the meaning of the regulations 
under Part 207 of Title 12 of the Code of Federal Regulations ("Regulation 
G"), Pledgor agrees to cooperate with Pledgee in making any amendments to the 
Note or providing any additional collateral as may be necessary to comply 
with such regulations.

    3.   VOTING RIGHTS.  During the term of this pledge and so long as all 
payments of principal and interest are made as they become due under the 
terms of the Note, Pledgor shall have the right to vote all of the Shares 
pledged hereunder.

    4.   STOCK ADJUSTMENTS.  In the event that during the term of the pledge 
any stock dividend, reclassification, readjustment or other changes are 
declared or made in the capital structure of Pledgee, all new, substituted 
and additional shares or other securities issued by reason of any such change 
shall be delivered to and held by the Pledgee under the terms of this 
Security Agreement in the same manner as the Shares originally pledged 
hereunder.  In the event of substitution of such securities, Pledgor, Pledgee 
and Pledgeholder shall cooperate and execute such documents as are reasonable 
so as to provide for the substitution of such Collateral and, upon such 
substitution, references to "Shares" in this Security Agreement shall include 
the substituted shares of capital stock of Pledgor as a result thereof.

    5.   OPTIONS AND RIGHTS.  In the event that, during the term of this 
pledge, subscription Options or other rights or options shall be issued in 
connection with the pledged Shares, such rights, Options and options shall be 
the property of Pledgor and, if exercised by Pledgor, all new stock or other 
securities so acquired by Pledgor as it relates to the pledged Shares then 
held by Pledgeholder shall be immediately delivered to Pledgeholder, to be 
held under the terms of this Security Agreement in the same manner as the 
Shares pledged.

    6.   DEFAULT.  Pledgor shall be deemed to be in default of the Note and 
of this Security Agreement in the event:

         a.   Payment of principal or interest on the Note shall be 
delinquent for a period of 10 days or more; or

         b.   Pledgor fails to perform any of the covenants set forth in the 
Option or contained in this Security Agreement for a period of 10 days after 
written notice thereof from Pledgee.

    In the case of an event of Default, as set forth above, Pledgee shall 
have the right to accelerate payment of the Note upon notice to Pledgor, and 
Pledgee shall thereafter be entitled to pursue its remedies under the 
California Commercial Code.

    7.   RELEASE OF COLLATERAL.  Subject to any applicable contrary rules 
under Regulation G, there shall be released from this pledge a portion of the 
pledged Shares held by Pledgeholder hereunder upon payments of the principal 
of the Note.  The number of the pledged Shares which shall be released shall 
be that number of full Shares which bears the same proportion to the initial 
number of

                                  -2-
<PAGE>

Shares pledged hereunder as the payment of principal bears to the initial full
principal amount of the Note.

    8.   WITHDRAWAL OR SUBSTITUTION OF COLLATERAL.  Pledgor shall not sell,
withdraw, pledge, substitute or otherwise dispose of all or any part of the
Collateral without the prior written consent of Pledgee.

    9.   TERM.  The within pledge of Shares shall continue until the payment of
all indebtedness secured hereby, at which time the remaining pledged stock shall
be promptly delivered to Pledgor, subject to the provisions for prior release of
a portion of the Collateral as provided in paragraph 7 above.

    10.  INSOLVENCY.  Pledgor agrees that if a bankruptcy or insolvency
proceeding is instituted by or against it, or if a receiver is appointed for the
property of Pledgor, or if Pledgor makes an assignment for the benefit of
creditors, the entire amount unpaid on the Note shall become immediately due and
payable, and Pledgee may proceed as provided in the case of default.

    11.  PLEDGEHOLDER LIABILITY.  In the absence of willful or gross
negligence, Pledgeholder shall not be liable to any party for any of his acts,
or omissions to act, as Pledgeholder.

    12.  INVALIDITY OF PARTICULAR PROVISIONS.  Pledgor and Pledgee agree that
the enforceability or invalidity of any provision or provisions of this Security
Agreement shall not render any other provision or provisions herein contained
unenforceable or invalid.

    13.  SUCCESSORS OR ASSIGNS.  Pledgor and Pledgee agree that all of the
terms of this Security Agreement shall be binding on their respective successors
and assigns, and that the term "Pledgor" and the term "Pledgee" as used herein
shall be deemed to include, for all purposes, the respective designees,
successors, assigns, heirs, executors and administrators.

    14.  GOVERNING LAW.  This Security Agreement shall be interpreted and
governed under the laws of the State of California.


                                  -3-
<PAGE>

    IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year first above written.



    "PLEDGOR"                By: _________________________________

                             _____________________________________
                             Print Name

              Address:       _____________________________________

                             _____________________________________


    "PLEDGEE"                SUPERGEN, INC.,
                             a California corporation


                     By:     _____________________________________

                     Title:  _____________________________________


    "PLEDGEHOLDER"   _____________________________________________
                             Secretary of 
                             SuperGen, Inc.



                                  -4-
<PAGE>

                                      EXHIBIT C

                                         NOTE


$_______________                                                [City, State]

                                                        ______________, 19___

    FOR VALUE RECEIVED, _______________ promises to pay to SuperGen, Inc., a 
California corporation (the "Company"), or order, the principal sum of 
_______________________ ($_____________), together with interest on the 
unpaid principal hereof from the date hereof at the rate of _______________ 
percent (____%) per annum, compounded semiannually.

    Principal and interest shall be due and payable on __________, 19___. 
Should the undersigned fail to make full payment of principal or interest for 
a period of 10 days or more after the due date thereof, the whole unpaid 
balance on this Note of principal and interest shall become immediately due 
at the option of the holder of this Note.  Payments of principal and interest 
shall be made in lawful money of the United States of America.

    The undersigned may at any time prepay all or any portion of the 
principal or interest owing hereunder.

    This Note is subject to the terms of the Option, dated as of 
________________.  This Note is secured in part by a pledge of the Company's 
Common Stock under the terms of a Security Agreement of even date herewith 
and is subject to all the provisions thereof.

    The holder of this Note shall have full recourse against the undersigned, 
and shall not be required to proceed against the collateral securing this 
Note in the event of default.

    In the event the undersigned shall cease to be a Director or Consultant 
of the Company for any reason, this Note shall, at the option of the Company, 
be accelerated, and the whole unpaid balance on this Note of principal and 
accrued interest shall be immediately due and payable.

    Should any action be instituted for the collection of this Note, the 
reasonable costs and attorneys' fees therein of the holder shall be paid by 
the undersigned.

                                    ____________________________________

                                    ____________________________________


<PAGE>

                                1993 STOCK OPTION PLAN

                       NOTICE OF GRANT OF STOCK PURCHASE RIGHT


    Unless otherwise defined herein, the terms defined in the Plan shall have
the same defined meanings in this Notice of Grant.

[Grantee's Name and Address]

    You have been granted the right to purchase Common Stock of the Company,
subject to the Company's Repurchase Option and your ongoing Continuous Status as
a Director or Consultant (as described in the Plan and the attached Restricted
Stock Purchase Agreement), as follows:

    Grant Number                       _________________________

    Date of Grant                      _________________________

    Price Per Share                    $________________________

    Total Number of Shares Subject     _________________________
      to This Stock Purchase Right

    Expiration Date:                   _________________________


    YOU MUST EXERCISE THIS STOCK PURCHASE RIGHT BEFORE THE EXPIRATION DATE OR 
IT WILL TERMINATE AND YOU WILL HAVE NO FURTHER RIGHT TO PURCHASE THE SHARES.  
By your signature and the signature of the Company's representative below, 
you and the Company agree that this Stock Purchase Right is granted under and 
governed by the terms and conditions of the 1993 Stock Option Plan and the 
Restricted Stock Purchase Agreement, attached hereto as Exhibit A-1, both of 
which are made a part of this document.  You further agree to execute the 
attached Restricted Stock Purchase Agreement as a condition to purchasing any 
shares under this Stock Purchase Right.

GRANTEE:                          SUPERGEN, INC.


___________________________       By:    ______________________________
Signature

___________________________       Title: ______________________________
Print Name


<PAGE>

                                     EXHIBIT A-1

                                1993 STOCK OPTION PLAN

                         RESTRICTED STOCK PURCHASE AGREEMENT

    Unless otherwise defined herein, the terms defined in the Plan shall have 
the same defined meanings in this Restricted Stock Purchase Agreement.

    WHEREAS the Purchaser named in the Notice of Grant, (the "Purchaser") is 
a Director or Consultant of the Company, and the Purchaser's continued 
participation is considered by the Company to be important for the Company's 
continued growth; and

    WHEREAS in order to give the Purchaser an opportunity to acquire an 
equity interest in the Company as an incentive for the Purchaser to 
participate in the affairs of the Company, the Administrator has granted to 
the Purchaser a Stock Purchase Right subject to the terms and conditions of 
the Plan and the Notice of Grant, which are incorporated herein by reference, 
and pursuant to this Restricted Stock Purchase Agreement (the "Agreement").

    NOW THEREFORE, the parties agree as follows:

    1.   SALE OF STOCK.  The Company hereby agrees to sell to the Purchaser 
and the Purchaser hereby agrees to purchase shares of the Company's Common 
Stock (the "Shares"), at the per Share purchase price and as otherwise 
described in the Notice of Grant.

    2.   PAYMENT OF PURCHASE PRICE.  The purchase price for the Shares may be 
paid by delivery to the Company at the time of execution of this Agreement of 
cash, a check, or some combination thereof.

    3.   REPURCHASE OPTION.

         (a)  In the event the Purchaser's Continuous Status as a Director or
Consultant terminates for any or no reason (including death or disability)
before all of the Shares are released from the Company's Repurchase Option (see
Section 4), the Company shall, upon the date of such termination (as reasonably
fixed and determined by the Company) have an irrevocable, exclusive option (the
"Repurchase Option") for a period of sixty (60) days from such date to
repurchase up to that number of shares which constitute the Unreleased Shares
(as defined in Section 4) at the original purchase price per share (the
"Repurchase Price").  The Repurchase Option shall be exercised by the Company by
delivering written notice to the Purchaser or the Purchaser's executor (with a
copy to the Escrow Holder) AND, at the Company's option, (i) by delivering to
the Purchaser or the Purchaser's executor a check in the amount of the aggregate
Repurchase Price, or (ii) by canceling an amount of the Purchaser's indebtedness
to the Company equal to the aggregate Repurchase Price, or (iii) by a
combination of (i) and (ii) so that the combined payment and cancellation of
indebtedness equals the aggregate Repurchase Price.  Upon delivery of such
notice and the payment of the aggregate Repurchase Price, the Company shall
become the legal and beneficial owner of the Shares being 


<PAGE>

repurchased and all rights and interests therein or relating thereto, and the 
Company shall have the right to retain and transfer to its own name the 
number of Shares being repurchased by the Company.

         (b)  Whenever the Company shall have the right to repurchase Shares 
hereunder, the Company may designate and assign one or more employees, 
officers, directors or shareholders of the Company or other persons or 
organizations to exercise all or a part of the Company's purchase rights 
under this Agreement and purchase all or a part of such Shares.  If the Fair 
Market Value of the Shares to be repurchased on the date of such designation 
or assignment (the "Repurchase FMV") exceeds the aggregate Repurchase Price 
of such Shares, then each such designee or assignee shall pay the Company 
cash equal to the difference between the Repurchase FMV and the aggregate 
Repurchase Price of such Shares.

    4.   RELEASE OF SHARES FROM REPURCHASE OPTION.

         (a)  _______________________  percent (______%) of the Shares shall 
be released from the Company's Repurchase Option    [ONE YEAR]    after the 
Date of Grant and __________________ percent (______%) of the Shares 
[AT THE END OF EACH MONTH THEREAFTER], provided that the Purchaser's 
Continuous Status as a Director or Consultant has not terminated prior to the 
date of any such release.

         (b)  Any of the Shares that have not yet been released from the 
Repurchase Option are referred to herein as "Unreleased Shares."

         (c)  The Shares that have been released from the Repurchase Option 
shall be delivered to the Purchaser at the Purchaser's request (see Section 
6).

    5.   RESTRICTION ON TRANSFER.  Except for the escrow described in Section 
6 or the transfer of the Shares to the Company or its assignees contemplated 
by this Agreement, none of the Shares or any beneficial interest therein 
shall be transferred, encumbered or otherwise disposed of in any way until 
such Shares are released from the Company's Repurchase Option in accordance 
with the provisions of this Agreement, other than by will or the laws of 
descent and distribution.

    6.   ESCROW OF SHARES.

         (a)  To ensure the availability for delivery of the Purchaser's 
Unreleased Shares upon repurchase by the Company pursuant to the Repurchase 
Option, the Purchaser shall, upon execution of this Agreement, deliver and 
deposit with an escrow holder designated by the Company (the "Escrow Holder") 
the share certificates representing the Unreleased Shares, together with the 
stock assignment duly endorsed in blank, attached hereto as Exhibit A-2.  The 
Unreleased Shares and stock assignment shall be held by the Escrow Holder, 
pursuant to the Joint Escrow Instructions of the Company and Purchaser 
attached hereto as Exhibit A-3, until such time as the Company's Repurchase 
Option expires.  As a further condition to the Company's obligations under 
this Agreement, the Company may require the spouse of Purchaser, if any, to 
execute and deliver to the Company the Consent of Spouse attached hereto as 
Exhibit A-4.


                                  -2-
<PAGE>

         (b)  The Escrow Holder shall not be liable for any act it may do or 
omit to do with respect to holding the Unreleased Shares in escrow while 
acting in good faith and in the exercise of its judgment.

         (c)  If the Company or any assignee exercises the Repurchase Option 
hereunder, the Escrow Holder, upon receipt of written notice of such exercise 
from the proposed transferee, shall take all steps necessary to accomplish 
such transfer.

         (d)  When the Repurchase Option has been exercised or expires 
unexercised or a portion of the Shares has been released from the Repurchase 
Option, upon request the Escrow Holder shall promptly cause a new certificate 
to be issued for the released Shares and shall deliver the certificate to the 
Company or the Purchaser, as the case may be.

         (e)  Subject to the terms hereof, the Purchaser shall have all the 
rights of a shareholder with respect to the Shares while they are held in 
escrow, including without limitation, the right to vote the Shares and to 
receive any cash dividends declared thereon.  If, from time to time during 
the term of the Repurchase Option, there is (i) any stock dividend, stock 
split or other change in the Shares, or (ii) any merger or sale of all or 
substantially all of the assets or other acquisition of the Company, any and 
all new, substituted or additional securities to which the Purchaser is 
entitled by reason of the Purchaser's ownership of the Shares shall be 
immediately subject to this escrow, deposited with the Escrow Holder and 
included thereafter as "Shares" for purposes of this Agreement and the 
Repurchase Option.

    7.   LEGENDS.  The share certificate evidencing the Shares issued 
hereunder shall be endorsed with the following legend (in addition to any 
legend required under applicable state securities laws):

    THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN 
RESTRICTIONS UPON TRANSFER AND RIGHTS OF REPURCHASE AS SET FORTH IN AN 
AGREEMENT BETWEEN THE COMPANY AND THE SHAREHOLDER, A COPY OF WHICH IS ON FILE 
WITH THE SECRETARY OF THE COMPANY.

    8.   ADJUSTMENT FOR STOCK SPLIT.  All references to the number of Shares 
and the purchase price of the Shares in this Agreement shall be appropriately 
adjusted to reflect any stock split, stock dividend or other change in the 
Shares which may be made by the Company after the date of this Agreement.

    9.   TAX CONSEQUENCES.  The Purchaser has reviewed with the Purchaser's 
own tax advisors the federal, state, local and foreign tax consequences of 
this investment and the transactions contemplated by this Agreement.  The 
Purchaser is relying solely on such advisors and not on any statements or 
representations of the Company or any of its agents.  The Purchaser 
understands that the Purchaser (and not the Company) shall be responsible for 
the Purchaser's own tax liability that may arise as a result of the 
transactions contemplated by this Agreement.  The Purchaser understands that 
Section 83 of the Internal Revenue Code of 1986, as amended (the "Code"), 
taxes as ordinary income the difference between the purchase price for the 
Shares and the Fair Market Value of the 


                                  -3-
<PAGE>

Shares as of the date any restrictions on the Shares lapse.  In this context, 
"restriction" includes the right of the Company to buy back the Shares 
pursuant to the Repurchase Option.  The Purchaser understands that the 
Purchaser may elect to be taxed at the time the Shares are purchased rather 
than when and as the Repurchase Option expires by filing an election under 
Section 83(b) of the Code with the IRS within 30 days from the date of 
purchase.  The form for making this election is attached as Exhibit A-5 
hereto.

         THE PURCHASER ACKNOWLEDGES THAT IT IS THE PURCHASER'S SOLE 
RESPONSIBILITY AND NOT THE COMPANY'S TO FILE TIMELY THE ELECTION UNDER 
SECTION 83(b), EVEN IF THE PURCHASER REQUESTS THE COMPANY OR ITS 
REPRESENTATIVES TO MAKE THIS FILING ON THE PURCHASER'S BEHALF.

    10.  GENERAL PROVISIONS.

         (a)  This Agreement shall be governed by the laws of the State of 
California.  This Agreement, subject to the terms and conditions of the Plan 
and the Notice of Grant, represents the entire agreement between the parties 
with respect to the purchase of the Shares by the Purchaser.  Subject to 
Section 15(c) of the Plan, in the event of a conflict between the terms and 
conditions of the Plan and the terms and conditions of this Agreement, the 
terms and conditions of the Plan shall prevail.  Unless otherwise defined 
herein, the terms defined in the Plan shall have the same defined meanings in 
this Agreement.

         (b)  Any notice, demand or request required or permitted to be given 
by either the Company or the Purchaser pursuant to the terms of this 
Agreement shall be in writing and shall be deemed given when delivered 
personally or deposited in the U.S. mail, First Class with postage prepaid, 
and addressed to the parties at the addresses of the parties set forth at the 
end of this Agreement or such other address as a party may request by 
notifying the other in writing.

         Any notice to the Escrow Holder shall be sent to the Company's 
address with a copy to the other party hereto.

         (c)  The rights of the Company under this Agreement shall be 
transferable to any one or more persons or entities, and all covenants and 
agreements hereunder shall inure to the benefit of, and be enforceable by the 
Company's successors and assigns.  The rights and obligations of the 
Purchaser under this Agreement may only be assigned with the prior written 
consent of the Company.

         (d)  Either party's failure to enforce any provision of this 
Agreement shall not in any way be construed as a waiver of any such 
provision, nor prevent that party from thereafter enforcing any other 
provision of this Agreement.  The rights granted both parties hereunder are 
cumulative and shall not constitute a waiver of either party's right to 
assert any other legal remedy available to it.

         (e)  The Purchaser agrees upon request to execute any further 
documents or instruments necessary or desirable to carry out the purposes or 
intent of this Agreement.


                                  -4-
<PAGE>

         (f)  PURCHASER ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES 
PURSUANT TO SECTION 4 HEREOF IS EARNED ONLY BY CONTINUING SERVICE AS A 
DIRECTOR OR CONSULTANT AT THE WILL OF THE COMPANY (AND NOT THROUGH THE ACT OF 
BEING HIRED OR PURCHASING SHARES HEREUNDER).  PURCHASER FURTHER ACKNOWLEDGES 
AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND 
THE VESTING SCHEDULE SET FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED 
PROMISE OF CONTINUED ENGAGEMENT AS A DIRECTOR OR CONSULTANT FOR THE VESTING 
PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE WITH PURCHASER'S 
RIGHT OR THE COMPANY'S RIGHT TO TERMINATE PURCHASER'S EMPLOYMENT OR 
CONSULTING RELATIONSHIP AT ANY TIME, WITH OR WITHOUT CAUSE.

    By Purchaser's signature below, Purchaser represents that he or she is 
familiar with the terms and provisions of the Plan, and hereby accepts this 
Agreement subject to all of the terms and provisions thereof.  Purchaser has 
reviewed the Plan and this Agreement in their entirety, has had an 
opportunity to obtain the advice of counsel prior to executing this Agreement 
and fully understands all provisions of this Agreement.  Purchaser agrees to 
accept as binding, conclusive and final all decisions or interpretations of 
the Administrator upon any questions arising under the Plan or this 
Agreement. Purchaser further agrees to notify the Company upon any change in 
the residence indicated in the Notice of Grant.

DATED:  _____________________

PURCHASER:                        SUPERGEN, INC.

______________________________    By:____________________________
Signature

______________________________    Title:_________________________
Print Name



                                  -5-
<PAGE>

                                     EXHIBIT A-2

                         ASSIGNMENT SEPARATE FROM CERTIFICATE



    FOR VALUE RECEIVED I, __________________________, hereby sell, assign and 
transfer unto ____________________________________________________________ 
__________________________ (__________) shares of the Common Stock of 
SuperGen, Inc. standing in my name of the books of said corporation 
represented by Certificate No. _____ herewith and do hereby irrevocably 
constitute and appoint ________________________________________ to transfer 
the said stock on the books of the within named corporation with full power 
of substitution in the premises.

    This Stock Assignment may be used only in accordance with the Restricted 
Stock Purchase Agreement (the "Agreement") between________________________ 
and the undersigned dated ______________, 19__.

Dated: _______________, 19__


                                  Signature:______________________________







INSTRUCTIONS:  Please do not fill in any blanks other than the signature 
line. The purpose of this assignment is to enable the Company to exercise the 
Repurchase Option, as set forth in the Agreement, without requiring 
additional signatures on the part of the Purchaser.                           

<PAGE>

                                     EXHIBIT A-3

                              JOINT ESCROW INSTRUCTIONS


                                                    _______________, 19__

Corporate Secretary
SuperGen, Inc.
Two Annabel Lane, Suite 220
San Ramon, California  94583

Dear _________________:

    As Escrow Agent for both SuperGen, Inc., a California corporation (the 
"Company"), and the undersigned purchaser of stock of the Company (the 
"Purchaser"), you are hereby authorized and directed to hold the documents 
delivered to you pursuant to the terms of that certain Restricted Stock 
Purchase Agreement ("Agreement") between the Company and the undersigned, in 
accordance with the following instructions:

    1.   In the event the Company and/or any assignee of the Company 
(referred to collectively as the "Company") exercises the Company's 
Repurchase Option set forth in the Agreement, the Company shall give to 
Purchaser and you a written notice specifying the number of shares of stock 
to be purchased, the purchase price, and the time for a closing hereunder at 
the principal office of the Company.  Purchaser and the Company hereby 
irrevocably authorize and direct you to close the transaction contemplated by 
such notice in accordance with the terms of said notice.

    2.   At the closing, you are directed (a) to date the stock assignments 
necessary for the transfer in question, (b) to fill in the number of shares 
being transferred, and (c) to deliver same, together with the certificate 
evidencing the shares of stock to be transferred, to the Company or its 
assignee, against the simultaneous delivery to you of the purchase price (by 
cash, a check, or some combination thereof) for the number of shares of stock 
being purchased pursuant to the exercise of the Company's Repurchase Option.

    3.   Purchaser irrevocably authorizes the Company to deposit with you any 
certificates evidencing shares of stock to be held by you hereunder and any 
additions and substitutions to said shares as defined in the Agreement. 
Purchaser does hereby irrevocably constitute and appoint you as Purchaser's 
attorney-in-fact and agent for the term of this escrow to execute with 
respect to such securities all documents necessary or appropriate to make 
such securities negotiable and to complete any transaction herein 
contemplated, including but not limited to the filing with any applicable 
state blue sky authority of any required applications for consent to, or 
notice of transfer of, the securities.  Subject to the provisions of this 
paragraph 3, Purchaser shall exercise all rights and privileges of a 
shareholder of the Company while the stock is held by you.


<PAGE>

    4.   Upon written request of the Purchaser, but no more than once per 
calendar year, unless the Company's Repurchase Option has been exercised, you 
shall deliver to Purchaser a certificate or certificates representing so many 
shares of stock as are not then subject to the Company's Repurchase Option. 
Within 90 days after cessation of Purchaser's continuous employment by or 
services to the Company, or any parent or subsidiary of the Company, you 
shall deliver to Purchaser a certificate or certificates representing the 
aggregate number of shares held or issued pursuant to the Agreement and not 
purchased by the Company or its assignees pursuant to exercise of the 
Company's Repurchase Option.

    5.   If at the time of termination of this escrow you should have in your 
possession any documents, securities, or other property belonging to 
Purchaser, you shall deliver all of the same to Purchaser and shall be 
discharged of all further obligations hereunder.

    6.   Your duties hereunder may be altered, amended, modified or revoked 
only by a writing signed by all of the parties hereto.

    7.   You shall be obligated only for the performance of such duties as 
are specifically set forth herein and may rely and shall be protected in 
relying or refraining from acting on any instrument reasonably believed by 
you to be genuine and to have been signed or presented by the proper party or 
parties. You shall not be personally liable for any act you may do or omit to 
do hereunder as Escrow Agent or as attorney-in-fact for Purchaser while 
acting in good faith, and any act done or omitted by you pursuant to the 
advice of your own attorneys shall be conclusive evidence of such good faith.

    8.   You are hereby expressly authorized to disregard any and all 
warnings given by any of the parties hereto or by any other person or 
corporation, excepting only orders or process of courts of law, and are 
hereby expressly authorized to comply with and obey orders, judgments or 
decrees of any court. In case you obey or comply with any such order, 
judgment or decree, you shall not be liable to any of the parties hereto or 
to any other person, firm or corporation by reason of such compliance, 
notwithstanding any such order, judgment or decree being subsequently 
reversed, modified, annulled, set aside, vacated or found to have been 
entered without jurisdiction.

    9.   You shall not be liable in any respect on account of the identity, 
authorities or rights of the parties executing or delivering or purporting to 
execute or deliver the Agreement or any documents or papers deposited or 
called for hereunder.

    10.  You shall not be liable for the outlawing of any rights under the 
statute of limitations with respect to these Joint Escrow Instructions or any 
documents deposited with you.

    11.  You shall be entitled to employ such legal counsel and other experts 
as you may deem necessary properly to advise you in connection with your 
obligations hereunder, may rely upon the advice of such counsel, and may pay 
such counsel reasonable compensation therefor.


                                  -2-
<PAGE>

    12.  Your responsibilities as Escrow Agent hereunder shall terminate if 
you shall cease to be an officer or agent of the Company or if you shall 
resign by written notice to each party.  In the event of any such 
termination, the Company shall appoint a successor Escrow Agent.

    13.  If you reasonably require other or further instruments in connection 
with these Joint Escrow Instructions or obligations in respect hereto, the 
necessary parties hereto shall join in furnishing such instruments.

    14.  It is understood and agreed that should any dispute arise with 
respect to the delivery and/or ownership or right of possession of the 
securities held by you hereunder, you are authorized and directed to retain 
in your possession without liability to anyone all or any part of said 
securities until such disputes shall have been settled either by mutual 
written agreement of the parties concerned or by a final order, decree or 
judgment of a court of competent jurisdiction after the time for appeal has 
expired and no appeal has been perfected, but you shall be under no duty 
whatsoever to institute or defend any such proceedings.

    15.  Any notice required or permitted hereunder shall be given in writing 
and shall be deemed effectively given upon personal delivery or upon deposit 
in the United States Post Office, by registered or certified mail with 
postage and fees prepaid, addressed to each of the other parties thereunto 
entitled at the following addresses or at such other addresses as a party may 
designate by ten days' advance written notice to each of the other parties 
hereto.

         COMPANY:            SuperGen, Inc.
                             Two Annabel Lane, Suite 220
                             San Ramon, California  94583

         PURCHASER:          ____________________________

                             ____________________________
                   
                             ____________________________

         ESCROW AGENT:       Corporate Secretary
                             SuperGen, Inc.
                             Two Annabel Lane, Suite 220
                             San Ramon, California  94583

    16.  By signing these Joint Escrow Instructions, you become a party hereto
only for the purpose of said Joint Escrow Instructions; you do not become a
party to the Agreement.


                                  -3-
<PAGE>


    17.  This instrument shall be binding upon and inure to the benefit of 
the parties hereto, and their respective successors and permitted assigns.

    18.  These Joint Escrow Instructions shall be governed by, and construed 
and enforced in accordance with, the laws of the State of California.

                                  Very truly yours,

                                  SUPERGEN, INC.


                             By:  _____________________________________
                                  

                             Title: ___________________________________


                                  PURCHASER:

                                  _____________________________________
                                            (Signature)


                                  _____________________________________
                                  (Typed or Printed Name)
ESCROW AGENT:


_____________________________________
Corporate Secretary



                                  -4-
<PAGE>

                                     EXHIBIT A-4

                                  CONSENT OF SPOUSE


    I, ____________________, spouse of ___________________, have read and 
approve the foregoing Restricted Stock Purchase Agreement (the "Agreement").  
In consideration of the Company's grant to my spouse of the right to purchase 
shares of SuperGen, Inc., as set forth in the Agreement, I hereby appoint my 
spouse as my attorney-in-fact in respect to the exercise of any rights under 
the Agreement and agree to be bound by the provisions of the Agreement 
insofar as I may have any rights in said Agreement or any shares issued 
pursuant thereto under the community property laws or similar laws relating 
to marital property in effect in the state of our residence as of the date of 
the signing of the foregoing Agreement.

Dated: _______________, 19__


                                  __________________________________________
                                  Signature of Spouse


<PAGE>

                                     EXHIBIT A-5

                             ELECTION UNDER SECTION 83(b)
                         OF THE INTERNAL REVENUE CODE OF 1986

The undersigned taxpayer hereby elects, pursuant to Section 83(b) of the
Internal Revenue Code of 1986, as amended, to include in taxpayer's gross income
for the current taxable year the amount of any compensation taxable to taxpayer
in connection with his or her receipt of the property described below:

1.  The name, address, taxpayer identification number and taxable year of the
    undersigned are as follows:

    NAME:                TAXPAYER:               SPOUSE: 

    ADDRESS:       

    IDENTIFICATION NO.:   TAXPAYER:              SPOUSE: 

    TAXABLE YEAR:

2.  The property with respect to which the election is made is described as
    follows: __________ shares (the "Shares") of the Common Stock of SuperGen,
    Inc. (the "Company").

3.  The date on which the property was transferred is: _____________, 19__. 

4.  The property is subject to the following restrictions:

    The Shares may be repurchased by the Company, or its assignee, upon certain
    events. This right lapses with regard to a portion of the Shares based on
    the continued performance of services by the taxpayer over time.

5.  The fair market value at the time of transfer, determined without regard to
    any restriction other than a restriction which by its terms will never
    lapse, of such property is:
    $_______________.

6.  The amount (if any) paid for such property is:

    $_______________.

The undersigned has submitted a copy of this statement to the person for whom 
the services were performed in connection with the undersigned's receipt of 
the above-described property.  The transferee of such property is the person 
performing the services in connection with the transfer of said property.

THE UNDERSIGNED UNDERSTANDS THAT THE FOREGOING ELECTION MAY NOT BE REVOKED
EXCEPT WITH THE CONSENT OF THE COMMISSIONER.

Dated:   ______________, 19____   _______________________________________
                                  Taxpayer
                                  

The undersigned spouse of taxpayer joins in this election.

Dated:   ______________, 19____   _______________________________________
                                  Spouse of Taxpayer