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                                                                   EXHIBIT 10.25


                                                               CUSTOMER NO. 1093
                             MASTER LEASE AGREEMENT


Lessor:        TRANSAMERICA BUSINESS CREDIT CORPORATION
               RIVERWAY II
               WEST OFFICE TOWER
               WEST HIGGINS
               ROSEMONT, ILLINOIS  60018


Lessee:        SIGNAL PHARMACEUTICALS, INC.
               5555 OBERLIN DRIVE
               SAN DIEGO, CALIFORNIA  92121


The lessor pursuant to this Master Lease Agreement ("Agreement") dated as of
January 1, 1998, is Transamerica Business Credit Corporation ("Lessor"). All
equipment, together with all present and future additions, parts, accessories,
attachments, substitutions, repairs, improvements, and replacements thereof or
thereto, which are the subject of a Lease (as defined in the next sentence)
shall be referred to as "Equipment." Simultaneous with the execution and
delivery of this Agreement, the parties are entering into one or more Lease
Schedules (each, a "Schedule") which refer to and incorporate by reference this
Agreement, each of which constitutes a lease (each, a "Lease") for the Equipment
specified therein. Additional details pertaining to each Lease are specified in
the applicable Schedule. Each Schedule that the parties hereafter enter into
shall constitute a Lease. Lessor and Lessee have no obligation to enter into any
additional leases with, or extend any future financing to, the other party.


     1. LEASE. Subject to and upon all of the terms and conditions of this
Agreement and each Schedule, Lessor hereby agrees to lease to Lessee and Lessee
hereby agrees to lease from Lessor the Equipment for the Term (as defined in
Paragraph 2 below) thereof. The timing and financial scope of Lessor's
obligation to enter into Leases hereunder are limited as set forth in the
Commitment Letter executed by Lessor and Lessee, dated as of November 14, 1997
and attached hereto as Exhibit A (the "Commitment Letter").

     2. TERM. Each Lease shall be effective and the term of each Lease ("Term")
shall commence on the commencement date specified in the applicable Schedule
and, unless sooner terminated (as hereinafter provided), shall expire at the end
of the term specified in such Schedule; provided, however, that obligations due
to be performed by Lessee during the Term shall continue until they have been
performed in full. Schedules will only be executed after the delivery of the
Equipment to Lessee or upon completion of deliveries of items of such Equipment
with aggregate cost of not less than $50,000.

     3. RENT. Lessee shall pay as rent to Lessor, for use of the Equipment
during the Term or Renewal Term (as defined in Paragraph 8), rental payments
equal to the sum of all rental payments including, without limitation, security
deposits, advance rents, and interim rents payable in the amounts and on the
dates specified in the applicable Schedule ("Rent"). If any Rent or other amount
payable by Lessee is not paid within five days after the day on which it becomes
payable, Lessee will pay on demand, as a late charge, an amount equal to 5% of
such unpaid Rent or other amount but only to the extent permitted by applicable
law. All payments provided for herein shall be payable to Lessor at its address
specified above, or at any other place designated by Lessor.

     4. LEASE NOT CANCELABLE; LESSEE'S OBLIGATIONS ABSOLUTE. No Lease may be
canceled or terminated except as expressly provided herein. Upon receipt of
funding from Lessor, Lessee's obligation to pay all Rent due or to become due
hereunder shall be absolute and unconditional and shall not be subject to any
delay, reduction, set-off, defense, counterclaim, or recoupment for any reason
whatsoever, including any failure of the Equipment or any representations by the
manufacturer or the vendor thereof. If the Equipment is unsatisfactory for any
reason, Lessee shall make any claim solely against the manufacturer or the
vendor thereof and shall, nevertheless, pay Lessor all Rent payable hereunder.



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     5. SELECTION AND USE OF EQUIPMENT. Lessee agrees that it shall be
responsible for the selection and use of, and results obtained from, the
Equipment and any other associated equipment or services.

     6. WARRANTIES. LESSOR MAKES NO REPRESENTATION OR WARRANTY, EXPRESS OR
IMPLIED, AS TO ANY MATTER WHATSOEVER, INCLUDING, WITHOUT LIMITATION, THE DESIGN
OR CONDITION OF THE EQUIPMENT OR ITS MERCHANTABILITY, SUITABILITY, QUALITY, OR
FITNESS FOR A PARTICULAR PURPOSE, AND HEREBY DISCLAIMS ANY SUCH WARRANTY. LESSEE
SPECIFICALLY WAIVES ALL RIGHTS TO MAKE A CLAIM AGAINST LESSOR FOR BREACH OF ANY
WARRANTY WHATSOEVER. LESSEE LEASES THE EQUIPMENT "AS IS." IN NO EVENT SHALL
LESSOR HAVE ANY LIABILITY, NOR SHALL LESSEE HAVE ANY REMEDY AGAINST LESSOR, FOR
ANY LIABILITY, CLAIM, LOSS, DAMAGE, OR EXPENSE CAUSED DIRECTLY OR INDIRECTLY BY
THE EQUIPMENT OR ANY DEFICIENCY OR DEFECT THEREOF OR THE OPERATION, MAINTENANCE,
OR REPAIR THEREOF OR ANY CONSEQUENTIAL DAMAGES AS THAT TERM IS USED IN SECTION
2-719(3) OF THE MODEL UNIFORM COMMERCIAL CODE, AS AMENDED FROM TIME TO TIME
("UCC"). Lessor grants to Lessee the benefits of any and all warranties made
available by the manufacturer or the vendor of the Equipment to the extent
assignable.

     7. DELIVERY. Lessor hereby appoints Lessee as Lessor's agent for the sole
and limited purpose of accepting delivery of the Equipment from each vendor
thereof. Lessee shall pay any and all delivery and installation charges. Lessor
shall not be liable to Lessee for any delay in, or failure of, delivery of the
Equipment.

     8. RENEWAL. So long as no Event of Default or event which, with the giving
of notice, the passage of time, or both, would constitute an Event of Default,
shall have occurred and be continuing, or the Lessee shall not have exercised
its purchase option under Paragraph 9 hereof, each Lease will automatically
renew for a term specified in the applicable Schedule (the "Renewal Term") on
the terms and conditions of this Agreement or as set forth in such Schedule;
provided, however, that Obligations due to be performed by the Lessee during the
Renewal Term shall continue until they have been performed in full.

     9. PURCHASE OPTION. So long as no Event of Default or event which, with the
giving of notice, the passage of time, or both, would constitute an Event of
Default, shall have occurred and be continuing, Lessee may, upon written notice
to Lessor received at least sixty days before the expiration of a Term, purchase
all, but not less than all, the Equipment covered by the applicable Lease on the
date specified therefor in the applicable Schedule ("Purchase Date"). The
purchase price for such Equipment shall be its fair market value as set forth in
the applicable Schedule determined on an "In-place, In-use" basis, as mutually
agreed by Lessor and Lessee, or, if they cannot agree, as determined by an
independent appraiser selected by Lessor and approved by Lessee, which approval
will not be unreasonably delayed or withheld. Lessee shall pay the cost of any
such appraisal. So long as no Event of Default or event which, with the giving
of notice, the passage of time, or both, would constitute an Event of Default
shall have occurred and be continuing, Lessee may, upon written notice to Lessor
received at least sixty days prior to the expiration of the Renewal Term,
purchase all, but not less than all, the Equipment covered by the applicable
Schedule by the last date of the Renewal Term (the "Alternative Purchase Date")
at a purchase price equal to its then fair market value on an "In-place, In-use"
basis. On the Purchase Date or the Alternative Purchase Date, as the case may
be, for any Equipment, Lessee shall pay to Lessor the purchase price, together
with all sales and other taxes applicable to the transfer of the Equipment and
any other amount payable and arising hereunder, in immediately available funds,
whereupon Lessor shall transfer to Lessee, without recourse or warranty of any
kind, express or implied, all of Lessor's right, title, and interest in and to
such Equipment on an "As Is, Where Is" basis.

     10. OWNERSHIP; INSPECTION; MARKING; FINANCING STATEMENTS. Lessee shall
affix to the Equipment any labels supplied by Lessor and reasonably acceptable
to Lessee indicating ownership of such Equipment. The Equipment is and shall be
the sole property of Lessor. Lessee shall have no right, title, or interest
therein, except as lessee under a Lease. The Equipment is and shall at all times
be and remain personal property and shall not become a fixture. Lessee shall
obtain and record such instruments and take such steps as may be necessary to
prevent any person from acquiring any rights in the Equipment by reason of the
Equipment being claimed or deemed to be real property. Upon request by Lessor,
Lessee shall obtain and deliver to Lessor valid and effective waivers, in
recordable form, by the owners, landlords, and mortgagees of the real property
upon which the Equipment is located or certificates of Lessee that it is the
owner of such real property or that such real property is



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neither leased nor mortgaged. Lessee shall make the Equipment and its
maintenance records available for inspection by Lessor at reasonable times and
upon reasonable notice. Lessee shall execute and deliver to Lessor for filing
any UCC financing statements or similar documents Lessor may reasonably request.

     11. EQUIPMENT USE. Lessee agrees that the Equipment will be operated by
competent, qualified personnel in connection with Lessee's business for the
purpose for which the Equipment was designed and in accordance with applicable
operating instructions, laws, and government regulations, and that Lessee shall
use reasonable precautions to prevent loss or damage to the Equipment from fire
and other hazards. Lessee shall procure and maintain in effect all orders,
licenses, certificates, permits, approvals, and consents required by federal,
state, or local laws or by any governmental body, agency, or authority in
connection with the delivery, installation, use, and operation of the Equipment.

     12. MAINTENANCE. Lessee, at its sole cost and expense, shall keep the
Equipment in a suitable environment as specified by the manufacturer's
guidelines or the equivalent, shall meet all recertification requirements, and
shall maintain the Equipment in its original condition and working order,
ordinary wear and tear excepted. At the reasonable request of Lessor, Lessee
shall furnish all proof of maintenance.

     13. ALTERATION; MODIFICATIONS; PARTS. Lessee may materially alter or modify
the Equipment only with the prior written consent of Lessor. Any alteration
shall be removed and the Equipment restored to its normal, unaltered condition
at Lessee's expense (without damaging the Equipment's originally intended
function or its value) prior to its return to Lessor. Any part installed in
connection with warranty or maintenance service or which cannot be removed in
accordance with the preceding sentence shall be the property of Lessor.

     14. RETURN OF EQUIPMENT. Except for Equipment that has suffered a Casualty
Loss (as defined in Paragraph 15 below) and is not required to be repaired
pursuant to Paragraph 15 below or Equipment purchased by Lessee pursuant to
Paragraph 9 above, upon the expiration of the Renewal Term of a Lease, or upon
demand by Lessor pursuant to Paragraph 22 below, Lessee shall contact Lessor for
shipping instructions and, at Lessee's own risk, immediately return the
Equipment, freight prepaid, to a location in the continental United States
specified by Lessor. At the time of such return to Lessor, the Equipment shall
(i) be in the operating order, repair, and condition as required by or specified
in the original specifications and warranties of each manufacturer and vendor
thereof, ordinary wear and tear excepted, (ii) meet applicable recertification
requirements, and (iii) be capable of being promptly assembled and operated by a
third party purchaser or third party lessee without further repair, replacement,
alterations, or improvements, and in accordance and compliance with any and all
statutes, laws, ordinances, rules, and regulations of any governmental authority
or any political subdivision thereof applicable to the use and operation of the
Equipment. Except as otherwise provided under Paragraph 9 hereof, at least sixty
days before the expiration of the Renewal Term, Lessee shall give Lessor notice
of its intent to return the Equipment at the end of such Renewal Term. During
the sixty-day period prior to the end of a Term or the Renewal Term, Lessor and
its prospective purchasers or lessees shall have, upon not less than two
business days' prior notice to Lessee and during normal business hours, or at
any time and without prior notice upon the occurrence and continuance of an
Event of Default, the right of access to the premises on which the Equipment is
located to inspect the Equipment, and Lessee shall cooperate in all other
respects with Lessor's remarketing of the Equipment. The provisions of this
Paragraph 14 are of the essence of the Lease, and upon application to any court
of equity having jurisdiction in the premises, Lessor shall be entitled to a
decree against Lessee requiring specific performance of the covenants of Lessee
set forth in this Paragraph 14. If Lessee fails to return the Equipment when
required, the terms and conditions of the Lease shall continue to be applicable
and Lessee shall continue to pay Rent until the Equipment is received by Lessor.

     15. CASUALTY INSURANCE; LOSS OR DAMAGE. Lessee will maintain, at its own
expense, liability and property damage insurance relating to the Equipment,
insuring against such risks as are customarily insured against on the type of
equipment leased hereunder by businesses in which Lessee is engaged in such
amounts, in such form, and with insurers satisfactory to Lessor; provided,
however, that the amount of insurance against damage or loss shall not be less
than the greater of (a) the replacement value of the Equipment and (b) the
stipulated loss value of the Equipment specified in the applicable Schedule
("Stipulated Loss Value"). Each liability insurance policy shall provide
coverage (including, without limitation, personal injury coverage) of not less



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than $1,000,000 for each occurrence, and shall name Lessor as an additional
insured; and each property damage policy shall, with respect to the Equipment,
name Lessor as sole loss payee and all policies shall contain a clause requiring
the insurer to give Lessor at least thirty days' prior written notice of any
alteration in the terms or cancellation of the policy. Lessee shall furnish to
Lessor a copy of each insurance policy (with endorsements) or other evidence
satisfactory to Lessor that the required insurance coverage is in effect;
provided, however, Lessor shall have no duty to ascertain the existence of or to
examine the insurance policies to advise Lessee if the insurance coverage does
not comply with the requirements of this Paragraph. If Lessee fails to insure
the Equipment as required, Lessor shall have the right but not the obligation to
obtain such insurance, and the cost of the insurance shall be for the account of
Lessee due as part of the next due Rent. Lessee consents to Lessor's release,
upon its failure to obtain appropriate insurance coverage, of any and all
information necessary to obtain insurance with respect to the Equipment or
Lessor's interest therein.

     Until the Equipment is returned to and received by Lessor as provided in
Paragraph 14 above, Lessee shall bear the entire risk of theft or destruction
of, or damage to, the Equipment including, without limitation, any condemnation,
seizure, or requisition of title or use ("Casualty Loss"). No Casualty Loss
shall relieve Lessee from its obligations to pay Rent except as provided in
clause (b) below. When any Casualty Loss occurs, Lessee shall immediately notify
Lessor and, at the option of Lessee, shall promptly (a) place such Equipment in
good repair and working order; or (b) pay Lessor an amount equal to the
Stipulated Loss Value of such Equipment and all other amounts (excluding Rent)
payable by Lessee hereunder, together with any applicable late charge on such
amounts at a rate per annum equal to the rate imputed in the Rent payments
hereunder (as reasonably determined by Lessor) from the date of the Casualty
Loss through the date of payment of such amounts, whereupon Lessor shall
transfer to Lessee, without recourse or warranty (express or implied), all of
Lessor's interest, if any, in and to such Equipment on an "AS IS, WHERE IS"
basis. The proceeds of any insurance payable with respect to the Equipment shall
be applied, at the option of Lessee, either towards (i) repair of the Equipment
or (ii) payment of any of Lessee's obligations hereunder. Lessee hereby appoints
Lessor as Lessee's attorney-in-fact to make claim for, receive payment of, and
execute and endorse all documents, checks or drafts issued with respect to any
Casualty Loss under any insurance policy relating to the Equipment.

     16. TAXES. Lessee shall pay when due, and indemnify and hold Lessor
harmless from, all sales, use, excise, and other taxes, charges, and fees
(including, without limitation, income, franchise, business and occupation,
gross receipts, licensing, registration, titling, personal property, stamp and
interest equalization taxes, levies, imposts, duties, charges, or withholdings
of any nature), and any fines, penalties, or interest thereon, imposed or levied
by any governmental body, agency, or tax authority upon or in connection with
the Equipment, its purchase, ownership, delivery, leasing, possession, use, or
relocation of the Equipment or otherwise in connection with the transactions
contemplated by each Lease or the Rent thereunder, excluding taxes on or
measured by the net income of Lessor, except where such charges result directly
from Lessor's gross negligence or willful misconduct. Upon request, Lessee will
provide proof of payment. Unless Lessor elects otherwise, Lessee will pay all
property taxes on the Equipment. Lessee shall timely prepare and file all
reports and returns which are required to be made with respect to any obligation
of Lessee under this Paragraph 16. Lessee shall, to the extent permitted by law,
cause all billings of such fees, taxes, levies, imposts, duties, withholdings,
and governmental charges to be made to Lessor in care of Lessee. Upon request,
Lessee will provide Lessor with copies of all such billings.

     17. LESSOR'S PAYMENT. If Lessee fails to perform its obligations under
Paragraph 15 or 16 above, or Paragraph 23 below, Lessor shall have the right,
after notice, to substitute performance, in which case Lessee shall immediately
reimburse Lessor therefor.

     18. GENERAL INDEMNITY. Each Lease is a net lease. Therefore, Lessee shall
indemnify Lessor and its successors and assigns against, and hold Lessor and its
successors and assigns harmless from, any and all claims, actions, damages,
obligations, liabilities, and all costs and expenses, including, without
limitation, legal fees incurred by Lessor or its successors and assigns arising
out of each Lease including, without limitation, the purchase, ownership,
delivery, lease, possession, maintenance, condition, use, or return of the
Equipment, or arising by operation of law, except that Lessee shall not be
liable for any claims, actions, damages, obligations, and costs and expenses
determined by an order of a court of competent jurisdiction to have occurred as
a result of the gross negligence or willful misconduct of Lessor or its
successors and assigns. Lessee agrees that upon written notice by Lessor of the
assertion of any claim, action, damage, obligation, liability, or lien, Lessee
shall assume full responsibility for the defense thereof, provided that Lessor's
failure to give such notice shall not



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limit or otherwise affect its rights hereunder. Any payment pursuant to this
Paragraph (except for any payment of Rent) shall be of such amount as shall be
necessary so that, after payment of any taxes required to be paid thereon by
Lessor, including taxes on or measured by the net income of Lessor, the balance
will equal the amount due hereunder. The provisions of this Paragraph with
regard to matters arising during a Lease shall survive the expiration or
termination of such Lease.

     19. ASSIGNMENT BY LESSEE. Lessee shall not, without the prior written
consent of Lessor, (a) assign, transfer, pledge, or otherwise dispose of any
Lease or Equipment, or any interest therein; (b) sublease or lend any Equipment
or permit it to be used by anyone other than Lessee and its employees; or (c)
move any Equipment from the location specified for it in the applicable
Schedule, except that Lessee may move Equipment to another location within the
United States provided that Lessee has delivered to Lessor (A) prior written
notice thereof and (B) duly executed financing statements and other agreements
and instruments (all in form and substance satisfactory to Lessor) necessary or,
in the opinion of the Lessor, desirable to protect Lessor's interest in such
Equipment. Notwithstanding anything to the contrary in the immediately preceding
sentence, Lessee may keep any Equipment consisting of motor vehicles or rolling
stock at any location in the United States.

     20. ASSIGNMENT BY LESSOR. Lessor may assign its interest or grant a
security interest in any Lease and the Equipment individually or together, in
whole or in part. If Lessee is given written notice of any such assignment, it
shall immediately make all payments of Rent and other amounts hereunder directly
to such assignee. Each such assignee shall have all of the rights of Lessor
under each Lease assigned to it. Lessee shall not assert against any such
assignee any set-off, defense, or counterclaim that Lessee may have against
Lessor or any other person.

     21. DEFAULT; NO WAIVER. Lessee or any guarantor of any or all of the
obligations of Lessee hereunder (together with Lessee, the "Lease Parties")
shall be in default under each Lease upon the occurrence of any of the following
events (each, an "Event of Default"): (a) Lessee fails to pay within two
business days after notice of failure to pay when due any amount required to be
paid by Lessee under or in connection with any Lease; (b) any of the Lease
Parties fails to perform any other provision under or in connection with a Lease
or violates any of the covenants or agreements of such Lease Party under or in
connection with a Lease; (c) any representation made or financial information
delivered or furnished by any of the Lease Parties under or in connection with a
Lease shall prove to have been inaccurate in any material respect when made; (d)
any of the Lease Parties makes an assignment for the benefit of creditors,
whether voluntary or involuntary, or consents to the appointment of a trustee or
receiver, or if either shall be appointed for any of the Lease Parties or for a
substantial part of its property without its consent and, in the case of any
such involuntary proceeding, such proceeding remains undismissed or unstayed for
forty-five days following the commencement thereof; (e) any petition or
proceeding is filed by or against any of the Lease Parties under any Federal or
State bankruptcy or insolvency code or similar law and, in the case of any such
involuntary petition or proceeding, such petition or proceeding remains
undismissed or unstayed for forty-five days following the filing or commencement
thereof, or any of the Lease Parties takes any action authorizing any such
petition or proceeding; (f) any of the Lease Parties fails to pay when due any
indebtedness for borrowed money or under conditional sales or installment sales
contracts or similar agreements, leases, or obligations evidenced by bonds,
debentures, notes, or other similar agreements or instruments to any creditor
(including Lessor under any other agreement) after any and all applicable cure
periods therefor shall have elapsed; (g) any judgment rendered by a court of
competent jurisdiction shall be rendered against any of the Lease Parties which
shall remain unpaid or unstayed for a period of sixty days; (h) any of the Lease
Parties shall dissolve, liquidate, wind up or cease its business, sell or
otherwise dispose of all or substantially all of its assets, or make any
material change in its basic lines of business; (i) any of the Lease Parties
shall amend or modify its name, unless such Lease Party delivers to Lessor,
within thirty days after any such proposed amendment or modification, written
notice of such amendment or modification and within ten days before such
amendment or modification delivers executed financing statements (in form and
substance satisfactory to the Lessor); (j) any of the Lease Parties shall merge
or consolidate with any other entity or make any material change in its capital
structure, in each case without Lessor's prior written consent, which shall not
be unreasonably withheld; (k) any of the Lease Parties shall suffer any loss or
suspension of any material license, permit, or other right or asset necessary to
the profitable conduct of its business, fail generally to pay its debts as they
mature, or call a meeting for purposes of compromising its debts; (l) any of the
Lease Parties shall deny or disaffirm its obligations hereunder or under any of
the documents delivered in connection herewith; (m) there is a change, which
change does not result from the sale of newly issued securities



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to investors, in more than 35% of the ownership of any equity interests of any
of the Lease Parties on the date hereof or more than 35% of such interests
become subject to any contractual, judicial or statutory lien, charge, security
interest, or encumbrance; or (n) any of the Lease Parties suffers a material
adverse change in the business, prospects, operations, results of operations,
assets, liabilities, or condition (financial or otherwise).

     22. REMEDIES. Upon the occurrence and continuation of an Event of Default,
Lessor shall have the right, in its sole discretion, to exercise any one or more
of the following remedies: (a) terminate each Lease; (b) declare any and all
Rent and other amounts then due and any and all Rent and other amounts to become
due under each Lease (collectively, the "Lease Obligations") immediately due and
payable; (c) take possession of any or all items of Equipment, wherever located,
without demand, notice, court order, or other process of law, and without
liability for entry to Lessee's premises, for damage to Lessee's property, or
otherwise; (d) demand that Lessee immediately return any or all Equipment to
Lessor in accordance with Paragraph 14 above, and, for each day that Lessee
shall fail to return any item of Equipment, Lessor may demand an amount equal to
the Rent payable for such Equipment in accordance with Paragraph 14 above; (e)
lease, sell, or otherwise dispose of the Equipment in a commercially reasonable
manner, with or without notice and on public or private bid; (f) recover the
following amounts from the Lessee (as damages, including reimbursement of costs
and expenses, liquidated for all purposes and not as a penalty): (i) all costs
and expenses of Lessor reimbursable to it hereunder, including, without
limitation, expenses of disposition of the Equipment, legal fees, and all other
amounts specified in Paragraph 23 below; (ii) an amount equal to the sum of (A)
any accrued and unpaid Rent through the later of (1) the date of the applicable
default, (2) the date that Lessor has obtained possession of the Equipment, or
(3) such other date as Lessee has made an effective tender of possession of the
Equipment to Lessor (the "Default Date") and (B) if Lessor resells or re-lets
the Equipment, Rent at the periodic rate provided for in each Lease for the
additional period that it takes Lessor to resell or re-let all of the Equipment;
(iii) the present value of all future Rent reserved in the Leases and contracted
to be paid over the unexpired Term of the Leases discounted at five percent
compound interest; (iv) the reversionary value of the Equipment as of the
expiration of the Term of the applicable Lease as set forth on the applicable
Schedule, discounted at five percent compound interest; and (v) any indebtedness
for Lessee's indemnity under Paragraph 18 above, plus a late charge at the rate
specified in Paragraph 3 above, less the amount received by Lessor, if any, upon
sale or re-let of the Equipment; and (g) exercise any other right or remedy to
recover damages or enforce the terms of the Leases. Upon the occurrence and
continuance of an Event of Default or an event which with the giving of notice
or the passage of time, or both, would result in an Event of Default, Lessor
shall have the right, whether or not Lessor has made any demand or the
obligations of Lessee hereunder have matured, to appropriate and apply to the
payment of the obligations of Lessee hereunder all security deposits and other
deposits (general or special, time or demand, provisional or final) now or
hereafter held by and other indebtedness or property now or hereafter owing by
Lessor to Lessee. Lessor may pursue any other rights or remedies available at
law or in equity, including, without limitation, rights or remedies seeking
damages, specific performance, and injunctive relief. Any failure of Lessor to
require strict performance by Lessee, or any waiver by Lessor of any provision
hereunder or under any Schedule, shall not be construed as a consent or waiver
of any other breach of the same or of any other provision. Any amendment or
waiver of any provision hereof or under any Schedule or consent to any departure
by Lessee herefrom or therefrom shall be in writing and signed by Lessor.

     No right or remedy is exclusive of any other provided herein or permitted
by law or equity. All such rights and remedies shall be cumulative and may be
enforced concurrently or individually from time to time.

     23. LESSOR'S EXPENSE. Lessee shall pay Lessor on demand all costs and
expenses (including legal fees and expenses) incurred in connection with the
preparation, execution and delivery of this Agreement and any other agreements
and transactions contemplated hereby, which expenses shall not exceed $2,500
without the written consent of Lessee and all costs and expenses in protecting
and enforcing Lessor's rights and interests in each Lease and the equipment,
including, without limitation, legal, collection, and remarketing fees and
expenses incured by Lessor in enforcing the terms, conditions, or provisions of
each Lease or upon the occurrence and continuation of an Event of Default.

     24. LESSEE'S WAIVERS. To the extent permitted by applicable law, Lessee
hereby waives any and all rights and remedies conferred upon a lessee by
Sections 2A-508 through 2A-522 of the UCC. To the extent permitted by applicable
law, Lessee also hereby waives any rights now or hereafter conferred by statute
or otherwise which may require Lessor to sell, lease, or otherwise use any
Equipment in mitigation of Lessor's damages as set forth in Paragraph 22 above
or which may otherwise limit or modify any of Lessor's rights



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or remedies under Paragraph 22. Any action by Lessee against Lessor for any
default by Lessor under any Lease shall be commenced within one year after any
such cause of action accrues.

     25. NOTICES; ADMINISTRATION. Except as otherwise provided herein, all
notices, approvals, consents, correspondence, or other communications required
or desired to be given hereunder shall be given in writing and shall be
delivered by overnight courier, hand delivery, or certified or registered mail,
postage prepaid, if to Lessor, then to Transamerica Technology Finance Division,
76 Batterson Park Road, Farmington, Connecticut 06032, Attention: Assistant Vice
President, Lease Administration, with a copy to Lessor at Riverway II, West
Office Tower, 9399 West Higgins Road, Rosemont, Illinois 60018, Attention: Legal
Department, if to Lessee, then to Signal Pharmaceuticals, Inc., 5555 Oberlin
Drive, San Diego, California 92121, Attention: Vice President Finance or such
other address as shall be designated by Lessee or Lessor to the other party. All
such notices and correspondence shall be effective when received.

     26. REPRESENTATIONS. Lessee represents and warrants to Lessor that (a)
Lessee is duly organized, validly existing, and in good standing under the laws
of the State of its incorporation; (b) the execution, delivery, and performance
by Lessee of this Agreement are within Lessee's powers, have been duly
authorized by all necessary action, and do not and will not contravene (i)
Lessee's organizational documents or (ii) any law, regulation, rule, or
contractual restriction binding on or affecting Lessee; (c) no authorization or
approval or other action by, and no notice to or filing with, any governmental
authority or regulatory body is required for the due execution, delivery, and
performance by Lessee of this Agreement; (d) each Lease constitutes the legal,
valid, and binding obligations of Lessee enforceable against Lessee in
accordance with its terms; (e) the cost of each item of Equipment does not
exceed the fair and usual price for such type of equipment purchased in like
quantity and reflects all discounts, rebates, and allowances for the Equipment
(including, without limitation, discounts for advertising, prompt payment,
testing, or other services) given to the Lessee by the manufacturer, supplier,
or any other person; and (f) all information supplied by Lessee to Lessor in
connection herewith is correct and does not omit any material statement
necessary to insure that the information supplied is not misleading.

     27. FURTHER ASSURANCES. Lessee, upon the request of Lessor, will execute,
acknowledge, record, or file, as the case may be, such further documents and do
such further acts as may be reasonably necessary, desirable, or proper to carry
out more effectively the purposes of this Agreement. Lessee hereby appoints
Lessor as its attorney-in-fact to execute on behalf of Lessee and authorizes
Lessor to file without Lessee's signature any UCC financing statements and
amendments Lessor deems advisable.

     28. FINANCIAL STATEMENTS. Lessee shall deliver to Lessor: (a) as soon as
available, but not later than 120 days after the end of each fiscal year of
Lessee and its consolidated subsidiaries, the consolidated balance sheet, income
statement, and statements of cash flows and shareholders equity for Lessee and
its consolidated subsidiaries (the "Financial Statements") for such year,
reported on by independent certified public accountants without an adverse
qualification; and (b) as soon as available, but not later than 60 days after
the end of each of the first three fiscal quarters in any fiscal year of Lessee
and its consolidated subsidiaries, the unaudited Financial Statements for such
fiscal quarter, together with a certification duly executed by a responsible
officer of Lessee that such Financial Statements have been prepared in
accordance with generally accepted accounting principles and are fairly stated
in all material respects (subject to normal year-end audit adjustments). Lessee
shall also deliver to Lessor as soon as available copies of all press releases
and other similar communications issued by Lessee.

     29. CONSENT TO JURISDICTION. Lessee irrevocably submits to the jurisdiction
of any Illinois state or federal court sitting in Illinois for any action or
proceeding arising out of or relating to this Agreement or the transactions
contemplated hereby, and Lessee irrevocably agrees that all claims in respect of
any such action or proceeding may be heard and determined in such Illinois state
or federal court.

     30. WAIVER OF JURY TRIAL. LESSEE AND LESSOR IRREVOCABLY WAIVE ALL RIGHT TO
TRIAL BY JURY IN ANY ACTION, PROCEEDING, OR COUNTERCLAIM ARISING OUT OF OR
RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

     31. FINANCE LEASE. Lessee and Lessor agree that each Lease is a "Finance
Lease" as



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<PAGE>   8

defined by Section 2A-103(g) of the UCC. Lessee acknowledges that Lessee has
reviewed and approved each written Supply Contract (as defined by UCC 2A-103(y))
covering Equipment purchased from each "Supplier" (as defined by UCC 2A-103(x))
thereof.

     32. NO AGENCY. Lessee acknowledges and agrees that neither the manufacturer
or supplier, nor any salesman, representative, or other agent of the
manufacturer or supplier, is an agent of Lessor. No salesman, representative, or
agent of the manufacturer or supplier is authorized to waive or alter any term
or condition of this Agreement or any Schedule and no representation as to the
Equipment or any other matter by the manufacturer or supplier shall in any way
affect Lessee's duty to pay Rent and perform its other obligations as set forth
in this Agreement or any Schedule.

     33. GOVERNING LAW; SEVERABILITY. EACH LEASE SHALL BE GOVERNED BY THE LAWS
OF THE STATE OF ILLINOIS WITHOUT GIVING EFFECT TO THE CONFLICT OF LAW PRINCIPLES
THEREOF. IF ANY PROVISION SHALL BE HELD TO BE INVALID OR UNENFORCEABLE, THE
VALIDITY AND ENFORCEABILITY OF THE REMAINING PROVISIONS SHALL NOT IN ANY WAY BE
AFFECTED OR IMPAIRED.

LESSEE ACKNOWLEDGES THAT LESSEE HAS READ THIS AGREEMENT AND THE SCHEDULE HERETO,
UNDERSTANDS THEM, AND AGREES TO BE BOUND BY THEIR TERMS AND CONDITIONS. FURTHER,
LESSEE AND LESSOR AGREE THAT THIS AGREEMENT, THE SCHEDULES DELIVERED IN
CONNECTION HEREWITH FROM TIME TO TIME, AND THE COMMITMENT LETTER ARE THE
COMPLETE AND EXCLUSIVE STATEMENT OF THE AGREEMENT BETWEEN THE PARTIES,
SUPERSEDING ALL PROPOSALS OR PRIOR AGREEMENTS, ORAL OR WRITTEN, AND ALL OTHER
COMMUNICATIONS BETWEEN THE PARTIES RELATING TO THE SUBJECT MATTER HEREOF. SHOULD
THERE EXIST ANY INCONSISTENCY BETWEEN THE TERMS OF THE COMMITMENT LETTER AND
THIS AGREEMENT, THE TERMS OF THIS AGREEMENT SHALL PREVAIL.

     IN WITNESS WHEREOF, the parties hereto have executed or caused this
Agreement to be duly executed by their duly authorized officers as of the date
first written above.


                                        SIGNAL PHARMACEUTICALS, INC.


                                        By:    /s/ BRADLEY B. GORDON
                                               ---------------------------------
                                        Name:  Bradley E. Gordon
                                               ---------------------------------
                                        Title:
                                        Federal Tax ID: 94-3174286


                                        TRANSAMERICA BUSINESS CREDIT
                                        CORPORATION


                                        By:    /s/ GARY P. MORO
                                               ---------------------------------
                                        Name:  Gary P. Moro
                                               ---------------------------------
                                        Title: Vice President



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