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                                                             Exhibit 10.16
                                                             Duplicate Original
                              MASTER LEASE AGREEMENT

MASTER LEASE AGREEMENT (the "Master Lease") dated May 7, 1990 by and between
COMDISCO, INC. ("Lessor") and Elitra Pharmaceuticals Inc. ("Lessee").

IN CONSIDERATION of the mutual agreements described below, the parties agree
as follows (all capitalized terms are defined in Section 14.18):

1. PROPERTY LEASED.

Lessor leases to Lessee all of the Equipment described on each Summary
Equipment Schedule.  In the event of a conflict, the terms of the applicable
Schedule prevail over this Master Lease.

2. TERM.

On the Commencement Date, Lessee will be deemed to accept the Equipment, will
be bound to its rental obligations for each Item of Equipment and the term of
a Summary Equipment Schedule will begin and continue through the Initial Term
and thereafter until terminated by either party upon prior written notice
received during the Notice Period.  No termination may be effective prior to
the expiration of the Initial Term.

3. RENT AND PAYMENT.

Rent is due and payable in advance on the first day of each Rent Interval at
the address specified in Lessor's invoice.  Interim Rent is due and payable
when invoiced.  If any payment is not made when due, Lessee will pay a Late
Charge on the overdue amount.  Upon Lessee's execution of each Schedule, Lessee
will pay Lessor the Advance specified on the Schedule.  The Advance will be
credited towards the final Rent payment if Lessee is not then in default.  No
interest will be paid on the Advance.

4. SELECTION; WARRANTY AND DISCLAIMER OF WARRANTIES.

4.1 SELECTION. Lessee acknowledges that it has selected the Equipment and
disclaims any reliance upon statements made by the Lessor, other than as set
forth in the Schedule.

4.2 WARRANTY AND DISCLAIMER OF WARRANTIES. Lessor warrants to Lessee that, so
long as Lessee is not in default, Lessor will not disturb Lessee's quiet and
peaceful possession, and unrestricted use of the Equipment.  To the extent
permitted by the manufacturer, Lessor assigns to Lessee during the term of
the Summary Equipment Schedule any manufacturer's warranties for the
Equipment.  LESSOR MAKES NO OTHER WARRANTY, EXPRESS OR IMPLIED AS TO ANY
MATTER WHATSOEVER, INCLUDING, WITHOUT LIMITATION, THE MERCHANTABILITY OF THE
EQUIPMENT OR ITS FITNESS FOR A PARTICULAR PURPOSE.  Lessor is not responsible
for any liability, claim, loss, damage or expense of any kind (including
strict liability in tort ) caused by the Equipment except for any loss or
damage caused by the willful misconduct or negligent acts of Lessor.  In no
event is Lessor responsible for special, incidental or consequential damages.

5. TITLE; RELOCATION OR SUBLEASE; AND ASSIGNMENT.

5.1 TITLE. Lessee holds the Equipment subject and subordinate to the rights
of the Owner, Lessor, any Assignee and any Secured Party. Lessee authorizes
Lessor, as Lessee's agent, and at Lessor's expense, to prepare, execute and
file in Lessee's name precautionary Uniform Commercial Code financing
statements showing the interest of the Owner, Lessor, and any Assignee or
Secured Party in the Equipment and to insert serial numbers in Summary
Equipment Schedules as appropriate.  Lessee will, at its expense, keep the
Equipment free and clear from any liens or encumbrances of any kind (except
any caused by Lessor) and will indemnify and hold the Owner, Lessor, any
Assignee and Secured Party harmless from and against any loss caused by
Lessee's failure to do so, except where such is caused by Lessor.

5.2 RELOCATION OR SUBLEASE. Upon prior written notice, Lessee may relocate
Equipment to any location within the continental United States provided (i)
the Equipment will not be used by an entity exempt from federal income tax,
and (ii) all additional costs (including any administrative fees, additional
taxes and Insurance coverage) are reconciled and promptly paid by Lessee.

Lessee may sublease the Equipment upon the reasonable consent of the Lessor
and the Secured Party.  Such consent to sublease will be granted if: (i)
Lessee meets the relocation requirements set out above, (ii) the sublease is
expressly subject and subordinate to the terms of the Schedule, (iii) Lessee
assigns its rights in the sublease to Lessor and the Secured Party as
additional collateral and security, (iv) Lessee's obligation to maintain and
insure the Equipment is not altered, (v) all financing statements required to
continue the Secured Party's prior perfected security interest are filed, and
(vi) Lessee executes sublease documents acceptable to Lessor.

No relocation or sublease will relieve Lessee from any of its obligations
under this Master Lease and the relevant Schedule.

5.3 ASSIGNMENT BY LESSOR.  The terms and conditions of each Schedule have
been fixed by Lessor in order to permit Lessor to sell and/or assign or
transfer its interest or grant a security interest in each Schedule and/or
the Equipment to a Secured Party or Assignee.  In that event, the term Lessor
will mean the Assignee and any Secured Party.  However, any assignment, sale
or other transfer by Lessor will not relieve Lessor of its obligations to
Lessee and will not materially change Lessee's duties or materially increase
the burdens or risks imposed on Lessee.  The Lessee consents to and will
acknowledge such assignments in a written notice given to Lessee.  Lessee
also agrees that:

(a)      The Secured Party will be entitled to exercise all of Lessor's
rights, but will not be obligated to perform any of the obligations of
Lessor.  The Secured Party will not disturb Lessee's quiet and peaceful
possession and unrestricted use of the Equipment so long as Lessee is not in
default and the Secured Party continues to receive all Rent payable under the
Schedule; and

(b)      Lessee will pay all Rent and all other amounts payable to the
Secured Party, despite any defense or claim which it has against Lessor.
Lessee reserves its right to have recourse directly against Lessor for any
defense or claim;

(c)      Subject to and without impairment of Lessee's leasehold rights in
the Equipment, Lessee holds the Equipment for the Secured Party to the extent
of the Secured Party's rights in that Equipment.

6. NET LEASE; TAXES AND FEES.

6.1 NET LEASE. Each Summary Equipment Schedule constitutes a net lease.
Lessee's obligation to pay Rent and all other amounts due hereunder is
absolute and unconditional and is not subject to any abatement, reduction,
set-off, defense, counterclaim, interruption, deferment or recoupment for any
reason whatsoever.

6.2 TAXES AND FEES. Lessee will pay when due or reimburse Lessor for all
taxes, fees, or any other charges (together with any related interest or
penalties not arising from the negligence of Lessor) accrued for or arising
during the term of each Summary Equipment Schedule against Lessor, Lessee or
the Equipment by any governmental authority (except only Federal, state,
local and franchise taxes on the capital or the net income of Lessor). Lessor
will file all personal property tax returns for the Equipment and pay all
such property taxes due.  Lessee will reimburse Lessor for property taxes
within thirty (30) days of receipt of an invoice.

7.  CARE, USE AND MAINTENANCE; INSPECTION BY LESSOR.

7.1 CARE, USE AND MAINTENANCE.  Lessee will maintain the Equipment in good
operating order and appearance, protect the Equipment from deterioration,
other than normal wear and tear, and will not use the Equipment for any
purpose other than that for which it was designed.  If commercially
available and considered common business practice for each item of Equipment,
Lessee will maintain in force a standard maintenance contract with the
manufacturer of the Equipment, or another party acceptable to Lessor, and
will provide Lessor with a complete copy of that contract.  If Lessee has the
Equipment maintained by a party other than the manufacturer or self
maintains, Lessee agrees to pay any costs necessary for the manufacturer to
bring the Equipment to then current release, revision and engineering change
levels, and to re-certify the Equipment as eligible for manufacturer's
maintenance at the expiration of the lease term, provided re-certification is
available and is required by Lessor.  The lease term will continue upon the
same terms and conditions until recertification has been obtained.

7.2 INSPECTION BY LESSOR.  Upon reasonable advance notice, Lessee, during
reasonable business hours and subject to Lessee's security requirements, will
make the Equipment and its related log and maintenance records available to
Lessor for inspection.

8.  REPRESENTATIONS AND WARRANTIES OF LESSEE. Lessee hereby represents,
warrants and covenants that with respect to the Master Lease and each
Schedule executed hereunder:

(a)      The Lessee is a corporation duly organized and validity existing in
good standing under the laws of the jurisdiction of its incorporation, is
duly qualified to do business in each jurisdiction (including the
jurisdiction where the Equipment is, or is to be, located) where its
ownership or lease of property or the conduct of its business requires such
qualification, except for where such lack of qualification would not have a
material adverse effect on the Company's business; and has full corporate
power and authority to hold property under the Master Lease and each Schedule
and to enter into and perform its obligations under the Master Lease and each
Schedule.

(b)      The execution and delivery by the Lessee of the Master Lease and
each Schedule and its performance thereunder have been duly authorized by all
necessary corporate action on the part of the Lessee, and the Master Lease
and each Schedule are not inconsistent with the Lessee's Articles of
Incorporation or Bylaws, do not

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contravene any law or governmental rule, regulation or order applicable to
it, do not and will not contravene any provision of, or constitute a default
under, any indenture, mortgage, contract or other instrument to which it is
a party or by which it is bound, and the Master Lease and each Schedule
constitute legal, valid and binding agreements of the Lessee, enforceable in
accordance with their terms, subject to the effect of applicable bankruptcy
and other similar laws affecting the rights of creditors generally and rules
of law concerning equitable remedies.

(c)       There are no actions, suits, proceedings or patent claims pending
or, to the knowledge of the Lessee, threatened against or affecting the
Lessee in any court or before any governmental commission, board or authority
which, if adversely determined, will have a material adverse effect on the
ability of the Lessee to perform its obligations under the Master Lease and
each Schedule.

(d)       The Equipment is personal property and when subjected to use by the
Lessee will not be or become fixtures under applicable law.

(e)       The Lessee has no material liabilities or obligations, absolute or
contingent (individually or in the aggregate), except the liabilities and
obligations of the Lessee as set forth in the Financial Statements and
liabilities and obligations which have occurred in the ordinary course of
business, and which have not been, in any case or in the aggregate,
materially adverse to Lessee's ongoing business.

(f)       To the best of the Lessee's knowledge, the Lessee owns, possesses,
has access to, or can become licensed on reasonable terms under all patents,
patent applications, trademarks, trade names, inventions, franchises,
licenses, permits, computer software and copyrights necessary for the
operations of its business as now conducted, with no known infringement of,
or conflict with, the rights of others.

(g)       All material contracts, agreements and instruments to which the
Lessee is a party are in full force and effect in all material respects, and
are valid, binding and enforceable by the Lessee in accordance with their
respective terms, subject to the effect of applicable bankruptcy and other
similar laws affecting the rights of creditors generally, and rules of law
concerning equitable remedies.

9.        DELIVERY AND RETURN OF EQUIPMENT.

Lessee hereby assumes the full expense of transportation and in-transit
insurance to Lessee's premises and installation thereat of the Equipment.
Upon termination (by expiration or otherwise) of each Summary Equipment
Schedule, Lessee shall, pursuant to Lessor's instructions and at Lessee's
full expense (including, without limitation, expenses of transportation and
in-transit insurance), return the Equipment to Lessor in the same operating
order, repair, condition and appearance as when received, less normal
depreciation and wear and tear.  Lessee shall return the Equipment to Lessor
at 8111 North River Road, Rosemount, Illinois 60018 or at such other address
within the continental United States as directed by Lessor, provided,
however, that Lessee's expense shall be limited to the cost of returning the
Equipment to Lessor's address as set forth herein. During the period
subsequent to receipt of a notice under Section 2, Lessor may demonstrate the
Equipment's operation in place and Lessee will supply any of its personnel as
may reasonably be required to assist in the demonstrations.

10. LABELING.

Upon request, Lessee will mark the Equipment indicating Lessor's interest
with labels provided by Lessor. Lessee will keep all Equipment free from any
other marking or labeling which might be interpreted as a claim of ownership.

11. INDEMNITY.

With regard to bodily injury and property damage liability only, Lessee will
indemnify and hold Lessor, any Assignee and any Secured Party harmless from
and against any and all claims, costs, expenses, damages and liabilities,
including reasonable attorneys' fees, arising out of the ownership (for
strict liability in tort only), selection, possession, leasing, operation,
control, use, maintenance, delivery, return or other disposition of the
Equipment during the term of this Master Lease or until Lessee's obligations
under the Master Lease terminate. However, Lessee is not responsible to a
party indemnified hereunder for any claims, costs, expenses, damages and
liabilities occasioned by the negligent acts of such indemnified party. Lessee
agrees to carry bodily injury and property damage liability insurance during
the term of the Master Lease in amounts and against risks customarily
insured against by the Lessee on equipment owned by it. Any amounts received by
Lessor under that insurance will be credited against Lessee's obligations
under this Section.

12. RISK OF LOSS.

Effective upon delivery and until the Equipment is returned, Lessee relieves
Lessor of responsibility for all risks of physical damage to or loss or
destruction of the Equipment. Lessee will carry casualty insurance for each
item of Equipment in an amount not less than the Casualty Value. All
policies for such insurance will name the Lessor and any Secured Party as
additional insured and as loss payee, and will provide for at least thirty
(30) days prior written notice to the Lessor of cancellation or expiration,
and will insure Lessor's interests regardless of any breach or violation by
Lessee of any representation, warranty or condition contained in such
policies and will be primary without right of contribution from any insurance
affected by Lessor. Upon the execution of any Schedule, the Lessee will
furnish appropiate evidence of such insurance acceptable to Lessor.

Lessee will promptly repair any damaged item of Equipment unless such
Equipment has suffered a Casualty Loss. Within fifteen (15) days of a Casualty
Loss, Lessee will provide written notice of that loss to Lessor and Lessee
will, at Lessee's option, either (a) replace the item of Equipment with Like
Equipment and marketable title to the Like Equipment will automatically vest
in Lessor or (b) pay the Casualty Value and after that payment and the
payment of all other amounts due and owing with respect to that item of
Equipment, Lessee's obligation to pay further Rent for the item of Equipment
will cease.

13. DEFAULT, REMEDIES AND MITIGATION.

13.1 DEFAULT.  The occurrence of any one or more of the following Events of
Default constitutes a default under a Summary Equipment Schedule:

(a)       Lessee's Failure to pay Rent or other amounts payable by Lessee
when due if that failure continues for five (5) business days after written
notice; or

(b)       Lessee's failure to perform any other term or condition of the
Schedule or the material inaccuracy of any representation or warranty made by
the Lessee in the Schedule or in any document or certificate furnished to the
Lessor hereunder if that failure or inaccuracy continues for ten (10)
business days after written notice; or

(c)       An assignment by Lessee for the benefit of its creditors, the
failure by Lessee to pay it debts when due, the insolvency of Lessee, the
filing by Lessee or the filing against Lessee of any petition under any
bankruptcy or insolvency law or for the appointment of a trustee or other
officer with similar powers, the adjudication of Lessee as insolvent, the
liquidation of Lessee, or the taking of any action for the purpose of the
foregoing; or

(d)       The occurrence of an Event of Default under any Schedule, Summary
Equipment Schedule or other agreement between Lessee and Lessor or its
Assignee or Secured Party.

13.2 REMEDIES.  Upon the occurrence of any of the above Events of Default,
Lessor, at its option, may:

(a)       enforce Lessee's performance of the provisions of the applicable
Schedule by appropriate court action in law or equity;

(b)       recover from Lessee any damages and or expences, including Default
Costs;

(c)       with notice and demand, recover all sums due and accelerate and
recover the present value of the remaining payment stream of all Rent due
under the defaulted Schedule (discounted at the same rate of interest at
which such defaulted Schedule was discounted with a Secured Party plus any
prepayment fees charged to Lessor by the Second Party or, if there is no
Secured Party, then discounted at 6%) together with all Rent and other amounts
currently due as liquidated damages and not as a penalty;

(d)       with notice and process of law and in compliance with Lessee's
security requirements, Lessor may enter on Lessee's premises to remove and
repossess the Equipment without being liable to Lessee for damages due to the
repossession, except those resulting from Lessor's, its assignees', agents' or
representatives' negligence; and

(e)       pursue any other remedy permitted by law or equity.

The above remedies, in Lessor's discretion and to the extent permitted by
law, are cumulative and may be exercised successively or concurrently.

13.3 MITIGATION.  Upon return of the Equipment pursuant to the terms of
Section 13.2, Lessor will use its best efforts in accordance with its normal
business procedures (and without obligation to give any priority to such
Equipment) to mitigate Lessor's damages as described below. EXCEPT AS SET
FORTH IN THIS SECTION, LESSEE HEREBY WAIVES ANY RIGHTS NOW OR HEREAFTER
CONFERRED BY STATUTE OR OTHERWISE WHICH MAY REQUIRE LESSOR TO MITIGATE ITS
DAMAGES OR MODIFY ANY OF LESSOR'S RIGHTS OR REMEDIES STATED HEREIN. Lessor
may sell, lease or otherwise dispose of all or any part of the Equipment at a
public or private sale for cash or credit with the privilege of purchasing
the Equipment. The proceeds from any sale, lease or other disposition of the
Equipment are defined as either:

(a)       If sold or otherwise disposed of, the cash proceeds less the Fair
Market Value of the Equipment at the expiration of the Initial Term less the
Default Costs; or

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(b)      if leased, the present value (discounted at 3 percent (3%) over the
U.S. Treasury Notes of comparable maturity to the term of the re-lease) of the
rentals for a term not to exceed the initial Term, less the Default Costs.

Any proceeds will be applied against liquidated damages and any other sums due
to Lessor from Lessee. However, Lessee is liable to Lessor for, and Lessor may
recover, the amount by which the proceeds are less than the liquidated damages
and other sums due to Lessor from Lessee.

14. ADDITIONAL PROVISIONS.

14.1 BOARD ATTENDANCE. One representative of Lessor will have the right to
attend Lessee's corporate Board of Directors meetings and Lessee will give
Lessor reasonable notice in advance of any special Board of Directors meeting,
which notice will provide an agenda of the subject matter to be discussed at
such board meeting. Lessee will provide Lessor with a certified copy of the
minutes of each Board of Directors meeting within thirty (30) days following the
date of such meeting held during the term of this Master Lease.

14.2 FINANCIAL STATEMENTS. As soon as practicable at the end of each month
(and in any event within thirty (30) days), Lessee will provide to Lessor the
same information which Lessee provides to its Board of Directors, but which
will include not less than a monthly income statement, balance sheet and
statement of cash flows prepared in accordance with generally accepted
accounting principles, consistently applied (the "Financial Statements"). As
soon as practicable at the end of each fiscal year, Lessee will provide to
Lessor audited Financial Statements setting forth in comparative form the
corresponding figures for the fiscal year (and in any event within ninety
(90) days), and accompanied by an audit report and opinion of the Independent
certified public accountants selected by Lessee. Lessee will promptly furnish
to Lessor any additional information (including, but not limited to, tax
returns, income statements, balance sheets and names of principal creditors)
as Lessor reasonably believes necessary to evaluate Lessee's continuing
ability to meet financial obligations. After the effective date of the
initial registration statement covering a public offering of Lessee's
securities, the term "Financial Statements" will be deemed to refer to only
those statements required by the Securities and Exchange Commission.

14.3 OBLIGATION TO LEASE ADDITIONAL EQUIPMENT. Upon notice to Lessee, Lessor
will not be obligated to lease any Equipment which would have a Commencement
Date after said notice if: (i) Lessee is in default under this Master Lease
or any Schedule; (ii) Lessee is in default under any loan agreement, the
result of which would allow the lender or any secured party to demand
immediate payment of any material indebtedness; (iii) there is a material
adverse change in Lessee's credit standing; or (iv) Lessor determines (in
reasonable good faith) that Lessee will be unable to perform its obligations
under this Master Lease or any Schedule.

14.4 MERGER AND SALE PROVISIONS. Lessee will notify Lessor of any proposed
Merger at least sixty (60) days prior to the closing date. Lessor may, in its
discretion, either (i) consent to the assignment of the Master Lease and all
relevant Schedules to the successor entity, or (ii) terminate the Lease and
all relevant Schedules. If Lessor elects to consent to the assignment, Lessee
and its successor will sign the assignment documentation provided by Lessor.
If Lessor elects to terminate the Master Lease and all relevant Schedules,
then Lessee will pay Lessor all amounts then due and owing and a termination
fee equal to the present value (discounted at 6%) of the remaining Rent for
the balance of the Initial Term(s) of all Schedules, and will return the
Equipment in accordance with Section 9. Lessor hereby consents to any Merger
in which the acquiring entity has a Moody's Bond Rating of BA3 or better or a
commercially acceptable equivalent measure of creditworthiness as reasonably
determined by Lessor.

14.5 ENTIRE AGREEMENT. This Master Lease and associated Schedules and Summary
Equipment Schedules supersede all other oral or written agreements or
understandings between the parties concerning the Equipment including, for
example, purchase orders. ANY AMENDMENT OF THIS MASTER LEASE OR A SCHEDULE, MAY
ONLY BE ACCOMPLISHED BY A WRITING SIGNED BY THE PARTY AGAINST WHOM THE AMENDMENT
IS SOUGHT TO BE ENFORCED.

14.6 NO WAIVER. No action taken by Lessor or Lessee will be deemed to constitute
a waiver of compliance with any representation, warranty or covenant contained
in this Master Lease or a Schedule. The waiver by Lessor or Lessee of a breach
of any provision of this Master Lease or a Schedule will not operate or be
construed as a waiver of any subsequent breach.

14.7 BINDING NATURE. Each Schedule is binding upon, and inures to the benefit of
Lessor and its assigns. LESSEE MAY NOT ASSIGN ITS RIGHTS OR OBLIGATIONS.

14.8 SURVIVAL OF OBLIGATIONS. All agreements, obligations including, but not
limited to those arising under Section 6.2, representations and warranties
contained in this Master Lease, any Schedule, Summary Equipment Schedule or in
any document delivered in connection with those agreements are for the benefit
of Lessor and any Assignee or Secured Party and survive the execution, delivery,
expiration or termination of this Master Lease.

14.9 NOTICES. Any notice, request or other communication to either party by the
other will be given in writing and deemed received upon the earlier of (1)
actual receipt or (2) three days after mailing if mailed postage prepaid by
regular or airmail to Lessor (to the attention of "the Comdisco Venture Group")
or Lessee, at the address set out in the Schedule, (3) one day after it is sent
by courier or (4) on the same day as sent via facsimile transmission, provided
that the original is sent by personal delivery or mail by the sending party.

14.10 APPLICABLE LAW. THIS MASTER LEASE HAS BEEN, AND EACH SCHEDULE WILL HAVE
BEEN MADE, EXECUTED AND DELIVERED IN THE STATE OF ILLINOIS AND WILL BE GOVERNED
AND CONSTRUED FOR ALL PURPOSES IN ACCORDANCE WITH THE LAWS OF THE STATE OF
ILLINOIS WITHOUT GIVING EFFECT TO CONFLICT OF LAW PROVISIONS. NO RIGHTS OR
REMEDIES REFERRED TO IN ARTICLE 2A OF THE UNIFORM COMMERCIAL CODE WILL BE
CONFERRED ON LESSEE UNLESS EXPRESSLY GRANTED IN THIS MASTER LEASE OR A SCHEDULE.

14.11 SEVERABILITY. If any one or more of the provisions of this Master Lease or
any Schedule is for any reason held invalid, illegal or unenforceable, the
remaining provisions of this Master Lease and any such Schedule will be
unimpaired, and the invalid, illegal or unenforceable provision replaced by a
mutually acceptable valid, legal and enforceable provision that is closest to
the original intention of the parties.

14.12. COUNTERPARTS. This Master Lease and any Schedule may be executed in any
number of counterparts, each of which will be deemed an original, but all such
counterparts together constitute one and the same instrument. If Lessor grants a
security interest in all or any part of a Schedule, the Equipment or sums
payable thereunder, only that counterpart Schedule marked "Secured Party's
Original" can transfer Lessor's rights and all other counterparts will be marked
"Duplicate."

14.13 LICENSED PRODUCTS. Lessee will obtain no title to Licensed Products which
will at all times remain the property of the owner of the Licensed Products. A
license from the owner may be required and it is Lessee's responsibility to
obtain any required license before the use of the Licensed Products. Lessee
agrees to treat the Licensed Products as confidential information of the owner,
to observe all copyright restrictions, and not to reproduce or sell the Licensed
Products.

14.14 SECRETARY'S CERTIFICATE. Lessor will, upon execution of this Master Lease,
provide Lessor with a secretary's certificate of incumbency and authority. Upon
the execution of each Schedule with a purchase price in excess of $1,000,000,
Lessee will provide Lessor with an opinion from Lessee's counsel in a form
acceptable to Lessor regarding the representations and warranties in Section B.

14.15 ELECTRONIC COMMUNICATIONS. Each of the parties may communicate with the
other by electronic means under mutually agreeable terms.

14.16 LANDLORD, MORTGAGEE WAIVER. Lessee agrees to provide Lessor with a
Landlord/Mortgagee Waiver with respect to the Equipment. Such waiver shall be in
a form satisfactory to Lessor.

14.17 EQUIPMENT PROCUREMENT CHARGES/PROGRESS PAYMENTS. Lessee hereby agrees that
Lessor shall not, by virtue of its entering into this Master Lease, be required
to remit any payments to any manufacturer or other third party until Lessee
accepts the Equipment subject to this Master Lease.

14.18 DEFINITIONS.

ADVANCE - means the amount due to Lessor by Lessee upon Lessee's execution of
each Schedule.

ASSIGNEE - means an entity to whom Lessor has sold or assigned its rights as
owner and Lessor of Equipment.

CASUALTY LOSS - means the irreparable loss or destruction of Equipment.

CASUALTY VALUE - means the greater of the aggregate Rent remaining to be paid
for the balance of the lease term or the Fair Market Value of the Equipment
immediately prior to the Casualty Loss. However, if a Casualty Value Table is
attached to the relevant Schedule its terms will control.

COMMENCEMENT DATE - is defined in each Schedule.

DEFAULT COSTS - means reasonable attorney's fees and remarketing costs resulting
from a Lessee default or Lessor's enforcement of its remedies.

DELIVERY DATE - means date of delivery of Inventory Equipment to Lessee's
address.

EQUIPMENT - means the property described on a Summary Equipment Schedule and any
replacement for that property required or permitted by this Master Lease or a
Schedule.

EVENT OF DEFAULT - means the events described in Subsection 13.1.

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FAIR MARKET VALUE - means the aggregate amount which would be obtainable in
an arm's-length transaction between an informed and willing buyer/user and an
informed and willing seller under no compulsion to sell.

INITIAL TERM - means the period of time beginning on the first day of the
first full Rent Interval following the Commencement Date for all Items of
Equipment and continuing for the number of Rent Intervals indicated on a
Schedule.

INTERIM RENT - means the pro-rata portion of Rent due for the period from the
Commencement Date through but not including the first day of the first full
Rent Interval included in the Initial Term.

LATE CHARGE - means the lesser of five percent (5%) of the payment due or the
maximum amount permitted by the law of the state where the Equipment is
located.

LICENSED PRODUCTS - means any software or other licensed products attached to
the Equipment.

LIKE EQUIPMENT - means replacement Equipment which is lien free and of the
same model, type, configuration and manufacture as Equipment.

MERGER - means any consolidation or merger of the Lessee with or into any
other corporation or entity, any sale or conveyance of all or substantially
all of the assets or stock of the Lessee by or to any other person or entity
in which Lessee is not the surviving entity.

NOTICE PERIOD - means not less than ninety (90) days nor more than twelve
(12) months prior to the expiration of the lease term.

OWNER - means the owner of Equipment.

RENT - means the rent Lessee will pay for each Item of Equipment expressed in
a Summary Equipment Schedule either as a specific amount or an amount equal
to the amount which Lessor pays for an Item of Equipment multiplied by a
lease rate factor plus all other amounts due to Lessor under this Master
Lease or a Schedule.

RENT INTERVAL - means a full calendar month or quarter as indicated on a
Schedule.

SCHEDULE - means either an Equipment Schedule or a Licensed Products Schedule
which incorporates all of the terms and conditions of this Master Lease.

SECURED PARTY - means an entity to whom Lessor has granted a security
interest for the purpose of securing a loan.

SUMMARY EQUIPMENT SCHEDULE - means a certificate provided by Lessor
summarizing all of the Equipment for which Lessor has received Lessee
approved vendor invoices, purchase documents and/or evidence of delivery
during a calendar quarter which will incorporate all of the terms and
conditions of the related Schedule and this Master Lease and will constitute
a separate lease for the equipment leased thereunder.

IN WITNESS WHEREOF, the parties herein have executed this Master Lease on or
as of the day and year first above written.

   ELITRA PHARMACEUTICALS, INC.             COMDISCO, INC.,
   AS LESSEE                                AS LESSOR

   By: /s/ Alana B. Wheeler                 By:          /s/ James Labe
      --------------------------------         ---------------------------------
                                                      James Labe, President
   Title:           CFO                     Title:  Comdisco Ventures Division
         -----------------------------            ------------------------------

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                                   ADDENDUM TO THE
                 MASTER LEASE AGREEMENT DATED AS OF MAY 7, 1999
                 BETWEEN ELITRA PHARMACEUTICALS INC., AS LESSEE
                            AND COMDISCO, INC., AS LESSOR

     The undersigned hereby agree that the terms and conditions of the above-
referenced Master Lease are hereby modified and amended as follows:

1)   Section 3., "RENT AND PAYMENT"

     In line 3 after the words "is not made" insert "within five days of the
     date" and delete "when".

2)   Section 5., "TITLE, RELOCATION OR SUBLEASE; AND ASSIGNMENT"

     Subsection 5.2, second paragraph, in line 8, after the word "documents",
     insert "reasonably".

     Subsection 5.3(d), at the beginning of the first sentence insert, "After
     receipt of written notice of assignment from Lessor,"

3)   Section 6., "NET LEASE: TAXES AND FEES"

     Subsection 6.2, add the following paragraph at the end of this
     subsection:

     "Lessee shall not be liable for any taxes, fees or charges to the extent
     the same result from any sale or assignment or grant of security
     interest by Lessor, or to the extent any such action increases the
     taxes, fees or charges that would otherwise be payable.  Lessee shall
     have the right to contest by proper legal proceedings any taxes levied,
     upon prior written notice to Lessor and Lessor will cooperate in any
     legal proceedings being prosecuted by Lessee with regard to any taxes,
     but Lessee will pay the expenses in such litigation. Lessee shall have
     the right to contest in good faith and by appropriate proceedings the
     validity or the amount of taxes unless such contest would adversely
     affect the title of the Lessor to the Equipment or would subject it to
     forfeiture or sale. Lessee shall have the rights to any refund received
     as a result of any such contest or proceeding to the extent Lessee has
     previously reimbursed Lessor for such taxes."

4)   Section 7., "CARE, USE AND MAINTENANCE, INSPECTION BY LESSOR"

     Subsection 7.1, line 7, after the words "another party acceptable to
     Lessor", add the words "including self-maintenance by Lessee upon
     Lessor's prior written consent, which consent shall not be unreasonably
     withheld".

<PAGE>

     Subsection 7.1, last sentence, delete "." and insert the following at
     the end thereof "or Lessee has exercised its option to purchase such
     Equipment."

5)   Section 8., "REPRESENTATIONS AND WARRANTIES OF LESSEE"

     Subsection (c), in line 3 and 4, delete the words "if adversely
     determined, will", and insert "are reasonably likely to"

6)   Section 9., "DELIVERY AND RETURN OF EQUIPMENT"

     Second sentence, after the word "Schedule", insert "and provided that
     the equipment is not purchased or the term extended as permitted by the
     applicable Schedule,"

7)   Section 11, "INDEMNITY"

     First sentence, line 6, after the word "Equipment", delete the words
     "during the term of this Master Lease or until Lessee's obligations
     under the Master Lease terminate" and insert "arising from acts or
     events during the period from the Commencement Date of each Summary
     Equipment Schedule until re-delivery of the Equipment to Lessor in
     accordance with the terms of this Master Lease."

     Second sentence, line 3, insert "or willful misconduct" at the end of
     the sentence.

8)   Section 13, "DEFAULT, REMEDIES AND MITIGATION"

     Subsection 13.1, paragraph (b), line 1, insert "applicable" before the
     word "Schedule".

     Subsection 13.1, paragraph (c), line 4, insert the following after
     "powers": "which petition or appointment is not dismissed or vacated
     within sixty (60) days."

     Subsection 13.2, introduction, insert "and during the continuance" after
     the word "occurence".

     Subsection 13.2, paragraph (d), line 5, insert "or willful misconduct"
     after "negligence".

     Subsection 13.3, second sentence, line 1, insert "AND TO THE EXTENT
     PERMITTED BY LAW" after the words "IN THIS SECTION".

9)   Section 14, "ADDITIONAL PROVISIONS"

     Subsection 14.1., delete this section in its entirety.

<PAGE>

     Subsection 14.2., line 8, delete "ninety (90)" and insert "one hundred
     twenty (120)".

     Subsection 14.4, in line 10, after the words "Section 9", insert "or
     purchase the Equipment for a mutually agreeable price" and at the end of
     the paragraph, insert "and Lessor shall not unreasonably withhold its
     consent to a Merger in other cases."

     Subsection 14.7., at the end of the second sentence, insert ", except as
     provided for in this Agreement."
     Subsection 14.9, line 5, insert "applicable" before "Schedule".

     Subsection 14.10, change "Illinois" to "California" in lines 2 and 4.
     Subsection 14.8, in line 1, after the words "greater or the", insert
     "present value of the" and in line 2, after the word "term", insert
     "discounted at the U.S. Treasury rate of comparable maturity to the
     remaining term, plus the residual value of the Equipment as of the
     expiration of the Initial Term"

Except as amended hereby, all other terms and conditions of the Master Lease
Agreement remain in full force and effect.

ELITRA PHARMACEUTICALS INC.           COMDISCO, INC.
AS LESSEE                             AS LESSOR

By:  /s/ Alana B. Wheeler             By:  /s/ James Labe
    -----------------------------         -------------------------------

                                                 James Labe, President
Title:  CFO                           Title:   Comdisco Ventures Division
       --------------------------            ----------------------------

Date:  5/11/99                        Date:  May 14, 1999
      ---------------------------           -----------------------------<PAGE>

THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 AS
AMENDED, OR ANY STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE,
PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT
RELATED THERETO OR AN OPINION OF COUNSEL (WHICH MAY BE COMPANY COUNSEL)
REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES
LAWS.

                                WARRANT AGREEMENT

              TO PURCHASE SHARES OF THE SERIES B PREFERRED STOCK OF

                           ELITRA PHARMACEUTICALS INC.

                 DATED AS OF JUNE 9, 1999 (THE "EFFECTIVE DATE")

         WHEREAS, ELITRA PHARMACEUTICALS INC., a Delaware corporation (the
"COMPANY") has entered into a Master Lease Agreement dated as of May 7, 1999,
Equipment Schedule No. VL-1 and VL-2 dated as of May 7, 1999, and related
Summary Equipment Schedules (collectively, the "LEASES") with COMDISCO, INC., a
Delaware corporation (the "WARRANTHOLDER"); and

         WHEREAS, the Company desires to grant to Warrantholder, in
consideration for such Leases, the right to purchase shares of its Series B
Preferred Stock;

         NOW, THEREFORE, in consideration of the Warrantholder executing and
delivering such Leases and in consideration of mutual covenants and agreements
contained herein, the Company and Warrantholder agree as follows:

1.       GRANT OF THE RIGHT TO PURCHASE PREFERRED STOCK.

         The Company hereby grants to the Warrantholder, and the Warrantholder
is entitled, upon the terms and subject to the conditions hereinafter set forth,
to subscribe to and purchase, from the Company, 17,606 fully paid and
non-assessable shares of the Company's Series B Preferred Stock ("PREFERRED
STOCK") at a purchase price of $0.71 per share (the "EXERCISE PRICE"). The
number and purchase price of such shares are subject to adjustment as provided
in Section 8 hereof.

         Notwithstanding the term of this Warrant Agreement as set forth above,
the right to purchase Preferred Stock as granted shall expire, if not previously
exercised, immediately upon the closing of either of the following events:

                  (i)      the issuance and sale of shares of Common Stock of
         the Company in the Company's first public offering of securities for
         its own account pursuant to an effective registration statement under
         the Securities Act of 1933, as amended (the "INITIAL PUBLIC

                                       1.
<PAGE>

         OFFERING"), provided that the underwriters so request that the
         Warrantholder exercise at that time.

                  (ii)     upon the closing of a merger or consolidation of the
         Company with or into another corporation when the Company is not the
         surviving corporation, or the sale of all or substantially all of the
         Company's properties and assets to any other person (the "MERGER")
         provided that the Acquirer request so in writing.

         The Company shall notify the Warrantholder if the Initial Public
Offering or Merger is proposed within a reasonable period of time prior to the
filing of a registration statement and if the Company fails to deliver such
written notice within a reasonable period of time, anything to the contrary in
his Warrant Agreement notwithstanding, the rights to purchase will not expire
until ten (10) business days after the Company delivers such notice to the
Warrantholder. Such notice shall also contain such details of the proposed
Initial Public Offering or Merger as are reasonable in the circumstances and
notice that this Warrant Agreement is expected to expire upon closing thereof.
If such closing does not take place, the Company shall promptly notify the
Warrantholder that such proposed transaction has been terminated. Anything to
the contrary in this Warrant Agreement notwithstanding, the Warrantholder may
rescind any exercise of its purchase rights promptly after such notice of
termination of the proposed transaction if the exercise of warrants occurred
after the Company notified the Warrantholder that the Initial Public Offering or
Merger was proposed or if the exercise were otherwise precipitated by such
proposed initial Public Offering or Merger. In the event of such rescission, the
Warrants will continue to be exercisable on the same terms and conditions.

2.       TERM OF THE WARRANT AGREEMENT.

         Except as otherwise provided for herein, including in Section 1(i)
hereof, the term of this Warrant Agreement and the right to purchase Preferred
Stock as granted herein shall commence on the Effective Date and shall be
exercisable for a period of (i) five (5) years from the Effective Date or (ii)
three (3) years from the effective date of the Company's Initial Public
Offering, whichever is shorter.

3.       EXERCISE OF THE PURCHASE RIGHTS.

         The purchase rights set forth in this Warrant Agreement are exercisable
by the Warrantholder, in whole or in part, at any time, or from time to time,
prior to the expiration of the term set forth in Section 2 above, by tendering
to the Company at its principal office a notice of exercise in the form attached
hereto as Exhibit I (the "NOTICE OF EXERCISE"), duly completed and executed.
Promptly upon receipt of the Notice of Exercise and the payment of the purchase
price in accordance with the terms set forth below, and in no event later than
twenty-one (21) days thereafter, the Company shall issue to the Warrantholder a
certificate for the number of shares of Preferred Stock purchased and shall
execute the acknowledgment of exercise in the form attached hereto as Exhibit II
(the "ACKNOWLEDGMENT OF EXERCISE") indicating the number of shares which remain
subject to future purchases, if any.

         The Exercise Price may be paid at the Warrantholder's election either
(i) by cash or check, or (ii) by surrender of Warrants ("NET ISSUANCE") as
determined below. If the

                                       2.
<PAGE>

Warrantholder elects the Net Issuance method, the Company will issue Preferred
Stock in accordance with the following formula:

                             X = Y(A-B)
                                 ------
                                   A

         Where:     X =  the number of shares of Preferred Stock to be issued to
                         the Warrantholder.

                    Y =  the number of shares of Preferred Stock requested to be
                         exercised under this Warrant Agreement.

                    A =  the fair market value of one (1) share of Preferred
                         Stock.

                    B =  the Exercise Price.

         For purposes of the above calculation, current fair market value of
Preferred Stock shall mean with respect to each share of Preferred Stock:

                  (i)      if the exercise is in connection with an initial
         public offering of the Company's Common Stock, and if the Company's
         Registration Statement relating to such public offering has been
         declared effective by the SEC, then the fair market value per share
         shall be the product of (x) the initial "Price to Public" specified in
         the final prospectus with respect to the offering and (y) the number of
         shares of Common Stock into which each share of Preferred Stock is
         convertible at the time of such exercise;

                  (ii)     if this Warrant is exercised after, and not in
         connection with the Company's Initial Public Offering, and:

                           (a)      if traded on a securities exchange, the fair
                  market value shall be deemed to be the product of (x) the
                  average of the closing prices over a five (5) day period
                  ending three days before the day the current fair market value
                  of the securities is being determined and (y) the number of
                  shares of Common Stock into which each share of Preferred
                  Stock is convertible at the time of such exercise; or

                           (b)      if actively traded over-the-counter, the
                  fair market value shall be deemed to be the product of (x) the
                  average of the closing bid and asked prices quoted on the
                  NASDAQ system (or similar system) over the five (5) day period
                  ending three days before the day the current fair market value
                  of the securities is being determined and (y) the number of
                  shares of Common Stock into which each share of Preferred
                  Stock is convertible at the time of such exercise;

                  (iii)    if at any time the Common Stock is not listed on any
         securities exchange or quoted in the NASDAQ System or the
         over-the-counter market, the current fair market value of Preferred
         Stock shall be the product of (x) the highest price per share which the
         Company could obtain from a willing buyer (not a current employee or
         director) for shares of Common Stock sold by the Company, from
         authorized but unissued shares, as determined in good faith by

                                       3.
<PAGE>

         its Board of Directors and (y) the number of shares of Common Stock
         into which each share of Preferred Stock is convertible at the time of
         such exercise, unless the Company shall become subject to a Merger,
         acquisition or other consolidation pursuant to which the Company is not
         the surviving party, in which case the fair market value of Preferred
         Stock shall be deemed to be the value received by the holders of the
         Company's Preferred Stock on a common equivalent basis pursuant to such
         merger or acquisition.

         Upon partial exercise by either cash or Net Issuance, the Company shall
promptly issue an amended Warrant Agreement representing the remaining number of
shares purchasable hereunder. All other terms and conditions of such amended
Warrant Agreement shall be identical to those contained herein, including, but
not limited to the Effective Date hereof.

4.       RESERVATION OF SHARES.

         (a)      AUTHORIZATION AND RESERVATION OF SHARES. During the term of
this Warrant Agreement, the Company will at all times have authorized and
reserved a sufficient number of shares of its Preferred Stock to provide for the
exercise of the rights to purchase Preferred Stock as provided for herein.

5.       NO FRACTIONAL SHARES OR SCRIP.

         No fractional shares or scrip representing fractional shares shall be
issued upon the exercise of the Warrant, but in lieu of such fractional shares
the Company shall make a cash payment therefor upon the basis of the Exercise
Price then in effect.

6.       NO RIGHTS AS SHAREHOLDER.

         This Warrant Agreement does not entitle the Warrantholder to any voting
rights or other rights as a shareholder of the Company prior to the exercise of
the Warrant.

7.       WARRANTHOLDER REGISTRY.

         The Company shall maintain a registry showing the name and address of
the registered holder of this Warrant Agreement.

8.       ADJUSTMENT RIGHTS.

         The purchase price per share and the number of shares of Preferred
Stock purchasable hereunder are subject to adjustment, as follows:

         (a)      MERGER AND SALE OF ASSETS. If at any time there shall be a
capital reorganization of the shares of the Company's stock (other than a
combination, reclassification, exchange or subdivision of shares otherwise
provided for herein), or a merger or consolidation of the Company with or into
another corporation whether or not the Company is the surviving corporation, or
the sale of all or substantially all of the Company's properties and assets to
any other person (hereinafter referred to as a "MERGER EVENT"), then, as a part
of such Merger Event, lawful provision shall be made so that the Warrantholder
shall thereafter be entitled to receive, upon exercise of the Warrant, the
number of shares of preferred stock or other securities of the

                                       4.
<PAGE>

successor corporation resulting from such Merger Event, equivalent in value to
that which would have been issuable if Warrantholder had exercised this Warrant
immediately prior to the Merger Event. In any such case, appropriate adjustment
(as determined in good faith by the Company's Board of Directors) shall be made
in the application of the provisions of this Warrant Agreement with respect to
the rights and interest of the Warrantholder after the Merger Event to the end
that the provisions of this Warrant Agreement (including adjustments of the
Exercise Price and number of shares of Preferred Stock purchasable) shall be
applicable to the greatest extent possible.

         (b)      RECLASSIFICATION OF SHARES. If the Company at any time shall,
by combination, reclassification, exchange or subdivision of securities or
otherwise, change any of the securities as to which purchase rights under this
Warrant Agreement exist into the same or a different number of securities of any
other class or classes, this Warrant Agreement shall thereafter represent the
right to acquire such number and kind of securities as would have been issuable
as the result of such change with respect to the securities which were subject
to the purchase rights under this Warrant Agreement immediately prior to such
combination, reclassification, exchange, subdivision or other change.

         (c)      SUBDIVISION OR COMBINATION OF SHARES. If the Company at any
time shall combine or subdivide its Preferred Stock, the Exercise Price shall be
proportionately decreased in the case of a subdivision, or proportionately
increased in the case of a combination.

         (d)      STOCK DIVIDENDS. If the Company at any time shall pay a
dividend payable in, or make any other distribution (except any distribution
specifically provided for in the foregoing subsections (a) or (b)) of the
Company's stock, then the Exercise Price shall be adjusted, from and after
the record date of such dividend or distribution, to that price determined by
multiplying the Exercise Price in effect immediately prior to such record
date by a fraction (i) the numerator of which shall be the total number of
all shares of the Company's stock outstanding immediately prior to such
dividend or distribution, and (ii) the denominator of which shall be the
total number of all shares of the Company's stock outstanding immediately
after such dividend or distribution. The Warrantholder shall thereafter be
entitled to purchase, at the Exercise Price resulting from such adjustment,
the number of shares of Preferred Stock (calculated to the nearest whole
share) obtained by multiplying the Exercise Price in effect immediately prior
to such adjustment by the number of shares of Preferred Stock issuable upon
the exercise hereof immediately prior to such adjustment and dividing the
product thereof by the Exercise Price resulting from such adjustment.

         (e)      RIGHT TO PURCHASE ADDITIONAL STOCK. If the Warrantholder's
total cost of equipment leased pursuant to the Leases exceeds $250,000,
Warrantholder shall have the right to purchase from the Company, at the Exercise
Price (adjusted as set forth herein), an additional number of shares, which
number shall be determined by (i) multiplying the amount by which the
Warrantholder's total equipment cost exceeds 250,000 by 5%, and (ii) dividing
the product thereof by the Exercise Price per share referenced above.

         (f)      ANTIDILUTION RIGHTS. Additional antidilution rights applicable
to the Preferred Stock purchasable hereunder are as set forth in the Company's
Certificate of Incorporation, as amended through the Effective Date, a true and
complete copy of which is attached hereto as

                                       5.
<PAGE>

Exhibit IV (the "CHARTER"). The Company shall promptly provide the Warrantholder
with any restatement, amendment, modification or waiver of the Charter. The
Company shall provide Warrantholder with prior written notice of any dilutive
issuance of its stock or other equity security to occur after the Effective Date
of this Warrant, which notice shall include (a) the price at which such stock or
security is to be sold, (b) the number of shares to be issued, and (c) such
other information as necessary for Warrantholder to determine if a dilutive
event has occurred.

         (g)      NOTICE OF ADJUSTMENTS. If: (i) the Company shall declare any
dividend or distribution upon its stock, whether in cash, property, stock or
other securities; (ii) the Company shall offer for subscription prorata to the
holders of any class of its Preferred or other convertible stock any additional
shares of stock of any class or other rights; (iii) there shall be any Merger
Event; (iv) there shall be an Initial Public Offering; or (v) there shall be any
voluntary dissolution, liquidation or winding up of the Company; then, in
connection with each such event, the Company shall send to the Warrantholder:
(A) at least twenty (20) days' prior written notice of the date on which the
books of the Company shall close or a record shall be taken for such dividend,
distribution, subscription rights (specifying the date on which the holders of
Preferred Stock shall be entitled thereto) or for determining rights to vote in
respect of such Merger Event, dissolution, liquidation or winding up; (B) in the
case of any such Merger Event, dissolution, liquidation or winding up, at least
twenty (20) days' prior written notice of the date when the same shall take
place (and specifying the date on which the holders of Preferred Stock shall be
entitled to exchange their Preferred Stock for securities or other property
deliverable upon such Merger Event dissolution, liquidation or winding up); and
(C) in the case of an Initial Public Offering, the Company shall give the
Warrantholder at least twenty (20) days written notice prior to the effective
date thereof.

         Each such written notice shall set forth, in reasonable detail, (i) the
event requiring the adjustment, (ii) the amount of the adjustment, (iii) the
method by which such adjustment was calculated, (iv) the Exercise Price, and (v)
the number of shares subject to purchase hereunder after giving effect to such
adjustment, and shall be given by first class mail, postage prepaid, addressed
to the Warrantholder, at the address as shown on the books of the Company.

         (h)      TIMELY NOTICE. Failure to timely provide such notice required
by subsection (g) above shall entitle Warrantholder to retain the benefit of the
applicable notice period notwithstanding anything to the contrary contained in
any insufficient notice received by Warrantholder. The notice period shall begin
on the date Warrantholder actually receives a written notice containing all the
information specified above.

9.       REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.

         (a)      RESERVATION OF PREFERRED STOCK. The Preferred Stock issuable
upon exercise of the Warrantholder's rights has been duly and validly reserved
and, when issued in accordance with the provisions of this Warrant Agreement,
will be validly issued, fully paid and non-assessable, and will be free of any
taxes, liens, charges or encumbrances of any nature whatsoever; PROVIDED,
HOWEVER, that the Preferred Stock issuable pursuant to this Warrant Agreement
may be subject to restrictions on transfer under state and/or Federal securities
laws.

                                       6.
<PAGE>

         The Company has made available to the Warrantholder true, correct and
complete copies of its Charter and Bylaws, as amended. The issuance of
certificates for shares of Preferred Stock upon exercise of the Warrant
Agreement shall be made without charge to the Warrantholder for any issuance tax
in respect thereof, or other cost incurred by the Company in connection with
such exercise and the related issuance of shares of Preferred Stock. The Company
shall not be required to pay any tax which may be payable in respect of any
transfer involved and the issuance and delivery of any certificate in a name
other than that of the Warrantholder.

         (b)      DUE AUTHORITY. The execution and delivery by the Company of
this Warrant Agreement and the performance of all obligations of the Company
hereunder, including the issuance to Warrantholder of the right to acquire the
shares of Preferred Stock, have been duly authorized by all necessary corporate
action on the part of the Company, and the Leases and this Warrant Agreement are
not inconsistent with the Company's Charter or Bylaws, do not contravene any law
or governmental rule, regulation or order applicable to it, do not and will not
contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument to which it is a party or by which it is
bound, and the Leases and this Warrant Agreement constitute legal, valid and
binding agreements of the Company, enforceable in accordance with their
respective terms.

         (c)      CONSENTS AND APPROVALS. No consent or approval of, giving of
notice to, registration with, or taking of any other action in respect of any
state, Federal or other governmental authority or agency is required with
respect to the execution, delivery and performance by the Company of its
obligations under this Warrant Agreement, except for the filing of notices
pursuant to Regulation D under the 1933 Act and any filing required by
applicable state securities law, which filings will be effective by the time
required thereby.

         (d)      ISSUED SECURITIES. All issued and outstanding shares of Common
Stock, Preferred Stock or any other securities of the Company have been duly
authorized and validly issued and are fully paid and nonassessable. All
outstanding shares of Common Stock, Preferred Stock and any other securities
were issued in full compliance with all Federal and state securities laws. In
addition:

                  (i)      The authorized capital of the Company consists of (A)
         10,000,000 shares of Common Stock, of which 3,338,010 shares are issued
         and outstanding, (B) 4,545,456 shares of Series A Preferred Stock, of
         which 4,545,456 shares are issued and outstanding and are convertible
         into 4,545,456 shares of Common Stock at $0.66 per share and (C)
         21,651,063 shares of Series B Preferred Stock, of which 20,000,000
         shares are issued and outstanding and are convertible into 20,000,000
         shares of Common Stock at $0.75 per share.

                  (ii)     The Company has reserved 1,988,425 shares of Common
         Stock for issuance under its 1998 Equity Incentive Plan, under which
         326,439 options are outstanding at an average price of $0.07 per share.
         There are no other options, warrants, conversion privileges or other
         rights presently outstanding to purchase or otherwise acquire any
         authorized but unissued shares of the Company's capital stock or other
         securities of the Company.

                                       7.
<PAGE>

                  (iii)    Other than as set forth in the Amended and Restated
         Investors Rights Agreement dated June 9, 1999 between the Company and
         certain shareholders, no shareholder of the Company has preemptive
         rights to purchase new issuances of the Company's capital stock.

         (e)      INSURANCE. The Company has in full force and effect insurance
policies, with extended coverage, insuring the Company and its property and
business against such losses and risks, and in such amounts, as are customary
for corporations engaged in a similar business and similarly situated and as
otherwise may be required pursuant to the terms of any other contract or
agreement.

         (f)      OTHER COMMITMENTS TO REGISTER SECURITIES. Except as set forth
in this warrant Agreement and Amended and Restated Investor Rights Agreement
dated as of June 9, 1999, the Company is not, pursuant to the terms of any other
agreement currently in existence, under any obligation to register under the
1933 Act any of its presently outstanding securities or any of its securities
which may hereafter be issued.

         (g)      EXEMPT TRANSACTION. Subject to the accuracy of the
Warrantholder's representations in Section 10 hereof, the issuance of the
Preferred Stock upon exercise of this Warrant will constitute a transaction
exempt from (i) the registration requirements of Section 5 of the 1933 Act, in
reliance upon Section 4(2) thereof, and (ii) the qualification requirements of
the applicable state securities laws.

         (h)      COMPLIANCE WITH RULE 144. Following the Initial Public
Offering, at the written request of the Warrantholder, who proposes to sell
Preferred Stock issuable upon the exercise of the Warrant in compliance with
Rule 144 promulgated by the Securities and Exchange Commission, the Company
shall furnish to the Warrantholder, within ten days after receipt of such
request, a written statement confirming the Company's compliance with the filing
requirements of the Securities and Exchange Commission as set forth in such
Rule, as such Rule may be amended from time to time.

10.      REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.

         This Warrant Agreement has been entered into by the Company in reliance
upon the following representations and covenants of the Warrantholder:

         (a)      INVESTMENT PURPOSE. The right to acquire Preferred Stock or
the Preferred Stock issuable upon exercise of the Warrantholder's rights
contained herein will be acquired for investment and not with a view to the sale
or distribution of any part thereof, and the Warrantholder has no present
intention of selling or engaging in any public distribution of the same except
pursuant to a registration or exemption.

         (b)      PRIVATE ISSUE. The Warrantholder understands (i) that the
Preferred Stock issuable upon exercise of this Warrant and the Common Stock
issuable upon conversion of the Preferred Stock is not registered under the 1933
Act or qualified under applicable state securities laws on the ground that the
issuance contemplated by this Warrant Agreement will be exempt from the
registration and qualifications requirements thereof, and (ii) that the
Company's reliance on such exemption is predicated on the representations set
forth in this Section 10.

                                       8.
<PAGE>

         (c)      DISPOSITION OF WARRANTHOLDER'S RIGHTS. In no event will the
Warrantholder make a disposition of any of its rights to acquire Preferred Stock
or Preferred Stock issuable upon exercise of such rights unless and until (i) it
shall have notified the Company of the proposed disposition, and (ii) if
requested by the Company, it shall have furnished the Company with an opinion of
counsel (which counsel may either be inside or outside counsel to the
Warrantholder) satisfactory to the Company and its counsel to the effect that
(A) appropriate action necessary for compliance with the 1933 Act has been
taken, or (B) an exemption from the registration requirements of the 1933 Act is
available. Notwithstanding the foregoing, the restrictions imposed upon the
transferability of any of its rights to acquire Preferred Stock or Preferred
Stock issuable on the exercise of such rights do not apply to transfers from the
beneficial owner of any of the aforementioned securities to its nominee or from
such nominee to its beneficial owner, and shall terminate as to any particular
share of Preferred Stock when (1) such security shall have been effectively
registered under the 1933 Act and sold by the holder thereof in accordance with
such registration or (2) such security shall have been sold without registration
in compliance with Rule 144 under the 1933 Act, or (3) a letter shall have been
issued to the Warrantholder at its request by the staff of the Securities and
Exchange Commission or a ruling shall have been issued to the Warrantholder at
its request by such Commission stating that no action shall be recommended by
such staff or taken by such Commission, as the case may be, if such security is
transferred without registration under the 1933 Act in accordance with the
conditions set forth in such letter or ruling and such letter or ruling
specifies that no subsequent restrictions on transfer are required. Whenever the
restrictions imposed hereunder shall terminate, as hereinabove provided, the
Warrantholder or holder of a share of Preferred Stock then outstanding as to
which such restrictions have terminated shall be entitled to receive from the
Company, without expense to such holder, one or more new certificates for the
Warrant or for such shares of Preferred Stock not bearing any restrictive
legend.

         (d)      FINANCIAL RISK. The Warrantholder has such knowledge and
experience in financial and business matters as to be capable of evaluating the
merits and risks of its investment, and has the ability to bear the economic
risks of its investment.

         (e)      RISK OF NO REGISTRATION. The Warrantholder understands that if
the Company does not register with the Securities and Exchange Commission
pursuant to Section 12 of the 1934 Act (the "1934 ACT"), or file reports
pursuant to Section 15(d), of the 1934 Act, or if a registration statement
covering the securities under the 1933 Act is not in effect when it desires to
sell (i) the rights to purchase Preferred Stock pursuant to this Warrant
Agreement, or (ii) the Preferred Stock issuable upon exercise of the right to
purchase, it may be required to hold such securities for an indefinite period.
The Warrantholder also understands that any sale of its rights of the
Warrantholder to purchase Preferred Stock or Preferred Stock which might be made
by it in reliance upon Rule 144 under the 1933 Act may be made only in
accordance with the terms and conditions of that Rule. The Warrantholder is
aware that the conditions for resale set forth in Rule 144 have not been
satisfied and that the Company presently has no plans to satisfy these
conditions until immediately following the Company's Initial Public Offering.

         (f)      ACCREDITED INVESTOR. Warrantholder is an "accredited investor"
within the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

                                       9.
<PAGE>

         (g)      LEGEND. The Warrantholder understands and agrees that all
certificates evidencing the shares to be issued to the Warrantholder may bear
the following legend:

                  THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
                  ACT OF 1933, AS AMENDED ("THE ACT"). THEY MAY NOT BE SOLD,
                  OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF
                  ANY EFFECTIVE REGISTRATION STATEMENT AS TO THE SECURITIES
                  UNDER THE ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE
                  COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.

11.      RIGHT OF FIRST OFFER.

         The Company covenants to use its best efforts to amend the Investor
Rights Agreement dated June 18, 1998 (the "RIGHTS AGREEMENT") to the extent
necessary such that the Warrantholder will be considered an "Investor" and the
Preferred Stock will be considered "Shares" only for the purposes of Section
4.1, 4.2, 4.3, 4.4 and 4.6 of the Rights Agreement; PROVIDED, HOWEVER, that the
Warrantholder shall receive no other rights under the Rights Agreement.

12.      TRANSFERS.

         Subject to the terms and conditions contained in Section 10 hereof,
this Warrant Agreement and all rights hereunder are transferable in whole or in
part by the Warrantholder and any successor transferee, PROVIDED, HOWEVER, in no
event shall the number of transfers of the rights and interests in all of the
Warrants exceed three (3) transfers. The transfer shall be recorded on the books
of the Company upon receipt by the Company of a notice of transfer in the form
attached hereto as Exhibit III (the "TRANSFER NOTICE"), at its principal offices
and the payment to the Company of all transfer taxes and other governmental
charges imposed on such transfer.

13.      MISCELLANEOUS.

         (a)      EFFECTIVE DATE. The provisions of this Warrant Agreement shall
be construed and shall be given effect in all respects as if it had been
executed and delivered by the Company on the date hereof. This Warrant Agreement
shall be binding upon any successors or assigns of the Company.

         (b)      ATTORNEY'S FEES. In any litigation, arbitration or court
proceeding between the Company and the Warrantholder relating hereto, the
prevailing party shall be entitled to attorneys' fees and expenses and all costs
of proceedings incurred in enforcing this Warrant Agreement.

         (c)      GOVERNING LAW. This Warrant Agreement shall be governed by and
construed for all purposes under and in accordance with the laws of the State of
Illinois.

                                      10.
<PAGE>

         (d)      COUNTERPARTS. This Warrant Agreement may be executed in two or
more counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         (e)      NOTICES. Any notice required or permitted hereunder shall be
given in writing and shall be deemed effectively given upon personal delivery,
facsimile transmission (provided that the original is sent by personal delivery
or mail as hereinafter set forth) or seven (7) days after deposit in the United
States mail, by registered or certified mail, addressed (i) to the Warrantholder
at 6111 North River Road, Rosemont, Illinois 60018, Attention: Venture Lease
Administration, cc: Legal Department, Attention: General Counsel, (and/or, if by
facsimile, (847) 518-5465 and (847) 518-5088) and (ii) to the Company at 3510
Dunhill Street, Suite A, San Diego, CA 92121, Attention: Chief Financial Officer
(and/or if by facsimile, (619) 410-3090) or at such other address as any such
party may subsequently designate by written notice to the other party.

         (f)      REMEDIES. In the event of any default hereunder, the
non-defaulting party may proceed to protect and enforce its rights either by
suit in equity and/or by action at law, including but not limited to an action
for damages as a result of any such default, and/or an action for specific
performance for any default where Warrantholder will not have an adequate remedy
at law and where damages will not be readily ascertainable. The Company
expressly agrees that it shall not oppose an application by the Warrantholder or
any other person entitled to the benefit of this Agreement requiring specific
performance of any or all provisions hereof or enjoining the Company from
continuing to commit any such breach of this Agreement.

         (g)      NO IMPAIRMENT OF RIGHTS. The Company will not, by amendment
of its Charter or through any other means, avoid or seek to avoid the
observance or performance of any of the terms of this Warrant, but will at
all times in good faith assist in the carrying out of all such terms and in
the taking of all such actions as may be necessary or appropriate in order to
protect the rights of the Warrantholder against impairment.

         (h)      SURVIVAL. The representations, warranties, covenants and
conditions of the respective parties contained herein or made pursuant to this
Warrant Agreement shall survive the execution and delivery of this Warrant
Agreement.

         (i)      SEVERABILITY. In the event any one or more of the provisions
of this Warrant Agreement shall for any reason be held invalid, illegal or
unenforceable, the remaining provisions of this Warrant Agreement shall be
unimpaired, and the invalid, illegal or unenforceable provision shall be
replaced by a mutually acceptable valid, legal and enforceable provision, which
comes closest to the intention of the parties underlying the invalid, illegal or
unenforceable provision.

         (j)      AMENDMENTS. Any provision of this Warrant Agreement may be
amended by a written instrument signed by the Company and by the Warrantholder.

         (k)      ADDITIONAL DOCUMENTS. The Company, upon execution of this
Warrant Agreement, shall provide the Warrantholder with certified resolutions
with respect to the representations, warranties and covenants set forth in
subparagraphs (a) through (d), (f) and (g)

                                      11.
<PAGE>

of Section 9 above. The Company shall also supply such other documents as the
Warrantholder may from time to time reasonably request.

         IN WITNESS WHEREOF, the parties hereto have caused this Warrant
Agreement to be executed by its officers thereunto duly authorized as of the
Effective Date.

                                        COMPANY:  ELITRA PHARMACEUTICALS INC.

                                        By: /s/ Harry F. Hixson Jr.
                                           -------------------------------------
                                        Title:  Chairman and CEO
                                              ----------------------------------

                                        WARRANTHOLDER: COMDISCO, INC.

                                        By: /s/ James Labe
                                           -------------------------------------
                                        Title: President
                                              ----------------------------------

                                      12.
<PAGE>

                                    EXHIBIT I

                               NOTICE OF EXERCISE

To:

(1)      The undersigned Warrantholder hereby elects to purchase ___________
         shares of the Series B Preferred Stock of _______________, pursuant to
         the terms of the Warrant Agreement dated the ______ day of
         _________________, 2000 (the "WARRANT AGREEMENT") between
         _______________________________ and the Warrantholder, and tenders
         herewith payment of the purchase price for such shares in full,
         together with all applicable transfer taxes, if any.

(2)      In exercising its rights to purchase the Series B Preferred Stock of
         _________________, the undersigned hereby confirms and acknowledges the
         investment representations and warranties made in Section 10 of the
         Warrant Agreement.

(3)      Please issue a certificate or certificates representing said shares of
         Series B Preferred Stock in the name of the undersigned or in such
         other name as is specified below.

____________________________
(Name)

____________________________
(Address)

WARRANTHOLDER:  COMDISCO, INC.
By:_________________________

Title:______________________

Date:_______________________

                                      13.
<PAGE>

                                   EXHIBIT II

                           ACKNOWLEDGMENT OF EXERCISE

         The undersigned _____________________ hereby acknowledge receipt of the
"Notice of Exercise" from COMDISCO, INC., to purchase _______________ shares of
the Series B Preferred Stock of _____________________, pursuant to the terms of
the Warrant Agreement, and further acknowledges that ____________shares remain
subject to purchase under the terms of the Warrant Agreement.

                                                     COMPANY:

                                                     By:________________________

                                                     Title:_____________________

                                                     Date:______________________

                                      14.
<PAGE>

                                   EXHIBIT III

                                 TRANSFER NOTICE

(TO TRANSFER OR ASSIGN THE FOREGOING WARRANT AGREEMENT EXECUTE THIS FORM AND
SUPPLY REQUIRED INFORMATION. DO NOT USE THIS FORM TO PURCHASE SHARES.)

         FOR VALUE RECEIVED, the foregoing Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to

_____________________________________________________
(Please Print)

whose address is ____________________________________

_____________________________________________________

                  Dated:_____________________________

                  Holder's Signature:________________

                  Holder's Address:__________________

Signature Guaranteed:________________________________

NOTE:    The signature to this Transfer Notice must correspond with the name as
         it appears on the face of the Warrant Agreement, without alteration or
         enlargement or any change whatever. Officers of corporations and those
         acting in a fiduciary or other representative capacity should file
         proper evidence of authority to assign the foregoing Warrant Agreement.

                                       1.

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