<PAGE>
                                                              Exhibit 10.24


                           BISHOP RANCH BUSINESS PARK

                                 BUILDING LEASE


<PAGE>

                                 SUPERGEN, INC.
                     BISHOP RANCH BUSINESS PARK-BUILDING LEASE
                                TABLE OF CONTENTS

                                                                            PAGE
                                                                            ----
1.   PREMISES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.   TERM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
     2.1  Term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
     2.2  Delay In Commencement. . . . . . . . . . . . . . . . . . . . . . . . 1
     2.3  Acknowledgment Of Commencement Date. . . . . . . . . . . . . . . . . 2

3.   RENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
     3.1  Base Rent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
     3.2  Adjustments  To  Base  Rent. . . . . . . . . . . . . . . . . . . . . 2
     3.3  Amounts Constituting Rent. . . . . . . . . . . . . . . . . . . . . . 2

4.   SECURITY DEPOSIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5.   TAX AND BUILDING OPERATING COST INCREASES . . . . . . . . . . . . . . . . 3
     5.1  Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     5.2  Tenant's Share . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     5.3  Notice and Payment . . . . . . . . . . . . . . . . . . . . . . . . . 5
     5.4  Tenant's Right to Audit. . . . . . . . . . . . . . . . . . . . . . . 6
     5.5  Additional Taxes . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     5.6  Tenant's Taxes . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6.   USE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.1  Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.2  Suitability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.3  Uses Prohibited. . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7.   SERVICE AND UTILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     7.1  Landlord's Obligations . . . . . . . . . . . . . . . . . . . . . . . 8
     7.2  Tenant's Obligation. . . . . . . . . . . . . . . . . . . . . . . . . 9
     7.3  Tenant's Additional Requirements . . . . . . . . . . . . . . . . . . 9
     7.4  After Hours Charges for Air Conditioning . . . . . . . . . . . . . .10
     7.5  Nonliability . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

8.   MAINTENANCE AND REPAIRS; ALTERATIONS AND ADDITIONS. . . . . . . . . . . .10
     8.1  Maintenance and Repairs. . . . . . . . . . . . . . . . . . . . . . .10
     8.2  Alterations and Additions. . . . . . . . . . . . . . . . . . . . . .11

9.   ENTRY BY LANDLORD . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

10.  LIENS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12


                                       -i-

<PAGE>


                                TABLE OF CONTENTS
                                    (CONTINUED)
                                                                            PAGE
                                                                            ----
11.  INDEMNITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
     11.1 Indemnity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
     11.2 Exemption of Landlord From Liability . . . . . . . . . . . . . . . .13

12.  INSURANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
     12.1 Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
     12.2 Insurance Policies . . . . . . . . . . . . . . . . . . . . . . . . .14
     12.3 Landlord's Insurance . . . . . . . . . . . . . . . . . . . . . . . .14
     12.4 Waiver of Subrogation. . . . . . . . . . . . . . . . . . . . . . . .14

13.  DAMAGE OR DESTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . .15
     13.1 Landlord's Duty to Repair. . . . . . . . . . . . . . . . . . . . . .15
     13.2 Landlord's Right to Terminate. . . . . . . . . . . . . . . . . . . .15
     13.3 Tenant's Right to Terminate. . . . . . . . . . . . . . . . . . . . .16
     13.4 Exclusive Rights . . . . . . . . . . . . . . . . . . . . . . . . . .16

14.  CONDEMNATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

15.  ASSIGNMENT AND SUBLETTING . . . . . . . . . . . . . . . . . . . . . . . .17
     15.1 Landlord's Consent Required. . . . . . . . . . . . . . . . . . . . .17
     15.2 Reasonable Consent . . . . . . . . . . . . . . . . . . . . . . . . .17
     15.3 Excess Consideration . . . . . . . . . . . . . . . . . . . . . . . .17
     15.4 No Release Of Tenant . . . . . . . . . . . . . . . . . . . . . . . .18
     15.5 Attorneys' Fees. . . . . . . . . . . . . . . . . . . . . . . . . . .18
     15.6 Transfer Of Ownership Interest . . . . . . . . . . . . . . . . . . .18
     15.7 Effectiveness of Transfer. . . . . . . . . . . . . . . . . . . . . .18
     15.8 Landlord's Right to Space. . . . . . . . . . . . . . . . . . . . . .18
     15.9 No Net Profits Leases. . . . . . . . . . . . . . . . . . . . . . . .18
     15.10 Permitted Assignment or Sublease. . . . . . . . . . . . . . . . . .19

16.  SUBORDINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
     16.1 Subordination. . . . . . . . . . . . . . . . . . . . . . . . . . . .19
     16.2 Junior Liens . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
     16.3 Subordination Agreements . . . . . . . . . . . . . . . . . . . . . .19
     16.4 Attornment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

17.  OUIET ENJOYMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20



                                    -ii-
<PAGE>


                                TABLE OF CONTENTS
                                   (CONTINUED)
                                                                            PAGE
                                                                            ----
18.  DEFAULT; REMEDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
     18.1 Default. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
     18.2 Remedies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
     18.4 Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
     18.5 Default By Landlord. . . . . . . . . . . . . . . . . . . . . . . . .23

19.  PARKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

20.  RELOCATION OF PREMISES. . . . . . . . . . . . . . . . . . . . . . . . . .24
     20.1 Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
     20.2 Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

21.  MORTGAGEE PROTECTION. . . . . . . . . . . . . . . . . . . . . . . . . . .24

22.  ESTOPPEL CERTIFICATES . . . . . . . . . . . . . . . . . . . . . . . . . .25

23.  SURRENDER. HOLDING OVER . . . . . . . . . . . . . . . . . . . . . . . . .25
     23.1 Surrender. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
     23.2 Holding Over . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

24.  HAZARDOUS MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . .26

25.  MISCELLANEOUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
     25.1 Attornment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
     25.2 Cautions: Attachments; Defined Terms . . . . . . . . . . . . . . . .27
     25.3 Entire Agreement . . . . . . . . . . . . . . . . . . . . . . . . . .27
     25.4 Severability . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
     25.5 Costs Of Suit. . . . . . . . . . . . . . . . . . . . . . . . . . . .28
     25.6 Time; Joint And Several Liability. . . . . . . . . . . . . . . . . .28
     25.7 Binding Effect; Choice Of Law. . . . . . . . . . . . . . . . . . . .28
     25.8 Waiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
     25.9 Force Majeure. . . . . . . . . . . . . . . . . . . . . . . . . . . .29
     25.10 Landlord's Liability. . . . . . . . . . . . . . . . . . . . . . . .29
     25.11 Consents and Approvals. . . . . . . . . . . . . . . . . . . . . . .29
     25.12 Signs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
     25.13 Rules And Regulations . . . . . . . . . . . . . . . . . . . . . . .30
     25.14 Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30



                                     -iii-

<PAGE>


                                TABLE OF CONTENTS
                                   (CONTINUED)
                                                                            PAGE
                                                                            ----
     25.15 Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
     25.16 Lease Guaranty. . . . . . . . . . . . . . . . . . . . . . . . . . .31
     25.17 Brokers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
     25.18 Reserved Rights . . . . . . . . . . . . . . . . . . . . . . . . . .31
     25.19 Option to Extend. . . . . . . . . . . . . . . . . . . . . . . . . .31


     EXHIBIT A - Site and Floor Plans
     EXHIBIT B - Work Letter
     EXHIBIT C - Space Plan
     EXHIBIT D - Rules and Regulations
     EXHIBIT E - Janitorial Specifications
     EXHIBIT F - Door Sign, Directory Strip and Mail Box Request
     EXHBIIT G - Commencement of Lease



                                      -iv-

<PAGE>




                           BISHOP RANCH BUSINESS PARK

                                 BUILDING LEASE


     This Lease is made and entered into this ________ day of
_______________, 1996, by and between ANNABEL INVESTMENT COMPANY, a
California partnership, (hereinafter "Landlord") and SUPERGEN, INC.
(hereinafter "Tenant").  For and in consideration of the rental and of the
covenants and agreements hereinafter set forth to be kept and performed by
Tenant, Landlord hereby leases to Tenant and Tenant hereby leases from
Landlord the premises herein described for the term, at the rental and
subject to and upon all of the terms, covenants and agreements hereinafter
set forth.

     1.   PREMISES

          Landlord hereby leases to Tenant and Tenant hereby leases from
Landlord the premises (the "Premises") crosshatched on Exhibit A containing
9,247 rentable square feet known as Suite 220, located on the Second floor of
Two Annabel Lane, Building B (including all tenant improvements thereto, the
"Building"), located at San Ramon, California 94583.  The Building is part of a
Complex containing the Building and one (1) other building (the "Complex").  The
Complex, which contains 95,432 rentable square feet, the land on which the
Complex is situated (the "Land"), the common areas of the Complex, any other
improvements in the Complex and the personal property used by Landlord in the
operation of the Complex (the "Personal Property") are herein collectively
called the "Project." Landlord shall pay the cost of "Suite Improvements" (as
such term is defined in the work letter attached hereto as Exhibit B, "the "Work
Letter") to the Premises up to a maximum amount of SEVENTY-EIGHT THOUSAND EIGHT
HUNDRED EIGHTY-FIVE AND NO/100 DOLLARS ($78,885.00 or $9.00 per usable square
foot of the Premises), with any cost in excess of this amount to be paid by
Tenant promptly as incurred.  In the event Tenant does not use the entire
allowance for improving the Premises, any remainder may be taken in the form of
a Rental Credit.

    2.    TERM

          2.1  TERM.  The term of this Lease shall commence on the "Commencement
Date" hereinafter defined to be the earlier of the date Landlord delivers
possession of the Premises to Tenant with all of the Suite Improvements
Substantially Completed, as defined in Exhibit B, or the date Landlord would
have completed the Premises and tendered the Premises to Tenant if Substantial
Completion had not been delayed by the number of days specified in any and all
Tenant Delay Notices given by Landlord as described in Exhibit B.  The term of
this Lease shall end Five (5) years thereafter (the "Expiration Date"), unless
sooner terminated pursuant to this Lease.

          2.2  DELAY IN COMMENCEMENT.  The Commencement Date is scheduled to
occur on January 15, 1997 (the "Scheduled Commencement Date"), but if there are
"Scheduled Commencement Adjustment Days" (referred to in Section 25.9 of this
Lease and Exhibit B), then the Scheduled Commencement Date shall be that Date
which is the same number of days after



<PAGE>

January 15, 1997 as the sum of the Scheduled Commencement Adjustment Days.
If for any reason the Commencement Date does not occur by the Scheduled
Commencement Date, Landlord shall not be liable for any damage thereby nor
shall such inability affect the validity of this Lease or the obligations of
Tenant hereunder.  If the Commencement Date has not occurred within sixty
(60) days after the Scheduled Commencement Date, Tenant at its option, to be
exercised by giving Landlord written notice within thirty (30) days after the
end of such sixty (60) day period, may terminate this Lease and, upon
Landlord's return of any monies previously deposited by Tenant, which shall
be returned within thirty (30) days after receipt of Tenant's written notice,
the parties shall have no further rights or liabilities toward each other.

          2.3  ACKNOWLEDGMENT OF COMMENCEMENT DATE.  Upon determination of the
Commencement Date, Landlord and Tenant shall execute a written acknowledgment of
the Commencement Date and Expiration Date in the form attached hereto as Exhibit
G.

     3.   RENT

          3.1  BASE RENT.  Tenant shall pay to Landlord monthly as base rent
("Base Rent") for the Premises in advance on the Commencement Date and on the
first day of each calendar month thereafter during the term of this Lease
without deduction, offset, prior notice or demand, in lawful money of the United
States of America, the sum of FIFTEEN THOUSAND FOUR HUNDRED ELEVEN AND 67/100
DOLLARS ($15,411.67). If the Commencement Date is not the first day of a month
or if the Lease terminates on other than the last day of a month, the Base Rent
payable for such partial month shall be equal to the number of days that the
term was in effect during such partial month TIMES the "daily Base Rent," which
shall be calculated by dividing the Base Rent then in effect by thirty (30).

          Concurrently with Tenant's execution of this Lease, Tenant shall pay
to Landlord the sum of FIFTEEN THOUSAND FOUR HUNDRED ELEVEN AND 67/100 DOLLARS
($15,411.67) to be applied against Base Rent when it becomes due.

          3.2  ADJUSTMENTS  TO  BASE  RENT.  (Intentionally Deleted)

          3.3  AMOUNTS CONSTITUTING RENT.  All amounts payable or reimbursable
by Tenant under this Lease, including late charges and interest, "Operating Cost
Payments" (as defined in Paragraph 5), and amounts payable or reimbursable under
the Work Letter and the other Exhibits hereto, shall constitute "Rent" and be
payable and recoverable as such.  Base Rent is due and payable as provided in
Paragraph 3.1 - "Base Rent", Operating Cost Payments are due and payable as
provided in Paragraph 5.3 - "Notice and Payment", and all other Rent payable to
Landlord on demand under the terms of this Lease, unless otherwise set forth
herein, shall be payable within thirty (30) days after written notice from
Landlord of the amounts due.  All Rent shall be paid to Landlord without
deduction or offset, except as otherwise set forth herein, in lawful money of
the United States of America at the address for notices or at such other place
as Landlord may from time to time designate in writing.


                                    -2-

<PAGE>

     4.   SECURITY DEPOSIT

          Concurrently with Tenant's execution of this Lease, Tenant shall
deposit with Landlord the sum of FIFTEEN THOUSAND FOUR HUNDRED ELEVEN AND
67/100 DOLLARS ($15,411.67) (the "Security Deposit").  In the event Tenant
installs a Lab in the Premises, the Security Deposit shall be THIRTY THOUSAND
EIGHT HUNDRED TWENTY-THREE AND 33/100 DOLLARS ($30,823.33).  The Security
Deposit shall be held by Landlord as security for the faithful performance by
Tenant of all of the terms, covenants and conditions of this Lease to be
performed by Tenant during the term hereof.  If Tenant defaults with respect
to any provision of this Lease, including the provisions relating to the
payment of any Rent, Landlord may (but shall not be required to) use, apply
or retain all or any part of the Security Deposit to cure such default or to
compensate Landlord for any other loss or damage which Landlord may suffer by
reason of Tenant's default.  If any portion of said deposit is so used or
applied, Tenant shall, within ten (10) days after written demand therefor,
deposit cash with Landlord in an amount sufficient to restore the Security
Deposit to its original amount; Tenant's failure to do so shall be a material
breach of this Lease. Landlord shall not be required to keep the Security
Deposit separate from its general funds, and Tenant shall not be entitled to
interest on such deposit.  If Tenant shall fully and faithfully perform every
provision of this Lease to be performed by it, the Security Deposit or any
balance thereof shall be returned to Tenant (or, at Landlord's option, to the
last assignee of Tenant's interest hereunder) within thirty (30) days after
the expiration of the Lease term and Tenant's vacating the Premises;
provided, however, that Landlord may elect, in its discretion, to retain a
portion of the Security Deposit in an amount to be determined by Landlord in
its reasonable judgment and Landlord shall, promptly upon determining the
increases in Operating Costs for the calendar year in which this Lease
terminates, pursuant to Paragraph 5.3 -"Notice and Payment," apply from such
retained portion of the Security Deposit any sums underpaid by Tenant with
respect to Operating Costs for the final year of the Lease term, and return
the balance, if any, to Tenant or its assignee.  In the event of termination
of Landlord's interest in this Lease, Landlord shall transfer the Security
Deposit to Landlord's successor in interest whereupon Landlord shall be
released from liability for the return of the Security Deposit or the
accounting therefor provided that such transferee assumes Landlord's
liability for the return of the Security Deposit or the accounting therefore
in writing.

    5.   TAX AND BUILDING OPERATING COST INCREASES

         5.1   DEFINITIONS.  For purposes of this paragraph, the following
terms are herein defined:

               (a)  BASE YEAR:  The calendar year in which this Lease commences.

               (b)  OPERATING COSTS:  Operating Costs shall include all costs
and expenses of ownership, operation, repair and maintenance of the Project
(excluding depreciation of the improvements in the Project and all amounts paid
on loans of Landlord) computed in accordance with Tax Basis accounting
principles adopted by Landlord consistently applied, including by way of
illustration but not limited to: real property taxes, taxes assessed on the
Personal Property, any other governmental impositions imposed on or by reason of
the ownership, operation or use of the Project,


                                    -3-

<PAGE>

and any tax in addition to or in lieu thereof, other than taxes covered by
Paragraph 5.4, whether assessed against Landlord or Tenant or collected by
Landlord or both; parts; equipment; supplies; insurance premiums; license,
permit and inspection fees; cost of services and materials (including
property management fees and costs); cost of compensation (including
employment taxes and fringe benefits) of all persons who perform duties
connected with the operation, maintenance and repair of the Project; costs of
providing utilities and services, including water, gas, electricity, sewage
disposal, rubbish removal, janitorial, gardening, security, parking, window
washing, supplies and materials, and signing (but excluding services not
uniformly available to substantially all of the Project tenants); costs of
capital improvements (i) required to cause the Project to comply with all
laws, statutes, ordinances, regulations, rules and requirements of any
governmental or public authority, including, without limitation, the
Americans with Disabilities Act of 1990 (the "ADA") (collectively, "Legal
Requirements"), except for costs, if any, of correcting any failure of the
Project to comply, as of the Commencement Date, with any Legal Requirement as
enacted as of the Commencement Date, or (ii) which reduce Operating Costs,
such costs, together with interest on the unamortized balance at the rate of
ten percent (10%) per annum, to be amortized over such reasonable periods as
Landlord shall determine; costs of maintenance and replacement of
landscaping; legal, accounting and other professional services incurred in
connection with the operation of the Project and the calculation of Operating
Costs; and rental expense or a reasonable allowance for depreciation of
personal property used in the maintenance, operation and repair of the
Project.  If the Project is not fully occupied for any calendar year during
the term of this Lease, Operating Costs shall be adjusted to the amount
which would have been incurred if the Project had been fully occupied for
the year.  (Tax Basis Accounting Principles are defined to be the Internal
Revenue Code and related rules, regulations, rulings, and applicable case law
applied by Landlord on a consistent basis in reporting income and expense,
including the capitalization of costs and related depreciation, to the
Internal Revenue Service.)

               (c)  Notwithstanding the foregoing, annual Operating Costs shall
not include the following:

                    (1)  Capital improvements, equipment, replacements,
alterations and repairs, except as Landlord reasonably determines are
attributable to services performed for the Complex;

                    (2)  Construction and installation of tenant improvements,
renovations, or decorating made for tenants or other occupants in the Complex or
for vacant tenant suites within the Building, including, without limitation,
fees and costs for space planning, architectural drawings, construction,
permits, licenses and inspections.

                    (3)  Negotiations and transactions with present or
prospective tenants or other occupants of the Complex for leases, subleases,
assignments and other related transactions, including, without limitation,
attorneys' fees for such negotiations and transactions;

                    (4)  Interest, principal, points and fees on debts or
amortization on any mortgage or any other debt instrument encumbering the
Building;


                                    -4-

<PAGE>

                    (5)  All items and services for which Tenant or any other
tenant in the Complex directly reimburses Landlord (other than through tenant's
share of Operating Expenses), or which Landlord provides selectively to one or
more tenants (other than Tenant) without reimbursement;

                    (6)  Marketing costs, including leasing commissions,
advertising and promotional expenditures, and costs of signs in or on the
Complex identifying the owner of the Complex or other tenants' signs; and

                    (7)  Upgrading the Complex to comply with handicap, life
safety, fire and safety codes to the extent the same were in effect prior to the
Commencement Date;

                    (8)  Legal fees and expenses incurred in connection with the
enforcement of any leases, disputes or defense of Landlord's title to or
interest in the Project, audits, or other litigation related to the Project.

          5.2  TENANT'S SHARE.  If Operating Costs during any calendar year
following the Base Year exceed the rentable square footage of the Building
multiplied by $8.00 (the "Expense Stop"), Tenant shall pay to Landlord "Tenant's
Share" multiplied by such excess ("Operating Cost Payments").  "Tenant's Share"
means 9.69%, which is calculated by dividing the rentable square footage of the
Premises by the rentable square footage of the Complex, as such rentable square
footages are set forth in Paragraph 1.

          5.3  NOTICE AND PAYMENT.  As soon as reasonably practical after the
end of each calendar year following the Base Year, Landlord shall furnish Tenant
a written statement showing in reasonable detail the Operating Costs for the
preceding calendar year, and the amount of any payment due from Tenant to
Landlord or from Landlord to Tenant, taking into account prior Operating Cost
Payments made by Tenant for such preceding calendar year.  Tenant shall have one
hundred eighty (180) days after receipt of Landlord's statement to notify
Landlord of any objections they have to such statement, or of their intention to
review supporting documentation for such statement.  If Tenant does not so
notify Landlord, such statement shall conclusively be deemed correct and Tenant
shall have no right thereafter to dispute or review support for such statement,
any item therein, or the computation of Operating Costs.  If Tenant does so
notify the Landlord within the one hundred eighty (180) day period, Tenant shall
have one (1) year from the date of receipt of Landlord's statement to complete
their review of the supporting documentation and notify Landlord of all
objections, if any, to such statement.  Landlord and Tenant hereby agree that
Tenant will submit in writing to Landlord on or before the end of said one (1)
year period, all objections to Landlord's statement, and Tenant's only rights
after said one (1) year period shall be nonreversible removals or reductions of
the said objections submitted to Landlord.  Landlord and Tenant hereby agree
that after said one (1) year period, Tenant has no further rights to review any
supporting documentation to Landlord's statement. Any notifications to Landlord
will be done in accordance with Paragraph 25.14.

          Coincidentally with the monthly Base Rent next due following Tenant's
receipt of such statement, Tenant shall pay to Landlord (in the case of an
underpayment) or Landlord shall credit


                                    -5-

<PAGE>

against the next Base Rent due from Tenant (in the case of an overpayment)
the difference between (i) Tenant's Share of any excess of Operating Costs
for the preceding calendar year over the Expense Stop (the "Prior Year's
Increase"), and (ii) the Operating Cost Payments made by Tenant for such
preceding calendar year.  In addition, Tenant shall pay to Landlord
coincidentally with such next due Base Rent an amount equal to (A)
one-twelfth (1/12) of the Prior Year's Increase, if any, multiplied by (B)
the number of months or partial months (including the then current month)
then elapsed in the current calendar year, less (C) the aggregate of any
Operating Cost Payments made by Tenant for such current calendar year.
Monthly thereafter until adjustment is made the following year pursuant to
this paragraph, Tenant shall pay together with the monthly Base Rent
one-twelfth (1/12) of any such Prior Year's Increase.  In no event will
Tenant be entitled to receive the benefit of a reduction in Operating Costs
below the Expense Stop.

          For any partial calendar year at the termination of this Lease,
Tenant's Share of any increases in Operating Costs for such year over the
Expense Stop shall be prorated on the basis of a 365-day year by computing
Tenant's Share of the increases in Operating Costs for the entire year and then
prorating such amount for the number of days this Lease was in effect during
such year. Notwithstanding the termination of this Lease, and within ten (10)
days after Tenant's receipt of Landlord's statement regarding the determination
of increases in Operating Costs for the calendar year in which this Lease
terminates, Tenant shall pay to Landlord or Landlord shall pay to Tenant, as the
case may be, an amount equal to the difference between Tenant's Share of the
increases in Operating Costs for such year (as prorated) and the amount
previously paid by Tenant toward such increases.

          5.4  TENANT'S RIGHT TO AUDIT.  In the event of any dispute or
uncertainty as to the amount of Operating Costs and Tenant's Share thereof,
Tenant may require clarification as to any disputed amount, including without
limitation, receiving and reviewing legible copies of all of Landlord's invoices
and paid receipts, with respect to the disputed items, and pursuing an audit as
hereinafter specified, provided Tenant notifies Landlord in writing within one
hundred eighty (180) days of its receipt of Landlord's statement that Tenant
elects to inspect and/or audit such records pursuant to this Paragraph.  Should
Tenant elect to inspect and/or audit such records, Tenant's inspection and/or
audit shall be conducted by Tenant's staff or by an independent certified Big
Six public accounting firm and shall be completed and the results thereof
submitted to Landlord no later than six (6) months after Tenant's receipt of
Landlord's statement.  If Landlord and Tenant are unable to agree as to any
disputed item, Tenant may, at its sole cost and expense, audit on its own
Landlord's records related to the disputed items, which audit shall be scheduled
promptly at the reasonable convenience of both Landlord and Tenant with such
audit to take place in Landlord's offices.  If the results of such audit by an
independent Big 6 public accounting firm approved by Landlord, whose approval
shall not be unreasonably withheld, and Tenant indicate that the aggregate cost
of the disputed items is incorrect by more than 5%, then the Landlord shall
refund the discrepancy.  If the amount of the discrepancy is more than five
percent (5%) of the Total Operating Costs, then Landlord shall pay for the
reasonable cost of the Big 6 public accounting firm audit, (not to exceed
$2,500.00).


                                    -6-

<PAGE>

          5.5  ADDITIONAL TAXES.  Tenant shall reimburse to Landlord, within
thirty (30) days after receipt of a demand therefor, Tenant's Share of any and
all taxes payable by Landlord (other than net income taxes or any taxes included
within Operating Costs), whether or not now customary or within the
contemplation of the parties hereto (i) upon, allocable to or measured by the
area of the Building, (ii) upon all or any portion of the Rent payable hereunder
and under other leases of space in the Building, including any gross receipts
tax or excise tax levied with respect to the receipt of such Rent, or (iii) upon
or with respect to the possession, leasing, operation, management, maintenance,
alteration, repair, use or occupancy of the Building or any portion thereof.
Tenant shall not be required to reimburse Landlord for taxes under this
Paragraph 5.4 to the extent Tenant has paid Tenant's Share of such taxes through
Operating Cost Payments under Paragraph 5.2.

          5.6  TENANT'S TAXES.  Tenant shall pay before delinquency (whether
levied on Landlord or Tenant), any and all taxes assessed upon or measured by
(i) Tenant's equipment, furniture, fixtures and other personal property
located in the Premises, (ii) any improvements or alterations made to the
Premises prior to or during the term of this Lease paid for by Tenant
("Above-Standard Improvements"), or (iii) this transaction or any document to
which Tenant is a party creating or transferring an interest or an estate in
the Premises.  For the purpose of determining said amounts, figures supplied
by the County Assessor as to the amount so assessed shall be conclusive.
Tenant shall comply with the provisions of any law, ordinance or rule of the
taxing authorities which require Tenant to file a report of Tenant's property
located in the Premises.

     6.   USE

          6.1  USE.  The Premises shall be used and occupied by Tenant for
general offices and administrative purposes and with Landlord's written consent,
research and development which may include the installation of a laboratory.
In the event Tenant receives Landlord's written consent to utilize a portion of
its Premises for research and development and laboratory use, said use shall
adhere to and conform with stipulations as set forth in Section 24 of this
Lease.  It is further agreed and understood that in the event Tenant installs a
laboratory in a portion of its Premises, Tenant shall at all times follow all
National Institute of Health (NIH) and Center for Disease Control (CDC)
guidelines (the "Guidelines") in their present form and as they may be amended
for handling etiologic or infections agents.  Further, Tenant agrees that it
shall not bring, or allow to be brought, into the Building any etiologic or
infectious agents for which the NIH or CDC recommend a Biosafety Level (BL) in
excess of two (2) (BL2). Tenant shall design, construct and maintain all of its
laboratory facilities and support areas in the Building to conform with and
satisfy the Guidelines for BLl and BL2 laboratory facilities, as the case may
be, depending on the kinds of agents which will be brought into the respective
laboratories.  If the Guidelines are amended, Tenant shall modify its facilities
accordingly.  In addition, Tenant shall adopt and follow all procedures,
practices and techniques prescribed in the Guidelines for the BLl and BL2 work
as the case may be.

          6.2  SUITABILITY.  Tenant acknowledges that neither Landlord nor any
agent of Landlord has made any representation or warranty with respect to the
Premises or the Building or with respect to the suitability of either for the
conduct of Tenant's business, nor has Landlord agreed to undertake any
modification, alteration or improvement to the Premises except as provided in
the


                                    -7-

<PAGE>

Work Letter.  The taking of possession of the Premises by Tenant shall
conclusively establish that the Premises and the Building were at such time
in satisfactory condition except for any latent defects, unless within ten
(10) days after such date Tenant shall give Landlord written notice
specifying in reasonable detail the respects in which the Premises or the
Building were not in satisfactory condition.

          6.3  USES PROHIBITED.

               (a)  Tenant shall not do nor permit anything to be done in or
about the Premises nor bring or keep anything therein which will in any way
increase the existing rate (unless Tenant agrees to pay for such increase) or
affect any fire or other insurance upon the Building or any of its contents, or
cause a cancellation of any insurance policy covering said Building or any part
thereof or any of its contents, nor shall Tenant sell or permit to be kept, used
or sold in or about said Premises any articles which may be prohibited by a
standard form policy of fire insurance.

               (b)  Tenant shall not do or permit anything to be done in or
about the Premises which will in any way obstruct or interfere with the rights
of other tenants or occupants of the Building, or injure or annoy them, or use
or allow the Premises to be used for any unlawful or objectionable purpose, nor
shall Tenant cause, maintain or permit any nuisance in or about the Premises.
Tenant shall not commit or suffer to be committed any waste in or upon the
Premises.  Tenant shall not bring onto the Premises any apparatus, equipment or
supplies that may overload the Premises or the Building or any utility or
elevator systems or jeopardize the structural integrity of the Building or any
part thereof.

               (c)  Tenant shall not use the Premises or permit anything to be
done in or about the Premises which will in any way conflict with, and at its
sole cost and expense shall promptly comply with, any Legal Requirement now in
force or which may hereafter be enacted or promulgated relating to the
condition, use or occupancy of the Premises, excluding structural changes not
relating to or affecting the condition, use or occupancy of the Premises or
Tenant's improvements or acts.  The judgment of any court of competent
jurisdiction or the admission of Tenant in any action against Tenant, whether
Landlord be a party thereto or not, that Tenant has violated any Legal
Requirement, shall be conclusive of the fact as between Landlord and Tenant.

     7.   SERVICE AND UTILITIES

          7.1  LANDLORD'S OBLIGATIONS.  Provided Tenant is not in default
hereunder, Landlord shall furnish to the Premises during reasonable hours of
generally recognized business days, to be determined by Landlord, and subject to
the rules and regulations of the Building, water, gas and electricity
("Utilities") suitable for the intended use of the Premises, heat and air
conditioning required in Landlord's reasonable judgment for the comfortable use
and occupancy of the Premises, scavenger, janitorial services as described in
Exhibit E attached hereto, window washing service and elevator service customary
in similar buildings in the competing geographical areas.  Landlord shall also
maintain and keep lighted the common lobbies, hallways, stairs and toilet rooms
in the Building.  Landlord's current hours of operation in Bishop Ranch II
(hereinafter "Hours of Operation") are 7 a.m. to 7 p.m., Monday through Friday,
excepting New Year's Day, President's Day, Memorial Day,



                                    -8-

<PAGE>

July 4th, Labor Day, Thanksgiving, and Christmas Day.  The building and its
Utilities are available to Tenant 24 hours a day, seven (7) days a week, 365
days a year.

          7.2  TENANT'S OBLIGATION.  Tenant shall pay for, prior to delinquency,
all telephone and all other materials and services, not expressly required to be
paid by Landlord, which may be furnished to or used in, on or about the Premises
during the term of this Lease.

          7.3  TENANT'S ADDITIONAL REQUIREMENTS.

               (a)  Tenant shall pay for heat and air conditioning furnished
at Tenant's request during non-business hours and/or on non-business days on
an hourly basis at a reasonable rate established by Landlord not to exceed
Landlord's actual, cost and a reasonable fee for wear and tear and supervision
thereof.  Tenant shall not use in excess of Building Standard amounts (as
reasonably determined by Landlord) of electricity, water or any other utility
without Landlord's prior written consent, which consent Landlord may not
unreasonably refuse.  Landlord may cause a water meter or electric current
meter to be installed in the Premises so as to measure the amount of water
and electric current consumed in excess of Building Standard amounts for any
such excess use.  The cost of such meters and of installation, maintenance
and repair thereof shall be paid by Tenant and Tenant agrees to pay Landlord
promptly upon demand by Landlord for all such water and electric current
consumed as shown by said meters, at the rates charged for such services by
the city in which the Building is located or by the local public utility
furnishing the same, plus any additional expense incurred in keeping account
of the water and electric current so consumed.  If a separate meter is not
installed to measure any such excess use, Landlord shall have the right to
estimate the amount of such use through qualified personnel.  In addition,
Landlord may impose a reasonable charge for the use of any additional or
unusual janitorial services required by Tenant because of any Suite
Improvements different from or above Building Standard, carelessness of
Tenant or the nature of Tenant's business (including hours of operation).
Notwithstanding the foregoing, Landlord agrees that at the time Tenant
provides Landlord with its approved construction drawings pursuant to Section
1.2 of Exhibit B attached hereto, Landlord shall notify Tenant in writing if
Tenant's initial Suite Improvements shall cause Tenant to use in excess of
building standard amounts of electricity, water, or any other utility.  If
Landlord determines that Tenant's initial installation shall be in excess of
building standard amounts, Landlord and Tenant shall agree to submeter Tenant's
Premises.

               (b)  If any lights other than Building Standard or equipment
are used in the Premises which affect the temperature otherwise maintained by
the air conditioning system, Landlord may install supplementary air
conditioning units in the Premises and the reasonable cost thereof, including
the cost of installation, operation and maintenance thereof, shall be paid by
Tenant to Landlord upon demand by Landlord.

               (c)  In no event shall Tenant (i) connect any apparatus, machine
or device through electrical outlets except in the manner for which such outlets
are designed and without the use of any device intended to increase the plug
capacity of any electrical outlet or (ii) maintain at any


                                    -9-

<PAGE>

time an electrical demand load in excess of four (4) watts per square foot of
usable area of the Premises.

          7.4  AFTERHOURS CHARGES FOR AIR CONDITIONING.  The hourly rate for
afterhours air conditioning service (as defined in Section 7.1) is $25.00 per
hour per floor.  This rate shall be subject to adjustment based upon the
increase or decrease in utilities costs as charged by PG&E.

          7.5  NONLIABILITY. Landlord shall not be liable for, and Tenant
shall not be entitled to any abatement or reduction of Rent, by reason of
Landlord's failure to furnish any of the foregoing when due to "Force Majeure
Events" (as defined in Paragraph 25.9).  If failure to furnish the foregoing
is within Landlord's reasonable control and Tenant is unable to occupy the
Premises due to such failure, Tenant shall be entitled to an abatement of
Base Rent commencing with the seventh (7TH) consecutive day of such failure
unless prior thereto Landlord commences to cure such failure and thereafter
diligently proceeds with such cure.  Any failure to furnish any of the
foregoing shall not constitute an eviction of Tenant, constructive or
otherwise and, notwithstanding any law to the contrary that may now or
hereafter exist, Tenant shall not be entitled to terminate this Lease on
account of such failure.  Landlord shall not be liable under any
circumstances for loss of or injury to property or business or consequential
damages, however occurring, through or in connection with failure to furnish
any of the foregoing.

     8.   MAINTENANCE AND REPAIRS; ALTERATIONS AND ADDITIONS

          8.1  MAINTENANCE AND REPAIRS.

               (a)  LANDLORD'S OBLIGATIONS.  Landlord shall maintain in good
order, condition and repair the structural and common areas of the Building, and
the basic heating, ventilating, air conditioning, electrical, plumbing, fire
protection, life safety, security and mechanical systems of the Building (the
"Building Systems"), and the telephone cabling and wiring in and to the
Premises, and shall cause the common areas of the Building to comply with all
Legal Requirements (including, without limitation, the ADA), provided that any
maintenance and repair caused by the negligent acts or omissions of Tenant or
Tenant's agents, employees, invitees, visitors (collectively "Tenant's
Representatives") shall be paid for by Tenant.  Notwithstanding any law to the
contrary that may now or hereafter exist, Tenant shall not have the right to
make repairs at Landlord's expense or to terminate this Lease because of
Landlord's failure to keep the foregoing in good order, condition and repair,
nor shall Landlord be liable under any circumstances for any consequential
damages or loss of business, however occurring, through or in connection with
any such failure.  Notwithstanding the provisions of this Section, in the event
Landlord fails or neglects to commence the repairs to the Building or the
Premises which Landlord is required to make in accordance with the terms of this
Lease within thirty (30) days after receipt of written notice from Tenant of the
necessity therefore, and appropriate notice from Tenant, then Tenant may, but
shall not be obligated to, make such repairs using union subcontractors approved
by Landlord and providing Landlord with the cost estimate to complete said
repair, then Landlord shall reimburse Tenant for the reasonable cost thereof
within thirty (30) days after receipt of a bill therefor and copies of
applicable invoices with interest at the Default Rate.



                                    -10-

<PAGE>

               (b)  TENANT'S OBLIGATIONS

                    (1)  Tenant, at Tenant's sole cost and expense, except for
services furnished by Landlord pursuant to Paragraph 7 and 8.1(a) hereof, shall
maintain the Premises in good order, condition and repair including the interior
surfaces of the ceilings, walls and floors, all doors, interior windows, and all
plumbing pipes, electrical wiring, switches, fixtures, nonbuilding standard
lights, and equipment installed for the use of the Premises, and shall cause the
Premises to comply with all Legal Requirements enacted after the Commencement
Date (including, without limitation, the ADA).  Notwithstanding any law to the
contrary that may  now or hereafter exist, Tenant shall not have the right to
make repairs at Landlord's expense or to terminate this Lease because of
Landlord's failure to keep the Premises in good order, condition and repair.

                    (2)  In the event Tenant fails to maintain the Premises in
good order, condition and repair, Landlord shall give Tenant notice to do such
acts as are reasonably required to  so maintain the Premises.  In the event
Tenant fails to promptly commence such work and diligently prosecute it to
completion, Landlord shall have the right to do such acts and expend such funds
at the expense of Tenant as are reasonably required to perform such work.  Any
amount so expended by Landlord shall be paid by Tenant promptly after demand
with interest from the date expended by Landlord until paid by Tenant at the
"Default Rate," as defined below.  Landlord shall have no liability to Tenant
for any damage, inconvenience or interference with the use of the Premises by
Tenant as a result of performing any such work.  As used in this Lease, "Default
Rate" shall mean the lesser of twelve percent per annum(12%) or the maximum rate
permitted by law.

               (c)  COMPLIANCE WITH LAW.  Landlord and Tenant shall each do all
acts required to comply with all applicable Legal Requirements relating to their
respective maintenance and repair obligations as set forth herein.

          8.2  ALTERATIONS AND ADDITIONS.

               (a)  Tenant shall make no alterations, additions or improvements
to the Premises or any part thereof without obtaining the prior written consent
of Landlord.

               (b)  Landlord may impose as a condition to the aforesaid consent
such requirements as Landlord may deem necessary in its reasonable discretion,
including without limitation thereto, performing the work itself, specifying the
manner in which the work is done, and selecting the contractor by whom the work
is to be performed and the times during which it is to be accomplished.  Tenant
shall pay to Landlord upon demand an amount equal to the reasonable costs and
expenses for time spent by Landlord's employees or contractors in supervising,
approving and administering such alterations.


                                    -11-

<PAGE>

               (c)  All such alterations, additions or improvements, all other
Above-Standard Improvements, and all work performed under the Work Letter shall
be the property of Landlord and shall remain upon and be surrendered with the
Premises or shall be removed by Tenant at the expiration or termination of this
Lease.  At the time Landlord consents to any alteration or addition subsequent
to the Commencement Date, Landlord shall specify in writing to Tenant whether
the same shall be surrendered with the Premises, or whether at Landlord's
request shall be removed by Tenant.

               (d)  All articles of personal property and all business and trade
fixtures, machinery and equipment, cabinetwork, furniture and movable partitions
owned by Tenant or installed by Tenant at its expense in the Premises shall be
and remain the property of Tenant and may be removed by Tenant at any time
during the Lease term when Tenant is not in default hereunder.

     9.   ENTRY BY LANDLORD

          Landlord and Landlord's agents shall upon reasonable notice and
consistent with Tenant's security requirements (except in the case of an
emergency) have the right to enter the Premises to inspect the same, to
supply janitorial service and any other service to be provided by Landlord to
Tenant hereunder, to show the Premises to prospective purchasers or during
the last one hundred eighty (180) days of the Lease Term or extended Term to
prospective tenants, to post notices of non-responsibility and "for lease"
signs, and to alter, improve or repair the Premises and any portion of the
Building, and may for that purpose erect scaffolding and other necessary
structures where reasonably required by the character of the work to be
performed, always providing the entrance to the Premises shall not be blocked
thereby.  Landlord shall use commercially reasonable efforts to conduct its
activities under this Paragraph 9 in a manner that will minimize
inconvenience to Tenant without incurring additional expense to Landlord. For
each of the aforesaid purposes, Landlord shall at all times have and retain a
key with which to unlock all of the doors in, upon and about the Premises,
excluding Tenant's vaults and safes, and Landlord and Landlord's agents shall
have the right to use any and all means which Landlord may deem proper to
open said doors in an emergency, in order to obtain entry to the Premises,
and any entry to the Premises obtained by Landlord or Landlord's agents by a
said means, or otherwise, shall not under any circumstance be construed or
deemed to be a forcible or unlawful entry into, or a detainer of, the
Premises, or an eviction of Tenant from the Premises or any portion thereof.
Tenant shall not be released from its obligations under this Lease nor be
entitled to any abatement of Rent on account of Landlord's entry under this
Paragraph, and Tenant hereby waives any claim for damages for any injury or
inconvenience to or interference with Tenant's business, any loss of
occupancy or quiet enjoyment of the Premises, and any other loss occasioned
thereby.

     10.  LIENS

     Tenant shall keep the Premises and the Building free from any liens arising
out of work performed, materials furnished, or obligations incurred by Tenant
and shall indemnify, hold harmless and defend Landlord from any liens and
encumbrances arising out of any work performed, materials furnished or
obligations incurred by or at the direction of Tenant, excepting the initial
Tenant


                                    -12-

<PAGE>

improvement work as shown on the attached Exhibit C performed by Landlord's
contractor or subcontractors.  In the event that Tenant shall not, within
twenty (20) days following the imposition of any such lien, cause such lien
to be released of record by payment or posting of a proper bond, Landlord
shall have, in addition to all other remedies provided herein and by law, the
right, but no obligation, to cause the same to be released by such means as
it shall deem proper, including payment of the claim giving rise to such
lien.  All such sums paid by Landlord and all expenses incurred by it in
connection therewith, including attorneys' fees and costs, shall be payable
to Landlord by Tenant on demand with interest at the Default Rate until paid.
Landlord shall have the right at all times to post and keep posted on the
Premises any notices permitted or required by law, or which Landlord shall
deem proper, for the protection of Landlord and the Premises, and any other
party having an interest therein, from mechanics' and materialmen's liens,
and Tenant shall give to Landlord at least three (3) business days prior
written notice of the expected date of commencement of any work relating to
alterations or additions to the Premises.

     11.  INDEMNITY

          11.1 INDEMNITY.  Tenant agrees to indemnify Landlord against and save
Landlord harmless from any and all loss, cost, penalties, fines and reasonable
attorneys' fees and disbursements arising from (i) any default or breach by
Tenant in the observance or performance of any of the material terms, covenants
or conditions of this Lease by Tenant or (ii) any negligence or willful
misconduct of Tenant, its agents, servants, employees invitees or licensees of
Tenant in, on, or about the Premises, or any part of the Complex, either during
prior occupancy or during the Term of this Lease.

               (b)  Landlord agrees to indemnify Tenant against and save Tenant
harmless from any and all loss, cost liability, damage, and expense, including
without limitation penalties, fines and reasonable attorneys' fees and
disbursements, incurred in connection with or arising from (i) any default or
breach by Landlord in the observance of the material terms, covenants, or
conditions of this Lease by the Landlord, or (ii) any negligence or willful
misconduct of Landlord, or its contractors, agents, servants, employees,
invitees, or licensees in, on, or about the Premises, or any part of the
Complex, either during prior occupancy or during the Term of this Lease.
Notwithstanding the foregoing, and in no event (except for Landlord's negligence
or willful misconduct, unless expressly defined in this Lease) shall Landlord be
liable for indirect or consequential damages of Tenant (including lost profits)
however occurring.

          11.2 EXEMPTION OF LANDLORD FROM LIABILITY.  Except for Landlord's
negligence or willful misconduct, Landlord shall not be liable for injury or
damage which may be sustained by the person or property of Tenant, its
employees, invitees or customers, or any other person in or about the Premises
caused by or resulting from fire, steam, electricity, gas, water or rain, which
may leak or flow from or into any part of the Premises, or from the breakage,
leakage, obstruction or other defects of the pipes, sprinklers, wires,
appliances, plumbing, air conditioning, telephone cabling or wiring, or lighting
fixtures of the same, whether the damage or injury results from conditions
arising upon the Premises or upon other portions of the Building of which the
Premises are a part, or from


                                    -13-

<PAGE>

other sources.  Landlord shall not be liable for any damages arising from any
act or neglect of any other tenant of the Building.

     12.  INSURANCE

          12.1 COVERAGE.  Tenant shall, at all times during the term of this
Lease, and at its own cost and expense, procure and continue in force the
following insurance coverage:

               (a)  Commercial General Liability Insurance with a combined
single limit for personal or bodily injury and property damage of not less
than $2,000,000 or such other reasonable level of coverage that Landlord may
require in its reasonable judgment.

               (b)  Fire and Extended Coverage Insurance, including vandalism
and malicious mischief coverage, covering and in an amount equal to the full
replacement value of all fixtures, furniture and improvements installed in the
Premises by or at the expense of Tenant.

          12.2 INSURANCE POLICIES.  The aforementioned minimum limits of
policies shall in no event limit the liability of Tenant hereunder.  The
aforesaid insurance shall name Landlord and its partners, property manager, and
mortgagees as an additional insured.  Said insurance shall be with a responsible
insurer, preapproved by Landlord and Landlord's insurer, which approval shall
not be unreasonably withheld, licensed to do business in California.  Tenant
shall furnish from the insurance companies or cause the insurance companies to
furnish certificates of coverage.  No such policy shall be cancelable or subject
to reduction of coverage or other modification or cancellation except after
thirty (30) days prior written notice to Landlord by the insurer.  All such
policies shall be written as primary policies, not contributing with and not in
excess of the coverage which Landlord may carry.  Tenant shall, at least twenty
(20) days prior to the expiration of such policies, furnish Landlord with
evidence of renewals or binders.  Tenant agrees that if Tenant does not take out
and maintain such insurance, Landlord may (but shall not be required to) procure
said insurance on Tenant's behalf and charge Tenant the premiums together with a
reasonable handling charge and Default Interest from the date paid by Landlord,
payable upon demand.  Tenant shall have the right to provide such insurance
coverage pursuant to blanket policies obtained by Tenant, provided such blanket
policies expressly afford coverage to the Premises and to Tenant as required by
this Lease.

          12.3 LANDLORD'S INSURANCE.  During the term of this Lease Landlord
shall maintain in effect insurance on the Building against fire, extended
coverage perils and vandalism and malicious mischief (to the extent such
coverages are available), with responsible insurers licensed to do business in
California, insuring the Building in an amount equal to at least ninety-five
percent (95%) of the replacement cost thereof, excluding foundations, footings
and underground installations.  Landlord may, but shall not be obligated to,
carry insurance against additional perils and/or in greater amounts.

          12.4 WAIVER OF SUBROGATION.  To the extent permitted by their
respective policies of insurance, Landlord and Tenant each hereby waive any
right of recovery against the other and the authorized representatives of the
other for any loss or damage that is covered by any policy of insurance
maintained by either party with respect to the Premises or the Project or any
operation


                                    -14-

<PAGE>

therein.  If any policy of insurance relating to this Lease, the Premises or
the Project does not permit the foregoing waiver or if the coverage under any
such policy would be invalidated as a result of such waiver, the party
maintaining such policy shall, if possible, obtain from the insurer under
such policy a waiver of all right of recovery by way of subrogation against
either party in right of recovery by way of subrogation against either party
in connection with any claim, loss or damage covered by such policy.

     13.  DAMAGE OR DESTRUCTION

          13.1 LANDLORD'S DUTY TO REPAIR.  If all or a substantial part of the
Premises are rendered untenantable or inaccessible by damage to all or any part
of the Project from fire or other casualty then, unless either party elects to
terminate this Lease pursuant to Paragraphs 13.2 or 13.3, Landlord shall, at its
expense, use its best efforts to repair and restore the Premises and/or access
thereto, as the case may be, to substantially their former condition to the
extent permitted by the then applicable codes, laws and regulations; provided,
however, that Tenant rather than Landlord shall be obligated at Tenant's expense
to repair or replace Tenant's personal property, trade fixtures and any items or
improvements that are required to be covered by Tenant's insurance under
Paragraph 12.1(b).

          If Landlord is required or elects to repair damage to the Premises
and/or access thereto, this Lease shall continue in effect but Tenant's Base
Rent and Operating Cost Payments from the date of the casualty through the
date of substantial completion of the repair shall be abated by a
proportionate amount based on the portion of the Premises that Tenant is
prevented from using by reason of such damage or its repair; provided,
however, that if the casualty is the result of the willful misconduct or
negligence of Tenant or Tenant's Representatives, there will be no such
rental abatement. In no event shall Landlord be liable to Tenant by reason of
any injury to or interference with Tenant's business or property arising from
fire or other casualty or by reason of any repairs to any part of the Project
made necessary by such casualty.

          13.2 LANDLORD'S RIGHT TO TERMINATE.  Landlord may elect to terminate
this Lease, effective as of the last day of the calendar month in which such
election is made, under the following circumstances:

               (a)  Where, in the reasonable judgment of Landlord, the damage
cannot be substantially repaired and restored under applicable laws and
governmental regulations within one hundred eighty (180) days after the date of
the casualty;

               (b)  Where, in the reasonable judgment of Landlord, adequate
proceeds are not, for any reason, made available to Landlord from Landlord's
insurance policies to make the required repairs;

               (c)  Where the Project is damaged or destroyed to the extent that
the cost to repair and restore the Project exceeds twenty-five percent (25%) of
the full replacement cost of the Project, whether or not the Premises are
damaged or destroyed; or

               (d)  Where the damage occurs within the last twelve (12) months
of the term of the Lease.

                    If any of the circumstances described in this Paragraph 13.2
arise, Landlord must notify Tenant in writing of that fact within sixty (60)
days after such circumstances arise and in such notice Landlord must also advise
Tenant whether Landlord has elected to terminate the Lease.


                                    -15-

<PAGE>

          13.3 TENANT'S RIGHT TO TERMINATE.  Tenant shall have the right to
terminate this Lease if all or a substantial part (greater than 50% of the
Premises) of the Premises are rendered untenantable or inaccessible by damage to
all or any part of the Project from fire or other casualty, provided that such
casualty is not the result of the willful misconduct or negligence of Tenant or
Tenant's Representatives, but only under the following circumstances:

               (a)  Tenant may elect to terminate this Lease if Landlord had the
right under Paragraph 13.2 to terminate this Lease but did not elect to so
terminate and Landlord failed to commence the required repair within ninety (90)
days after the date it received proceeds to commence such repair. In such
event, Tenant may terminate this Lease as of the date of the casualty by notice
to Landlord given before the earlier of the date on which Landlord commences
such repair or ten (10) days after the expiration of such ninety (90)-day
period; or

               (b)  Tenant may elect to terminate this Lease in the circumstance
described in Subparagraph 13.2 (a).  In such event, Tenant may terminate this
Lease as of the date of the casualty by notice to Landlord given within thirty
(30) days after Landlord's notice to Tenant pursuant to Paragraph 13.2.

          13.4 EXCLUSIVE RIGHTS.  Landlord and Tenant each hereby agree that,
notwithstanding any law to the contrary that may now or hereafter exist, neither
party shall have any right to terminate this Lease in the event of any damage or
destruction under any circumstances other than as provided in Paragraphs 13.2
and 13.3.

     14.  CONDEMNATION

          If all or a material portion of the Premises shall be taken or
appropriated for public or quasi-public use by right of eminent domain with or
without litigation or transferred by agreement in connection with such public or
quasi-public use, either party hereto shall have the right at its option,
exercisable within thirty (30) days of receipt of notice of such taking, to
terminate this Lease as of the date possession is taken by the condemning
authority, provided, however, that before Tenant may terminate this Lease by
reason of taking or appropriation as provided hereinabove, such taking or
appropriation shall be of such an extent and nature as to substantially
handicap, impede or impair Tenant's use of the Premises. If any part of the
Building other than the Premises shall be so taken or appropriated, Landlord
shall have the right at its option to terminate this Lease.  No award for any
partial or entire taking shall be apportioned, and Tenant hereby assigns to
Landlord any award which may be made in such taking or condemnation, together
with any and all rights of Tenant now or hereafter arising in or to the same or
any part thereof; provided, however, that nothing contained herein shall be
deemed to give Landlord any interest in or to require Tenant to assign to
Landlord any award made to Tenant for the taking of personal property and
fixtures belonging to Tenant and/or for Tenant's unamortized cost of leasehold
improvements, reasonable moving or relocation expenses, so long as such award to
Tenant does not decrease the value of the award that would otherwise be made to
Landlord in such taking or condemnation.  In the event of a partial taking which
does not result in a termination of this Lease, rent shall be abated in the
proportion which the part of Premises so made unusable bears to the rented area
of the Premises immediately prior to the taking, and Landlord, at


                                    -16-

<PAGE>

Landlord's cost, shall restore the Premises remaining to an architectural
whole with the Base Rent reduced in proportion to what the area taken bears
to the Premises prior to the taking.  No temporary taking of the Premises
and/or of Tenant's rights therein or under this Lease shall give Tenant the
right to terminate this Lease or to any abatement of Rent thereunder.  Any
award made to Tenant by reason of any such temporary taking where Landlord
does not terminate this Lease shall belong entirely to Tenant so long as said
award does not diminish Landlord's award.

     15.  ASSIGNMENT AND SUBLETTING

          15.1 LANDLORD'S CONSENT REQUIRED.  Tenant shall not assign, transfer,
mortgage, pledge, hypothecate or encumber this Lease or any interest therein
(each a "Transfer"), and shall not sublet the Premises or any part thereof,
without the prior written consent of Landlord and any attempt to do so without
such consent being first had and obtained shall be wholly void and shall
constitute a breach of this Lease.

          15.2 REASONABLE CONSENT.

               (a)  If Tenant complies with the following conditions, Landlord
shall not unreasonably withhold its consent to the subletting of the Premises or
any portion thereof or the assignment of this Lease.  Tenant shall submit in
writing to Landlord (i) the name and legal composition of the proposed subtenant
or assignee; (ii) the nature of the business proposed to be carried on in the
Premises; (iii) the terms and provisions of the proposed sublease; (iv) such
reasonable financial information as Landlord may request concerning the proposed
subtenant or assignee; and (v) the form of the proposed sublease or assignment.
Within ten (10) business days after Landlord receives all such information it
shall notify Tenant whether it approves such assignment or subletting or if it
elects to proceed under Paragraph 15.8 below.

               (b)  The parties hereto agree and acknowledge that, among
other circumstances for which Landlord could reasonably withhold its consent
to a sublease or assignment, it shall be reasonable for Landlord to withhold
its consent where (i) the assignee or subtenant (a "Transferee") does not
itself occupy the entire portion of the Premises assigned or sublet, (ii)
Landlord reasonably disapproves of the Transferee's reputation or
creditworthiness or the character of the business to be conducted by the
Transferee at the Premises, (iii) the assignment or subletting would increase
the burden on the Building services or the number of people occupying the
Premises, or (iv) Landlord otherwise determines that the assignment or
sublease would have the effect of decreasing the value of the Project or
increasing the expenses associated with operating the Project. In no event
may Tenant publicly advertise or offer all or any portion of the Premises for
assignment or sublease at a rental less than that then sought by Landlord for
comparable space in the project.

          15.3 EXCESS CONSIDERATION.  In the event of an assignment or
sublease to an affiliate or wholly-owned subsidiary of Tenant, Tenant shall
be entitled to 100% of any additional Rent or excess consideration.  If
Landlord consents to the assignment or sublease, Landlord shall be entitled
to receive as additional Rent hereunder one-half of any consideration paid by
the Transferee for the assignment or sublease and, in the case of a sublease,
one-half of the excess of the rent and other

                                    -17-

<PAGE>

consideration payable by the subtenant over the amount of Base Rent and
Operating Cost Payments payable hereunder applicable to the subleased space.

          15.4 NO RELEASE OF TENANT.  No consent by Landlord to any assignment
or subletting by Tenant shall relieve Tenant of any obligation to be performed
by Tenant under this Lease, whether occurring before or after such consent,
assignment or subletting, and the Transferee shall be jointly and severally
Tenant for the payment of Rent (or that portion applicable to the subleased
space in the case of a sublease) and for the performance of all other terms and
provisions of the Lease.  The consent by Landlord to any assignment or
subletting shall not relieve Tenant and any such Transferee from the obligation
to obtain Landlord's express written consent to any subsequent assignment or
subletting.  The acceptance of rent by Landlord from any other person shall not
be deemed to be a waiver by Landlord of any provision of this Lease or to be a
consent to any assignment, subletting or other transfer.  Consent to one
assignment, subletting or other transfer shall not be deemed to constitute
consent to any subsequent assignment, subletting or other transfer.

          15.5 ATTORNEYS' FEES.  Tenant shall pay Landlord's reasonable
attorneys' fees (not to exceed $500.00] incurred in connection with reviewing
any proposed assignment or sublease.

          15.6 TRANSFER OF OWNERSHIP INTEREST.  Subject to the provisions of
Paragraph 15.10, if Tenant is a business entity, any direct or indirect transfer
of 50 percent or more of the ownership interest of the entity (whether all at
one time or over the term of the Lease) shall be deemed a Transfer.

          15.7 EFFECTIVENESS OF TRANSFER.  No permitted assignment by Tenant
shall be effective until Landlord has received a counterpart of the assignment
and an instrument in which the assignee assumes all of Tenant's obligations
under this Lease arising on or after the date of assignment.  The voluntary,
involuntary or other surrender of this Lease by Tenant, or a mutual cancellation
by Landlord and Tenant, shall not work a merger, and any such surrender or
cancellation shall, at the option of Landlord, either terminate all or any
existing subleases or operate as an assignment to Landlord of any or all of such
subleases.

          15.8 LANDLORD'S RIGHT TO SPACE.  Except for the provisions set forth
in 15.6, notwithstanding any of the above provisions of this Paragraph 15 to the
contrary, if Tenant notifies Landlord that it desires to assign this Lease or
sublet all or any part of the Premises, Landlord, in lieu of consenting to such
assignment or sublease, may elect to terminate this Lease (in the case of an
assignment or a sublease of the entire Premises), or to terminate this Lease as
it relates to the space proposed to be subleased by Tenant (in the case of a
sublease of less than the entire Premises).  In such event, this Lease (or
portion thereof) will terminate on the date the assignment or sublease was to be
effective, and Landlord may lease such space to any party, including the
prospective Transferee identified by Tenant.

          15.9 NO NET PROFITS LEASES.  Anything contained in the foregoing
provisions of this Paragraph 15 to the contrary notwithstanding, neither Tenant,
nor any other person having an interest in the possession, use, occupancy or
utilization of the Premises, shall enter into any lease, sublease,


                                    -18-

<PAGE>

license, concession or other agreement for the use, occupancy or utilization
of space in the Premises which provides for rental or other payment for such
use, occupancy or utilization based in whole or in part on the net income or
profits derived by any person from the premises leased, used, occupied or
utilized (other than an amount based on a fixed percentage or percentages of
receipts or sales), and any such purported lease, sublease, license,
concession or other agreement shall be void and ineffective as a conveyance
of any right or interest in the possession, use, occupancy or utilization of
any part of the Premises.

          15.10     PERMITTED ASSIGNMENT OR SUBLEASE.  Notwithstanding any
provision to the contrary in Section 15, Tenant shall not be required to obtain
Landlord's consent to an assignment or sublease of the Premises to an entity
which controls, is controlled by or is under common control with Tenant or which
succeeds to substantially all of Tenant's assets and business by merger,
reorganization or purchase provided that such entity has a net worth equal to or
greater than that of Tenant's net worth as of the Commencement Date of this
Lease.

   16.    SUBORDINATION

          16.1 SUBORDINATION.  Except as provided in the next sentence, or as
the Tenant and the mortgagee or trustee of any "First Mortgage" (as defined
below) may otherwise agree, this Lease, at Landlord's option, shall be subject
and subordinate to all ground or underlying leases which now exist or may
hereafter be executed affecting all or any part of the Project, and to the lien
of any first mortgages or first deeds of trust (each a "First Mortgage") in any
amount or amounts whatsoever now or hereafter placed on or against the Land or
Building, Landlord's interest or estate therein, or any ground or underlying
lease, without the necessity of the execution and delivery of any further
instruments on the part of Tenant to effectuate such subordination.  If any
mortgagee or trustee of a First Mortgage or ground lessor shall elect to have
this Lease prior to the lien of its First Mortgage or ground lease, and shall
give written notice thereof to Tenant, this Lease shall be deemed prior to such
First Mortgage or ground lease, whether this Lease is dated prior to or
subsequent to the date of said First Mortgage or ground lease or the date of the
recording thereof.

          16.2 JUNIOR LIENS.  Tenant hereby agrees that this Lease shall be
superior to the lien of any present or future mortgages or deeds of trust that
are junior to any First Mortgage.

          16.3 SUBORDINATION AGREEMENTS.  Tenant will execute and deliver upon
demand without charge therefor, except for Tenant's reasonable attorneys' fees
(not to exceed $500.00) such further instruments evidencing the subordination of
this Lease to any First Mortgage or ground lease, or the subordination of any
First Mortgage or ground lease to such Lease, pursuant to Section 16.1, as the
case may be, as may be required by Landlord.  Tenant's failure to comply with
its obligations under this Paragraph 16.3 within thirty (30) days of demand
shall constitute an Event of Default and Landlord shall have the right, in such
event, to impose upon Tenant a monetary penalty of $1,000.00 for such
noncompliance, in addition to all other remedies available to Landlord under
this Lease and by law.


                                    -19-

<PAGE>

          16.4 ATTORNMENT.  If this Project is transferred to any purchaser
pursuant to or in lieu of proceedings to enforce any mortgage, deed of trust or
ground lease (collectively, "Encumbrance"), and this Lease will not be barred,
terminated, cut off or foreclosed nor will the rights and possession of Tenant
thereunder be disturbed if Tenant is not in default under the terms of the
Lease.  Tenant shall attorn to such purchaser as the Landlord under the Lease so
long as the rights of Tenant hereunder shall not be disturbed, diminished, or
interfered with, but shall continue in full force and effect so long as Tenant
shall not be in default hereunder, is either prior to such Encumbrance or the
mortgagee or trustee of a First Mortgage or ground lessor of the Project elects
to have this Lease survive such transfer, Tenant shall attorn to such purchaser
and recognize such purchaser as the landlord under this Lease, and this Lease
shall continue as a direct lease between such purchaser and Tenant.

     17.  OUIET ENJOYMENT

          Landlord covenants and agrees with Tenant that upon Tenant paying the
Rent and performing its other covenants and conditions under this Lease, Tenant
shall have the quiet possession of the Premises for the term of this Lease as
against any persons or entities lawfully claiming by, through or under Landlord,
subject, however, to the terms of this Lease and of any Encumbrance.

     18.  DEFAULT; REMEDIES

          18.1 DEFAULT.  The occurrence of any of the following shall constitute
an "Event of Default" by Tenant:

               (a)  Tenant fails to pay Rent when due and such failure continues
for five (5) days after written notice thereof to Tenant;

               (b)  Tenant fails to deliver any subordination agreement
requested by Landlord within the period described in Paragraph 16;

               (c)  Tenant fails to deliver any estoppel certificate requested
by Landlord within the period described in Paragraph 22;

               (d)  Tenant Transfers or attempts to Transfer this Lease without
complying with the provisions of Paragraph 15;

               (e)  Tenant fails to observe and perform any other provision of
this Lease to be observed or performed by Tenant, where such failure continues
for twenty (20) days after written notice thereof by Landlord to Tenant;
provided, however, that if the nature of the default is such that the same
cannot reasonably be cured within said twenty (20) day period, Tenant shall not
be deemed to be in default if Tenant shall within such period commence such cure
and thereafter diligently prosecute the same to completion;


                                    -20-

<PAGE>

               (f)  Tenant abandons the Premises; or

               (g)  The making by Tenant of any general assignment or general
arrangement for the benefit of creditors; the filing by or against Tenant of a
petition seeking relief under any law relating to bankruptcy (unless, in the
case of a petition filed against Tenant, the same is dismissed within sixty (60)
days); the appointment of a trustee or receiver to take possession of
substantially all of Tenant's assets located at the Premises or of Tenant's
interest in this Lease, where possession is not restored to Tenant within thirty
(30) days; or the attachment, execution or other judicial seizure of
substantially all of Tenant's assets located at the Premises or of Tenant's
interest in this Lease, where such seizure is not discharged within thirty (30)
days.

          18.2 REMEDIES.  Upon the occurrence of an Event of Default, Landlord
may, at any time thereafter exercise the following remedies, which shall be in
addition to any other rights or remedies now or hereafter available to Landlord
at law or in equity:

               (a)  Maintain this Lease in full force and effect and recover
Rent as it becomes due, without terminating Tenant's right to possession
irrespective of whether Tenant shall have abandoned the Premises.  In the event
Landlord elects not to terminate the Lease, Landlord shall have the right to
attempt to relet the Premises at such rent and upon such conditions and for such
a term, and to do all acts necessary to maintain or preserve the Premises as
Landlord deems reasonable and necessary without being deemed to have elected to
terminate the Lease, including removal of all persons and property from the
Premises; such property may be removed and stored in a public warehouse or
elsewhere at the cost of and for the account of Tenant.  In the event any such
reletting occurs, rents received by Landlord from such subletting shall be
applied (i) first, to the payment of the costs of maintaining, preserving,
altering and preparing the Premises for subletting and other costs of
subletting, including but not limited to brokers' commissions, attorneys' fees
and expenses of removal of Tenant's personal property, trade fixtures,
alterations and leasehold improvements; (ii) second, to the payment of Rent then
due and payable; (iii) third, to the payment of future Rent as the same may
become due and payable hereunder; and (iv) fourth, the balance, if any, shall be
paid to Tenant upon (but not before) expiration of the term of this Lease.  If
the rents received by Landlord from such subletting, after application as
provided above, are insufficient in any month to pay the Rent due and payable
hereunder for such month, Tenant shall pay such deficiency to Landlord monthly
upon demand.  Notwithstanding any such subletting for Tenant's account without
termination, Landlord may at any time thereafter, by written notice to Tenant,
elect to terminate this Lease by virtue of a previous Event of Default. During
the continuance of an Event of Default, for so long as Landlord does not
terminate Tenant's right to possession of the Premises, Landlord shall not
unreasonably withhold its consent to an assignment of this Lease or a sublease
of the Premises as set forth in Paragraph 15.2 - "Reasonable Consent".

               (b)  Terminate Tenant's right to possession of the Premises at
any time by written notice to Tenant, in which case Tenant shall immediately
surrender possession of the Premises to Landlord.  Tenant expressly acknowledges
that in the absence of such written notice from Landlord, no other act of
Landlord, including, but not limited to, its re-entry into the Premises, its
efforts to relet the Premises, its reletting of the Premises for Tenant's
account, its storage of Tenant's


                                    -21-

<PAGE>

personal property and trade fixtures, its acceptance of keys to the Premises
from Tenant or its exercise of any other rights and remedies under this
Paragraph 18.2, shall constitute an acceptance of Tenant's surrender of the
Premises or constitute a termination of this Lease or of Tenant's right to
possession of the Premises.  If Landlord terminates Tenant's right to
possession in writing, Landlord shall be entitled to recover from Tenant all
damages as provided in California Civil Code Section 1951.2 or any other
applicable existing or future law, ordinance or regulation providing for
recovery of damages for such breach, including but not limited to the
following:

                    (1)  The reasonable cost of recovering the Premises; plus

                    (2)  The reasonable cost of removing Tenant's alterations,
trade fixtures and Above-Standard Improvements; plus

                    (3)  All unpaid Rent due or earned hereunder prior to the
date of termination, less the proceeds of any reletting or any rental received
from subtenants prior to the date of termination applied as provided in
subsection (a) above, together with interest at the Default Rate, on such sums
from the date such Rent is due and payable until the date of the award of
damages; plus

                    (4)  The amount by which the Rent which would be payable by
Tenant hereunder, including Operating Cost Payments as reasonably estimated by
Landlord, from the date of termination until the date of the award of damages
exceeds the amount of such rental loss Tenant proves could have been reasonably
avoided, together with interest at the Default Rate on such sums from the date
such Rent is due and payable until the date of the award of damages; plus

                    (5)  The amount by which the Rent which would be payable by
Tenant hereunder, including Operating Cost Payments, as reasonably estimated by
Landlord, for the remainder of the then term, after the date of the award of
damages exceeds the amount of such rental loss as Tenant proves could have been
reasonably avoided, discounted at the discount rate published by the Federal
Reserve Bank of San Francisco for member banks at the time of the award plus one
percent (l%); plus

                    (6)  Such other amounts in addition to or in lieu of the
foregoing as may be permitted from time to time by applicable law.

               (c)  During the continuance of an Event of Default, Landlord may
enter the Premises without terminating this Lease and remove all Tenant's
personal property, and trade fixtures from the Premises.  If Landlord removes
such property from the Premises and stores it at Tenant's risk and expense, and
if Tenant fails to pay the cost of such removal and storage after written demand
therefor and/or to pay any Rent then due, after the property has been stored for
a period of thirty (30) days or more Landlord may sell such property at public
or private sale, in the manner and at such times and places as Landlord in its
sole discretion deems commercially reasonable following reasonable notice to
Tenant of the time and place of such sale.  The proceeds of any such sale shall
be applied first to the payment of the expenses for removal and storage of the
property, preparation for


                                    -22-

<PAGE>

and conducting such sale, and attorneys' fees and other legal expenses
incurred by Landlord in connection therewith, and the balance shall be
applied as provided in subsection (a) above.

     Tenant hereby waives all claims for damages that may be caused by
Landlord's reentering and taking possession of the Premises or removing and
storing Tenant's personal property pursuant to this Paragraph, and Tenant shall
hold Landlord harmless from and against any loss, cost or damage resulting from
any such act.  No reentry by Landlord shall constitute or be construed as a
forcible entry by Landlord.

               (d)  Landlord may cure the Event of Default at Tenant's expense.
If Landlord pays any sum or incurs any expense in curing the Event of Default,
Tenant shall reimburse Landlord upon demand for the amount of such payment or
expense with interest at the Default Rate from the date the sum is paid or the
expense is incurred until Landlord is reimbursed by Tenant.

          18.3 LATE CHARGES.  Tenant hereby acknowledges that late payment by
Tenant to Landlord of Rent will cause Landlord to incur costs not contemplated
by this Lease, the exact amount of which will be extremely difficult to
ascertain.  Such costs include, but are not limited to, processing and
accounting charges. Accordingly, if any installment of Base Rent, Rent, or
Operating Costs Payments is not received by Landlord or Landlord's designee
within seven (7) days of the date such amount shall be due, or if any
installment of other Rent is not received by Landlord or Landlord's designee on
or before the date such amount shall be due, Tenant shall pay to Landlord a late
charge equal to five percent (5%) of such overdue amount.  The parties hereby
agree that such late charge represents a fair and reasonable estimate of the
costs Landlord will incur by reason of late payment by Tenant. Acceptance of
such late charge by Landlord shall in no event constitute a waiver of Tenant's
default with respect to such overdue amount nor prevent Landlord from exercising
any of the other rights and remedies granted hereunder.  Notwithstanding the
foregoing, Tenant is hereby granted one (1) grace period which shall not exceed
fifteen (15) days during each calendar year of this Lease.

          18.4 INTEREST.  In addition to the late charges referred to above
which are intended to defray Landlord's costs resulting from late payments, any
late payment of Rent shall, at Landlord's option, bear interest from the due
date of any such payment to the date the same is paid at the Default Rate,
provided, however, that if Landlord imposes a late charge on any overdue
payment, such overdue payment shall not begin to bear interest under this
Paragraph 18.4 until thirty (30) days after the due date thereof.

          18.5 DEFAULT BY LANDLORD.  Landlord shall not be in default unless
Landlord fails to perform obligations required of Landlord within a reasonable
time, but in no event later than thirty (30) days after written notice by Tenant
to Landlord and to any mortgagee, trustee or ground lessor of the Project (each
a "Holder") whose name and address shall have theretofore been furnished to
Tenant in writing, specifying that Landlord has failed to perform such
obligations; provided, however, that if the nature of Landlord's obligation is
such that more than thirty (30) days are required for performance, then Landlord
shall not be in default if Landlord commences performance within such thirty
(30) day period and thereafter diligently prosecutes the same to completion.


                                    -23-

<PAGE>

     19.  PARKING

          At no additional charge during the initial Lease Term, Tenant and
Tenant's employees, invitees and customers shall have the right to use the
parking areas of the Building subject to such regulations as Landlord shall
adopt from time to time, and subject to the right of Landlord to restrict the
use by Tenant and Tenant's Representatives when in the sole judgment of Landlord
such use is excessive for the parking area in relationship to the reasonable use
required by other Tenants.  If Landlord becomes obligated under applicable laws
or regulations or any other directive of any governmental or quasi-governmental
authority to pay or assess fees or charges for parking in the Building's parking
area, Tenant shall pay such amounts to Landlord as additional Rent.

     20.  RELOCATION OF PREMISES

          20.1 CONDITIONS.  For the purpose of maintaining an economical and
proper distribution of Tenants throughout Bishop Ranch acceptable to Landlord,
Landlord shall have the right from time to time during the term of this Lease to
relocate the Premises within Bishop Ranch, subject to the following terms and
conditions:

               (a)  The rented and usable areas of the new Premises must be of
equal size to the existing Premises (subject to a variation of up to ten percent
(10%) provided the amount of Base Rent payable under this Lease is not
increased);

               (b)  Landlord shall pay the cost of providing tenant improvements
in the new Premises comparable to the tenant improvements in the existing
Premises;

               (c)  Landlord shall pay the expenses reasonably incurred by
Tenant in connection with such substitution of Premises, including but not
limited to costs of moving, door lettering, telephone relocation and reasonable
quantities of new stationery and Tenant literature;

          20.2 NOTICE.  Landlord shall deliver to Tenant written notice of
Landlord's election to relocate the Premises, specifying the new location and
the amount of rent payable therefore at least one hundred twenty (120) days
prior to the date the relocation is to be effective.  If the relocation of the
Premises is not acceptable to Tenant, Tenant for a period of ten (10) days after
receipt of Landlord's notice to relocate shall have the right (by delivering
written notice to Landlord) to terminate this Lease.  If Tenant so notifies
Landlord, Landlord at its option may withdraw its relocation notice, in which
event this Lease shall continue and Tenant shall not be relocated, or accept
Tenant's termination notice, in which event this Lease shall terminate effective
as of the date the relocation was to be effective.

     21.  MORTGAGEE PROTECTION

          Tenant agrees to give any Holder, by registered mail, a copy of any
notice of default served upon the Landlord, provided that prior to such notice
Tenant has been notified in writing (by way of notice of assignment of rents and
leases, or otherwise) of the address of such Holder.  If


                                    -24-

<PAGE>

Landlord shall have failed to cure such default within the time period set
forth in Paragraph 18.5 the Holder shall have an additional thirty (30) days
within which to cure such default or if such default cannot be cured within
that time, then such additional time as may be necessary to cure such default
(including the time necessary to foreclose or otherwise terminate its
Encumbrance, if necessary to effect such cure), and this Lease shall not be
terminated so long as such remedies are being diligently pursued.

     22.  ESTOPPEL CERTIFICATES

          (a)  Upon ten (10) days' notice from Landlord, Tenant shall execute
and deliver to Landlord, in form reasonably provided by or satisfactory to
Landlord, a certificate stating that this Lease is in full force and effect,
describing any amendments or modifications hereto, acknowledging that this Lease
is subordinate or prior, as the case may be, to any Encumbrance and stating any
other information Landlord may reasonably request, including the term of this
Lease, the monthly Base Rent, the estimated Operating Cost Payments, the date to
which Rent has been paid, the amount of any security deposit or prepaid Rent,
whether either party hereto is in default under the terms of the Lease, whether
Landlord has completed its construction obligations hereunder and any other
information reasonably requested by Landlord. Any person or entity purchasing,
acquiring an interest in or extending financing with respect to the Project
shall be entitled to rely upon any such certificate.

          (b)  Tenant's failure to deliver such statement within such time shall
be conclusive upon Tenant:

               (1)  That this Lease is in full force and effect, without
modification except as may be represented by Landlord;

               (2)  That there are no uncured defaults in Landlord's
performance; and

               (3)  That not more than one month's Rent has been paid in
advance; and

               (4)  That Landlord has completed its construction obligations.

          (c)  If Landlord desires to finance or refinance the Building, or any
part thereof, Tenant hereby agrees to deliver to any lender designated by
Landlord such financial statements of Tenant as may be reasonably required by
such lender which are then in the possession of Tenant provided such financial
statements shall be held in the strictest confidence.  All such financial
statements shall be received by Landlord in confidence and shall be used only
for the purposes herein set forth.

     23.  SURRENDER. HOLDING OVER

          23.1 SURRENDER.  Upon the expiration or termination of this Lease,
Tenant shall surrender the Premises to Landlord in its original condition,
except for reasonable wear and tear and damage from casualty or condemnation;
provided, however, that prior to the expiration or


                                    -25-

<PAGE>

termination of this Lease Tenant shall remove from the Premises all Tenant's
personal property, trade fixtures, alterations and other Above-Standard
Improvements that Tenant has the right or is required by Landlord to remove
under the provisions of this Lease. Tenant shall also be responsible for
removal of all CRT, data and telephone equipment, and any other form of
cabling. that exists in Tenant's space.  If any of such removal is not
completed at the expiration or termination of this Lease, Landlord may remove
the same at Tenant's expense.  Any damage to the Premises or the Building
caused by such removal shall be repaired promptly by Tenant or, if Tenant
fails to do so, Landlord may do so at Tenant's expense, in which event Tenant
shall immediately reimburse Landlord for such expenses together with interest
at the Default rate until so paid.  Tenant's obligations under this Paragraph
shall survive the expiration or termination of this Lease.  Upon expiration
or termination of this Lease or of Tenant's possession, Tenant shall
surrender all keys to the Premises or any other part of the Building and
shall make known to Landlord the combination of locks on all safes, cabinets
and vaults that may be located in the Premises.

          23.2 HOLDING OVER.  If Tenant remains in possession of the Premises
after the expiration or termination of this Lease, Tenant's continued possession
shall be on the basis of a tenancy at the sufferance of Landlord, and Tenant
shall continue to comply with or perform all the terms and obligations of the
Tenant under this Lease, except that the Base Rent during Tenant's holding over
shall be one hundred twenty-five percent (25%) of the monthly Base Rent payable
in the last month prior to the termination or expiration hereof.  Tenant shall
indemnify and hold Landlord harmless from and against all claims, liability,
damages, costs or expenses, including reasonable attorneys fees and costs of
defending the same, incurred by Landlord and arising directly or indirectly from
Tenant's failure to timely surrender the Premises, including (i) any loss, cost,
penalties, or damages, including lost profits, claimed by any prospective tenant
of the Premises, and (ii) Landlord's damages as a result of such prospective
tenant rescinding or refusing to enter into the prospective lease of the
Premises by reason of such failure to timely surrender the Premises.

     24.  HAZARDOUS MATERIALS

          Tenant shall not (either with or without negligence) cause or permit
the escape, disposal or release of any biologically or chemically active or
other hazardous substances or materials. Tenant shall not allow the storage or
use of such substances or materials in any manner not sanctioned by law or by
the highest standards prevailing in the industry for the storage and use of such
substances or materials, nor allow to be brought into the Project any such
materials or substances except to use in the ordinary course of Tenant's
business, and then only after written notice is given to Landlord of the
identity of such substances or materials.  Without limitation, hazardous
substances and materials shall include those described in the Comprehensive
Environmental Response Compensation and Liability Act of 1980, as amended, 42
U.S.C. Section 9601 et seq., any applicable state or local laws and the
regulations adopted under these acts.  If any lender or governmental agency
shall ever require testing to ascertain whether or not there has been any
release of hazardous materials used or stored by Tenant in the Premises, then
Tenant shall promptly notify Landlord of the same, and the reasonable costs
thereof shall be reimbursed by Tenant to Landlord upon demand as additional
charges if such requirement applies to the Premises due to Tenant's use or
storage thereof.  Landlord shall have the right, but not the obligation, to
enter the Premises at any


                                    -26-

<PAGE>

reasonable time to perform any required testing, to confirm Tenant's
compliance with the provisions of this Paragraph, and to perform Tenant's
obligations under this Paragraph if Tenant has failed to do so. In addition,
Tenant shall execute affidavits, representations and the like from time to
time at Landlord's request concerning Tenant's best knowledge and belief
regarding the presence of hazardous substances or materials on the Premises.
In all events, Tenant shall indemnify Landlord in the manner elsewhere
provided in this Lease from any release of hazardous materials on the
Premises occurring while Tenant is in possession, or elsewhere if caused by
Tenant or persons acting under Tenant.  The within covenants shall survive
the expiration or earlier termination of the lease term.

          24.1 Landlord agrees to indemnify and defend Tenant against any and
all claims, actions, losses, costs, liabilities, damages and expense, including,
without limitation, reasonable attorneys' fees, to the extent caused by the
release of any Hazardous Materials on the Project by Landlord or by reason of
the failure of the Project as of the Commencement Date to comply with the above-
mentioned statutes, laws and regulations related to the regulation of Hazardous
Materials in effect and as interpreted at the date of this Lease.

   25.    MISCELLANEOUS

          25.1 ATTORNMENT.  Upon any transfer by Landlord of Landlord's interest
in the premises or the Building (other than a transfer for security purposes
only), Tenant agrees to attorn to any transferee or assignee of Landlord.

          25.2 CAUTIONS: ATTACHMENTS; DEFINED TERMS.

               (a)  The captions of the paragraphs of this Lease are for
convenience only and shall not be deemed to be relevant in resolving any
question of interpretation or construction of any paragraph of this Lease.  The
provisions of this Lease shall be construed in accordance with the fair meaning
of the language used and shall not be strictly construed against either party.
When required by the contents of this Lease, the singular includes the plural.
Wherever the term "including" is used in this Lease, it shall be interpreted as
meaning "including, but not limited to," the matter or matters thereafter
enumerated.

               (b)  Exhibits attached hereto, and addenda and schedules
initialed by the parties, are deemed to constitute part of this Lease and are
incorporated herein.

               (c)  The words "Landlord" and "Tenant" as used herein, shall
include the plural as well as the singular.  Words used in neuter gender include
the masculine and feminine and words in the masculine or feminine gender include
the neuter.  The obligations of this Lease as to a Tenant which consists of
husband and wife shall extend individually to their sole and separate property
as well as community property.

          25.3 ENTIRE AGREEMENT.  This Lease along with any exhibits and
attachments hereto constitutes the entire agreement between Landlord and Tenant
relative to the Premises, and this Lease and the exhibits and attachments may be
altered, amended or revoked only by instrument in writing


                                    -27-

<PAGE>

signed by both Landlord and Tenant.  Landlord and Tenant agree hereby that
all prior or contemporaneous oral agreements between and among themselves and
their agents or representatives relative to the leasing of the Premises are
merged in or revoked by this Lease.

          25.4 SEVERABILITY.  If any term or provision of this Lease shall, to
any extent, be determined by a court of competent jurisdiction to be invalid or
unenforceable, the remainder of this Lease shall not be affected thereby, and
each term and provision of this Lease shall be valid and be enforceable to the
fullest extent permitted by law.

          25.5 COSTS OF SUIT.

               (a)  If Tenant or Landlord brings any action for the enforcement
or interpretation of this Lease, including any suit by Landlord for the recovery
of Rent or possession of the Premises, the losing party shall pay to the
prevailing party a reasonable sum for attorneys' fees.  The "prevailing party"
will be determined by the court before whom the action was brought based upon an
assessment of which party's major arguments or positions taken in the suit or
proceeding could fairly be said to have prevailed over the other party's major
arguments or positions on major disputed issues in the court's decision.

               (b)  Should Landlord, without fault on Landlord's part, be made a
party to any litigation instituted by Tenant or by any third party against
Tenant, or by or against any person holding under or using the Premises by
license of Tenant, or for the foreclosure of any lien for labor or material
furnished to or for Tenant or any such other person or otherwise arising out of
or resulting from any act or transaction of Tenant or of any such other person,
Tenant covenants to save and hold Landlord harmless from any judgment rendered
against Landlord or the Premises or any part thereof, and all costs and
expenses, including reasonable attorneys' fees, incurred by Landlord in or in
connection with such litigation.

          25.6 TIME; JOINT AND SEVERAL LIABILITY.  Time is of the essence of
this Lease and each and every provision hereof, except as to the conditions
relating to the delivery of possession of the Premises to Tenant. All the terms,
covenants and conditions contained in this Lease to be performed by either
party, if such party shall consist of more than one person or organization,
shall be deemed to be joint and several, and all rights and remedies of the
parties shall be cumulative and nonexclusive of any other remedy at law or in
equity.

          25.7 BINDING EFFECT; CHOICE OF LAW.  The parties hereto agree that all
provisions hereof are to be construed as both covenants and conditions as though
the words imparting such covenants and conditions were used in each separate
paragraph hereof.  Subject to any provisions hereof restricting assignment or
subletting by Tenant, all of the provisions hereof shall bind and inure to the
benefit of the parties hereto and their respective heirs, legal representatives,
successors and assigns.  This Lease shall be governed by the laws of the State
of California.

          25.8 WAIVER.  No covenant, term or condition or the breach thereof
shall be deemed waived, except by written consent of the party against whom the
waiver is claimed, and any waiver or


                                    -28-

<PAGE>

breach of any covenant, term condition shall not be deemed to be a waiver of
any preceding or succeeding breach of the same or any other covenant, term or
condition. Acceptance by Landlord of any performance by Tenant after the time
the same shall have become due shall not constitute a waiver by Landlord of
the breach or default of any covenant, term or condition unless otherwise
expressly agreed to by Landlord in writing.

          25.9 FORCE MAJEURE.  In the event Landlord is delayed, interrupted or
prevented from performing any of its obligations under this Lease, including its
obligations under the Work Letter, and such delay, interruption or prevention is
due to fire, act of God, governmental act, strike, labor dispute, unavailability
of materials or any other cause outside the reasonable control of Landlord and
other than for financial reasons, then the time for performance of the affected
obligations of Landlord shall be extended for a period equivalent to the period
of such delay, interruption or prevention and in the case of work to be
performed by Landlord under the Work Letter, each day of delay under this
Subsection shall result in one (1) Scheduled Commencement Adjustment Day.

          25.10     LANDLORD'S LIABILITY.  The term "Landlord", as used in this
Lease, shall mean only the owner or owners of the Project at the time in
question.  Notwithstanding any other term or provision of this Lease, the
liability of Landlord for its obligations under this Lease is limited solely to
Landlord's interest in the Project as the same may from time to time be
encumbered, and no personal liability shall at any time be asserted or
enforceable against any other assets of Landlord or against Landlord's
stockholders, directors, officers or partners on account of any of Landlord's
obligations or actions under this Lease.  In addition, in the event of any
conveyance of title to the Building or the Project, then from and after the date
of such conveyance, Landlord shall be relieved of all liability with respect to
Landlord's obligations to be performed under this Lease after the date of such
conveyance.  Upon any conveyance of title to the Building or the Project, the
grantee or transferee, by accepting such conveyance, shall be deemed to have
assumed Landlord's obligations to be performed under this Lease from and after
the date of transfer, subject to the limitations on liability set forth above in
this Paragraph 25.10.  In no event will Landlord be liable under this Lease for
consequential or indirect damages or loss of profits.

          25.11     CONSENTS AND APPROVALS.  Wherever the consent, approval,
judgment or determination of Landlord is required or permitted under this
Lease, Landlord may exercise its good faith business judgment in granting or
withholding such consent or approval or in making such judgment or
determination without reference to any extrinsic standard of reasonableness,
unless the provision providing for such consent, approval, judgment or
determination specifies that Landlord's consent or approval is not to be
unreasonably withheld, or that such judgment or determination is to be
reasonable, or otherwise specifies the standards under which Landlord may
withhold its consent. If it is determined that Landlord failed to give its
consent where it was required to do so under this Lease, Tenant shall be
entitled to specific performance but not to monetary damages for such
failure, unless Landlord withheld its consent maliciously and in bad faith.
Notwithstanding the foregoing, Landlord shall not unreasonably withhold its
consent or approval.

     The review and/or approval by Landlord of any item to be reviewed or
approved by Landlord under the terms of this Lease or any Exhibits hereto shall
not impose upon Landlord any liability for


                                    -29-

<PAGE>

accuracy or sufficiency of any such item or the quality or suitability of
such item for its intended use.  Any such review or approval is for the sole
purpose of protecting Landlord's interest in the Project under this Lease,
and no third parties, including Tenant or Tenant's Representatives or any
person or entity claiming by, through or under Tenant, shall have any rights
hereunder.

          25.12     SIGNS.  Tenant shall not place or permit to be placed in or
upon the Premises where visible from outside the Premises or any part of the
Building, any signs, notices, drapes, shutters, blinds or displays of any type
without the prior consent of Landlord.  Landlord shall include Tenant in the
Building directories located in the Building.  Landlord reserves the right in
Landlord's sole discretion to place and locate on the roof, exterior of the
Building, and in any area of the Building not leased to Tenant such signs,
notices, displays and similar items as Landlord deems appropriate in the proper
operation of the Building.

          25.13     RULES AND REGULATIONS.  Tenant and Tenant's Representatives
shall observe and comply fully and faithfully with all reasonable and
nondiscriminatory rules and regulations adopted by Landlord for the care,
protection, cleanliness and operation of the Building and its tenants including
those annexed to this Lease as Exhibit D and any modification or addition
thereto adopted by Landlord, provided Landlord shall give written notice thereof
to Tenant.  Landlord shall not be responsible to Tenant for the nonperformance
by any other tenant or occupant of the Building of any of said rules and
regulations.  Notwithstanding the foregoing, Tenant shall not be required to
comply with any new rule or regulation, unless the same applies
nondiscriminatorily to all Tenants of the Project and use not unreasonably
interfere with Tenant's use of the Premises or Tenant's parking rights.

          25.14     NOTICES.  All notices or demands of any kind required or
desired to be given by Landlord or Tenant hereunder shall be in writing and
shall be personally delivered, sent in the United States mail, certified or
registered, postage prepaid, or sent by private messenger, addressed to the
Landlord or Tenant respectively at the addresses set forth below:

Landlord:                          Tenant:

ANNABEL INVESTMENT COMPANY         SUPERGEN, INC.
One Annabel Lane, Suite 201        Attn:  Accounting Administrator
P. O. Box 640                      Two Annabel Lane, Suite 220
San Ramon, CA  94583               San Ramon, CA  94583

or such other address as shall be established by notice to the other pursuant to
this paragraph.  Notices personally delivered or delivered by private messenger
shall be deemed delivered when received at the address for such party designated
pursuant to this paragraph.  Notices sent by mail shall be deemed delivered on
the earlier of the third business day following deposit thereof with the United
States Postal Service by certified mail, or the delivery date shown on the
return receipt prepared in connection therewith.



                                    -30-

<PAGE>

          25.15     AUTHORITY.  If Tenant is a corporation or a partnership,
each individual executing this Lease on behalf of Tenant represents and warrants
that Tenant is a duly organized and validly existing entity, the persons signing
on behalf of Tenant, are duly authorized to execute and deliver this Lease on
behalf of Tenant and this Lease is binding upon Tenant in accordance with its
terms.  If Tenant is a corporation, Tenant shall, within thirty (30) days after
execution of this Lease, deliver to Landlord a certified copy of a resolution of
the board of directors of said corporation authorizing or ratifying the
execution of this Lease.

          25.16     LEASE GUARANTY.  (Deleted)

          25.17     BROKERS.  Tenant warrants and represents to Landlord that in
the negotiating or making of this Lease neither Tenant nor anyone acting on its
behalf has dealt with any real estate broker or finder who might be entitled to
a fee or commission for this Lease.  Tenant agrees to indemnify and hold
Landlord harmless from any claim or claims, including costs, expenses and
attorney's fees incurred by Landlord asserted by any other broker or finder for
a fee or commission based upon any dealings with or statements made by Tenant or
its agents, employees or representatives.

          25.18     RESERVED RIGHTS.  Landlord retains and shall have the rights
set forth below, exercisable without notice and without liability to Tenant for
damage or injury to property, person or business and without effecting an
eviction, constructive or actual, or disturbance of Tenant's use or possession
of the Premises or giving rise to any claim for set-off or abatement of Rent, to
reduce, increase, enclose or otherwise change at any time and from time to time
the size, number, location, lay-out and nature of the common areas and
facilities and other tenancies and premises in the Project and to create
additional rentable areas through use or enclosure of common areas, provided
that the foregoing shall not materially restrict or otherwise impair Tenant's
access to, use or occupancy of the Premises.

          25.19     OPTION TO EXTEND.  Landlord hereby grants Tenant with one
(1) Option to Extend the Term of this Lease for a period of five (5) years at
the then Fair Market Value for Bishop Ranch. In order to exercise this Option to
Extend, Tenant shall provide Landlord with nine (9) months' prior written notice
indicating their desire to exercise this Option to Extend.  In the event Tenant
fails to provide Landlord with written notice within the aforementioned time
frame, then Tenant shall be deemed to have waived its rights to this Option to
Extend.


                                    -31-

<PAGE>

     Landlord and Tenant have executed this Lease on the date and year set forth
at the beginning of this Lease.


Landlord:                          Tenant:

ANNABEL INVESTMENT COMPANY,        SUPERGEN, INC.
a California partnership



By:  /s/ Judith K. Martin           By:  /s/ Dr. Joseph Rubinfeld
    ---------------------------        --------------------------------
                                        Authorized Agent

                                    -32-

<PAGE>


                                 SITE PLAN

                            EXHIBIT A - Page 1
                            ------------------

                             BISHOP RANCH 12
                            TWO ANNABEL LANE
                           SAN RAMON, CA 94583


<PAGE>

                       TYPICAL SECOND FLOOR PLAN

                          EXHIBIT A - Page 2
                          ------------------

                        BISHOP RANCH 12 BLDG. B
                             SUITE 220
                           SECOND FLOOR
                            9,247 RSF


<PAGE>


                                    EXHIBIT B

                        ATTACHED TO AND FORMING A PART OF
                                 LEASE AGREEMENT
                          DATED AS OF OCTOBER 14, 1996
                                    BETWEEN

                               ANNABEL INVESTMENT
                              COMPANY, AS LANDLORD,
                                      AND
                                 SUPERGEN, INC.,
                                   AS TENANT
                                   ("LEASE")



                                   WORK LETTER


     1.   SUITE  IMPROVEMENTS.  Landlord shall construct and install in the
Premises the improvements and fixtures provided for in this Construction Rider
("Suite Improvements").

          1.1  PLANS.  With reasonable diligence after the execution of the
Lease, Landlord will cause the space planner for the Premises (the "Space
Planner") to prepare and deliver to Tenant detailed plans and specifications
sufficient to permit the construction of the Suite Improvements by Landlord
("Construction Documents") which describes the improvements to be made to the
Premises beyond the "Building Shell" utilizing "Building Standard Materials" (as
such terms are described in the attached Schedule I.) Tenant will approve said
Construction Documents on or before November 1, 1996.

          1.2  CONSTRUCTION.  Upon approval by Tenant of the Final Construction
Documents, Landlord shall proceed with reasonable diligence to cause the Suite
Improvements to be "Substantially Completed" on or prior to the Scheduled
Commencement Date.  The Suite Improvements shall be deemed to be "Substantially
Completed" when they have been completed in accordance with the Final
Construction Documents except for finishing details, minor omissions,
decorations and mechanical adjustments of the type normally found on an
architectural "punch list".  (The definition of Substantially Completed shall
also define the terms "Substantial Completion" and "Substantially Complete.")

          1.3  COST OF SUITE IMPROVEMENTS. See Section 1 of Building Lease
entitled PREMISES.

         1.4   TENANT DELAYS.  Tenant shall be responsible for, and shall pay to
Landlord, any and all reasonable costs and expenses incurred by Landlord in
connection with any delay in the commencement or completion of any Suite
Improvements and any increase in the cost of Suite Improvements (whether
Building Standard or Above-Standard) caused by (i) Tenant's failure to approve
the Construction Documents by November 1, 1996, (conditioned upon Tenant's
receipt of Final Construction Drawings acceptable to Tenant by October 26,
1996), (ii) Tenant's requesting more than one revision to the Construction
Documents after Tenant's final approval, (iii) Above-Standard Suite Improvements
requested by Tenant, (iv) any changes or modifications in the work requested by
Tenant following approval of the Final Construction Documents, or (v) any other
delay requested or caused by Tenant (collectively, "Tenant Delays").
Notwithstanding the foregoing, no




<PAGE>

Tenant Delay shall be deemed to have occurred unless and until Landlord gives
written notice to Tenant specifying the action, inaction or occurrence
constituting the Tenant Delay and the number of days of such Tenant Delay
("Tenant Delay Notice").  Each Tenant Delay day will result in one (1)
Scheduled Commencement Adjustment Day.

     2.   COMMENCEMENT OF TERM.  Upon Substantial Completion of the Suite
improvements, Landlord shall deliver possession of the Premises to Tenant.  The
Commencement Date will be the date after the earlier of Substantial Completion
of the Suite Improvements or the date Landlord would have Substantially
Completed the Premises and tendered the Premises to Tenant if Substantial
Completion had not been delayed by the number of days specified in any and all
Tenant Delay Notices given by Landlord, as described in Paragraph 1.4.

     3.   ACCESS TO PREMISES.  Landlord, at its discretion, may allow Tenant or
Tenant's Representatives to enter the Premises prior to the Commencement Date to
permit Tenant to make the Premises ready for its use and occupancy; provided,
however, that prior to such entry, Tenant shall provide evidence reasonably
satisfactory to Landlord that Tenant's insurance, as described in Paragraph 12
of the Lease, shall be in effect as of the time of such entry.  Such permission
may be revoked at any time upon twenty-four (24) hours notice, and Tenant or its
Representatives shall not interfere with Landlord or Landlord's contractor in
completing the Building or the Suite Improvements.  Tenant agrees that Landlord
shall not be liable in any way for any injury, loss or damage which may occur to
any of Tenant's property placed upon or installed in the Premises prior to the
Commencement Date, the same being at Tenant's sole risk, and Tenant shall be
liable for all injury, loss or damage to persons or property arising as a result
of such entry of the Premises by Tenant or its Representatives.

     4.   OWNERSHIP OF SUITE IMPROVEMENTS.  All Suite Improvements, whether
Building Standard or Above-Standard, and whether installed by Landlord or
Tenant, shall become a part of the Premises, shall be the Property of Landlord
and, unless Landlord elects otherwise as provided in the Lease, shall be
surrendered by Tenant with the Premises, without any compensation to Tenant, at
the expiration or termination of the Lease.



                                    -2-

<PAGE>

                             SCHEDULE 1 TO EXHIBIT B

                                 BUILDING SHELL

*    All core areas, elevator lobbies and restrooms complete.

*    Main HVAC loop in place ready to receive mixing boxes for zoning.

*    Main fire sprinkler risers and grid in place ready for drop down.

*    All perimeter walls sheetrocked and ready for finish.

*    Upper floors covered with 3-1/2 inch concrete.

*    Electrical service to closets on floor.

*    Telephone outlet/conduit to closets on floor.


                           BUILDING STANDARD MATERIALS

ELECTRICAL

*    Day Bright 277 light fixtures with energy conserving ballasts and lamps;
     per Title 24 requirements.

*    Double switching in individual offices.

*    One duplex 110 receptacle at each work station.

*    One telephone outlet at each work station.

HVAC

*    One zone per 800 usable square feet.

*    Individual pneumatic thermostats per 800 usable square feet.

FIRE SPRINKLERS

     One 165 degree rate, semi-recessed sprinkler head per 144 usable square
     feet.


                                    -3-

<PAGE>

PARTITIONS AND DOORS

*    5/8-inch drywall on 2-1/2 inch steel studs with smooth finish.

*    Solid core oak doors 36" x 96".

*    Aluminum door jambs.

*    Schlage door latches or equal.

PAINT

*    Kelly Moore or equal.

RATED CEILING ASSEMBLY

*    USG: Aurora Reveal Tile.

CARPET, TILE AND BASE

*    Carpet: 38 oz.  Design Weave.

*    Armstrong Imperial Modern Excelon Tile or equal.

*    3/8 inch nylon composition pad.

*    4 inch rubber top set base or equal.

WINDOW COVERING

*    Mini Blinds.


                                    -4-

<PAGE>







                             EXHIBIT C - SPACE PLAN





                                 TO BE PROVIDED




<PAGE>

                                    EXHIBIT D

                              RULES AND REGULATIONS


     1.   No sign, placard, picture, advertisement, name or notice shall be
inscribed, displayed, printed, affixed or otherwise displayed by Tenant on or to
any part of the outside or inside of the Building or the Premises without the
prior written consent of Landlord and Landlord shall have the right to remove
any such sign, placard, picture, advertisement, name or notice without notice to
and at the expense of Tenant.  All approved signs or lettering on doors shall be
printed, painted, affixed or inscribed at the expense of Tenant by a person
approved by Landlord.  Tenant shall not place anything or allow anything to be
placed near the glass of any window, door, partition or wall which may appear
unsightly from outside the Premises; provided, however that Tenant may request
Landlord to furnish and install a building standard window covering at all
exterior windows at Tenant's cost.  Tenant shall not install any radio or
television antenna, loud speaker, or other device on or about the roof area or
exterior walls of the Building.

     2.   The sidewalks, halls, passages, exits, entrances, elevators and
stairways shall not be obstructed by Tenant or used by it for any purpose other
than for ingress to and egress from the Premises.  The halls, passages, exits,
entrances, elevators, stairways, balconies and roof are not for the use of the
general public and Landlord shall in all cases retain the right to control and
prevent access thereto by all persons whose presence in the judgment of the
Landlord shall be prejudicial to the safety, character, reputation and interests
of the Building and its tenants, provided that nothing herein contained shall be
construed to prevent such access to the common areas by persons with whom Tenant
normally deals in the ordinary course of its business unless such persons are
engaged in illegal activities.  In no event may Tenant go upon the roof of the
Building.

     3.   Landlord will furnish Tenant with _______ keys to the Premises, free
of charge.  Additional keys shall be obtained only from Landlord and Landlord
may make a reasonable charge for such additional keys.  No additional locking
devices shall be installed in the Premises by Tenant, nor shall any locking
devices be changed or altered in any respect without the prior written consent
of Landlord.  All locks installed in the Premises excluding Tenant's vaults and
safes, or special security areas (which shall be designated by Tenant in a
written notice to Landlord), shall be keyed to the Building master key system.
Landlord may make reasonable charge for any additional lock or any bolt
(including labor) installed on any door of the Premises.  Tenant, upon the
termination of its tenancy, shall deliver to Landlord all keys to doors in the
Premises.

     4.   The toilet rooms, urinals, wash bowls and other apparatus shall not be
used for any purpose other than that for which they were constructed and no
foreign substance of any kind whatsoever shall be deposited therein and Tenant
shall bear the expense of any breakage, stoppage or damage resulting from its
violation of this rule.

     5.   Tenant shall not overload the floor of the Premises or mark, drive
nails, screw or drill into the partitions, woodwork or plaster or in any way
deface the Premises or any part thereof, except



<PAGE>

to hang pictures or whiteboards. No boring, cutting or stringing of wires or
laying of linoleum or other similar floor coverings or installation of
wallpaper or paint shall be permitted except with the prior written consent
of the Landlord and as the Landlord may direct.

     6.   Tenant may use the freight elevators in accordance with such
reasonable scheduling as Landlord shall deem appropriate. Tenant shall schedule
with Landlord, by written notice given no less than forty-eight (48) hours in
advance, its move into or out of the Building which moving shall occur after
5:00 p.m. or on weekend days if required by Landlord; and Tenant shall reimburse
Landlord upon demand for any additional security or other charges incurred by
Landlord as a consequence of such moving.  The persons employed by Tenant to
move equipment or other items in or out of the Building must be acceptable to
Landlord.  The floors, corners and walls of elevators and corridors used for
moving of equipment or other items in or out of the Project must be adequately
covered, padded and protected and, Landlord may provide such padding and
protection at Tenant's expense if Landlord determines that such measures
undertaken by Tenant or Tenant's movers are inadequate. Landlord shall have the
right to prescribe the weight, size and position of all safes and other heavy
equipment or furnishings brought into the Building and also the times and manner
of moving the same in or out of the Building.  Safes or other heavy objects
shall, if considered necessary by Landlord, stand on wood strips of such
thickness as is necessary to properly distribute the weight. Landlord will not
be responsible for loss of or damage to any such safe or property from any cause
and all damage done to the Building by moving or maintaining any such safe or
other property shall be repaired at the expense of Tenant.  There shall not be
used in any space, or in the public halls of the Building, either by any Tenant
or others, any hand trucks except those equipped with rubber tires and side
guards.

     7.   Tenant shall not employ any person or persons other than the janitor
of Landlord for the purpose of cleaning the Premises unless otherwise agreed to
by Landlord in writing.  Except with the written consent of Landlord, no person
or persons other than those approved by Landlord shall be permitted to enter the
Building for the purpose of cleaning the same.  Tenant shall not cause any
unnecessary labor by reason of Tenant's carelessness or indifference in the
preservation of good order and cleanliness. Landlord shall in no way be
responsible to any Tenant for any loss of property on the Premises, however
occurring, or for any damage done to the effects of Tenant by the janitor or any
other employee or any other person.  Janitor service will not be furnished on
nights when rooms are occupied after 9:30 p.m.  Window cleaning shall be done
only by Landlord.

     8.   Tenant shall not use or keep in the Premises or the Building any
kerosene, gasoline or flammable, combustible or noxious fluid or material, or
use any method of heating or air conditioning other than that supplied by
Landlord.  Tenant shall not use, keep or permit or suffer the Premises to be
occupied or used in a manner offensive or objectionable to the Landlord or other
occupants of the Building by reason of noise, odors and/or vibrations, or
interfere in any way with other tenants or those having business therein, nor
shall any animals or birds be brought in or kept in or about the Premises or the
Building.  Tenant shall not make or permit to be made any unseemly or disturbing
noises or disturb or interfere with occupants of this or neighboring Buildings
or premises or those having business with them whether by the use of any musical
instrument, radio, phonograph, unusual noise, or in any other way.



                                    -2-

<PAGE>

     9.   The Premises shall not be used for the storage of merchandise except
as such storage may be incidental to the use of the Premises for general office
purposes.  Tenant shall not occupy or permit any portion of the Premises to be
occupied for the manufacture or sale of liquor, narcotics, or tobacco in any
form. The Premises shall not be used for lodging or sleeping or for any illegal
purposes.  No cooking shall be done or permitted by Tenant on the Premises,
except that use by Tenant of Underwriters' Laboratory approved portable
equipment for brewing coffee, tea and similar beverages and of microwave ovens
approved by Landlord shall be permitted provided that such use is in accordance
with all applicable federal, state and local laws, codes, ordinances, rules and
regulations.

     10.  Landlord will direct electricians as to where and how telephone wires
and any other cables or wires are to be installed. No boring or cutting for
cables or wires will be allowed without the consent of Landlord.  The location
of telephones, call boxes and other office equipment affixed to the Premises
shall be subject to the approval of Landlord.

     11.  Tenant shall not lay linoleum, tile, carpet or other similar floor
covering so that the same shall be affixed to the floor of the Premises in any
manner except as approved by the Landlord.  Tenant shall bear the expense of
repairing any damage resulting from a violation of this rule or removal of any
floor covering.

     12.  No furniture, packages, supplies, equipment or merchandise will be
received in the Building or carried up or down in the elevators, except between
such hours and in such elevators as shall be designated by Landlord.  In its
use of such, Tenant shall not obstruct or permit the obstruction of walkways,
ingress and egress to the Building and tenant spaces and at no time shall Tenant
park vehicles which will create traffic and safety hazards or create other
obstructions.

     13.  On Saturdays, Sundays and legal holidays all day, and on other days
between the hours of 7:00 p.m.  and 7:00 a.m.  the following day, access to the
Building or to the halls, corridors, elevators, or stairways in the Building, or
to the Premises may be refused unless the person seeking access is known to the
person or employee of the Building in charge and has a pass or is properly
identified.  Landlord shall in no case be liable for damages for any error with
regard to the admission to or exclusion from the Building of any person.  Tenant
assumes all responsibility for protecting its Premises from theft, robbery and
pilferage.  In case of invasion, mob, riot, public excitement, or other
commotion, the Landlord reserves the right to prevent access to the Building
during the continuance of the same by closing the doors or otherwise, for the
safety of the Tenants and protection of property in the Building and the
Building.  Landlord reserves the right to close and keep locked all entrance and
exit doors of the Building on Saturdays, Sundays and legal holidays all day, and
on other days between the hours of 7:00 p.m.  and 7:00 a.m.  and during such
further hours as Landlord may deem advisable for the adequate protection of said
Building and the property of its tenants, and to implement such additional
security measures as Landlord deems appropriate for such purposes.  The cost of
such additional security measures, as reasonably allocated by Landlord to
Tenant, shall be reimbursed by Tenant within thirty (30) days after receipt of
Landlord's demand therefor.


                                    -3-

<PAGE>

     14.  Tenant shall see that the doors of the Premises are closed and
securely locked before leaving the Building and must observe strict care and
caution that all water faucets, water apparatus and utilities are entirely
shut off before Tenant or Tenant's employees leave the Building, and that all
electricity shall likewise be reasonably shut off, so as to prevent waste or
damage and for any default or carelessness Tenant shall make good all
injuries sustained by other tenants or occupants of the Building or Landlord.
 On multiple-tenancy floors, all tenants shall keep the doors to the Building
corridors closed at all times except for ingress and egress, and all tenants
shall at all times comply with any rules and orders of the fire department
with respect to ingress and egress.

     15.  Landlord reserves the right to exclude or expel from the Building
any person who, in the judgment of Landlord, is intoxicated or under the
influence of liquor or drugs, or who shall in any manner do any act in
violation of any of the rules and regulations of the Building.

     16.  Landlord shall attend to the requests of Tenant after notice
thereof from Tenant by telephone, in writing or in person at the Office of
the Landlord. Employees of Landlord shall not perform any work or do anything
outside of their regular duties unless under special instructions from the
Landlord.

     17.  No vending machine or machines of any description shall be
installed, maintained or operated upon the Premises without the written
consent of the Landlord.

     18.  Tenant agrees that it shall comply with all fire and security
regulations that may be issued from time-to-time by Landlord and Tenant also
shall provide Landlord with the name of a designated responsible employee to
represent Tenant in all matters pertaining to such fire or security
regulations.

     19.  Landlord may waive any one or more of these Rules and Regulations for
the benefit of any particular tenant or tenants, but no such waiver by Landlord
shall be construed as a waiver of those Rules and Regulations in favor of any
other tenant or tenants, nor prevent Landlord from thereafter enforcing any such
Rules and Regulations against any or all of the tenants of the Project.

     20.  Canvassing, soliciting, peddling or distribution of handbills or other
written material in the Building and Project is prohibited and Tenant shall
cooperate to prevent same.

     21.  Landlord reserves the right to (i) select the name of the Project and
Building and to make such change or changes of name, street address or suite
numbers as it may deem appropriate from time to time, (ii) grant to anyone the
exclusive right to conduct any business or render any service in or to the
Building and its tenants, provided such exclusive right shall not operate to
require Tenant to use or patronize such business or service or to exclude Tenant
from its use of the Premises expressly permitted in the Lease, and (iii) reduce,
increase, enclose or otherwise change at any time and from time to time the
size, number, location, layout and nature of the common areas and facilities and
other tenancies and premises in the Project and to create additional rentable
areas through use or enclosure of common areas.  Tenant shall not refer to the
Project by any name other than the name as selected by Landlord (as same may be
changed from time to time), or the postal address, approved by



                                    -4-

<PAGE>

the United States Post Office. Without the written consent of Landlord,
Tenant shall not use the name of the Building or Bishop Ranch Business Park
in connection with or in promoting or advertising the business of Tenant or
in any respect except as Tenant's address.

     22.  Tenant shall store all its trash and garbage within the Premises until
removal of same to such location in the Project as may be designated from time
to time by Landlord.  No material shall be placed in the Project trash boxes or
receptacle if such material is of such nature that it may not be disposed of in
the ordinary and customary manner of removing and disposing of trash and garbage
in the City of San Ramon without being in violation of any law or ordinance
governing such disposal.

     23.  Landlord shall furnish heating and air conditioning during the hours
of 7:00 a.m. and 7:00 p.m., Monday through Friday, except for holidays.  In the
event Tenant requires heating and air conditioning during off hours, Saturdays,
Sundays or holidays, Landlord shall on notice provide such services at the rate
established by Landlord from time-to-time.  Landlord shall have the right to
control and operate the public portions of the Building and the public
facilities, and heating and air conditioning, as well as facilities furnished
for the common use of the Tenants, in such manner as it deems best for the
benefit of the Tenants generally.

     24.  The directory of the Building will be provided for the display of the
name and location of tenants and Landlord reserves the right to exclude any
other names therefrom.  Any additional name that Tenant shall desire to place
upon the directory must first be approved by Landlord and, if so approved, a
charge will be made for each such name.

     25.  Except with the prior written consent of Landlord, Tenant shall not
sell, or permit the sale from the Premises of, or use or permit the use of any
sidewalk or common area adjacent to the Premises for the sale of newspapers,
magazines, periodicals, theater tickets or any other goods, merchandise or
service, nor shall Tenant carry on, or permit or allow any employee or other
person to carry on, business in or from the Premises for the service or
accommodation of occupants of any other portion of the Building, nor shall the
Premises be used for manufacturing of any kind, or for any business or activity
other than that specifically provided for in Tenant's lease.

     26.  The word "Tenant" occurring in these Rules and Regulations shall mean
Tenant and Tenant's Representatives.  The word "Landlord" occurring in these
Rules and Regulations shall mean Landlord's assigns, agents, clerks, employees
and visitors.


ACKNOWLEDGED AND ACCEPTED:

Landlord:                           Tenant:

By:  /s/ Judith K. Martin           By:  /s/ Dr. Joseph Rubinfeld
   ------------------------------      ----------------------------------

Date: October 14, 1996              Date: October 10, 1996
     ----------------------------        --------------------------------




                                    -5-

<PAGE>

                                    EXHIBIT E

                            JANITORIAL SPECIFICATIONS

     The following specific janitorial services will be provided in accordance
with provisions of Paragraph 7.1, Landlord's Obligations:

OFFICE AREAS (DAILY)

1.   Empty all waste baskets and disposal cans, if liners used, replace as
     necessary.
2.   Spot dust desks, chairs, file cabinets, counters and furniture.
3.   Spot vacuum all carpets and walk-off mats; spot as necessary.
4.   Sweep all hard surface floors with treated dust mop.

OFFICE AREAS (WEEKLY)

1.   Vacuum carpets completely, including around base boards, etc.
2.   Perform low dusting of furniture.
3.   Dust window sills and ledges.

OFFICE AREAS (QUARTERLY)

1.   Perform all high dusting of doors, sashes, moldings, etc.
2.   Dust venetian blinds as needed.

OFFICE AREA CORRIDORS AND LOBBIES (DAILY SERVICE)

1.   Vacuum carpets and dust mop any hard floors.
2.   Spot clean carpets of all spillage.
3.   Clean all thresholds.

OFFICE AREA CORRIDORS AND LOBBIES (WEEKLY)

1.   Perform all high dusting of doors, sashes, moldings, etc.
2.   Vacuum and clean all ceiling vents.
3.   Polish any metal railings, placards, etc.

STAIRWAYS (DAILY)

1.   Sweep all hard surface steps.
2.   Dust banisters.



<PAGE>


STAIRWAYS (WEEKLY)

1.   Sweep all hard surfaces.
2.   Spot mop all spills as needed.

RESTROOMS COMMON AREA (DAILY SERVICE)

1.   Empty all waste containers and replace liners as needed.
2.   Clean all metal, mirrors, and fixtures.
3.   Sinks, toilet bowls and urinals are to be kept free of scale.
4.   Clean all lavatory fixtures using disinfectant cleaners.
5.   Wash and disinfect underside and tops of toilet seats.
6.   Wipe down walls around urinals.
7.   Refill soap, towel, and tissue dispensers.
8.   Wet mop tile floors with disinfectant solution.
9.   Refill sanitary napkin machines as necessary.

RESTROOMS COMMON AREA (WEEKLY)

1.   Perform high dusting and vacuum vents.
2.   Use germicidal solution in urinal traps, lavatory traps, and floor drains.

RESTROOMS COMMON AREA (MONTHLY)

1.   Scrub floors with power machine.
2.   Wash down all ceramic tile and toilet compartments.

ELEVATORS (DAILY)

1.   Vacuum floors.
2.   Clean thresholds.
3.   Spot walls and polish surfaces.

GENERAL

All glass entry doors to offices, corridors, or lunch rooms are to
be cleaned as necessary.


                                    -2-

<PAGE>

                                    EXHIBIT F

                 DOOR SIGN, DIRECTORY STRIP AND MAIL BOX REQUEST

1.   I, the undersigned, hereby authorize Landlord to order one door sign of
     (    ) wood, (    ) vinyl, (    ) chrome.  The business name on it shall
     be:

           SuperGen, Inc.
     _________________________________________________________________________


2.   The directory strip shall read:

           SuperGen, Inc.
     _________________________________________________________________________


3.   The mail box strip shall read:

           SuperGen, Inc.
     _________________________________________________________________________


             /s/  Dr. Joseph Rubinfeld                 October 9, 1996

     _________________________________________________________________________
               Signature                                   Date


     Street Address:   Two Annabel Lane
                    ----------------------------------------------------------
     Suite Number:     220
                    ----------------------------------------------------------

     Complex:          Bishop Ranch 12, Building B
                    ----------------------------------------------------------


<PAGE>

                                    EXHIBIT G

                              COMMENCEMENT OF LEASE


     It is hereby agreed to that (a) the "Commencement Date" under that certain
Lease dated _____________________ by and between ANNABEL INVESTMENT COMPANY as
Landlord and SUPERGEN, INC. as Tenant, covering Premises located at TWO ANNABEL
LANE, SUITE 220, is ___________, 19__, (b) the "Expiration Date" thereof is 5:00
P.M. on ___________, 19__, and (c) Landlord has completed all of its
construction obligations under the Work Letter.





ACKNOWLEDGED AND ACCEPTED:


Landlord:                          Tenant:


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

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





                                    -2-