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                                                                   Exhibit 10.14

                      INDUSTRIAL LEASE - MULTIPLE TENANT


THIS LEASE AGREEMENT made this 6th day of September, 2000, by and between
Benaroya Capital Company, LLC, a Washington limited liability company (the
"Lessor") and ICOS Corporation, a Delaware corporation (the "Lessee").

1.   Premises.  Lessor does hereby lease to Lessee those certain premises, to
     wit: 16,025 square feet of space in Suite 100 in the Building known as
     Canyon Park - 4 located at 2222 - 220th Street SE, in Bothell, Washington
     as outlined on Exhibit A attached hereto (hereinafter called "Premises").
     The multiple building complex of which the Building is a part is hereafter
     sometimes referred to as the "Project". In addition, the Lessee has the
     right, in common with other tenants in the Project and subject to the Rules
     and Regulations, to use of the Common Areas including the parking areas.

2.   Term.  This Lease shall be for a term of sixty (60) months commencing April
     1, 2001 (the "Commencement Date") and terminating March 31, 2006.

3.   Rent.  Lessee covenants and agrees to pay Lessor at 1001 Fourth Avenue,
     Suite 4700, Seattle, WA 98154, or to such other party or at such other
     place as Lessor may hereafter designate, monthly rent in advance without
     offset or deduction, on or before the first (1st) day of each month of the
     Lease term in the amounts as follows:

          Months:          Base Rent:
          -------          ----------

          1 through 36     $12,888.00 per month
          37 through 60    $14,176.00 per month

4.   Security Deposit.  Lessee has deposited with Lessor on the date hereof
     Fourteen Thousand One Hundred Seventy-Six and No/100 dollars ($14,176.00).
     Said sum shall be held by Lessor as security for the faithful performance
     by Lessee of all the terms, covenants and conditions of this Lease to be
     kept and performed by Lessee during the entire Term hereof. If Lessee
     defaults with respect to any provision of this Lease, including, but not
     limited to, the provisions relating to the payment of Rent or other charges
     or sums due under this Lease, Lessor may (but shall not be required to)
     use, apply or retain all or any part of the security deposit for the
     payment of any Rent or other charges or sums due under this Lease or any
     sum in default, or for the payment of any amount which Lessor may spend or
     become obligated to spend by reason of Lessee's default, or to compensate
     Lessor for any other loss, damage, cost or expense (including reasonable
     attorneys' fees) which Lessor may suffer or incur by reason of Lessee's
     default. If any portion of said security deposit is so used or applied,
     Lessee shall, within five (5) days after written demand therefor, deposit a
     certified or cashier's check with Lessor in an amount sufficient to restore
     the security deposit to its original amount and Lessee's failure to do so
     shall be a default under this Lease. Lessor shall not be required to keep
     the security deposit separate from its general funds and Lessee shall not
     be entitled to interest on such deposit. If Lessee shall fully and
     faithfully perform every provision of this Lease to be performed by it, the
     security deposit or any balance thereof after deduction hereunder by Lessor
     shall be returned to Lessee (or, at Lessor's option, to the last assignee
     of Lessee's interest hereunder) within thirty (30) days following
     expiration of the Lease Term; provided, that in the event this Lease shall
     be terminated upon the default of the Lessee, the security deposit shall be
     retained by Lessor and all of Lessee's interest therein shall terminate and
     the security deposit will be applied against the damages suffered by Lessor
     by reason of the Lessee's default. In the event of termination of Lessor's
     interest in this Lease, Lessor shall transfer said deposit to Lessor's
     successor in interest.

5.   Use.  Lessee shall use and occupy the Premises for the purposes of office,
     laboratory, process development and related support services (including
     light manufacturing and storage related to the foregoing) and for no other
     purposes, without prior written consent of Lessor (which consent shall not
     be unreasonably withheld or delayed), and shall comply with all
     governmental laws, ordinances, regulations, orders and directives and
     insurance requirements applicable to Lessee's use of the Premises. Lessee
     shall not occupy or use or permit any portion of the Premises to be
     occupied or used in such a

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     manner or for any purpose which would increase the cost of insurance
     coverage upon the Premises, the building or the contents thereof.

6.   Rules and Regulations.  Lessee agrees to comply with any Rules and
     Regulations attached hereto, any recorded Covenants, Conditions and
     Restrictions affecting the Project, as well as such other reasonable rules
     and regulations as may from time to time be adopted by Lessor for the
     management, good order and safety of common areas, the building and its
     Lessee(s), provided, however, such rules, regulations, covenants,
     conditions or restrictions do not prohibit or prevent Lessee's permitted
     use of the Premises. Lessee shall be responsible for the compliance with
     such rules and regulations by its employees, agents and invitees. Lessor's
     failure to enforce any of such rules and regulations against Lessee or any
     other Lessee shall not be deemed to be a waiver of same, provided, however,
     Lessor agrees to enforce the rules and regulations equitably among all
     tenants of the Project.

7.   Maintenance.  Lessee agrees by taking possession that the Premises are in
     tenantable and good condition. Lessee shall at its expense and at all times
     keep, maintain, repair and replace the Premises, including but not limited
     to storefronts, exterior doors and windows, Lessee division walls and
     mechanical, electrical, sprinkler and other utility systems, together with
     connections to utility distribution systems, in good condition, repair and
     order and in accordance with applicable laws, ordinances, rules,
     regulations and requirements of government authorities and insurance rating
     bureaus. Lessee agrees to maintain a preventative maintenance contract, or
     to establish a preventative maintenance program, providing for the regular
     inspection and maintenance of the heating and air conditioning systems with
     a licensed mechanical contractor and containing terms and specifications
     acceptable to Lessor. Lessee shall further keep the Premises and adjoining
     common areas in a neat, clean, safe and sanitary condition; protect water,
     drain, gas and other pipes to prevent freezing or clogging and repair all
     leaks and damage caused thereby; replace all glass and panels in windows
     and doors of the Premises which become cracked, broken or damaged; and
     remove ice and snow from entries and common areas immediately adjacent to
     the Premises. After reasonable notice from Lessee, Lessor shall repair the
     roof, exterior walls (excluding storefronts, doors and windows),
     foundations and common areas and facilities, if any, and the cost thereof
     shall be shared as provided in Section 9 hereof.

8.   Utilities and Fees.  Lessee agrees to pay promptly when due all charges for
     light, heat, water, sewer, garbage, fire protection and other utilities and
     services to the Premises, and all license fees and other governmental
     charges levied on Lessee's property and the operation of Lessee's business
     on the Premises. Lessor shall not be liable for any injury or damages
     suffered as a result of the interruption of utilities or services by fire,
     or other casualty, strike, riot, vandalism, the making of necessary repairs
     or improvements, or other causes beyond Lessor's reasonable control.

9.   Monthly Operating Expense Adjustments.  Lessee shall pay as additional
     monthly rent its prorata share of all expenses incurred by Lessor for
     operation of the Project during the term or any extension hereof, as
     follows:

     A.   Real Estate taxes and assessments, together with any assessments
          levied by the Owner's Association, if any.

     B.   Usual and necessary costs of operation, management, maintenance and
          repair (including replacement) as determined by standard accounting
          practice, including without limitation, all utilities and services not
          metered or charged directly to Lessee, insurance (including, but not
          limited to the insurance provided for under Paragraph 16 C below),
          painting, upkeep and repair of building exterior, roofing, parking,
          landscaping, and all common areas and facilities.  If any portion of
          the Property, or any system or equipment is replaced by Lessor, and if
          the useful life of such replaced item extends beyond the term of this
          Lease (as such term may be extended by the exercise of any options),
          the cost of such replacement will be amortized over its useful life
          and Lessee will be responsible only for that portion of the cost which
          is applicable to the lease term (as extended).

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     C.   A Management fee equal to four and one quarter percent (4 1/4%) of
          Lessee's monthly rent, including Base Rent and any Additional Rent.
          Lessor shall from time to time estimate and provide notice to Lessee
          of its monthly expense based upon existing or expected costs. Such
          monthly estimated amount shall be paid by Lessee on or before the
          first day of each month. Lessor, annually or upon termination hereof,
          shall compute Lessee's actual expenses. Any overpayment shall be
          applied as a credit to Lessee against future expense payments.

          Any deficiency shall be paid to Lessor by Lessee within fifteen (15)
          days after the date of Lessor's statement. Lessor's records showing
          expenditures made for such expenses shall be available for Lessee's
          inspection at any reasonable time.

          The determination of actual costs and estimated costs allocable to the
          Premises shall be made by Lessor. Lessor or its agent shall keep
          records showing all expenditures made for the items enumerated above,
          which records shall be available for inspection and review by Lessee.
          The Lessee shall have the right, at reasonable times and upon
          reasonable prior notice to the Lessor to review the Lessor's records
          relating to the actual costs and estimated costs allocable to the
          Premises for a particular Lease Year, which review must be conducted
          within six (6) months after Lessee's receipt of the statement of
          actual costs allocable to the Premises for that particular Lease Year.
          Lessor shall repay Lessee any overstated amount(s) within thirty (30)
          days following Lessor's and Lessee's mutual agreement that such
          overpayment by Lessor did occur. If such review is not conducted
          within such six (6) month period, then the matters set forth in the
          statement of actual costs allocable to the Premises for that
          particular Lease Year shall be deemed conclusive. The Lessee shall pay
          the costs and expenses of such review unless such review reveals that
          the Lessor has overstated the Operating Expenses for the Lease Year in
          question by an amount equal to 5% or more for that particular Lease
          Year in which event the Lessor shall pay up to $1,000 in payment of
          the actual costs incurred by Lessee in the performance of such review.

10.  Lessor's Reservations.  Lessor reserves the right without liability to
     Lessee: (a) at reasonable times and with notice that is reasonable under
     the circumstances (except in the case of an emergency when no notice is
     required) to inspect the Premises, and to show them to prospective Lessees
     within the last twelve (12) months of the Lease Term or earlier termination
     thereof, partners or lenders and if they are vacated, to prepare them for
     re-occupancy; (b) to retain at all times and to use in appropriate
     instances keys to doors within and into the Premises; (c) to make repairs,
     alterations, additions or improvements, whether structural or otherwise, in
     or about the building, and for such purposes to enter upon the Premises and
     during the continuance of any work, to close common areas and to interrupt
     or temporarily suspend building services and facilities, all without
     affecting any of Lessee's obligations hereunder, so long as the Premises
     are reasonably accessible; and (d) generally to perform any act relating to
     the safety, protection and preservation of the Premises or building.

11.  Possession.  If Lessor does not deliver possession of the Premises at the
     Commencement Date of the term of this Lease, then, unless such delay is
     caused by Lessee, Lessee may give Lessor written notice of its intention to
     cancel this Lease if possession is not delivered within ninety (90) days
     after receipt of such notice by Lessor. Lessor shall not be liable for any
     damages caused by failure to deliver possession of the Premises and Lessee
     shall not be liable for any rent for such time and until such time as
     Lessor delivers possession. A delay of possession shall not extend the
     termination date. Notwithstanding the above, in the event the delay was
     caused by Lessee, then the payment of Rent shall commence on the
     Commencement Date and Lessee shall not have any right to cancel this Lease
     as a result of such delay. If Lessor offers access to the Premises or any
     portion thereof prior to the Commencement Date of the term of this Lease,
     and if Lessee accepts such early access, then both parties shall be bound
     by all of the covenants and terms contained herein during such period.

12.  Assignment and Subletting.  Lessee shall not either voluntarily or by
     operation of law assign, transfer, convey or encumber this Lease or any
     interest under it, or sublet its right to occupy or use all or any portion
     of the Premises without Lessor's prior written

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     consent, which consent shall not be unreasonably withheld or delayed. Among
     the criteria to be used by Lessor in evaluating a request for assignment or
     subletting will be (i) the proposed use of the Premises; (ii) the
     anticipated impact, if any, on parking; (iii) the financial capacity of the
     assignee/sublessee to perform the obligations under this Lease; (iv) the
     compatibility of the proposed user with the remainder of the tenants and
     operation of the Building. Lessor reserves the right to recapture the
     Premises or applicable portion thereof in lieu of giving its consent by
     notice given to Lessee within twenty (20) days after receipt of Lessee's
     written request for assignment or subletting. Such recapture shall
     terminate this Lease as to the applicable space effective on the
     prospective date of assignment or subletting, which shall be the last day
     of a calendar month and not earlier than sixty (60) days after receipt of
     Lessee's request hereunder. Lessee may condition its request for Lessor's
     consent to an assignment or subletting on Lessor's waiver of its recapture
     right. In the event that Lessor shall not elect to recapture and shall
     thereafter give its consent, Lessee shall pay Lessor a reasonable fee, not
     to exceed One Thousand And No/100 Dollars ($1,000.00) to reimburse Lessor
     for processing costs incurred in connection with such consent. Lessor's
     consent shall not release or discharge Lessee from future liability under
     this Lease and shall not waive Lessor's right to consent to any future
     assignment or sublease. Any assignment or subletting without Lessor's
     consent shall be void and shall, at Lessor's option, constitute a default
     under this Lease. A transfer by the present majority shareholders of
     ownership or control of a majority of the voting stock of a corporate
     Lessee, or the change in form of entity of the Lessee, shall be deemed an
     assignment.

     The Lessee shall not assign its interest in or under this Lease for
     security purposes, nor shall the Lessee grant any security interest, lien
     or encumbrance against its interest in this Lease or in or to any property
     in or affixed to the Premises without the prior written consent of the
     Lessor, which consent shall be granted, withheld or conditioned in Lessor's
     sole discretion. In no event shall the Lessee grant, or allow to exist, any
     security interest in, or lien or encumbrance against the fee title to the
     Premises, the building in which the Premises is located or the real
     property on which the building is located.

13.  Alterations.  Lessee shall lease the Premises in its "as is" broomswept
     clean condition, as delivered to Lessee by Lessor. After obtaining the
     prior written consent of Lessor, Lessee may make minor alterations,
     additions and improvements in said Premises (so long as such alterations,
     additions or improvements are not structural in nature and not visible from
     the exterior of the Premises) at its sole cost and expense. Lessee agrees
     to save Lessor harmless from any damage, loss, or expense arising therefrom
     and to comply with all laws, ordinances, rules and regulations. Upon
     termination of this Lease, all alterations, additions and improvements made
     in, to or on the Premises (including without limitation all electrical,
     lighting, plumbing, heating, air conditioning, and communications equipment
     and systems, doors, windows, partitions, drapery, carpeting, shelving,
     counters, and physically attached fixtures, except trade fixtures, unless
     otherwise excluded by written agreement annexed hereto), shall remain upon
     and be surrendered as a part of the Premises; provided however, upon
     Lessor's request, Lessee shall remove its trade fixtures and those items
     excluded by written agreement, and those additions, alterations, or
     improvements as may be specified by Lessor, and repair and restore the
     Premises to is original condition at Lessee's sole cost and expense prior
     to expiration of the Term. Lessee may accompany its request for consent
     with an additional request for a determination by Lessor of its
     requirements with regard to the disposition of such improvements at the
     expiration of the Lease. Lessor will respond to such request along with it
     response to the request for consent.

14.  Liens.  Lessee shall keep the Premises free from any liens arising out of
     any work performed, materials furnished, equipment supplied, or obligations
     incurred by or on behalf of Lessee. No work performed, material furnished,
     equipment supplied or obligations incurred by or on behalf of Lessee shall
     be deemed to be for the immediate use and benefit of Lessor so that no
     mechanic's lien or other lien shall be allowed against Lessor's estate in
     the premises. Lessee shall provide, at Lessee's own cost, waivers of lien
     signed by any party (including the Lessee) who performs work, furnishes
     materials, or supplies equipment to the Premises. For any single project,
     the cost of which will exceed Two Hundred Fifty Thousand and No/100 dollars
     ($250,000.00), Lessor may

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     require, at Lessee's sole cost and expense, a lien release and completion
     bond in an amount equal to either the actual contract price or one and one-
     half times the estimated cost of any improvements, additions or alterations
     in the Premises which Lessee desires to make, to insure Lessor against any
     liability for lien and to insure completion of the work.

15.  Signs.  All signs or symbols placed by Lessee in the windows and doors of
     the Premises, or upon any exterior part of the building, shall be subject
     to Lessor's prior written approval. Prior to termination of this Lease,
     Lessee will remove all signs placed by it upon the Premises, and will
     repair any damages caused by such removal.

16.  Insurance.

     A.   Lessee shall pay for and maintain, during the entire Lease Term, the
          following policies of insurance:

          (i)  Commercial general liability insurance, including products,
               completed operations coverage and auto liability insurance
               covering Lessee's operations and the Premises with limits of not
               less than $2,000,000 combined single limit for death, personal
               injury and property damage per occurrence, including Lessor as an
               additional insured. Such policies shall be endorsed to provide
               contractual liability insurance covering all liability assumed by
               Lessee under the provisions of this Lease and a copy of said
               endorsement will be delivered to Lessor prior to commencement of
               the Term.

          (ii) Special cause of loss or "all risk" perils and sprinkler leakage
               property insurance upon all building improvements and alterations
               on the Premises for which Lessee is responsible and upon Lessee's
               property in the amount of one hundred percent (100%) full
               replacement cost. The policy shall include Lessor and Lessor's
               mortgagee, if any, as additional insureds, as their interests may
               appear, with a loss payable clause in favor of Lessor and
               Lessor's mortgagee to the extent of their interest in the
               property.

     B.   Each policy provided by Lessee shall expressly provide that it shall
          not be subject to cancellation or material change without at least
          thirty (30) days prior written notice to the Lessor. Lessee shall
          furnish Lessor, prior to commencement of the Term, with insurance
          certificates naming Lessor as additional insured and, upon request,
          copies of such policies required to be maintained hereunder.

     C.   Lessor shall maintain property insurance during the entire Lease Term
          in the amount of one hundred percent (100%) full replacement value of
          the Building and Lessor's improvements. Lessors coverage may include
          the perils of Special cause of loss ("all risk") and earthquake.

17.  Indemnity Against Liability for Loss or Damage

     A.   Lessee assumes all liability for and shall indemnify, hold harmless
          and defend Lessor from and against all loss, damage or expense which
          the Lessor may sustain or incur, and against any and all claims,
          demands, suits and actions whatsoever, including expense of
          investigation and litigation, on account of injury to or death of
          persons, including without limitation employees of Lessor, employees
          of Lessee or its affiliated companies or on account of damage to or
          destruction of property, including without limitation property owned
          by and property in the care, custody or control of Lessor during the
          Term, due to or arising in any manner from:

          (i)   The acts or negligence of Lessee or any contractor,
                subcontractor, or agent of Lessee or their respective employees;

          (ii)  The condition, use or operation of the Premises and/or materials
                or substances used by Lessee or any of its contractors,
                subcontractors or

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                agents of Lessee or by their respective employees, regardless of
                whether or not furnished by Lessor under this Lease or
                otherwise;

          (iii) Any damage or injury to persons or property arising out of
                Lessee's breach or this Lease, including, but not limited to,
                obligations of Lessee under Section 7, Maintenance.

     B.   Lessor shall have no liability to Lessee as a result of loss or damage
          to Lessee's property or for death or bodily injury caused by the acts
          or omissions of other tenants in the project or by third parties
          (including criminal acts).

     C.   Lessee shall not be obligated to indemnify Lessor for the portion of
          any claim or liability caused by or arising from the act, or
          negligence of Lessor.

     D.   Lessee, its agents, trustees, officers, employees, contractors and
          invitees, shall not be liable to Lessor or its agents, employees,
          contractors or invitees or to any third party for any damage to person
          or the Premises caused by or arising from or in connection with any
          act, or negligence of Lessor. Lessor agrees to indemnify, hold
          harmless and defend Lessee, its agents, trustees, officers, employees,
          contractors and invitees from and against any and all liability
          claims, causes of action, damages, costs and expenses (including,
          without limitation, attorney's fees) arising from or in connection
          with any act, or neglect of Lessor or its agents, employees,
          contractors or invitees; and from any breach or default under this
          Lease by Lessor.

     E.   It is mutually understood and agreed that the assumption of
          liabilities and indemnification provided for in this Section 17 shall
          survive any termination of this Lease.

18.  Damage or Destruction.  If any of the Premises, or a substantial part of
     the building in which the Premises are located, shall be damaged or
     destroyed by fire or other insured casualty to the extent of more than 40%
     of its replacement cost, and repair of the damage can not be completed
     within one hundred eighty (180) days, following receipt by Lessor of actual
     notice of such damage or destruction Lessor shall have the option either
     (a) to repair or rebuild within a reasonable time utilizing the insurance
     proceeds to effect such repair, or (b) not to repair or rebuild, and to
     cancel this Lease on thirty (30) days notice. If Lessor fails to give
     Lessee written notice of its election within thirty (30) days from the date
     of damage, or if the restoration of the Premises cannot be completed within
     one hundred eighty (180) days from date of notice, Lessee may cancel this
     Lease at its option on thirty (30) days notice. During the period of
     untenantability, rent shall abate in the same ratio as the portion of the
     Premises rendered untenantable bears to the whole of the Premises; provided
     that if the damage is due to the fault or neglect of Lessee, there shall be
     no abatement of rent.

     If the Premises or the building in which the Premises are located shall be
     damaged or destroyed by fire or other insured casualty, and repair of the
     damage can be completed within one hundred eighty (180) days, Lessor shall
     repair or rebuild within a reasonable time utilizing the insurance proceeds
     to effect such repair.

     If a substantial part of the Premises or the building in which the Premises
     are located shall be damaged or destroyed by an uninsured casualty Lessor
     shall have the option either (a) to repair or rebuild within a reasonable
     time, or (b) not to repair or rebuild, and to cancel this Lease on thirty
     (30) days notice. In the event of cancellation by Lessor as a result of an
     uninsured casualty, Lessee shall have the right, within five (5) days
     following Lessor's notice of cancellation, to override such cancellation by
     agreeing to repair the damage at Lessee's sole cost and expense. In such
     event, the Lessee shall repair or rebuild within a reasonable time
     following the damage or destruction.

19.  Eminent Domain. If the whole of the Premises shall be taken by any public
     authority under the power of eminent domain, or purchased by the condemnor
     in lieu thereof, then the term of this Lease shall cease as of the date
     possession is taken by such public authority. If only part of the Premises
     shall be so taken, the Lease shall terminate only as to the portion taken,
     and shall continue in full force and effect as to the remainder of

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     said Premises, and the monthly rent shall be reduced proportionately;
     provided, however, if the remainder of the Premises cannot be made
     tenantable for the purposes for which Lessee has been using the Premises or
     if more than twenty-five percent (25%) of the rentable square footage of
     the Premises shall be so taken, then either party, by written notice to the
     other, given at least thirty (30) days prior to the date that possession
     must be surrendered to the public authority, may terminate this Lease
     effective as of such surrender of possession. If any part of the building
     other than the Premises shall be so taken so as to render in Lessor's
     opinion the termination of this Lease beneficial to the remaining portion
     of the building, Lessor shall have the right within sixty (60) days of said
     taking to terminate this Lease upon thirty (30) days written notice to
     Lessee. In the event of any taking, whether whole or partial, Lessor shall
     be entitled to all awards, settlements, or compensation which may be given
     for the land and buildings. Lessee shall have no claim against Lessor for
     the value of any unexpired term of this Lease. Lessee shall have the right
     to seek an independent and separate award from the condemning authority so
     long as such award does not diminish the amount of the award payable to
     Lessor.

20.  Insolvency.  If Lessee shall be declared insolvent or bankrupt, or if
     Lessee's leasehold interest herein shall be levied upon or seized under
     writ of any court of law, or if a trustee, receiver or assignee be
     appointed for the property of Lessee, whether under operation of State or
     Federal statutes, then Lessor may, at its option, immediately, without
     notice (notice being expressly waived), terminate this Lease and take
     possession of said Premises.

21.  Default and Re-Entry.  If Lessee fails to keep or perform any of the
     covenants and agreements herein contained, then the same shall constitute a
     breach hereof, and if Lessee has not remedied such breach within three (3)
     days after written notice thereof from Lessor if the breach is non-payment
     of rent or other charges, or within ten (10) days after written notice
     thereof from Lessor in the event of the breach of any other covenant,
     except that if the breach cannot reasonably be cured within such ten (10)
     day period, then if Lessee fails to commence to cure within such ten (10)
     day period and thereafter, diligently prosecute such cure to completion,
     then Lessor may, at its option, without further notice or demand:

     A.   Cure such breach for the account and at the expense of Lessee
          (including entry upon the Premises to make repairs on behalf of the
          Lessee where Lessee has failed to make such repairs as required under
          this Lease) and such expense shall be deemed additional rent due on
          the first of the following month; or

     B.   Re-enter the Premises, remove all persons therefrom, take possession
          of the Premises and remove all personal property therein at Lessee's
          risk and expense and (1) terminate this Lease, or (2) without
          terminating the Lease or in any way affecting the rights and remedies
          of Lessor or the obligations of Lessee, re-let the whole or any part
          of the Premises as agent for Lessee, upon such terms and conditions as
          Lessor may deem advisable. In either event, any moneys received from
          Lessee and any deposit or other amounts held by Lessor may first be
          applied by Lessor to any damages suffered by Lessor as a result of
          such default, including without limitation, costs and expenses
          incurred on re-entry and re-letting, any unamortized tenant
          improvements and commissions, cleaning, necessary repairs, restoration
          and alteration, and any commissions incurred on re-letting, and the
          balance of such amounts may be applied toward payment of other sums
          due to Lessor hereunder. In the event the Premises are re-let for
          Lessee's account, Lessee shall pay to Lessor monthly any deficiency;
          however, Lessor shall not be required to pay any excess to Lessee.
          Upon termination of this Lease or of Lessee's right to possession,
          Lessor has the right to recover from Lessee: (1) The worth of the
          unpaid rent that had been earned at the time of such termination; (2)
          The worth of the amount of the unpaid rent that would have been earned
          after the date of such termination; and (3) Any other amount,
          including court, reasonable attorney and collection costs, necessary
          to compensate Lessor. "The Worth," as used in Section (1) is to be
          calculated allowing interest at 18% per year (or, if applicable, at
          such lower rate as may represent the highest legal limit allowed in
          the State of Washington). "The worth" as used for Section (2) is to be
          computed by discounting the amount at

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          the discount rate of the Federal Reserve Bank of San Francisco at the
          time of termination. The above remedies of Lessor are cumulative and
          in addition to any other remedies now or hereafter allowed by law or
          elsewhere provided for in this Lease. Notwithstanding anything to the
          contrary in this Section 21, Lessee does not waive any right it may
          have to require Lessor to mitigate its damages.

22.  Removal of Property.  Any property of Lessee removed by Lessor in
     accordance with Section 21 above may be stored, sold, or disposed of by
     Lessor without any additional notice to Lessee at the sole risk and expense
     of Lessee and without any further responsibility of Lessor. Proceeds
     therefrom may be applied by Lessor upon any indebtedness due from Lessee to
     Lessor. Lessee waives all claims for damages that may be caused by Lessor
     re-entering the Premises and removing or disposing of said property as
     herein provided.

23.  Costs and Attorneys' Fees.  In the event either party shall commence legal
     action to enforce any provision of this Lease, the court shall award to the
     prevailing party all reasonable attorneys' fees and all costs incurred in
     connection therewith, including fees and costs on appeal. Any action
     relating to this Lease shall be brought in the County in which the Premises
     are located or, at Lessor's election, in King County, Washington.

24.  Subrogation Waiver.  Lessor and Lessee each herewith and hereby release and
     relieve the other and waive its entire right of recovery against the other
     for loss or damage arising out of or incident to the perils of fire,
     explosion or any other perils described in the "all risk" insurance and the
     events covered under the property insurance coverages required under this
     Lease, whether due to the negligence of either party, their agents,
     employees or otherwise. Each party shall obtain from its respective insurer
     under each insurance policy that it maintains a waiver of all rights of
     subrogation which the insurer may have against the other party for claims
     that are released under this Section 24.

25.  Holding Over.  If Lessee, with the express consent of Lessor, shall hold
     over after the expiration of the term of this Lease, Lessee shall remain
     bound by all the covenants and agreements herein, except that (a) the
     tenancy shall be from month-to-month and (b) the monthly rent to be paid by
     Lessee shall be determined by multiplying the monthly rent in effect
     immediately preceding such expiration times 150%. If Lessee holds
     possession of the Demised Premises after the expiration of the Lease
     without the express written consent of Lessor, Lessee shall remain bound by
     all the covenants and agreements herein, except that (a) the tenancy shall
     be from month-to-month and (b) the monthly rent to be paid by Lessee shall
     be the greater of twice the Monthly Minimum Rent in effect immediately
     preceding such expiration or the total loss to Lessor as a result of
     Lessee's holdover, if, effective during the term of such holdover, Lessor
     has leased all or part of the Premises to other Lessee(s). Any such tenancy
     may be terminated with twenty (20) days prior notice as provided by
     Washington State law.

     In the event of any unauthorized holding over, Lessee shall also indemnify
     and hold Lessor harmless from and against all liability, losses, claims,
     causes of action, damages, costs and expenses (including without limitation
     attorney fees) resulting from Lessee's failure to surrender the Premises,
     including without limitation claims made by succeeding Lessees resulting
     from Lessee's failure to surrender the Premises.

     Lessee's obligations under this Section 25 shall survive the expiration or
     termination of this Lease.

26.  Subordination and Attornment; Mortgage Protection.

     A.   Subordination-Notice to Mortgagee. At the request of Lessor, Lessee
          shall promptly execute, acknowledge and deliver, all instruments which
          may be required to subordinate this Lease to any existing or future
          mortgages, deeds of trust and/or other security documents on or
          encumbering the Premises or on the leasehold interest held by Lessor,
          and to any extensions, renewals, or replacements thereof, provided
          that the mortgagee or beneficiary, as the case may be, shall agree to
          recognize this Lease in the event of foreclosure if Lessee is

                                       8
<PAGE>

          not in material default at such time by providing a subordination and
          non-disturbance agreement in a commercially reasonable form.

     B.   Lessee's Certificate.  Lessee shall at any time and from time to time,
          within fourteen (14) days after written notice from Lessor execute,
          acknowledge and deliver to Lessor a statement in writing (a)
          certifying that this Lease is unmodified and in full force and effect
          (or, if modified, stating the nature of such modification and
          certifying that this Lease as so modified is in full force and
          effect), and the date to which the rental and other charges are paid
          in advance, if any; and (b) acknowledging that there are not, to
          Lessee's knowledge, any uncured defaults on the part of the Lessor or
          Lessee hereunder, or specifying such defaults if any are claimed; and
          (c) setting forth the date of commencement of rents and expiration of
          the Lease Term hereof; and, (d) such other information as the Lessor
          shall reasonably require. Any such statement may be relied upon by any
          prospective purchaser or encumbrancer of all or any portion of the
          Premises of which the Premises are a part.

     C.   Mortgagee Protection Clause.  Lessee agrees to notify any mortgagee
          and/or trust deed holders, by registered mail, with a copy of any
          notice of default served upon the Lessor, provided that prior to such
          notice Lessee has been notified in writing (by way of Notice of
          Assignment of Rents and Lease, or otherwise) of the addresses of such
          mortgagees and/or trust deed holders. Lessee further agrees that if
          Lessor shall have failed to cure such default, then the mortgagees
          and/or trust deed holders have thirty (30) days within which to cure
          such default or if such default cannot be cured within that time, then
          such additional times as may be necessary if within such thirty (30)
          days any mortgagee and/or trust deed holder has commenced and is
          diligently pursuing the remedies necessary to cure such default
          (including but not limited to commencement of foreclosure proceedings
          if necessary to affect such cure), in which event this Lease shall not
          be terminated if such remedies are being so diligently pursued.

27.  Surrender of Possession.  Lessee shall, prior to the termination of this
     Lease or of Lessee's right to possession, remove from the Premises all
     personal property which Lessee is entitled to remove and those alterations,
     additions, improvements or signs which may be required by Lessor to be
     removed, pursuant to Sections 13 and 15 above, and shall repair or pay for
     all damage to the Premises caused by such removal. All such property
     remaining and every interest of Lessee in the same shall be conclusively
     presumed to have been conveyed by Lessee to Lessor under this Lease as a
     bill of sale, without compensation, allowance, or credit to Lessee. Lessee
     shall upon termination of this Lease or of Lessee's right of possession,
     deliver all keys to Lessor and peacefully quit and surrender the Premises
     without notice, neat and clean, and in as good condition as when Lessee
     took possession, except for reasonable wear and tear as determined by
     Lessor and except for damage by casualty or condemnation.

28.  Late Payment and Interest.  If any amount due from Lessee is not received
     in the office of Lessor on or before the fifth (5th) day following the
     date upon which such amount is due and payable, a late charge of five
     percent (5%) of said amount shall become immediately due and payable, which
     late charge Lessor and Lessee agree represents a fair and reasonable
     estimate of the processing and accounting costs that Lessor will incur by
     reason of such late payment. All past due amounts owing to Lessor under
     this Lease, including rent, shall be assessed interest at an annual
     percentage rate of eighteen percent (18%) from the date due until paid.

29.  Notice.  Any notice, communication or remittance required or permitted by
     this Lease by either party to the other shall be deemed given, served or
     delivered, in writing, delivered personally or by courier or by telephonic
     facsimile transmission with automatic confirmation, addressed to the Lessor
     at the address specified for the payment of rent under paragraph 3 of this
     Lease or to Lessee at the Premises or to such other address as either party
     may designate to the other in writing from time to time.

                                       9
<PAGE>

30.  No Waiver of Covenants.  Time is of the essence of this Lease. Any waiver
     by either party of any breach hereof by the other shall not be considered a
     waiver of any future similar or other breach.

31.  Entire Agreement.  It is expressly understood and agreed by Lessor and
     Lessee that there are no promises, agreements, conditions, understandings,
     inducements, warranties, or representations, oral or written, express or
     implied, between them, other than as herein set forth and that this Lease
     shall not be modified in any manner except by an instrument in writing
     executed by the parties.

32.  Binding on Heirs, Successors and Assigns.  The covenants and agreements of
     this Lease shall be binding upon the heirs, executors, administrators,
     successors and assigns of both parties hereto, except as hereinabove
     provided.

33.  Lessor's Assignment.  It is fully understood that Lessor shall have the
     full right to assign this Lease, without any notice to Lessee, thereby
     relieving Lessor from all and any liabilities; provided however, that the
     assignee assumes all Lessor's responsibilities as set forth in this Lease.

34.  Environmental.  See Rider One attached and incorporated into this Lease by
     this reference.

35.  Brokers; Agency Disclosure; Brokerage Relationships.

               [Intentionally deleted.]

36.  Force Majeure.  Lessor shall have no liability to Lessee on account of the
     following acts of "force majeure," which shall include (a) the inability of
     Lessor to fulfill, or delay in fulfilling, any of Lessor's obligations
     under this Lease by reason of strike, lockout, other labor trouble, dispute
     or disturbance; (b) governmental regulation, moratorium, action, inaction,
     preemption or priorities or other controls, including delays in receipt of
     permits; (c) shortages of fuel, supplies or labor; (d) any failure or
     defect in the supply, quantity or character of electricity or water
     furnished to the Premises by reason of any requirement, act or omission of
     the public utility or others furnishing the Building with electricity or
     water; or (e) for any other reason, whether similar or dissimilar to the
     above, or for act of God, beyond Lessor's reasonable control. If this Lease
     specifies a time period for performance of an obligation of Lessor, that
     time period shall be extended by the period of any delay in Lessor's
     performance caused by any of the events of force majeure described herein.

37.  Limitation of Liability.  The recourse of Lessee to recover any claim
     against Lessor arising under this Lease shall be limited to Lessor's
     interest in the Building and to the rents, issues and profits from the
     Building. Lessee waives any and all recourse for any such liability against
     Lessor's members, partners, shareholders, trustees or beneficiaries, or any
     property or assets of Lessor other than the Building.

38.  Option to Extend.  Lessor hereby grants to Lessee two successive options to
     extend this Lease for additional terms of five (5) years each commencing on
     the first day after the Expiration Date of the previous term. Lessee must
     exercise the option to extend, if at all, by giving Lessor written notice
     of such exercise not less than twelve (12) months prior to the expiration
     date of the then current term. Upon the exercise of the option to extend,
     the term of this Lease shall be extended through the expiration date of the
     Renewal Term on the same terms and conditions as contained herein, except
     that there shall be no option to extend the term of this Lease beyond the
     Second Renewal Term, and the Base Monthly Rent during the Renewal Terms
     shall be determined pursuant to this Section.

     Base Monthly Rent for each Renewal Term shall be the greater of (a) the
     Base Monthly Rent scheduled for the final month of the preceding term (the
     initial term or the First Renewal Term, as the case may be), or (b) the
     fair market base rental value of the Premises.

                                       10
<PAGE>

     Lessor and Lessee agree to be reasonable in their negotiation of rent for
     the option periods. Lessor and Lessee shall have thirty (30) days after
     Lessee provides Lessor of its notice to exercise its Option to Renew to set
     the rent for the option period(s). If Lessor and Lessee are unable to
     establish the rent for the option period(s) within the thirty (30) day
     period then Lessor and Lessee shall each appoint an appraiser with not less
     than ten (10) years experience in real estate appraisal in the Bellevue
     real estate market, to set the rent for the option period(s). If the rents
     proposed by each appraiser are within ten (10%) percent of each other, then
     the rent for the option period(s) shall be the average of the two rents. If
     the rents proposed by each appraiser are greater than ten (10%) percent
     from each other then the two appraisers will select a third appraiser who
     shall also have at least (10) years real estate appraisal experience in the
     Bellevue real estate market, to set the rent for the option period(s). The
     rent established by the third appraiser will be binding on Lessor and
     Lessee and will be no less than the rent proposed by Lessee and no higher
     than the rent proposed by Lessor. The total cost of all of the appraiser's
     fees will be the responsibility of the party whose proposed rental rate is
     farthest from that of the final rental rate established by the appraisers.

39.  Right of First Opportunity to Purchase.

     39.1  Grant of Rights.  In the event Lessor intends to sell or to make the
     Building in which the Premises are located available for purchase to
     unrelated third parties, and provided Lessor is not selling the Building as
     part of a portfolio of buildings, Lessor shall give Lessee written notice
     of this intention and of the intended offering sale price of the Premises
     ("Lessor's Notice"). Lessor will offer the sales price to Lessee in good
     faith. In the event Lessee desires to purchase the Premises at the offering
     sale price indicated by Lessor, Lessee shall give to Lessor a written
     notice of such desire ("Lessee's Notice") within seven days of receipt of
     the Lessor's Notice. If the Lessee's Notice is not timely given by Lessee,
     Lessee shall have no further rights under this Section 39. In the event
     Lessee's Notice is timely given by Lessee, then Lessor and Lessee shall
     negotiate during the remainder of the 30 day period following the giving of
     Lessor's Notice in good faith to attempt to execute a definitive purchase
     and sale agreement whereby Lessor would sell to Lessee and Lessee would
     purchase from Lessor the Premises at the price stated in Lessor's Notice.
     During the 30 day period any offer of the property publicly or privately
     will be subject to Lessee's rights hereunder. Neither party shall have any
     obligation to execute a purchase and sale agreement not acceptable to such
     party, in its sole and absolute discretion. In the event the parties fail
     to execute a mutually agreeable purchase and sale agreement within the 30
     day period allowed, or in the event such a purchase and sale agreement is
     executed but is subsequently terminated without consummation of the sale,
     Lessee shall have no further rights under this Section 39. In no event
     shall Lessee have the right to assert any right to purchase the Building
     once Lessor has executed a contract for the sale of the Premises to a third
     party as otherwise permitted under this Section 39, even if the price under
     such contract, as the same may be amended, is less than the price stated in
     Lessor's Notice. It is expressly agreed that any price set forth in
     Lessor's Notice given to Lessee, and any transaction whereby the Building
     is sold to Lessee, will be on the basis that Lessor shall pay no real
     estate commission on account of such sale to any broker representing
     Lessee. It is further acknowledged that Lessor may subsequently offer the
     Premises to third parties at a price less than, equal to or greater than
     the price set forth in the Lessor's Notice.

     39.2  Limitation of Rights.  The notification and negotiation rights
     allowed to Lessee pursuant to Section 39.1 are allowed on a "one time"
     basis only, and except as otherwise provided in Section 39.1 above, Lessor
     shall have no obligation to re-notify Lessee of any changes in its sales
     intentions or offering price, nor to re-notify Lessee of subsequent sales
     efforts if Lessor does not sell the Building following the Lessor's Notice.

     39.3  Exclusions.  The rights of Lessee under this Section 39 are limited
     to notification and negotiation in anticipation of Lessor offering the
     Building to purchase by unrelated third parties. There shall be no
     notification or negotiation rights of Lessee in any other case whatsoever,
     including but not limited to cases of (a) a conveyance by Lessor to an
     affiliated party and any conveyance in connection with a merger or other
     corporate transaction, (b) a conveyance by Lessor to a lender who then
     holds a lien on the

                                       11
<PAGE>

     Premises, (c) a conveyance in connection with a foreclosure sale, (d) a
     conveyance or taking in connection with a condemnation, (e) a conveyance
     which is part of a financing transaction (for example, a sale and master
     lease back), (f) a conveyance by any subsequent owner of the Building other
     than the Lessor originally named herein, or (g) a sale or offering in which
     Lessor packages the Building with one or more other properties owned by
     Lessor and/or any affiliate of Lessor for sale as a group, on the open
     market or otherwise. No conveyance of any or all of the ownership interests
     within Lessor (for example, membership interests in the limited liability
     company) shall be deemed a conveyance or sale of the Premises.

     39.4  Personal Nature of Rights.  Upon any assignment of this Lease or of
     any sublease of all or a part of the Premises, the rights granted to Lessee
     pursuant to Section 39.1 shall terminate. The rights granted to Lessee
     pursuant to Section 39.1 shall also terminate upon the termination of this
     Lease or of Lessee's right of possession.

40.  Exhibits.  The following exhibits or riders are made a part of this Lease
     and are incorporated herein by reference:
          Rider One - Environmental
          Exhibit A - Premises
          Exhibit B - Rules and Regulations
          Rider Two - Additional Lease Provisions



     LESSOR:                           LESSEE:

     Benaroya Capital Company, LLC     ICOS Corporation

     /s/ Larry R. Benaroya

     By:  Larry R. Benaroya            By: /s/ Gary Wilcox
                                           ---------------------------
     Its:  Manager                     Its:
                                           ---------------------------

     Date: 9/25/00                     Date:  9/18/00
          -------------------------         --------------------------

                                       12
<PAGE>

STATE OF WASHINGTON ]
                    ] ss.
COUNTY OF KING      ]

     I certify that I know or have satisfactory evidence that Larry R. Benaroya
is the person who appeared before me, a Notary Public in and for the State of
Washington duly commissioned and sworn, and acknowledged that he is the Manager
of Benaroya Capital Company, LLC, a Washington limited liability company, who
executed the within and foregoing instrument, and acknowledged the instrument to
be the free and voluntary act and deed of said company for the uses and purposes
therein mentioned, and on oath stated that affiant is authorized to execute said
instrument on behalf of said company.

IN WITNESS WHEREOF I have hereunto set my hand and affixed my official seal the
day and year first above written.

                               /s/ Rebecca A. Bethel
                              ---------------------------------------------
                              Notary Public in and for the
                              State of
                                        Washington
                                      -------------------------------------
                              residing at
                                           Seattle
                                         ----------------------------------
                              Commission expires
                                                  11/9/02
                                                ---------------------------
                              Print Name
                                          Rebecca A. Bethel
                                        -----------------------------------


STATE OF WASHINGTON ]
                    ] ss.
COUNTY OF Snohomish ]
         -----------

     I certify that I know or have satisfactory evidence that Gary Wilcox is
the person who appeared before me, a Notary Public in and for the State of
Washington duly commissioned and sworn, and acknowledged that he/she is the
Executive Vice President, of ICOS Corporation, a Delaware corporation, who
executed the within and foregoing instrument, and acknowledged the instrument to
be the free and voluntary act and deed of said corporation for the uses and
purposes therein mentioned, and on oath stated that affiant is authorized to
execute said instrument on behalf of said corporation.

IN WITNESS WHEREOF I have hereunto set my hand and affixed my official seal the
day and year first above written.

                                /s/ Lori Briseno
                              ---------------------------------------------
                              Notary Public in and for the
                              State of
                                        Washington
                                      -------------------------------------
                              residing at
                                           Snohomish
                                         ----------------------------------
                              Commission expires
                                                  4/29/02
                                                ---------------------------
                              Print Name
                                          Lori Briseno
                                        -----------------------------------

                                       13
<PAGE>

                                   RIDER ONE
                 EMISSIONS; STORAGE, USE AND DISPOSAL OF WASTE

a.   Emissions.  Lessee shall not discharge, emit or permit to be discharged or
     emitted, any liquid, solid or gaseous matter, or any combination thereof,
     into the atmosphere, the ground or any body of water, which does or may
     pollute or contaminate the same, or does or may adversely affect the health
     or safety of persons, or the use or enjoyment of the Premises. Lessee may
     transmit, receive or permit to be transmitted or received, any
     electromagnetic, microwave or other radiation in, on or about the Premises,
     provided, however, that such electromagnetic, microwave or other radiation
     is used in connection with Lessee's Permitted Use of the Premises, and that
     such use complies with all pertinent federal, state, and local statutes,
     rules, regulations, ordinances and orders that such use does not interfere
     with the use of any other tenant or owner within Canyon Park.

b.   Storage.  If, with or without violation of this Lease, Lessee possesses at
     the Premises any matter described in Section A above or any Hazardous
     Substances (as defined below), Lessee shall store the same in appropriate
     leak proof containers and/or areas which comply with all laws and all
     prudent practices.

c.   Disposal of Waste.  Lessee shall not keep any trash, garbage, waste or
     other refuse on the Premises except in sanitary containers and shall
     regularly and frequently remove same from the Premises. Lessee shall keep
     all such containers in a clean and sanitary condition. Lessee shall
     properly dispose of all sanitary sewage and shall not use the sewage system
     for the disposal of anything except sanitary sewage, nor in excess of
     capacity. Lessee shall not cause any obstruction in the sewage disposal
     system.

d.   Compliance of Law.  Notwithstanding any other provision in the Lease to the
     contrary, Lessee shall comply with all Laws in complying with its
     obligations under this Lease, and in particular, Laws relating to the
     storage, use and disposal of Hazardous Substances (as defined below).

e.   Indemnification for Breach.  Lessee shall defend, indemnify and hold
     Lessor, the Project and the holder of a trust deed or mortgage on the
     Project harmless from any loss, claim, liability or expense, including,
     without limitation, attorneys fees and costs, at trial and/or on appeal and
     review, arising out of or in connection with its failure to observe or
     comply with the provisions of this Rider. This indemnity shall survive the
     expiration or earlier termination of the term of the Lease or the
     termination of Lessee's right of possession and be fully enforceable
     thereafter.

f.   Indemnification Regarding Hazardous Substances.  In addition to the
     indemnity obligations contained elsewhere herein, Lessee shall indemnify,
     defend and hold harmless Lessor, the Premises, the Project, and the holder
     of a trust deed or mortgage on the Project, from and against all claims,
     losses, damages, monitoring costs, response costs, liabilities, and other
     costs expenses caused by, arising out of, or in connection with, the
     generation, release, handling, storage, discharge, transportation, deposit
     or disposal in, on, under or about the Premises by Lessee or any of
     Lessee's agents of the following (collectively referred to as "Hazardous
     Substances"): hazardous materials, hazardous substances, toxic wastes,
     toxic substances, pollutants, petroleum products, underground tanks, oils,
     pollution, asbestos, PCB's, radioactive materials, or contaminants, as
     those terms are commonly used or as defined by federal, state, and/or local
     law or regulation related to protection of health or the environment as any
     of same may be amended from time to time, and/or by any rules and
     regulations promulgated thereunder. Such damages, costs, liability and
     expenses shall include such as are claimed by any regulating and/or
     administering agency, any ground lessor or master lessor of the Project,
     the holder of any Mortgage or Deed of Trust on the Project, and/or any
     successor of the Lessor named herein. This indemnity shall include (i)
     claims of third parties, including governmental agencies, for damages,
     fines, penalties, response costs, monitoring costs, injunctive or other
     relief; (ii) the costs, expenses or losses resulting from any injunctive
     relief, including preliminary or temporary injunctive relief; (iii) the
     expenses, including fees of attorneys and experts, of report the existence
     of Hazardous Substances to an agency of the State of which the Premises is
     located or of the United States as required by applicable laws and
     regulations; and (iv) any and all expenses or obligations, including
     attorney's fees, incurred at, before and after any

                                       14
<PAGE>

     administrational proceeding, trial, appeal and review. This indemnity shall
     survive the expiration or earlier termination of the term of the Lease or
     the termination of Lessee's right of possession and shall remain fully
     enforceable thereafter.

g.   Information.  Lessee shall give prior written notice to Lessor of any use,
     whether incidental or otherwise, of Hazardous Substances on the Premises,
     and shall immediately deliver to Lessor a copy of any notice of any
     violation of any Law with respect to such use. Lessee shall also provide to
     Lessor, upon request, with any and all information regarding Hazardous
     Substances in the Premises, including contemporaneous copies of all filings
     and reports to governmental entities, and any other information requested
     by Lessor. In the event of any accident, spill or other incident involving
     Hazardous Substances, Lessee shall immediately report the same to Lessor
     and supply Lessor with all information and reports with respect to the
     same. All information described herein shall be provided to Lessor
     regardless of any claim by Lessee that it is confidential or privileged.

                                       15
<PAGE>

                                   EXHIBIT A
                                   PREMISES


                                       16
<PAGE>

                                   EXHIBIT B
                             RULES AND REGULATIONS

1.   Except as specifically provided in the Lease to which these Rules and
     Regulations are attached, no sign, placard, picture, advertisement, name or
     notice shall be installed or displayed on any part of the outside or inside
     of the Building or Project without the prior written consent of Lessor.
     Lessor shall have the right to remove, at Lessee's expense and without
     notice, any sign installed or displayed in violation of this rule. All
     approved signs or lettering on doors and walls shall be printed, painted,
     affixed or inscribed at the expense of Lessee by a person approved by
     Lessor.

2.   If Lessor objects in writing to any curtains, blinds, shades, screens or
     hanging plants or other similar objects attached to or used in connection
     with any window or door of the Premises, or placed on any windowsill, which
     is visible from the exterior of the Premises, Lessee shall immediately
     discontinue such use. Lessee shall not place anything against or near glass
     partitions or doors or windows which may appear unsightly from outside the
     Premises.

3.   Lessee shall not obstruct any sidewalks, halls, passages, exits, entrances,
     elevators or stairways of the Project. The halls, passages, exits,
     entrances, elevators and stairways are not open to the general public, but
     are open, subject to reasonable regulations, to Lessee's business invitees.
     Lessor shall in all cases retain the right to control and prevent access
     thereto of all persons whose presence in the judgment of Lessor would be
     prejudicial to the safety, character, reputation and interest of the
     Project and its Lessees; provided that nothing herein contained shall be
     construed to prevent such access to personnel with whom any Lessee normally
     deals in the ordinary course of its business, unless such persons are
     engaged in illegal or unlawful activities. No Lessee and no employee or
     invitee of any Lessee shall go upon the roof(s) of the Project, except
     certified HVAC employees of Lessee or Lessee's HVAC contractor.

4.   Lessor will furnish Lessee, free of charge, with two keys to each door lock
     in the Premises. Lessor may make a reasonable charge for any additional
     keys. Lessee shall have the right to install a card key system and to make
     or have made additional keys, and Lessee shall have the right to lock or
     install a new additional lock or bolt on any door of its Premises, provided
     Lessee provides Lessor with a pass key to access the Premises or any
     portion thereof. Lessee, upon the termination of its tenancy, shall deliver
     to Lessor the keys of all doors which have been furnished to Lessee, and in
     the event of loss of any keys so furnished, shall pay Lessor therefor.

5.   If Lessee requires telegraphic, telephonic, burglar alarm or similar
     services, it shall first obtain, and comply with, Lessor's instructions in
     their installation.

6.   No equipment, materials, furniture, packages, supplies, merchandise or
     other property will be received in the Building or carried in the elevators
     except between such hours and in such elevators as may be designated by
     Lessor. Lessee's initial move in and subsequent deliveries of bulky items,
     such as furniture, safes and similar items shall, unless otherwise agreed
     in writing by Lessor, be made during the hours of 6:00 p.m. to 6:00 a.m. or
     on Saturday or Sunday. Deliveries during normal office hours shall be
     limited to normal office supplies and other small items. No deliveries
     shall be made which impede or interfere with other Lessees or the operation
     of the Building.

7.   Lessee shall not place a load upon any floor of the Premises which exceeds
     the load per square foot which such floor was designed to carry and which
     is allowed by Law. Lessor shall have the right to prescribe the weight,
     size and position of all equipment, materials, furniture or other property
     brought into the Building. Heavy objects shall, if considered necessary by
     Lessor, stand on such platforms as determined by Lessor to be necessary to
     properly distribute the weight, which platforms shall be provided at
     Lessee's expense. Business machines and mechanical equipment belonging to
     Lessee which cause noise or vibration that may be transmitted to the
     structure of the Building or to any space therein shall be placed and
     maintained by Lessee, at Lessee's expense, on vibration eliminators, or
     other devices sufficient to eliminate noise or vibration. The persons
     employed to move such equipment in or out of the Building must be
     acceptable to Lessor. Lessor will not be responsible for loss of, or damage
     to, any such equipment

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<PAGE>

     or other property from any cause, and all damage done to the building by
     maintaining or moving such equipment or other property shall be repaired at
     the expense of Lessee.

8.   Lessee shall use the Premises only for general office, laboratory,
     research, process and product development and related uses, including
     without limitation, light manufacturing and storage. Lessee shall not allow
     any use of the Premises which will negatively affect cost of coverage of
     Lessor's insurance on the Project. Lessee shall not allow any use of the
     Premises which would cause the value of any part of the Premises to
     diminish or would interfere with the use of any other tenant within Canyon
     Park. Lessee shall not permit any nuisance or waste upon the Premises, or
     allow any offensive noise or odor in or around the Premises.

9.   Lessee shall use heating or air conditioning systems supplied by the
     Lessor, and/or heating and air conditioning systems added to the building
     by the Lessee.

10.  Lessee shall not waste electricity, water or air conditioning and agrees
     to cooperate fully with Lessor to assure the most effective operation of
     the Building's heating and air conditioning and to comply with any
     governmental energy-saving rules, laws or regulations of which Lessee has
     actual notice, and shall refrain from attempting to adjust controls. Lessee
     shall keep corridor doors closed, and shall close window coverings at the
     end of each business day.

11.  Lessor reserves the right, exercisable without notice and without
     liability to Lessee, to change the name and street address of the Building.

12.  Lessor reserves the right to exclude from the Building between the hours of
     6 p.m. and 7 a.m. the following day, or such other hours as may be
     established from time to time by Lessor, and on Sundays and legal holidays,
     any person unless that person is known to the person or employee in charge
     of the Building and has a pass or is properly identified. Lessee shall be
     responsible for all persons for whom it requests passes and shall be liable
     to Lessor for all acts of such persons. Lessor shall not be liable for
     damages for any error with regard to the admission to or exclusion from the
     Building of any person. Lessor reserves the right to prevent access to the
     Building in case of invasion, mob, riot, public excitement or other
     commotion by closing the doors or by other appropriate action.

13.  Lessee shall entirely shut off any water faucets or other water apparatus,
     and electricity, gas or air outlets before Lessee and its employees leave
     the Premises. Lessee shall be responsible for any damage or injuries
     sustained by other Lessees or occupants of the Building or by Lessor for
     noncompliance with this rule.

14.  The toilet rooms, toilets, urinals, wash bowls and other apparatus shall
     not be used for any purpose other than that for which they were constructed
     and no foreign substance of any kind whatsoever shall be thrown therein.
     The expense of any breakage, stoppage or damage resulting form the
     violation of this rule shall be borne by the Lessee who, or whose employees
     or invitees, shall have caused it.

15.  Lessee shall not sell, or permit the sale at retail of newspapers,
     magazines, periodicals, theater tickets or any other goods or merchandise
     to the general public in or on the Premises. Lessee shall not make any
     room-to-room solicitation of business from other Lessees in the Project.
     Lessee shall not use the Premises for any business or activity other than
     that specifically provided for in Lessee's Lease. Canvassing, soliciting
     and distribution of handbills or any other written material, and peddling
     in the Project are prohibited, and Lessee shall cooperate to prevent such
     activities.

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<PAGE>

16.  Lessee shall not install any radio or television antenna, loudspeaker or
     other devices on the roof(s) or exterior walls of the Building or Project.
     Lessee shall not interfere with radio or television broadcasting or
     reception from or in the Project or elsewhere.

17.  Lessee shall not mark, drive nails, screw or drill into the partitions,
     woodwork or plaster or in any way deface the Premises or any part thereof,
     except in accordance with the provisions of the Lease pertaining to
     alterations. Lessor reserves the right to direct electricians as to where
     and how telephone and telegraph wires are to be introduced to the Premises.
     Lessee shall not cut or bore holes for wires. Lessee shall not affix any
     floor covering to the floor of the Premises in any manner except as
     approved by Lessor. Lessee shall repair any damage resulting from
     noncompliance with this rule.

18.  Lessee shall not install, maintain or operate upon the Premises any vending
     machines without the written consent of Lessor.

19.  Lessor reserves the right to exclude or expel from the Project any person
     who, in Lessors' judgment, is intoxicated or under the influence of liquor
     or drugs or who is in violation of any of the Rules and Regulations of the
     Building.

20.  Lessee shall store all its trash and garbage within its own storage
     facilities on the Premises, and shall be responsible, at its sole cost and
     expense, for disposal of its trash and garbage (in a manner reasonably
     acceptable to Lessor). Lessee shall not place in any trash box or
     receptacle any material which cannot be disposed of in the ordinary and
     customary manner of trash and garbage disposal.

21.  Except as otherwise provided herein, the Premises shall not be used for
     the storage of merchandise held for sale to the general public, or for
     lodging or for manufacturing of any kind, nor shall the Premises be used
     for any improper, immoral or objectionable purpose. No cooking shall be
     done or permitted on the Premises without Lessor's consent, except that
     used by Lessee of Underwriters' Laboratory approved equipment for brewing
     coffee, tea, hot chocolate and similar beverages or use of microwave ovens
     for employee use shall be permitted, provided that such equipment and use
     is in accordance with all applicable Laws.

22.  Lessee shall not use in any space or in the public halls of the Project any
     hand truck except those equipped with rubber ties and side guards or such
     other material-handling equipment as Lessor may approve. Lessee shall not
     bring any other vehicles of any kind into the Building or Project.

23.  Lessee shall comply with all safety, fire protection and evacuation
     procedures and regulations established by Lessor or any governmental
     agency.

24.  Lessee assumes any and all responsibility for protecting its Premises from
     theft, robbery and pilferage, which includes keeping doors locked and other
     means of entry to the Premises closed.

25.  Lessee's requirements will be attended to only upon appropriate application
     to the Project management office by an authorized individual. Employees of
     Lessor shall not perform any work or do anything outside of their regular
     duties unless under special instructions from Lessor.

26.  Lessor may waive any one or more of these Rules and Regulations for the
     benefit of Lessee or any other Lessee, but no such waiver by Lessor shall
     be construed as a waiver of such Rules and Regulations in favor of Lessee
     or any other Lessee, nor prevent Lessor from thereafter enforcing any such
     Rules and Regulations against any or all of the Lessees of the Project.

27.  These Rules and Regulations are in addition to, and shall not be construed
     to in any way modify or amend, in whole or in part, the terms, covenants,
     agreements and conditions of the Lease.

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<PAGE>

28.  Lessor reserves the right to make such other and reasonable Rules and
     Regulations as, in its judgment, may from time to time be needed for safety
     and security, for care and cleanliness of the Project and for the
     preservation of good order therein. Lessee agrees to abide by all such
     Rules and Regulations hereinabove stated and any additional rules and
     regulations which are adopted.

29.  Lessee shall be responsible for the observance of all of the foregoing
     rules by Lessee's employees, agents, clients, customers, invitees and
     guests.

30.  Lessee shall comply with the "No Smoking" policy in all interior areas of
     the building.

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<PAGE>

                                   RIDER TWO
                          ADDITIONAL LEASE PROVISIONS

1.   Additional Provisions Concerning Operating Expenses

     Notwithstanding anything to the contrary contained in the Lease, the
following items shall be excluded (or, as applicable, deducted) from the
calculation of Lessee's share (if any) of operating costs and expenses of the
Building and/or Project:

     (a)  The cost of repairs or other work occasioned by fire, windstorm or
other casualty or loss in excess of the insurance proceeds therefore (or, if
greater, the proceeds that would have been available had Lessor maintained the
insurance required to be maintained by Lessor pursuant to this Lease), or by the
exercise of eminent domain;

     (b)  Deductibles under Lessor's insurance policies in excess of $50,000.00;

     (c)  Costs resulting from the correction of any latent construction defects
in all or any portion of the Building or Project, or any condition with regard
to the structure and the common areas that is, as of the date of this Lease, not
in compliance with applicable laws, codes rules or regulations;

     (d)  Rental concessions or lease buyouts;

     (e)  The costs of renovating or otherwise improving or decorating, painting
or redecorating space (exclusive of common areas) for any lessee or other
occupants of the Building or Project, including, without limitation, Lessee;

     (f)  Depreciation of the real property;

     (g)  Payments of principal, interest or other payments of any kind on any
deeds to secure debt, mortgages, ground or underlying leases, or other
hypothecations for security of all or any part of the Building or Project by
Lessor;

     (h)  Rents payable in connection with any ground or underlying lease of all
or any portion of the Building or Project;

     (i)  Lessor's general overhead and any other expense not directly related
to the Building or Project (other than the management fee referred to in
paragraph 9(c) above);

     (j)  All items, services and/or goods for which Lessee or any other lessee,
occupant, person or other party is obligated to reimburse Lessor or to pay third
parties;

     (k)  Advertising and promotional expenses with respect to leasing space in
or selling the Building or Project;

     (l)  Brokerage, legal and professional fees expended by Lessor in
connection with negotiating and entering into any leases and any related
instruments (including, without limitation, guaranties, surrender agreements,
leasing amendments and consents to assignment or subletting) with any lessee or
other occupant of any portion of the Building or Project, and the enforcement of
any such instruments; or which are expended or incurred by Lessor in connection
with the negotiation and entering of sale, ground lease, financing, partnership
or similar transactions pertaining to the Building, Project, or any portion
thereof, and/or to Lessor or an interest in Lessor, including without
limitation, promissory notes, security deeds, mortgages, ground or master
leases, purchase and sale agreements, options, and any and all similar and/or
related documents, instruments and agreements;

     (m)  Estate, inheritance, gift, franchise and income taxes of Lessor;

     (n)  Wages, salaries and other compensation paid to employees of the Lessor
who are at or above the level of Property Manager;

     (o)  All items that would be capitalized under generally accepted
accounting principles as of the date hereof except as expressly provided in
Section 9 of this Lease;

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<PAGE>

     (p)  The cost of defending against claims in regard to the existence or
release of hazardous substances or materials at the Building or Project and
costs of any cleanup of any such hazardous substances or materials (except with
respect to those costs for which Lessee is otherwise responsible pursuant to the
express Terms of this Lease);

     (q)  Costs and expenses incurred in connection with compliance with or the
contesting or settlement of any claimed violation of law or requirements of law;

     (r)  Interest, penalties or damages incurred by Lessor for late payment of
taxes or assessments or under any agreement to which Lessor is a party by reason
of the breach or default of Lessor;

     (s)  Expenses incurred in connection with relocating lessee in the Building
or Project;

     (t)  Amounts received by Lessor through proceeds of insurance to the extent
the proceeds are compensation for expenses which were previously included in
Building operating costs charged to lessees;

     (u)  Costs related to public transportation, transit or van pools, unless
required by an appropriate government or quasi-government authority or as a
result of the activities of Lessee; and

     (v)  All other items for which Lessee or any other lessee, occupant or
other party compensates Lessor, so that no duplication of payments by Lessee or
to Lessor shall occur.

2.   Assignment and Subletting by Lessee

     Lessor hereby consents to an assignment of this Lease or a subletting of
all or part of the Premises to (a) a parent of Lessee, the parent of such
parent, or a wholly owned subsidiary of Lessee, of such parent, or of the parent
of such parent and (b) any entity to whom Lessee sells all or substantially of
its assets provided that any such entity expressly assumes all Lessee's
obligations hereunder.

3.   Hazardous Substances

     To the best of Lessor's knowledge, after reasonable inquiry, there are no
hazardous wastes or substances in the soil or groundwater of the real property
on which the building is located and Lessor has not disposed of or approved any
disposal by any other party of any hazardous wastes or substances on or from the
Building.

4.   Notice

     Any notice required to be given to Lessee shall be sent via facsimile,
overnight express mail or U.S. mail, postage prepaid, addressed as follows:

          ICOS Corporation
          22021 20th Avenue SE
          Bothell, Washington  98021
          Attn:  Facilities Manager
          Fax:  (206) 481-8305

     Notices shall be effective upon receipt.

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