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                                                                 Exhibit  10.24

                            MARTIN SELIG REAL ESTATE
                               1000 SECOND AVENUE
                                  OFFICE LEASE



         THIS LEASE, made the 19th day of December, 1997, by and between MARTIN
SELIG, whose address is 1000 Second Avenue, Suite 1800, Seattle, Washington,
98104-1046, hereinafter referred to as "Lessor," and Immunex Corporation, whose
address is 51 University Street, Seattle, Washington 98101, hereinafter referred
to as "Lessee".

         1. DESCRIPTION. Lessor, in consideration of the agreements contained in
this  lease, does hereby lease to Lessee, upon the terms and conditions
hereinafter set forth, that certain space consisting of the rentable square
footage of 16,546 on the 9th floor and 16,584 on the 10th floor (hereinafter
referred to as the "Premises") of the 1000 Second Avenue Building, 1000 Second
Avenue, City of Seattle, State of Washington 98104, the legal description of
which is:

                  Parcel "A" Lots 1 and 4 in Block 11 of the Town of Seattle,  
                  as laid out on the claims of C. D. Boren and A. A. Denny;  
                  (commonly known as Boren & Denny's addition to the City of 
                  Seattle), as per plat recorded in Volume 1 of plats, on Page
                  27, records of King County, Washington; except the  
                  westerly 12 feet thereof condemned by the City of Seattle
                  for the widening of Second Avenue by judgment entered in
                  District Court No. 7097, pursuant to Ordinance No. 1107 of 
                  said city;

                  Parcel "B" Lots 5 and 8 in Block 11 of the Town of Seattle, as
                  laid out on the claims of C. D. Boren and A. A. Denny;
                  (commonly known as Boren & Denny's addition to the City of
                  Seattle), as per plat recorded in Volume 1 of plats, on Page
                  27, records of King County, Washington; except the westerly 12
                  feet thereof condemned by the City of Seattle for the widening
                  of Second Avenue by judgment entered in District Court No.
                  1107 of said city; situate in the County of King, State of
                  Washington.

         2. TERM. The term of this lease shall be for a period of 60 months,
commencing on the date that Lessor delivers possession of the 9th floor space to
Lessee for the purposes of doing Lessee's initial tenant improvement work in the
Premises, which Lessor agrees will be no earlier than January 1, 1998. Lessee's
obligation to pay rent for the Premises will commence, with respect to the 9th
floor space, on the day that is 60 days after Lessor delivers possession of the
9th floor space to Lessee for the purposes of doing its initial tenant
improvement work in the 9th floor space, and, with respect to the 10th floor
space, on the day that is 60 days after Lessor delivers possession of the 10th
floor space to I-essee for purposes of doing its initial tenant improvement work
in the 10th floor space.

         Each of the 9th floor space and the 10th floor space shall be deemed
substantially completed when it is accessible and fully usable by Lessee for its
normal business operations. If the 9th floor space or the 10th floor space is
not substantially completed within 60 days after Lessor delivers possession of
such space to Lessee, and the delay is caused by Lessor, the commencement of
Lessee's obligation to pay rent for such space shall be postponed in such a
manner as to reflect the delay occasioned by the failure of the Premises to be
substantially completed. In no event shall Lessor or Lessee be liable for any
further damages. However, if Lessor fails to deliver possession of the 9th floor
space so that Lessee may begin its tenant improvement work in such space by
January 1, 1998, or if Lessor fails to deliver possession of the 10th floor
space so that Lessee may begin its tenant improvement work in such space by June
1, 1998, Lessee shall have the right to terminate this lease upon written notice
to Lessor.

         3. RENT. Lessee covenants and agrees to pay Lessor rent each month in
advance on the first day of each calendar month. Rent shall be computed at the
annual base rental rate of $24.00 per square foot ($397,104 per year for the 9th
floor; $398,016 per year for the 10th floor; $795,120 per year for both floors,
when rent becomes payable for both floors). Rent and additional rent for
increases in Base Year Costs for any fractional calendar month at the beginning
or end of the term shall be the pro rated portion of the rent computed on an
annual basis (i.e., a 365 day calendar year).


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           4. USES. Lessee agrees that Lessee will use and occupy said
Premises for general offices and related purposes and for no other purposes.

           5. RULES AND REGULATIONS. Lessee and its agents, employees, servants
or those claiming under Lessee will at all times observe, perform and abide by
all of the Rules and Regulations printed on this instrument, or which may be
hereafter promulgated by Lessor, provided they are reasonable and Lessee is
given written notice thereof, all of which it is covenanted and agreed by the
parties hereto shall be and are hereby made a part of this lease.

           6. CARE AND SURRENDER OF PREMISES. Lessee shall take good care of the
Premises and shall promptly make all necessary repairs except those required
herein to be made by Lessor. At the expiration or sooner termination of this
lease, Lessee, without notice, will immediately and peacefully quit and
surrender the Premises in good order, condition and repair (damage by reasonable
wear, the elements, or fire excepted). Lessee shall be responsible for removal
of all personal property from the Premises, (excepting fixtures being that which
is attached to the Premises, and property of the Lessor) including, but not
limited to, the removal of Lessee's telephone equipment (but not Lessee's
communication cabling) and signage. Lessee shall be responsible for repairing
any damage to the Premises caused by such removal. If Lessee fails to so remove
and repair the Premises at lease expiration, then Lessor shall have the right,
after giving Lessee prior written notice of the work to be done and the cost
thereof, to remove said property and repair the Premises, and Lessee shall be
responsible for all costs associated therewith.

           7. ALTERATIONS. Lessee shall not make any alterations or improvements
in or additions to said Premises costing more the $20,000 in any one instance,
without first obtaining the written consent of Lessor, whose consent shall not
be unreasonably withheld or delayed. Except as provided in Section 29 of this
lease, all such alterations, additions and improvements shall be at the sole
cost and expense of Lessee and shall become the property of Lessor and shall
remain in and be surrendered with the Premises as a part thereof at the
termination of this lease, without disturbance, molestation or injury, except
for Lessee's personal property and trade fixtures. Lessee shall do all
alterations, additions and improvements in accordance with all applicable laws,
and shall deliver to Lessor updated plans showing changes to the layout of the
Premises or the building systems. Lessee shall be permitted to add data and\or
communications cabling without Lessor's prior consent.


         8. RESTRICTIONS. Lessee will not use or permit to be used in said
Premises anything that will increase the rate of insurance on said building or
any part thereof, nor anything that may be dangerous to life or limb; nor in any
manner deface or injure said building or any part thereof; nor overload any
floor or part thereof; nor permit any objectionable noise or odor to escape or
to be emitted from said Premises, or do anything or permit anything to be done
upon said Premises in any way tending to create a nuisance or to unreasonably
disturb any other tenant or occupant of any part of said building. Lessee, at
Lessee's expense, will comply with all health, fire and police regulations
respecting said Premises. The Premises shall not be used for lodging or
sleeping, and no animals or birds will be allowed in the building.

         9. WEIGHT RESTRICTIONS. Safes and bully articles in excess of 2,000
pounds may be moved in or out of said Premises, and major furniture moves (i.e.,
moves involving more than 5 offices at a time) may be accomplished only at such
hours and in such manner as will least inconvenience other tenants, which hours
and manner shall be at the reasonable discretion of Lessor. No safe or other
article of over 2,000 pounds shall be moved into said Premises without the
consent of Lessor, whose consent shall not be unreasonably withheld or delayed,
and Lessor shall have the right to locate the position of any article of such
weight in said Premises if Lessor so desires.

        10. SIGN RESTRICTION. No sign, picture, advertisement or notice shall be
displayed, inscribed, painted or affixed to any of the glass or woodwork of the
building without the prior approval of Lessor, which shall not be unreasonably
withheld or delayed.

        11. LOCKS. No additional locks shall be placed upon any existing entry
doors of the Premises, but Lessee may install locks on any new doors installed
by Lessee. Lessor shall provide Lessee with access to the Premises 24 hours per
day, 365 days per year via the building's security access system. Lessor shall
provide each of Lessee's employees (including those hired after the term of this
lease commences) with one door key to the Premises and one access card at no
additional cost to Lessee.


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         12. KEY. Lessor, his janitor, engineer or other agents may retain a
pass key to said Premises to enable him to examine the Premises from time to
time with reference to any emergency or to the general maintenance of said
Premises. Lessor shall give Lessee 48 hours' prior notice of any such entry,
except for any entry required by an emergency or for routine janitorial
purposes.

         13. TELEPHONE SERVICE. If Lessee desires telephonic or any other
electric connection, Lessor will direct Lessee's electricians as to where and
how the wires are to be introduced, and, without such directions, no boring or
cutting for wires or installation thereof will be permitted.

         14. SERVICES. Lessor shall maintain Premises and the public and common
areas of building, such as lobbies, stairs, corridor and restrooms, in such good
order and condition as is fitting for a first class office building, except for
damage occasioned by the act of Lessee.

         Lessor shall furnish the Premises with electricity for lighting and
operation of low power usage office machines (including without limitation,
hotocopiers, personal computers and peripherals), heat, normal office
air-conditioning, and elevator services from 6:00 a.m. to 10:00 p.m. on weekdays
and from 6:00 a.m. to 1:00 p.m. on weekend days. (Lessee has informed Lessor,
and Lessor acknowledges, that up to 20% of Lessee's employees may be working in
the Premises after the building's normal business hours.) Air-conditioning units
and electricity therefor for special air-conditioning requirements, such as for
computer centers, shall be at Lessee's expense. Lessor shall also provide
lighting replacement for Lessor furnished lighting, toilet room supplies, window
washing with reasonable frequency, and customary janitor service, as is fitting
for a first class office building.

         Except in cases of emergency, Lessor shall give Lessee 48 hour's prior
notice of any repairs to be made to the Premises or of any repairs to the
building that will cause any variation, interruption or failure of services
supplied to the Premises or common areas. Lessor shall not be liable to Lessee
for any loss or damage caused by or resulting from any variation, interruption
or any failure of said services due to any cause whatsoever, except for Lessor's
negligence or willful misconduct. No temporary interruption or failure of such
services incident to the making of repairs, alterations, or improvements, or due
to accidents or strikes or conditions or events not under Lessor's control shall
be deemed as an eviction of Lessee or relieve Lessee from any of Lessee's
obligations hereunder.

         In the event of any lack of attention on the part of Lessor and any
dissatisfaction with the service of the building, or any unreasonable annoyance
of any kind, Lessee is requested to make complaints to Lessor's building office
and not to Lessor's employees or agents seen within the building. Lessee is
further requested to remember that Lessor is as anxious as Lessee that a high
grade of service be maintained, and that the Premises be kept in a state to
enable Lessee to transact business with the greatest possible ease and comfort.
The rules and regulations are not made to unnecessarily restrict Lessee, but to
enable Lessor to operate the building to the best advantage of both parties
hereto. To this end, Lessor shall have the right to waive from time to time, and
in a nondiscriminatory manner, such part or parts of these rules and regulations
as in his reasonable judgment may not be necessary for the proper maintenance or
operation of the building or consistent with good service, and may from time to
time make such further reasonable rules and regulations as in his judgment may
be needed for the safety, care and cleanliness of the Premises and the building
and for the preservation of order therein. Lessee shall be given written notice
of all new rules and regulations.

         15. SOLICITORS. Lessor will make an effort to keep solicitors
out of the building, and Lessee will not oppose Lessor in his attempt to 
accomplish this end.

         16. FLOOR PLAN. The floor plan of the Premises shall be attached 
hereto and marked Exhibit A.

         17. ASSIGNMENT. Lessee will not assign this lease, or any interest
hereunder, and this lease, or any interest hereunder, shall not be assigned by
operation of law. Lessee will not sublet said Premises or any part thereof and
will not permit the use of said Premises by others other than Lessee and the
agents of Lessee without first obtaining the written consent of Lessor, whose
consent shall not be unreasonably withheld or delayed. In the event such written
consent shall be given, no other or subsequent assignment or subletting shall be
made without the previous written consent of Lessor, whose consent shall not be
unreasonably withheld or delayed.


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         Anything in this lease to the contrary  notwithstanding,  Lessor hereby
consents to an  assignment  of this  lease,  or a sublease of all or part of the
Premises, (a) to the parent of Lessee or to a wholly-owned  subsidiary of Lessee
or of such parent, (b) to any corporation into or with which Lessee may be
merged or consolidated, or (c) in connection with the transfer of substantially
all the assets of Lessee to any assignee or subtenant, provided that any such
assignment of lease shall contain an assumption of all of the terms, covenants
and conditions of this lease to be performed by Lessee, and any subtenant shall
agree to perform all applicable provisions of this lease to be performed by
Lessee. Lessee agrees that no such assignment or subletting shall be effective
unless and until Lessee gives Lessor written notice thereof, together with a
true copy of the assignment or of the sublease.

         18. OPERATING SERVICES AND REAL ESTATE TAXES. The annual base rental
rate per rentable square foot in Paragraph 3 includes Lessee's proportionate
share of Operating Services Costs and Real Estate Taxes for the first twelve
months of the lease term (collectively referred to as "Base Year Costs"). Only
actual increases from these Base Year Costs, if any, will be passed on to Lessee
on a proportionate basis.

                                   DEFINITIONS

Base Year
For computing the Base Year Costs, the "Base Year" for the 9th and 10th floors
shall be the calendar year 1998, unless the term commences during a later
calendar year, in which case the base year shall be the calendar year in which
the lease term commences.

Comparison Year
The Comparison Year(s) shall be the calendar year(s) subsequent to the base
year.

Operating Services
"Operating Services Costs" include, but are not limited to, the charges incurred
by Lessor for: building operation salaries, benefits, management fee of 3% of
gross income for the building, insurance, electricity, janitorial, supplies,
telephone, HVAC, repair and maintenance, window washing, water and sewer,
security, landscaping, disposal, elevator, etc. Operating Services shall also
include the amortization cost of capital investment items and of the
installation thereof, which are solely for the purpose of safety, demonstrably
saving energy, or reducing operating costs, or which may be required by
governmental authority (all such costs shall be amortized over the reasonable
life of the capital investment item, with the reasonable life and amortization
schedule being determined in accordance with generally accepted accounting
principles). Notwithstanding anything to the contrary contained herein,
Operating Services Costs shall not include any of the following:

                  (i)      Real Estate Taxes

                  (ii)     legal fees, auditing fees, brokerage 
commissions, advertising costs, or other related expenses incurred by Lessor 
in an effort to generate rental income;

                  (iii)    repairs, alterations, additions, improvements, or
replacements made to rectify or correct any defect in the original design,
materials or workmanship of the building or common areas (but not including
repairs, alterations, additions, improvements or replacements made as a result
of ordinary wear and tear);

                  (iv)     damage and repairs attributable to fire or other 
casualty;

                  (v)      damage and repairs necessitated by the negligence
or willful misconduct of Lessor, Lessor's employees, contractors or agents;

                  (vi)     executive salaries to the extent that such 
services are not in connection with the management, repair, operation or 
maintenance of the building;

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                  (vii)    Lessor's general overhead expenses not related to 
the building;

                  (viii)   legal fees, accountant's fees and other expenses
incurred in connection with disputes with tenants or other occupants of the
building or associated with the enforcement of the terms of any leases with
tenants or the defense of Lessor's title to or interest in the building or any
part thereof;

                  (ix)     costs (including permit, license and inspection 
fees) incurred in renovating or otherwise improving, decorating painting or 
altering (1) vacant space (excluding common areas) in the building or (2) 
space for tenants or other occupants in the building, and costs incurred in 
supplying any item or service to less than all of the tenants in the building;

                  (x)      costs incurred due to violation by Lessor or any 
other tenant of the building of applicable law or the terms and conditions of 
a lease or any other legal obligation;

                  (xi)     cost of any specific  service provided to Lessee 
or other occupants of the building for which Lessor is reimbursed (but 
not including Operating Services Costs and Real Estate Tax increases above 
Base Year Costs to the extent reimbursed Lessor) or any other expense for 
which Lessor is or will be reimbursed by another source (i.e., expenses 
covered by insurance or warranties);

                  (xii)    costs and expenses which would be capitalized 
under generally accepted accounting principles, with the exception of the 
capital investment items specified hereinabove;

                  (xiii)   building management fees in excess of the management
fees specified hereinabove;

                  (xiv)    cost incurred  with owning and/or operating the 
parking lot(s) serving the building by independent parking operator(s);

                  (xv)     fees paid to Lessor or any affiliate of Lessor for 
goods or services in excess of the fees that would typically be charged by 
unrelated, independent persons or entities for similar goods and services;

                  (xvi)    rent called for under any ground lease or master 
lease;

                  (xvii)   principal and/or interest payments called for 
under any debt secured by a mortgage or deed of trust on the building;

                  (xviii)  depreciation of or reserves for replacement of 
Lessor's assets; and

                  (xix)    any Operating Services Costs to the extent they 
exceed Operating Services Costs for comparable properties in the 
Seattle Central Business District.

Operating Services Costs shall be adjusted for the Base Year to reflect the
greater of actual occupancy or 95% occupancy.

Real Estate Taxes

Real Estate Taxes shall be the taxes paid by Lessor in the Base Year and each
respective Comparison Year. Real Estate Taxes shall be a separate category and
shall be treated as such.

         Notwithstanding anything in this lease to the contrary, Real Estate
Taxes shall not include, and Lessee shall not be responsible for, (a) any
franchise, corporate, estate, inheritance, succession, capital levy or transfer
tax of Lessor, (b) any income, profits, business and occupation or revenue tax
of Lessor, or (c) any tax or assessment on rent or other charge payable by
Lessor under this lease imposed by any local, state, federal or other regulatory
agency.

         If, after Lessee shall have made a payment of additional rent for Real
Estate Taxes, Lessor shall receive a refund of any portion of the Real Estate
Taxes payable during any Comparison Year upon which such payment of additional
rent shall have been based, as a result of a reduction of such Real Estate Taxes
by final determination of legal proceedings, settlement or otherwise, Lessor
shall, within 10 days after receiving the refund, pay to Lessee Lessee's share
of the refund.

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Proportionate Basis

Lessee's share of Base Year and Comparison Year(s) Costs shall be a fraction,
the numerator of which shall be the number of rentable square feet contained in
the Premises (see Paragraph 1) and the denominator of which shall be the number
of rentable square feet in the building in which the leased Premises are
located, which Lessor represents and warrants is 411,100/RSF. (Lessee's share is
4.02 % for the 9th floor; 4.03 % for the 10th floor; 8.06 % for both floors.)

Computation of Adjustments to Base Year Costs

Any adjustment to Base Year Costs will commence to occur in Month 13 of the
lease term with subsequent adjustments commencing every twelve months of the
lease term or in Months 25, 37, 49, etc. as appropriate under the lease term.
Lessee shall be responsible for any increase between Lessee's proportionate
share of Base Year Costs and Lessee's proportionate share of each respective
Comparison Year(s) Costs. The increase shall be the increase to each expense
individually. These costs shall be initially calculated based on estimated
(projected) costs with reconciliation to actual costs when annual audited
numbers are completed, which shall be no later than May 1 of each calendar year.
For the purpose of calculating projected increases to Base Year Cost, Lessor
shall review historical data to predict if any estimated increases would be
anticipated in a Comparison Year(s). If they are, then commencing in Month 13
and/or every twelve month period thereafter, Lessor will assess a monthly charge
to be paid together with monthly base rent. Once actual cost data for Comparison
Year(s) Real Estate Taxes and Operating Services Costs for the entire building
is formulated in accordance with generally accepted accounting principles (but
no later than May 1 of each calendar year), then Lessee's estimated pass-through
costs shall be corrected with Lessee or Lessor, as appropriate, reimbursing the
other for the difference between the estimated and actual costs, at that time in
lump sum payment.

Upon termination of this lease, the amount of any corrected amount between
estimated and actual costs with respect to the final comparison year shall
survive the termination of the lease and shall be paid to Lessee or Lessor as
appropriate within 30 days after final reconciliation. Computation of or
adjustment to Operating Services Costs and/or Real Estate Taxes pursuant to this
paragraph or to rent pursuant to Paragraph 3 shall be computed based on a
365-day year.

         The statements of Operating Services Costs furnished by Lessor to
Lessee shall be certified by Lessor, shall be detailed and shall constitute a
final determination as between Lessor and Lessee of Operating Services Costs for
the periods represented thereby unless Lessee shall give a notice to Lessor that
it disputes their accuracy or their appropriateness, which notice shall specify
the particular respects in which the statement is inaccurate or inappropriate.
Lessee or Lessee's agent shall have the right, during reasonable business hours
and upon not less than 5 business days' prior written notice to Lessor, with
respect to current records, or 10 business days' prior written notice to Lessor,
with respect to archived records, to examine Lessor's books and records in
Lessor's office with respect to the foregoing.

         Any dispute regarding Operating Services Costs shall be resolved (a) by
arbitration in Seattle, Washington by 3 arbitrators, each of whom shall have at
least 10 years' experience in the supervision of the operation and management of
commercial office buildings in Seattle, Washington, and (b) in accordance with
the Commercial Arbitration Rules of the American Arbitration Association, and
judgment upon the award rendered by the arbitrators may be entered in any court
having jurisdiction thereof. Pending the resolution of such dispute, Lessee
shall continue to pay additional rent to Lessor in the same amounts as before
Lessee received the statement that is the subject of such dispute. Within 30
days after the resolution of such dispute, Lessee shall pay to Lessor any
deficiency in additional rent found by the arbitrators to be owing to Lessor by
Lessee, or Lessor shall refund any overage in additional rent found by the
arbitrators to have been paid by Lessee to Lessor. The cost of the arbitration
shall be borne by the losing party.

         19. LATE PAYMENTS. Any payment required to be made pursuant to this
lease that is not made on the date that is 5 business days after Lessee receives
written notice that it is overdue shall bear interest at a rate equal to 3%
above the prime rate of interest charged from time to time by Seafirst National
Bank, or its successor.

         In addition to any interest charged herein, a late charge of 5% of the
payment amount shall be incurred for payments received more than 5 business days
after Lessee receives written notice that it is overdue.


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         20. RISK. All personal property of any kind or description whatsoever
in the Premises shall be at Lessee's sole risk. Lessor shall not be liable for
any damage done to or loss of such personal property or damage or loss suffered
by the business or occupation of the Lessee arising from any acts or neglect of
co-tenants or other occupants of the building, or of Lessor or the employees of
Lessor, or for any other persons, or from bursting, overflowing or leaking of
water, sewer or steam pipes, or from the heating, or plumbing or sprinklering
fixtures, or from electric wires, or from gas, or odors, or caused in any other
manner whatsoever except in the case of negligence or wilful misconduct on the
part of Lessor. Lessee shall keep in force throughout the term of this lease
such casualty and general liability insurance as a prudent tenant occupying and
using the Premises would keep in force. Lessor shall keep in force throughout
the term of the lease such casualty and general liability insurance as a prudent
landlord/owner of the building in which the Premises are located would keep in
force.


         21. INDEMNIFICATION. Lessee will defend, indemnify and hold harmless
Lessor from any claim, liability or suit, including reasonable attorney's fees,
on behalf of any person, persons, corporation and/or firm for any injuries or
damages occurring in or about the said Premises or on or about the sidewalk,
stairs, or thoroughfares adjacent thereto to the extent said damages or injury
was caused or partially caused by the ordinary or gross negligence or
intentional act of Lessee and/or by Lessee's agents, employees, or servants.

         Lessor shall defend, indemnify and hold harmless Lessee from any claim,
liability or suit, including reasonable attorney's fees, on behalf of any
person, persons, corporation and/or firm for any injuries or damages occurring
in the common areas of the building or caused or partially caused by the
ordinary or gross negligence or intentional act of Lessor or Lessor's agents,
employees or servants.

         22. WAIVER OF SUBROGATION. Lessee and Lessor do hereby release and
relieve the other, and waive their entire claim of recovery for loss, damage,
injury and all liability of every kind and nature which may arise out of, or be
incident to, fire and extended coverage perils, in, on, or about the Premises
herein described, whether due to negligence of either of said parties, their
agents, or employees, or otherwise.

         23. SUBORDINATION. This lease and all interest and estate of Lessee
hereunder is subject to and is hereby subordinated to all present and future
mortgages and deeds of trust affecting the Premises or the property of which
said Premises are a part. Lessee agrees to execute, at no expense to the Lessor,
any instrument which may be deemed necessary or desirable by the Lessor to
further effect the subordination of this lease to any such mortgage or deed of
trust. In the event of a sale or assignment of Lessor's interest in the
Premises, or in the event of any proceedings brought for the foreclosure of, or
in the event of exercise of the power of sale under any mortgage or deed of
trust made by Lessor covering the Premises, Lessee shall attorn to the purchaser
and recognize such purchaser as Lessor. Lessee agrees to execute, at no expense
to Lessor, any estoppel certificate deemed necessary or desirable by Lessor to
further effect the provisions of this paragraph, provided Lessor makes such
reasonable revisions to such estoppel certificate as Lessee may request.
Notwithstanding the foregoing, Lessee shall not be obligated to subordinate this
lease or attom to any transferee of Lessor's interest under this lease unless
the transferee agrees in writing (a) that Lessee shall not be disturbed under
this lease as long as Lessee is not in default under this lease beyond any
applicable notice and cure period and (b) to perform all of Lessor's obligations
hereunder.

        24. CASUALTY. In the event the leased Premises or the said building is
destroyed or injured by fire, earthquake or other casualty to the extent that
they are untenantable in whole or in part, then Lessor may, at Lessor's option,
proceed with reasonable diligence to rebuild and restore the said Premises or
such part thereof as may be injured as aforesaid, provided that within sixty
(60) days after such destruction or injury Lessor will notify Lessee of Lessor's
intention to do so, and during the period of such rebuilding and restoration the
rent shall be abated in proportion to the portion of the Premises that is unfit
for occupancy. Lessor will provide access to any needed alternative space for
Lessee at the fair market rate, not to exceed Lessee's rental rate hereunder.
Notwithstanding the foregoing, if the repairs would foreseeably require more
than 180 days to complete or such repairs cannot be made under applicable laws,
this lease may be terminated at the option of Lessee, upon 30 days' written
notice to Lessor. Furthermore, if Lessor begins to make such repairs and is
unable to complete same within 180 days, or if a total or partial destruction of
the Premises or building occurs during the last 2 years of the lease term,
Lessee may terminate this lease upon 30 days' written notice to Lessor.


<PAGE>



         25. INSOLVENCY. If Lessee becomes insolvent, or makes an assignment for
the benefit of creditors, or a receiver is appointed for the business or
property of Lessee, or a petition is filed in a court of competent jurisdiction
to have Lessee adjudged bankrupt, then Lessor may, at Lessor's option, terminate
this lease. Said termination shall reserve unto Lessor all of the rights and
remedies available under Paragraph 26 ("Default") hereof, and Lessor may accept
rents from such assignee or receiver without waiving or forfeiting said right of
termination. As an alternative to exercising his right to terminate this lease,
Lessor may require Lessee to provide adequate assurances, including the posting
of a cash bond, of Lessee's ability to perform its obligations under this lease.

       26. DEFAULT. If this lease is terminated in accordance with any of the
terms herein (with the exception of Paragraph 25), or if Lessee vacates the
Premises or if Lessee shall fail at any time to keep or perform any of the
covenants or conditions of this lease, i.e. specifically the covenant for the
payment of monthly rent by the 5th business day after Lessee receives written
notice that is overdue, then, and in any of such events Lessor may with or
without notice or demand, at Lessor's option, and without being deemed guilty of
trespass and/or without prejudicing any remedy or remedies which might otherwise
be used by Lessor for arrearages or preceding breach of covenant or condition of
this lease, enter into and repossess said Premises and expel Lessee and all
those claiming under Lessee. (Notwithstanding the foregoing, if Lessee fails to
fulfill any of the covenants of this lease, other than the covenants for the
payment of base rent or additional rent, Lessee shall not be in default until
Lessee receives written notice of the failure and a 30 day period in which to
cure it. If the failure is not reasonably susceptible of cure within 30 days,
then Lessee shall be entitled to such longer cure period as is reasonably
necessary, as long as Lessee commences the cure within the initial 30-day period
and diligently pursues the cure thereafter.) In such event Lessor may eject and
remove from said Premises all goods and effects (forcibly if necessary). This
lease if not otherwise terminated may immediately be declared by Lessor as
terminated. The termination of this lease pursuant to this Article shall not
relieve Lessee of its obligations to make the payments required herein. In the
event this lease is terminated pursuant to this Article, or if Lessor enters the
Premises without terminating this lease and Lessor relets all or a portion of
the Premises, Lessee shall be liable to Lessor for all the costs of relenting,
including necessary repairs, but not renovation and alteration of the leased
Premises. Lessee shall remain liable for all unpaid rental which has been earned
plus late payment charges pursuant to Paragraph 19 and for the remainder of the
term of this lease for any deficiency between the amounts received following
reletting and the amounts due from Lessee, or if Lessor elects, Lessee shall be
immediately liable for all rent and additional rent (Paragraph 17) that would be
owing to the end of the term, less any rental loss Lessee proves could be
reasonably avoided, which amount shall be discounted by the discount rate of the
Federal Reserve Bank situated nearest to the Premises, plus one percent (1%).

         27. PARKING. Lessor shall grant Lessee parking in the building based 
or a ratio of one (1) stall per every 1,000 rentable square feet leased (16.5 
spaces for the 9th floor; 16.5 spaces for the 10th floor; 33 spaces for both 
floors, when both floors are leased). The monthly cost for such parking shall 
be at the prevailing market rate, which shall mean the average rate then 
charged for comparable parking stalls located within the area that has the 
following boundaries: University Street, Columbia Street, Fourth Avenue and 
Western Avenue.

         28. EARLY POSSESSION. In order to construct its tenant improvements,
Lessee shall be allowed to occupy the 9th floor on January 1, 1998, and the 10th
floor on June 1, 1998. Lessee shall not be required to pay rent on the Premises
until the dates outlined in Paragraph 2 TERM.

         29. TENANT IMPROVEMENT ALLOWANCE. Lessee shall be entitled to a tenant
improvement allowance at $15.00 per rentable square foot. This allowance will be
paid upon submittal of Lessee's paid invoices, which Lessee may submit, at its
option, either all at once or from time to time. If Lessor does not reimburse
Lessee for an invoiced amount within 5 days after submittal of the paid invoice
thereof, Lessee may offset such against rent owed to Lessor.

         30. RIGHT OF FIRST OFFER. Lessor herein grants to Lessee the right of
first offer to lease any space on the 11th floor which becomes available during
the term of this lease. Promptly after Lessor becomes aware that any 11th floor
space will become available, but no earlier than 6 months before the space
becomes available, Lessor shall give Lessee written notice of the upcoming,
availability. The notice shall contain an offer by Lessor to lease the space to
Lessee for a base rent equal to 90% of the fair market rental value of the space
on the date of Lessor's offer to Lessee, determined in accordance with the
second sentence of Paragraph 41(ii), for a term to expire on the date this lease
expires, with a Base Year to be the calendar year in which the leasing of the
space commences, and otherwise on substantially the same terms

<PAGE>


and conditions as are contained in this lease. Lessee shall have until
60 days after receiving Lessor's offer to elect to lease all or any portion of
the offered space and to execute a binding lease therefor. If Lessee shall fail
to timely make such election and execute such lease, Lessee's rights with
respect to the refused space shall expire until the earlier of the date that is
6 months after the date of Lessor's offer with respect to the space, provided
Lessor shall not have leased the space to a third party during the 6-month
period, or the date when Lessor becomes aware that the space will once again
become available, when Lessee's rights under this paragraph with respect to the
space shall revive.

         31. REAL ESTATE LEASING FEE. Lessor shall pay to Lessee's agent, David
Alexander Company, a real estate leasing fee equivalent to $3.50 per rentable
square foot or $115,822.00. Fifty percent (50%) of this fee is due upon full
execution of this lease and 50% is due upon occupancy of the 9th floor. If the
real estate commission has not been paid by Lessor within 30 days of when due,
Lessee may offset such against rents owing to Lessor. If Lessee exercises its
right of first refusal to rent additional space on the 11th floor, David
Alexander only shall be entitled to a real estate commission equal to $0.7 per
rentable square foot of space leased, multiplied by the number of years then
remaining in the term.

         32. BINDING EFFECT. The parties hereto further agree with each other
that each of the provisions of this lease shall extend to and shall, as the case
may require, bind and inure to the benefit, not only of Lessor and Lessee, but
also of their respective heirs, legal representatives, successors and assigns,
subject, however, to the provisions of Paragraph 17 of this lease.

         33. LEASE CONSTRUCTION. It is also understood and agreed that the terms
"Lessor" and 'Lessee" and verbs and pronouns in the singular number are
uniformly used throughout this lease regardless of gender, number or fact of
incorporation of the parties hereto. The typewritten riders or supplemental
provisions, if any, attached or added hereto are made a part of this lease by
reference. It is further mutually agreed that no waiver by Lessor of a breach by
Lessee of any covenant or condition of this lease shall be construed to be a
waiver of any subsequent breach of the same or any other covenant or condition.

         34. HOLDING OVER. If Lessee holds possession of the Premises after term
of this lease, Lessee shall be deemed to be a month-to-month tenant upon the
same terms and conditions as contained herein, except rent which shall be
revised to reflect the then current market rate. During month-to-month tenancy,
Lessee acknowledges Lessor will be attempting to relet the Premises. Lessee
agrees to cooperate with Lessor and Lessee further acknowledges Lessor's
statutory right to terminate the lease with proper notice.

         35. ATTORNEY'S FEES. If any legal action is commenced to enforce any
provision of this lease, the prevailing party shall be entitled to an award of
reasonable attorney's fees and disbursements. The phrase "prevailing party'
shall include a party who receives substantially the relief desired, whether by
dismissal, summary judgment, judgment, settlement or otherwise.

         36. NO REPRESENTATIONS. The Lessor has made no representations or 
promises except as contained herein or in some future writings signed by Lessor.

         37. QUIET ENJOYMENT. So long as Lessee pays the rent and performs the
covenants contained in this lease, Lessee shall hold and enjoy the Premises
peaceably and quietly, subject to the provisions of this lease.

         38. RECORDATION. Lessee shall not record this lease without the prior
written consent of Lessor. However, both parties shall execute a memorandum or
"short form" of this lease for the purposes of recordation in a form customarily
used for such purpose. Said memorandum or short form of this lease shall
describe the parties, the Premises and the lease term, and shall incorporate
this lease by reference.

         39. MUTUAL PREPARATION OF LEASE. It is acknowledged and agreed that
this lease was prepared mutually by both parties. In the event of ambiguity, it
is agreed by both parties that it shall not be construed against either party as
the drafter of this lease.

         40. GOVERNING LAW. This lease shall be governed by, construed and 
enforced in accordance with the laws of the State of Washington.


<PAGE>



         41. RENEWAL OPTION. Lessee shall have options to renew and extend the
term of this lease for up to a total of 7 years, which Lessee may exercise for
periods of no less than one year at a time, but for as many years as Lessee may
desire at a time, as long as the total number of years does not exceed 7 (each
period of time selected by Lessee shall be referred to as a "Renewal Term").
During each Renewal Term, the same terms and conditions as are contained in this
lease shall apply (unless changed or modified by mutual agreement) except that
(a) the base rent shall be as hereinafter set forth, and (b) the Base Year shall
be as hereinafter defined. The exercise of such options shall only be effective
upon strict compliance with the following terms and conditions:

                  (i) Written notice of the exercise of each such option shall
be given by Lessee to Lessor no later than 6 months prior to the expiration date
of the previous term of this lease.

                  (ii) If Lessee extends the term of this lease, the base rent
shall be adjusted on the anniversary of the commencement date of the initial
term of this lease and, if applicable, on the tenth anniversary of the
commencement date of the initial term of this lease (each, an "Adjustment
Date"), as follows: The base rent payable shall be adjusted to 90% of the fair
market rental value of the Premises as of the Adjustment Date, taking into
account the then-current rentals at which leases are being concluded for
comparable space in the building and in comparable buildings in the same rental
area as the building, the provisions of this paragraph, and no other provisions
of this lease. Lessor and Lessee shall seek to agree upon such fair market
rental value. If Lessor and Lessee cannot agree upon such fair market rental
value by the date that is 30 days before the Adjustment Date, such value shall
be determined by arbitration, initiated by either Lessor or Lessee and conducted
in Seattle, Washington by a 3-member panel composed of licensed real estate
brokers doing business in Seattle, Washington and having not less than 15 years'
active experience as real estate brokers in Seattle, Washington, in accordance
with the rules of the American Arbitration Association then obtaining. The
determination by the arbitrators shall be conclusive and binding on Lessor and
Lessee.

         If, by an Adjustment Date, the amount of the base rent payable shall
not have been determined, then pending such determination, Lessee shall continue
to pay base rent at the rate payable immediately prior to the Adjustment Date
and within 30-days after the determination by the arbitrators, Lessee shall pay
to Lessor, for the period after the Adjustment Date during which such
determination was pending, the amount, if any, by which the base rent for such
period at the rate determined by the arbitrators exceeds the base rent for such
period at the rate theretofore paid, or Lessor shall pay to Lessee, for the
period after the Adjustment Date during which the determination was pending, the
amount, if any, by which the base rent for such period at the rate theretofore
paid by Lessee exceeds the base rent for such period at the rate determined by
the arbitrators.

                 (iii) Upon determination of the adjusted base rent, Lessor and
Lessee shall execute, acknowledge and deliver to each other an agreement
specifying the amount of the adjusted base rent. However, failure of either
party to do so shall not affect the validity or binding nature of such
determination.

                 (iv) Effective as of each Adjustment Date, the Base Year for
purposes of determining the expense escalation hereunder shall be adjusted to be
the calendar year in which the Adjustment Date occurs. If an Adjustment Date is
not the first day of a calendar year, then the additional rent due hereunder
shall be prorated on an actual per them basis.

         42. HAZARDOUS SUBSTANCES. Lessor shall be solely responsible for and
shall defend, indemnify and hold harmless Lessee and its employees and agents
against all liabilities, obligations, damages, penalties, claims, causes of
action, costs, charges and expenses, including reasonable attorneys' fees, court
costs, administrative costs, and costs of appeals arising out of or in
connection with the presence of Hazardous Materials on, in or under the building
or other parts of the property on which the building is located, except to the
extent arising out of or in connection with or resulting from the acts or
omissions of any kind by Lessee or its employees, agents, licensees, invitees or
contractors. Lessor's obligations under this paragraph shall survive the
expiration or termination of this lease.

         "Hazardous Material" shall mean any matter (whether gaseous, liquid or
solid) that is or may be harmful to persons or property, including but not
limited to petroleum products and byproducts, asbestos and any other materials,
now or hereafter designated as a hazardous substance or material pursuant to
Section 101 of the Comprehensive Environmental Response, Compensation and
Liability Act of 1980, as now or hereafter amended, 42 U. S. C. 960 1, et seq.,
or that is now or hereafter regulated by any applicable law pertaining to
health, industrial hygiene or the environment.


<PAGE>



         43. REPRESENTATIONS. Lessor represents and warrants to Lessee that it
is the fee simple owner of the building and that it has full right and power to
execute and perform this lease and to grant the estate leased herein.

         44. CONSENT. Notwithstanding anything in this lease to the contrary,
Lessor shall not unreasonably withhold or delay any consent or approval that
Lessee is obligated to obtain from Lessor under this lease. If Lessor fails to
give Lessee notice that Lessor either gives or denies its consent or approval
within 5 business days after Lessee's request (or such other period as may be
set forth in this lease with respect to the consent or approval in question),
such consent or approval shall be deemed given.

         45. NOTICES. Any notice or document required or permitted to be
delivered hereunder from one party to the other shall be in writing and shall be
deemed given when personally delivered, delivered by facsimile with prompt
confirmation of receipt by telephone or delivered by private courier service
(such as Federal Express) or 5 days after being deposited in the United States
Mail, in registered or certified form, return receipt requested, to the other
party's address or facsimile number set forth below or such other address or
facsimile number as shall have been last designated by notice in writing from
one party to the other.


         If to Lessee, as follows:

                  Lessee:                    Immunex Corporation
                                             51 University Street
                                             Seattle, WA 98101
                                             Attn: Vice President, Operations
                                             Phone:  (206) 587-0430
                                             Fax:  (206) 587-0606

                  Lessee Counsel:            Davis Wright Tremaine LLP
                                             2600 Century Square
                                             1501 Fourth Avenue
                                             Seattle, WA 98101-1688
                                             Attention: Janine V. Roberts
                                             Phone: (206) 622-3150
                                             Fax: (206) 628-7040
         If to the Lessor, as follows:

                   Lessor:                    Martin Selig Real Estate
                                              1000 Second Avenue, Suite 1800
                                              Seattle, WA 98104-1046
                                              Attn:   Martin Selig
                                              Phone:  (206) 467-7600
                                              Fax:  (206) 386-5296


<PAGE>





IN WITNESS WHEREOF, the parties hereof have executed this lease the day and year
first above written.

                                                 IMMUNEX CORPORATION

/S/ Martin Selig                                 /S/ D.G. Southern
-------------------------------                  ------------------------------
Martin Selig                                     By: D. G. Southern
                                                 ------------------------------
                                                 Its: Senior Vice President
                                                 ------------------------------

               "Lessor"                                  "Lessee


Attachment