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                           STANDARD FORM OF LOFT LEASE
                    The Real Estate Board of New York, Inc.
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Agreement of Lease, made as of this 15th day of December 1998, between 180
VARICK STREET CORPORATION c/o Olmstead Properties, Inc., 575 Eighth Avenue,
Suite 2400, New York, New York 10018 party of the first part, hereinafter
referred to as OWNER, or LANDLORD, and IMCLONE SYSTEMS INCORPORATED, a Delaware
Corporation having an office at 180 Varick Street, New York, New York 10014
party of the second part, hereinafter referred to as TENANT,

Witnesseth: Owner hereby leases to Tenant and Tenant hereby hires from Owner the
            entire 6th and 7th floors (the "Demised Premises")

in the building known as 180 Varick Street (the "Building") in the Borough of
Manhattan, City of New York, for the term of six (6) years (or until such term
shall sooner cease and expire as hereinafter provided) to commence on the first
day of January nineteen hundred and ninety-nine, and to end on the thirty-first
day of December two thousand and four both dates inclusive, at an annual rental
rate of

                             See Article 41 (a) (i)

which Tenant agrees to pay in lawful money of the United States which shall be
legal tender in payment of all debts and dues, public and private, at (the time
of payment, in equal monthly installments in advance on the first day of each
month during said term, at the office of Owner or such other place as Owner may
designate, without any set off or deduction whatsoever, except that Tenant shall
pay the first       monthly installment(s) on the execution hereof (unless this
lease be a renewal).

      In the event that, at the commencement of the term of this lease, or
thereafter, Tenant shall be in default in the payment of rent to Owner pursuant
to the terms of another lease with Owner or with Owner's predecessor in
interest, Owner may at Owner's option and without notice to Tenant add the
amount of such arrears to any monthly installment of rent payable hereunder and
the same shall be payable to Owner as additional rent.

      The parties hereto, for themselves, their heirs, distributees, executors,
administrators, legal representatives, successors and assigns, hereby covenant
as follows:

Rent:       1. Tenant shall pay the rent as above and as hereinafter provided.

Occupancy:  2. Tenant shall use and occupy demised premises for 

                               see Article 41(h)

provided such use is in accordance with, the certificate of occupancy for the
building, if any, and for no other purpose.

Alterations:

3. Tenant shall make no changes in or to the demised premises of any nature
without Owner's prior written consent. Subject to the prior written consent of
Owner, which shall not be unreasonably withheld, and to the provisions of this
article, Tenant, at Tenant's expense, may make alterations, installations,
additions or improvements which are nonstructural and which do not affect
utility services or plumbing and electrical lines, in or to the interior of the
demised premises using contractors or mechanics first approved in each instance
by Owner, which approval shall not be unreasonably withheld, Tenant shall, at
its expense, before making any alterations, additions, installations or
improvements obtain all permits, approval and certificates required by any
governmental or quasi-governmental bodies and (upon completion) certificates of
final approval thereof and shall deliver promptly duplicates of all such
permits, approvals and certificates to Owner. Tenant agrees to carry and will
cause Tenant's contractors and sub-contractors to carry such workman's
compensation, general liability, personal and property damage insurance as Owner
may require. If any mechanic's lien is filed against the demised premises, or
the building of which the same forms a part, for work claimed to have been done
for, or materials furnished to, Tenant, whether or not done pursuant to this
article, the same shall be discharged by Tenant within thirty days thereafter,
at Tenant's expense. by payment or filing the bond required by law or otherwise.
All fixtures and all paneling, partitions. railings and like installations,
installed in the premises at any time, either by Tenant or by Owner on Tenant's
behalf, shall, upon installation, become the property of Owner and shall remain
upon and be surrendered with the demised premises unless Owner, by notice to
Tenant given at the time Landlord gives its written approval to such
installation (if, in fact, Landlord approves of such installation), provided,
however, that in Tenant's request for approval of such installation, it
expressly requests, highlighted in bold face or underlining, Landlord's approval
to allow such installation to remain upon and be surrendered with the Demised
Premises at the end of the term of this lease, elects to relinquish Owner's
right thereto and to have them removed by Tenant, in which event the same shall
be removed from the demised premises by Tenant prior to the expiration of the
lease, at Tenant's expense. Anything contained herein to the contrary
notwithstanding, Tenant shall retain ownership of all laboratory equipment
installed in the Demised Premises and shall remove such equipment on or before
the expiration or sooner termination of the term of this lease. Nothing in this
Article shall be construed to give Owner title to or to prevent Tenant's removal
of trade fixtures, moveable office furniture and equipment, but upon removal of
any such from the premises or upon removal of other installations as may be
required by Owner, as hereinabove provided, Tenant shall immediately and at its
expense, repair and restore the premises to the condition existing prior to
installation and repair any damage to the demised premises or the building due
to such removal. All property permitted or required to be removed by Tenant at
the end of the term remaining in the premises after Tenant's removal shall be
deemed abandoned and may, at the election of Owner, either be retained as
Owner's property or removed from the premises by Owner, at Tenant's expense.

Repairs:

4. Owner shall maintain and repair the exterior of and the public portions of
the building. Tenant shall, throughout the term of this lease, take good care of
the demised premises including the bathrooms and lavatory facilities (if the
demised premises encompass the entire floor of the building) and the windows and
window frames and, the fixtures and appurtenances therein and at Tenant's sole
cost and expense promptly make all repairs thereto and to the building, whether
structural or non-structural in nature, caused by or resulting from the
carelessness, omission, neglect or improper conduct of Tenant, Tenant's
servants, employees, invitees, or licensees, and whether or not arising from
such Tenant conduct or omission, when required by other provisions of this
lease, including Article 6. Tenant shall also repair all damage to the building
and the demised premises caused by the moving of Tenant's fixtures, furniture or
equipment. All the aforesaid repairs shall be of quality or class equal to the
original work or construction. If Tenant fails, after ten days notice, to
proceed with due diligence to make repairs required to be made by Tenant, the
same may be made by the Owner at the expense of Tenant, and the expenses thereof
incurred by Owner shall be collectible, as additional rent, after rendition of a
bill or statement therefor. If the demised premises be or become infested with
vermin, Tenant shall, at its expense, cause the same to be exterminated. Tenant
shall give Owner prompt notice of any defective condition in any plumbing,
heating system or electrical lines located in the demised premises and following
such notice, Owner shall remedy the condition with due diligence, but at the
expense of Tenant, if repairs are necessitated by damage or injury attributable
to Tenant, Tenant's servants, agents, employees, invitees or licensees as
aforesaid. Except as specifically provided in Article 9 or elsewhere in this
lease, there shall be no allowance to the Tenant for a diminution of rental
value and no liability on the part of Owner by reason of inconvenience,
annoyance or injury to business arising from Owner, Tenant or others making or
failing to make any repairs, alterations, additions or improvements in or to any
portion of the building or the demised premises or in and to the fixtures,
appurtenances or equipment thereof. It is specifically agreed that Tenant shall
not be entitled to any set off or reduction of rent by reason of any failure of
Owner to comply with the covenants of this or any other article of this lease.
Tenant agrees that Tenant's sole remedy at law in such instance will be by way
of any action for damages for breach of contract, `The provisions of this
Article 4 with respect to the making of repairs shall not apply in the case of
fire or other casualty with regard to which Article 9 hereof shall apply.

Window Cleaning:

5. Tenant will not clean nor require, permit, suffer or allow any window in the
demised premises to be cleaned from the outside in violation of Section 202 of
the New York State Labor law or any other applicable law or of the Rules of the
Board of Standards and Appeals, or of any other Board or body having or
asserting jurisdiction.

Requirements of Law, Fire Insurance:

6. Prior to the commencement of the lease term, if Tenant is then in possession,
and at all times thereafter Tenant shall, at Tenant's sole cost and expense,
promptly comply with all present and future laws, orders and regulations of all
state, federal, municipal and local governments, departments, commissions and
hoards and any direction of any public officer pursuant to law, and all orders,
rules and regulations of the New York Board of Fire Underwriters, or the
Insurance Services Office, or any similar body which shall impose any violation,
order or duty upon Owner or Tenant with respect to the demised premises, whether
or not arising out of Tenant's use or manner of use thereof, or, with respect to
the building, if arising out of Tenant's use or manner of use of the demised
premises of the building (including the use permitted under the lease). Except
as provided in Article 30 hereof, nothing herein shall require Tenant to make
structural repairs or alterations unless Tenant has, by its manner of use of the
demised premises or method of operation therein, violated any such laws,
ordinances, orders, rules, regulations or requirements with respect thereto.
Tenant shall not do or

                                                                  Please Initial

                                                        Tenant:_________________
                                                        Landlord:_______________

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permit any act or thing to be done in or to the demised premises which is
contrary to law, or which will invalidate or be in conflict with public
liability, fire or other policies of insurance at any time carried by or for the
benefit of Owner. Tenant shall not keep anything in the demised premises except
as now or hereafter permitted by the Fire Department, Board of Fire
Underwriters, Fire Insurance Rating Organization and other authority having
jurisdiction, and then only in such manner and such quantity so as not to
increase the rate for fire insurance applicable to the building, nor use the
premises in a manner which will increase the insurance rate for the building or
any property located therein over that in effect prior to the commencement of
Tenant's occupancy. If by reason of failure to comply with the foregoing the
fire insurance rate shall, at the beginning of this lease or at any rate shall,
at the beginning of this lease or at any time thereafter, be higher than it
otherwise would be, then Tenant shall reimburse Owner, as additional rent
hereunder, for that portion of all fire insurance premiums thereafter paid by
Owner which shall have been charged because of such failure by Tenant. In any
action or proceeding wherein Owner and Tenant are parties, a schedule or
"make-up" or rate for the building or demised premises issued by a body making
fire insurance rates applicable to said premises shall be conclusive evidence of
the facts therein stated and of the several items and charges in the fire
insurance rates then applicable to said premises. Tenant shall not place a load
upon any floor of the demised premises exceeding the floor load per square foot
area which it was designed to carry and which is allowed by law. Owner reserves
the right to prescribe the weight and position of all safes, business machines
and mechanical equipment. Such installation shall be placed and maintained by
Tenant, at Tenant's expense, in setting sufficient, in Owner's reasonable
judgement, to absorb and prevent vibration, noise and annoyance.

Subordination:

7. This lease is subject and subordinate to all ground or underlying leases and
to all mortgages which may now or hereafter affect such leases or the real
property of which demised premises are a part and to all renewals, modification,
consolidations, replacements and extensions of any such underlying leases and
mortgages. This clause shall be self-operative and no further instrument or
subordination shall be required by any ground or underlying lessor or by any
mortgagee, affecting any lease or the real property of which the demised
premises are a part. In confirmation of such subordination. Tenant shall from
time to time execute promptly any certificate that Owner may reasonably request.

Tenant's Liability Insurance Property Loss, Damage Indemnity:

8. Owner or its agents shall not be liable for any damage to property of Tenant
or of others entrusted to employees of the building, nor for loss of or damage
to any property of Tenant by theft or otherwise, nor for any injury or damage in
persons or property resulting from any cause of whatsoever nature, unless caused
by or due to the negligence of Owner, its agent, servant or employees; Owner or
its agents shall not be liable for any damage caused by other tenants or persons
in, upon or about said building or caused by operations in connection of any
private, public or quasi public work. If at any time any windows of the demised
premises are temporarily closed, darkened or bricked up (or permanently closed,
darkened or bricked up, if required by law) for any reason whatsoever including,
but not limited to Owner's own acts, Owner shall not be liable for any damage
Tenant may sustain thereby and Tenant shall not be entitled to any compensation
therefor nor abatement or diminution of rent nor shall the same release Tenant
from its obligations hereunder nor constitute an eviction. Tenant shall
indemnify and save harmless Owner against and from all liabilities, obligations,
damages, penalties, claims, costs and expenses for which Owner shall not be
reimbursed by insurance, including reasonable attorney's fees, paid, suffered or
incurred as a result of any breach by Tenant, Tenant's agents, contractors,
employees, invitees, or licensees, of any covenant or condition of this lease,
or the carelessness, negligence or improper conduct of the Tenant, Tenant's
agents, contractors, employees, invitees or licensees. Tenant's liability under
this lease extends to the acts and omissions of any sub-tenant, and any agent,
contractor, employee, invitee or licensee of any sub-tenant. In case any action
or proceeding is brought against Owner by reason of any such claim, Tenant, upon
written notice from Owner, will, at Tenant's expense, resist or defend such
action or proceeding by counsel approved by Owner in writing, such approval not
to be unreasonably withheld.

Destruction Fire and Other Casualty:

9. (a) If the demised premises or any part thereof shall be damaged by fire or
other casualty, Tenant shall give immediate notice thereof to Owner and this
lease shall continue in full force and effect except as hereinafter set forth.
(b) If the demised premises are partially damaged or rendered partially unusable
by fire or other casualty, the damages thereto shall be repaired by and at the
expense of Owner and the rent and other items of additional rent, until such
repair shall be substantially completed, shall be apportioned from the day
following the casualty according to the part of the premises which is usable.
(c) If the demised premises are totally damaged or rendered wholly unusable by
fire or other casualty, then the rent and other items of additional rent as
hereinafter expressly provided shall be proportionately paid up to the time of
the casualty and thenceforth shall cease until the date when the premises shall
have been repaired and restored by Owner (or sooner reoccupied in part by Tenant
then rent shall be apportioned as provided in subsection (b) above), subject to
Owner's right to elect not to restore the same as hereinafter provided. (d) If
the demised premises are rendered wholly unusable or (whether or not the demised
premises are damaged in whole or in part) if the building shall be so damaged
that Owner shall decide to demolish it or to rebuild it, then, in any of such
events, Owner may elect to terminate this lease by written notice to Tenant,
given within 90 days after such fire or casualty, or 30 days after adjustment of
the insurance claim for such fire or casualty, whichever is sooner, specifying a
date for the expiration of the lease, which date shall not be more than 60 days
after the giving of such notice, and upon the date specified in such notice the
term of this lease shall expire as fully and completely as if such date were the
date set forth above for the termination of this lease and Tenant shall
forthwith quit, surrender and vacate the premises without prejudice however, to
Owner's rights and remedies against Tenant under the lease provisions in effect
prior to such termination, and any rent owing shall be paid up to the date of
the casualty, or such later date that Tenant surrenders full and complete vacant
possession of the Demised Premises to Landlord, and any payment of rent made by
Tenant which were an account of any period subsequent to such date shall be
returned to Tenant. Unless Owner shall serve a termination notice as provided
for herein. Owner shall make the repairs and restorations under the conditions
of (b) and (c) hereof, with all reasonable expedition, subject to delays due to
adjustments of insurance claims, labor troubles and causes beyond Owner's
control. After any such casualty, Tenant shall cooperate with Owner's
restoration by removing from the premises as promptly as reasonably possible,
all of Tenant's salvageable inventory and movable equipment, furniture, and
other property. Tenant's liability for rent shall resume five (5) days after
written notice from Owner that the premises are substantially ready for Tenant's
occupancy. (c) Nothing contained hereinabove shall relieve Tenant from liability
that may exist as a result of damage from fire or other casualty.
Notwithstanding the foregoing, including Owner's obligation to restore under
subparagraph (b) above, each party shall look first to any insurance in its
favor before making any claim against the other party for recovery for loss or
damage resulting from fire or other casualty, and to the extent that such
insurance is in force and collectible and to the extent permitted by law, Owner
and Tenant each hereby releases and waives all right of recovery with respect to
subparagraphs (b), (d) and (e) above, against the other or any one claiming
through or under each of them by way of subrogation or otherwise. The release
and waiver herein referred to shall be deemed to include any loss or damage to
the demised premises and/or to any personal property, equipment, trade fixtures,
goods and merchandise located therein. The foregoing release and waiver shall be
in force only if both releasors' insurance policies contain a clause providing
that such a release or waiver shall not invalidate the insurance. If, and to the
extent, that such waiver can be obtained only by the payment of additional
premiums, then the party benefitting from the waiver shall pay such premium
within ten days after written demand or shall be deemed to have agreed that the
party obtaining insurance coverage shall be free of any further obligation under
the provisions hereof with respect to waiver of subrogation. Tenant acknowledges
that Owner will not carry insurance on Tenant's furniture and or furnishings or
any fixtures or equipment, improvements, or appurtenances removable by Tenant
and agrees that Owner will not be obligated to repair any damage thereto or
replace the same. (f) Tenant hereby waives the provisions of Section 227 of the
Real Property Law and agrees that the provisions of this article shall govern
and control in lieu thereof.

Eminent Domain:

10. If the whole or any part of the demised premises shall be acquired or
condemned by Eminent Domain for any public or quasi public use or purpose, then
and in that event, the term of this lease shall cease and terminate from date of
title vesting in such proceeding and Tenant shall have no claim for the value of
any unexpired term of said lease. Tenant shall have the right to make an
independent claim to the condemning authority for the value of Tenant's moving
expenses and personal property, trade fixtures and equipment, provided Tenant is
entitled pursuant to the terms of the lease to remove such property, trade
fixtures and equipment at the end of the term and provided further such claim
does not reduce Owner's award.

Assignment, Mortgage, Etc.:

11. Tenant, for itself, its heirs, distributees, executors, administrators,
legal representatives, successors and assigns, expressly covenants that it shall
not assign, mortgage or encumber this agreement, nor underlet, or suffer or
permit the demised premises or any part thereof to be used by others, without
prior written consent of Owner in each instance. Transfer of the majority of the
stock of a corporate Tenant or the majority partnership interest of a
partnership Tenant shall be deemed an assignment. If this lease be assigned, or
if the demised premises or any part thereof be underlet or occupied by anybody
other than Tenant, Owner may, after default by Tenant, collect rent from the
assignee, under tenant or occupant, and apply the net amount collected to the
rent herein reserved, but no such assignment, underletting, occupancy or
collections shall be deemed a waiver of this covenant, or the acceptance of the
assignee, under-tenant or occupant as tenant, or a release of Tenant from the
further performance by Tenant of covenants on the part of Tenant herein
contained. The consent by Owner to an assignment or underletting shall not in
any wise be construed to relieve Tenant from obtaining the express consent in
writing of Owner to any further assignment or underletting.

Electric Current:

12. Rates and conditions in respect to submetering or rent inclusion, as the
case may be, to be added in [CLIPART OMITTED] RIDER attached hereto. Tenant
covenants and agrees that at all times its use of electric current shall not
exceed the capacity of existing feeders to the building of the risers or wiring
installation and Tenant may not use any electrical equipment which, in Owner's
opinion, reasonably exercised, will overload such installations or interfere
with the use thereof by other tenants of the building. The change at any time of
the character of electric service shall in no wise make Owner liable or
responsible to Tenant, for any loss, damages or expenses which Tenant may
sustain.

Access to Premises:

13. Owner or Owner's agents shall have the right (but shall not be obligated) to
enter the demised premises in any emergency at any time, and, at other
reasonable times upon prior reasonable notice to Tenant to examine the same and
to make such repairs, replacements and improvements as Owner may deem necessary
and reasonably desirable to any portion of the building or which Owner may elect
to perform in the premises after Tenant's failure to make repairs of perform any
work which Tenant is obligated to perform under this lease, or for the purpose
of complying with laws regulations and other directions of governmental
authorities. Tenant shall permit Owner to use and maintain and replace pipes and
conduits in and through the demised premises and to erect new pipes and conduits
therein provided, wherever possible, they are within walls or otherwise
concealed. Owner may, during the progress of any work in the demised premises,
take all necessary materials and equipment into said premises without the same
constituting an eviction nor shall the Tenant be entitle to any abatement of
rent while such work is in progress nor to any damages by reason of loss or
interruption of business or otherwise. Throughout the term hereof Owner shall
have the right to enter the demised premises at reasonable hours for the purpose
of showing the same to prospective purchasers or mortgagees of the building, and
during the last six months of the term for the purpose of showing the same to
prospective tenants and may, during said six month period, place upon

                                                                  Please Initial

                                                        Tenant:_________________
                                                        Landlord:_______________

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[CLIPART OMITTED] Rider to be added if necessary.

<PAGE>

the demised premises the usual notices "To Let" and "For Sale" which notices
Tenant shall permit to remain thereon without molestation. If Tenant is not
present to open and permit an entry into the demised premises, Owner or Owner's
agents may enter the same whenever such entry may be necessary or permissible by
master key or forcibly and provided reasonable care is exercised to safeguard
Tenant's property, such entry shall not render Owner or its agents liable
therefor, nor in any event shall the obligations of Tenant hereunder be
affected. If during the last month of the term Tenant shall have removed all or
substantially all of Tenant's property therefrom. Owner may immediately enter,
alter, renovate or redecorate the demised premises without limitation or
abatement of rent, or incurring liability to Tenant for any compensation and
such act shall have no effect on this lease or Tenant's obligation hereunder.

Vault, Vault Space, Area:

14. No Vaults, vault space or area, whether or not enclosed or covered, not
within the property line of the building is leased hereunder anything contained
in or indicated on any sketch, blue print or plan, or anything contained
elsewhere in this lease to the contrary notwithstanding. Owner makes no
representation as to the location of the property line of the building. All
vaults and vault space and all such areas not within the property line of the
building, which Tenant may be permitted to use and/or occupy, is to be used
and/or occupied under a revocable license, and if any such license be revoked,
or if the amount of such space or area be diminished or required by any federal,
state or municipal authority or public utility, Owner shall not be subject to
any liability nor shall Tenant be entitled to any compensation or diminution or
abatement of rent, nor shall such revocation, diminution or requisition be
deemed constructive or actual eviction. Any tax, fee or charge of municipal
authorities for such vault or area shall be paid by Tenant, if used by Tenant,
whether or not specifically leased hereunder.

Occupancy:

15. Tenant will not at any time use or occupy the demised premises in violation
of the certificate of occupancy issued for the building of which the demised
premises are a part. Tenant has inspected the premises and accepts them as is,
subject to the riders annexed hereto with respect to Owner's work, if any. In
any event, Owner makes no representation as to the condition of the premises and
Tenant agrees to accept the same subject to violations, whether or not of
record. If any governmental license or permit shall be required for the proper
and lawful conduct of Tenant's business, Tenant shall be responsible for and
shall procure and maintain such license or permit.

Bankruptcy:

16. (a) Anything elsewhere in this lease to the contrary notwithstanding, this
lease may be cancelled by Owner by sending of a written notice to Tenant within
a reasonable time after the happening of any one or more of the following
events: (1) the commencement of a case in bankruptcy or under the laws of any
state naming Tenant as the debtor; or (2) the making by Tenant of an assignment
or any other arrangement for the benefit of creditors under any state statute.
Neither Tenant nor any person claiming through or under Tenant, or by reason of
any statute or order of court, shall thereafter be entitled to possession of the
premises demised but shall forthwith quit and surrender the premises. If this
lease shall be assigned in accordance with its terms, the provisions of this
Article 16 shall be applicable only to the party then owning Tenant's interest
in this lease.

            (b) It is stipulated and agreed that in the event of the termination
of this lease pursuant to (a) hereof, Owner shall forthwith, not withstanding
any other provisions of this lease to the contrary, be entitled to recover from
Tenant as and for liquidated damages an amount equal to the difference between
the rental reserved hereunder for the unexpired portion of the term demised and
the fair and reasonable rental value of the demised premises for the same
period. In the computation of such damages the difference between any
installment of rent becoming due hereunder after the date of termination and the
fair and reasonable rental value of the demised premises for the period for
which such installment was payable shall be discounted to the date of
termination at the rate of four percent (4%) per annum. If such premises or any
part thereof be relet by the Owner for the unexpired term of said lease, or any
part thereof, before presentation of proof of such liquidated damages to any
court, commission or tribunal, the amount of rent reserved upon such reletting
shall be deemed to be the fair and reasonable rental value for the part or the
whole of the premises so re-let during the term of the re-letting. Nothing
herein contained shall limit or prejudice the right of the Owner to prove for
and obtain as liquidated damages by reason of such termination, an amount equal
to the maximum allowed by any statute or rule of law in effect at the time when,
and governing the proceedings in which, such damages are to be proved, whether
or not such amount be greater, equal to, or less than the amount of the
difference referred to above.

Default:

17. (1) If Tenant defaults in fulfilling any of the covenants of this lease
other than the covenants for the payment of rent or additional rent; "or if this
lease be rejected under ss.235 of Title 11 of the U.S. Code (bankruptcy code);"
or if any execution or attachment shall be issued against Tenant or any of
Tenant's property whereupon the demised premises shall be taken or occupied by
someone other than Tenant; or if Tenant shall make default with respect to any
other lease between Owner and Tenant; or if Tenant shall have failed, after five
(5) days written notice, to redeposit with Owner any portion of the security
deposited hereunder which Owner has applied to the payment of any rent and
additional rent due and payable hereunder or failed to move into or take
possession of the premises within thirty (30) days after the commencement of the
term of this lease, of which fact Owner shall be the sole judge; then in any one
or more of such events, upon Owner serving a written fifteen (15) days notice
upon Tenant specifying the nature of said default and upon the expiration of
said fifteen (15) days, if Tenant shall have failed to comply with or remedy
such default, or if the said default or omission complained of shall be of a
nature that the same cannot be completely cured or remedied within said fifteen
(15) day period, and if Tenant shall not have diligently commenced during such
default within such fifteen (15) day period, and shall not thereafter with
reasonable diligence and in good faith, proceed to remedy or cure such default,
then Owner may serve a written five (5) days' notice of cancellation of this
lease upon Tenant, and upon the expiration of said five (5) days this lease and
the term thereunder shall end and expire as fully and completely as if the
expiration of such five (5) day period were the day herein definitely fixed for
the end and expiration of this lease and the term thereof and Tenant shall then
quit and surrender the demised premises to Owner but Tenant shall remain liable
as hereinafter provided.

            (2) If the notice provided for in (1) hereof shall have been given,
and the term shall expire as aforesaid; or if Tenant shall make default in the
payment of the rent reserve herein or any item of additional rent herein
mentioned or any part of either or in making any other payment herein required;
then and in any of such events Owner may without notice, re-enter the demised
premises either by force or otherwise, and dispossess Tenant by summary
proceedings or otherwise, and the legal representative of Tenant or other
occupant of demised premises and remove their effects and hold the premises as
if this lease had not been made, and Tenant hereby waives the service of notice
of intention to re-enter or to institute legal proceedings to that end. If
Tenant shall make default hereunder prior to the date fixed as the commencement
of any renewal or extension of this lease, Owner may cancel and terminate such
renewal or extension agreement by written notice.

Remedies of Owner and Waiver of Redemption:

18. In case of any such default, re-entry, expiration and/or dispossess by
summary proceedings or otherwise, (a) the rent, and additional rent, shall
become due thereupon and be paid up to the time of such re-entry, dispossess
and/or expiration, (b) Owner may re-let the premises or any part or parts
thereof, either in the name of Owner or otherwise, for a term or terms, which
may at Owner's option be less than or exceed the period which would otherwise
have constituted the balance of the term of this lease and may grant concessions
or free rent or charge a higher rental than that in this lease, (c) Tenant or
the legal representatives of Tenant shall also pay Owner as liquidated damages
for the failure of Tenant to observe and perform said Tenant's covenants herein
contained, any deficiency between the rent hereby reserved and or covenanted to
be paid and the net amount, if any, of the rents collected on account of the
subsequent lease or leases of the demised premises for each month of the period
which would otherwise have constituted the balance of the term of this lease.
The failure of Owner to re-let the premises or any part or parts thereof shall
not release or affect Tenant's liability for damages. In computing such
liquidated damages there shall be added to the said deficiency such expenses as
Owner may reasonably incur in connection with re-letting, such as legal
expenses, reasonable attorneys' fees, brokerage, advertising and for keeping the
demised premises in good order or for preparing the same for re-letting. Any
such liquidated damages shall be paid in monthly installments by Tenant on the
rent day specified in this lease and any suit brought to collect the amount of
the deficiency for any month shall not prejudice in any way the rights of Owner
to collect the deficiency for any subsequent month by a similar proceedings.
Owner, in putting the demised premises in good order or preparing the same for
re-rental may, at Owner's option, make such alterations, repairs, replacements,
and/or decorations in the demised premises as Owner, in Owner's sole judgment,
considers advisable and necessary for the purpose of re-letting the demised
premises, and the making of such alterations, repairs, replacements, and/or
decorations shall not operate or be construed to release Tenant from liability
hereunder as aforesaid. Landlord shall advertise and list the availability of
the Demised Premises with real estate brokers. Owner shall in no event be liable
in any way whatsoever for failure to re-let the demised premises, or in the
event that the demised premises are re-let, for failure to collect the rent
thereof under such re-letting, and in no event shall Tenant be entitled to
receive any excess, if any, of such net rents collected over the sums payable by
Tenant to Owner hereunder. In the event of a breach or threatened breach by
Tenant of any of the covenants or provisions hereof, Owner shall have the right
of injunction and the right to invoke any remedy allowed at law or in equity as
if re-entry, summary proceedings and other remedies were not herein provided
for. Mention in this lease of any particular remedy, shall not preclude Owner
from any other remedy, in law or in equity. Tenant hereby expressly waives any
and all rights of redemption granted by or under any present or future laws.

Fees and Expenses:

19. If Tenant shall default in the observance or performance of any term or
covenant on Tenant's part to be observed or performed under or by virtue of any
of the terms or provisions in any article of this lease, after notice if
required and upon expiration of any applicable grace period if any, (except in
an emergency), then, unless otherwise provided elsewhere in this lease, Owner
may immediately or at any time thereafter and without notice perform the
obligations of Tenant thereunder. If Owner, in connection with the foregoing or
in connection with any default by Tenant in the covenant to pay rent hereunder,
makes any expenditures or incurs any obligations for the payment of money,
including but not limited to reasonable attorney's fees, in instituting,
prosecuting or defending any action or proceedings, and prevails in any such
action or proceeding, then Tenant will reimburse Owner for such sums so paid or
obligations incurred with interest and costs. The foregoing expenses incurred by
reason of Tenant's default shall be deemed to be additional rent hereunder and
shall be paid by Tenant to Owner within ten (10) days of rendition of any bill
or statement to Tenant therefor. If Tenant's lease term shall have expired at
the time of making of such expenditures or incurring of such obligations, such
sums shall be recoverable by Owner as damages.

Building Alterations and Management:

20. Owner shall have the right at any time without the same constituting an
eviction and without incurring liability to Tenant therefor to change the
arrangement and or location of public entrances, passageways, doors, doorways,
corridors, elevators, stairs, toilets or other public parts of the building and
to change the name, number or designation by which the building may be known.
There shall be no allowance to Tenant for diminution of rental value and no
liability on the part of Owner by reason of inconvenience, annoyance or injury
to business arising from Owner or other Tenant making any repairs in the
building or any such alterations, additions and improvements. Furthermore,
Tenant shall not have any claim against Owner my reason of Owner's imposition of
any controls of the manner of access to the building by Tenant's social or
business visitors as the Owner may deem necessary for the security of the
building and its occupants.

                                                                  Please Initial

                                                         Tenant_________________

                                                         Landlord_______________
<PAGE>

No Representations by Owner:

21. Neither Owner nor Owners agents have made any representations or promises
with respect to the physical condition of the building, the land upon which it
is erected or the demised premises, the rents, leases, expenses of operation or
any other matter or thing affecting or related to the demised premises or the
building except as herein expressly set forth and no rights, easements or
licenses are acquired by Tenant by implication or otherwise except as expressly
set forth in the provisions of this lease. Tenant has inspected the building and
the demised premises and is thoroughly acquainted with their condition and
agrees to take the same "as is" on the date possession is tendered and
acknowledges that the taking of possession of the demised premises by Tenant
shall be conclusive evidence that the said premises and the building of which
the same form a part were in good and satisfactory condition at the time such
possession was so taken, except as to latent defects. All understandings and
agreements heretofore made between the parties hereto are merged in this
contract, which alone fully and completely expresses the agreement between Owner
and Tenant and any executory agreement hereafter made shall be ineffective to
change, modify, discharge or effect an abandonment of it in whole or in part,
unless such executory agreement is in writing and signed by the party against
whom enforcement of the change, modification, discharge or abandonment is
sought.

End of Term:

22. Upon the expiration or other termination of the term of this lease, Tenant
shall quit and surrender to Owner the demised premises, broom clean, in good
order and condition, ordinary wear and damages which Tenant is not required to
repair as provided elsewhere in this lease excepted, and Tenant shall remove all
its property from the demised premises. Tenant's obligation to observe or
perform this covenant shall survive the expiration or other termination of this
lease. If the last day of the term of this Lease or any renewal thereof, falls
on Sunday, this lease shall expire at noon on the preceding Saturday unless it
be a legal holiday in which case it shall expire at noon on the preceding
business day.

Quiet Enjoyment:

23. Owner covenants and agrees with Tenant that upon Tenant paying the rent and
additional rent and observing and performing all the terms, covenants and
conditions, on Tenant's part to be observed and performed, Tenant may peaceably
and quietly enjoy the premises hereby demised, subject, nevertheless, to the
terms and conditions of this lease including, but not limited to, Article 34
hereof and to the ground leases, underlying leases and mortgages hereinbefore
mentioned.

Failure to Give Possession:

24. If Owner is unable to give possession of the demised premises on the date of
the commencement of the term hereof, because of the holding-over or retention of
possession of any Tenant, undertenant or occupants or if the demised premises
are located in a building being constructed, because such building has not been
sufficiently completed to make the premises ready for occupancy or because of
the fact that a certificate of occupancy has not been procured or if Owner has
not completed any work required to be performed by Owner, or for any other
reason, Owner shall not be subject to any liability for failure to give
possession on said date and the validity of the lease shall not be unpaired
under such circumstances, nor shall the same be construed in any wise to extend
the term of this lease, but the rent payable hereunder shall be abated (provided
Tenant is not responsible for Owner's inability to obtain possession or complete
any work required) until after Owner shall have given Tenant notice that Owner
is able to deliver possession in the condition required by this lease. If
permission is given to Tenant to enter into the possession of the demised
premises or to occupy premises other than the demised premises prior to time
date specified as the commencement of the term of this lease, Tenant covenants
and agrees that such possession and/or occupancy shall be deemed to be under all
the terms, covenants, conditions and provisions of this lease, except the
obligation to pay the fixed annual rent set forth in page one of this lease. The
provisions of this article are intended to constitute "an express provision to
the contrary" within the meaning of Section 223-a of the New York Real Property
law.

No Waiver:

25. The failure of Owner to seek redress for violation of, or to insist upon the
strict performance of any covenant or condition of this lease or of any of the
Rules or Regulations, set forth or hereafter adopted by Owner, shall not prevent
a subsequent act which would have originally constituted a violation from having
all the force and effect of the original violation. The receipt by Owner of rent
with knowledge of the breach of any covenant of this lease shall not be deemed a
waiver of such breach and no provision of this lease shall be deemed to have
been waived by Owner unless such waiver be in writing signed by Owner. No
payment by Tenant on receipt by Owner of a lesser amount than the monthly rent
herein stipulated shall be deemed to be other than on account of the earliest
stipulated rent, nor shall any endorsement or statement of any check or any
letter accompanying any check or payment as rent be deemed an accord and
satisfaction, and Owner may accept such check or payment without prejudice to
Owner's right to recover the balance of such rent or pursue any other remedy in
this lease provided. All checks tendered to Owner as and for the rent of the
demised premises shall be deemed payments for the account of Tenant. Acceptance
by Owner of rent from anyone other than Tenant shall not be deemed to operate as
an attornment to Owner by the payor of such rent or as a consent by Owner to any
assignment or subletting by Tenant of the demised premises to such payor, or as
a modification of the provisions of this lease. No act or thing done by Owner or
Owner's agents during the term hereby demised shall be deemed an acceptance of a
surrender of said premises and no agreement to accept such surrender shall be
valid unless in writing signed by Owner. No employee of Owner or Owner's agent
shall have any power to accept the keys of said premises prior to the
termination of the lease and the delivery of keys to any such agent or employee
shall not operate as a termination of the lease or a surrender of the premises.

Waiver of Trial by Jury:

26. It is mutually agreed by and between Owner and Tenant that the respective
parties hereto shall and they hereby do waive trial by jury in any action,
proceeding or counterclaim brought by either of the parties thereto against the
other (except for personal injury or property damage) on any matters whatsoever
arising out of or in any way connected with this lease, the relationship of
Owner and Tenant, Tenant's use of or occupancy of said premises, and any
emergency statutory or any other statutory remedy. It is further mutually agreed
that in the event Owner commences any proceeding or action for possession
including a summary proceeding for possession of the premises, Tenant will not
interpose any counterclaim of whatever nature or description in any such
proceeding including a counterclaim under Article 4 except for statutory
mandatory counterclaims.

Inability to Perform:

27. This Lease and the obligation of both parties (except for the obligation of
Tenant to pay rent hereunder) to perform all of the covenants and agreements
hereunder on part of either party to be performed shall in no wise be affected,
impaired or excused because either party is unable to fulfill any of its
obligations under this lease or to supply or is unable to make, or is delayed in
making any repair, additions, alterations or decorations or is unable to supply
or is delayed in supplying any equipment, fixtures or other materials if either
party is prevented or delayed from doing so by reason of strike or labor
troubles or any cause whatsoever beyond either party's sole control including,
but not limited to, government preemption or restrictions or by reason of any
rule, order or regulation of any department or subdivision thereof of any
government agency or by reasons of the conditions which have been or are
affected, either directly or indirectly, by war or other emergency.

Bills and Notices:

28. Except as otherwise in this lease provided, a bill statement, notice or
communication which Owner may desire or be required to give to Tenant, shall be
deemed sufficiently given or rendered if, in writing, delivered to Tenant
personally or sent by registered or certified mail addressed to Tenant at the
building of which the demised premises form a part or at the last known
residence address or business address of Tenant or left at any of the aforesaid
premises addressed to Tenant, and the time of the rendition of such bill or
statement and of the giving of such notice or communication shall be deemed to
be the time when the same is delivered to Tenant, mailed, or left at the
premises as herein provided. Any notice by Tenant to Owner must be served by
registered or certified mail addressed to Owner at the address first hereinabove
given or at such other address as Owner shall designate by written notice.

Water Charges:

29. It Tenant requires, uses or consumes water for any purpose in addition to
ordinary lavatory purposes (of which fact Tenant constitutes Owner to be the
sole judge) Owner may install a water meter and thereby measure Tenant's water
consumption for all purposes. Tenant shall pay Owner for the cost of the meter
and the cost of the installation, thereof and throughout the duration of
Tenant's occupancy Tenant shall keep said meter and installation equipment in
good working order and repair at Tenant's own cost and expense in default of
which Owner may cause such meter and equipment to be replaced or repaired and
collect the cost thereof from Tenant, as additional rent. Tenant agrees to pay
for water consumed, as shown on said meter as and when bills are rendered, and
on default in making such payment Owner may pay such charges and collect the
same from Tenant, as additional rent. Tenant covenants and agrees to pay, as
additional rent, the sewer rent, charge or any other tax, rent, levy or charge
which now or hereafter is assessed, imposed or a lien upon the demised premises
or the realty of which they are part pursuant to law, order or regulation made
or issued in connection with the use, consumption, maintenance or supply of
water, water system or sewage or sewage connection or system. If the building or
the demised premises or any part there is supplied with water through a meter
through which water is also supplied to other premises Tenant shall pay to
Owner, as additional rent, on the first day of each month, [CLIP ART OMITTED] %
($[CLIP ART OMITTED]) of the total meter charges as Tenant's portion.
Independently of and in addition to any of the remedies reserved to Owner
hereinabove or elsewhere in this lease, Owner may sue for and collect any monies
to be paid by Tenant or paid by Owner for any of the reasons or purposes
hereinabove set forth.

Sprinklers:

30. Anything elsewhere in this lease to the contrary notwithstanding, if the New
York Board of Fire Underwriters or the New York Fire Insurance Exchange or any
bureau, department or official office federal, state or city government
recommend or require the installation of a sprinkler system or that any changes,
modifications, alterations, or additional sprinkler heads or other equipment be
made or supplied in an existing sprinkler system by reason of Tenant's business,
or the location of partitions, trade fixtures, or other contents of the demised
premises, or for any other reason, or if any such sprinkler system
installations, modifications, alterations, additional sprinkler heads or other
such equipment, become necessary to prevent the imposition of a penalty or
charge against the full allowance for a sprinkler system in fire insurance rate
set by any said Exchange or by any fire insurance company, Tenant shall, at
Tenant's expense, promptly make such sprinkler system installations, changes,
modifications, alterations, and supply additional sprinkler heads or other
equipment as required whether the work involved shall be structural or
non-structural in nature. Tenant shall pay to Owner as additional rent the sum
$[CLIP ART OMITTED], of on the first day of each month during the term of this
lease, as Tenant's portion of the contract price for sprinkler supervisory
service.

Elevators, Heat, Cleaning:

31. Owner shall: (a) provide necessary passenger elevator facilities on business
days from 8 a.m to 6 p.m. and on Saturday from 8 a.m. to 1 p.m.: and have at
least one passenger elevator available twenty four hours a day, seven days a
week; (b) if freight elevator service is provided, same shall be provided only
on regular business days Monday through Friday inclusive, and on those days only
between the hours of 9 a.m. and 12 noon and between 1 p.m. and 5 p.m.; (c)
furnish heat, water and other services supplied by Owner to the demised
premises, when and as required by law, on business days from 8 a.m. t 6 p.m. and
on Saturdays from 8

                                                                  Please Initial

                                                         Tenant_________________

                                                         Landlord_______________

----------
[CLIP ART OMITTED] Space to be filled in or deleted.

<PAGE>

a.m. to p.m.; (d) clean the public halls and pubic portions of the building
which are used in common by all tenants. Tenant shall, at Tenant's expense, keep
the demised premises, including the windows, clean and in order, to the
reasonable satisfaction of Owner, and for that purpose shall employ the person
or persons, or corporation approved by Owner. Tenant shall pay to Owner the cost
of removal of any of Tenant's refuse and rubbish from the building. Bills for
the same shall be rendered by Owner to Tenant at such time as Owner may elect
and shall be due and payable hereunder, and the amount of such bills shall be
deemed to be, and be paid as, additional rent. Tenant shall, however, have the
option of independently contracting for the removal of such rubbish and refuse
in the event that Tenant does not wish to have same done by employees of Owner.
Under such circumstances, however, the removal of such refuse and rubbish by
others shall he subject to such rules and regulations as, in the judgment of
Owner, are necessary for the proper operation of the building. Owner reserves
the right to stop service of the heating, elevator, plumbing and electric
systems, when necessary, by reason of accident, or emergency, or for repairs,
alterations, replacements or improvements, in the judgment of Owner desirable or
necessary to be made, until said repairs, alterations, replacements or
improvements shall have been completed. If the building of which the demised
premises are a part supplies manually operated elevator service, Owner may
proceed diligently with alterations necessary to substitute automatic control
elevator service without in any way affecting the obligations of Tenant
hereunder.

Security:

32. Tenant has deposited with Owner the sum of $154,445.50 as security for the
faithful performance and observance by Tenant of the terms, provisions and
conditions of this lease; it is agreed that in the event Tenant defaults in
respect of any of the terms, provisions and conditions of this lease, including,
but not limited to, the payment of rent and additional rent, Owner may use,
apply or retain the whole or any part of the security so deposited to the extent
required for the payment of any rent and additional rent or any other sum as to
which Tenant is in default or for any sum which Owner may expend or may be
required to expend by reason of Tenant's default in respect of any of the terms,
covenants and conditions of this lease, including but not limited to, any
damages or deficiency in the reletting of the premises, whether such damages or
deficiency accrued before or after summary proceedings or other re-entry by
Owner. In the event that Tenant shall fully and faithfully comply with all the
terms, provisions, covenants and conditions of this lease, the security shall be
returned to Tenant after the date fixed as the end of the Lease and after
delivery of entire possession of the demised premises to Owner. In the event of
a sale of the land and building or leasing of the building, of which the demised
premises form a part, Owner shall have the right to transfer the security to the
vendee or lessee and Owner shall thereupon be released by Tenant from all
liability for the return of such security; and Tenant agrees to look to the new
Owner solely for the return of said security, and it is agreed that the
provisions hereof shall apply to every transfer or assignment made of the
security to a new Owner. Tenant further covenants that it will not assign or
encumber or attempt to assign or encumber the monies deposited herein as
security and that neither Owner nor its successors or assigns shall be bound by
any such assignment, encumbrance, attempted assignment or attempted encumbrance
-- See Article 79

Captions:

33. The Captions are inserted only as a matter of convenience and for reference
and in no way define, limit or describe the scope of this lease nor the intent
of any provision thereof.

Definitions:

34. The term "Owner" as used in this lease means only the owner of the fee or of
the leasehold of the building, or the mortgagee in possession, for the time
being of the land and building (or the owner of a lease of the building or of
the land and building) of which the demised premises form a part, so that in the
event of any sale or sales of said land and building or of said lease, or in the
event of a lease of said building, or of the land and building, the said Owner
shall be and hereby is entirely freed and relieved of all covenants and
obligations of Owner hereunder, and it shall be deemed and construed without
further agreement between the parties or their successors in interest, or
between the parties and the purchaser, at any such sale, or the said lessee of
the building, or of the land and building, that the purchaser or the lessee of
the building has assumed and agreed to carry out any and all covenants and
obligations of Owner hereunder. The words "re-enter" and "re-entry" as used in
this lease are not restricted to their technical legal meaning. The term "rent"
includes the annual rental rate whether so expressed or expressed in monthly
installments, and "additional rent." "Additional rent" means all sums which
shall be due to Owner from Tenant under this lease, in addition to the annual
rental rate. The term "business days" as used in this lese, shall exclude
Saturdays, Sundays and all days observed by the State or Federal Government as
legal holidays and those designated as holidays by the applicable building
service union employees service contract or by the applicable building service
union employees service contract or by the applicable Operating Engineers
contract with respect to HVAC service. Wherever it is expressly provided in this
lease that consent shall not be unreasonably withheld, such consent shall not be
unreasonably delayed.

Adjacent Excavation-Shoring:

35. If an excavation shall be made upon land adjacent to the demised premises,
or shall be authorized to be made, Tenant shall afford to the person causing or
authorized to cause such excavation, license to enter upon the demised premises
for the purpose of doing such work as said person shall deem necessary to
preserve the wall or the building of which demised premises form a part from
injury or damage and to support the same by proper foundations without any claim
for damages or indemnity against Owner, or diminution or abatement of rent.

Rules and Regulations:

36. Tenant and Tenant's servants, employees, agents, visitors, and licensees
shall observe faithfully, and comply strictly with, the Rules and Regulations
annexed hereto and such other and further reasonable Rules and Regulations as
Owner or Owner's agents may from time to time adopt. Notice of any additional
rules or regulations shall be given in such manner as Owner may elect. In case
Tenant disputes the reasonableness of any additional Rule or Regulation
hereafter made or adopted by Owner or Owner's agents, the parties hereto agree
to submit the question of the reasonableness of such Rule or Regulation for
decision to the New York office of the American Arbitration Association, whose
determination shall be final and conclusive upon the parties hereto. The right
to dispute the reasonableness of any additional Rule or Regulation upon Tenant's
part shall be deemed waived unless the same shall be asserted by service of a
notice, in writing upon Owner within fifteen (15) days after the giving of
notice thereof. Nothing in this lease contained shall be construed to impose
upon Owner any duty or obligation to enforce the Rules and Regulations or terms,
covenants or conditions in any other lease, as against any other tenant and
Owner shall not be liable to Tenant for violation of the same by any other
tenant, its servants, employees, agents, visitors or licensees.

Glass:

37: Owner shall replace, at the expense of the Tenant (unless caused by the
negligence or willful acts of Landlord, its agents, employees or contractors, in
which event same shall be performed at Landlord's sole cost and expense) any and
all plate and other glass damaged or broken from any cause whatsoever in and
about the demised premises. Owner may insure, and keep insured, at Tenant's
expense, all plate and other glass in the demised premises for and in the name
of Owner. Bills for the premiums therefor shall be rendered by Owner to Tenant
at such times as Owner may elect, and shall be due from, and payable by, Tenant
when rendered, and the amount thereof shall be deemed to be, and be paid, as
additional rent.

Estoppel Certificate:

38. Tenant, at arty time, and from time to time, upon at least 10 days' prior
notice by Owner, shall execute, acknowledge and deliver to Owner, and/or to any
other person, firm or corporation specified by Owner, a statement certifying
that this Lease is unmodified in full force and effect (or, if there have been
modifications, that the same is in full force and effect as modified and stating
the modifications), stating the dates to which the rent and additional rent have
been paid, and stating whether or not there exists any default by Owner under
this Lease, and, if so, specifying each such default.

Directory Board Listing:

39. If, at the request of and as accommodation to Tenant, Owner shall place upon
the directory board in the lobby of the building, one or more names of persons
other than Tenant, such directory board listing shall not be construed as the
consent by Owner to an assignment or subletting by Tenant to such person or
persons.

Successors and Assigns:

40. The covenants, conditions and agreements contained in this lease shall bind
and inure to the benefit of Owner and Tenant and their respective heirs,
distributees, executors, administrators, successors, and except as heirs,
distributees, executors, administrators, successors, and except as otherwise
provided in this lease, their assigns. Tenant shall look only to Owner's estate
and interest in the land and building for the satisfaction of Tenant's remedies
for the collection of a judgement (or other judicial process) against Owner in
the event of any default by Owner hereunder, and no other property or assets of
such Owner (or any partner, member, officer or director thereof, disclosed or
undisclosed), shall be subject to levy, execution or other enforcement procedure
for the satisfaction of Tenant's remedies under or with respect to this lease,
the relationship of Owner and Tenant hereunder, or Tenant's use and occupancy
of the demised premises.

                SEE RIDER ATTACHED HERETO AND MADE A PART HEREOF

In Witness Whereof, Owner and Tenant have respectively signed and sealed this
lease as of the day and year first above written.


                            180 VARICK STREET CORPORATION     [CORP. SEAL]
Witness for Owner:          -------------------------------

                            By:                               [L.S]
------------------------    -------------------------------
                                 Vice President

Witness for Tenant          IMCLONE SYSTEMS, INCORPORATED     [CORP. SEAL]

                            By:                               [L.S]
------------------------    -------------------------------

                                                                  Please Initial

                                                         Tenant_________________

                                                         Landlord_______________

<PAGE>

                                ACKNOWLEDGEMENTS

CORPORATE TENANT
STATE OF NEW YORK,       ss.:
County of


      On this          day of          , 19    , before me personally came
to me known, who being by me duly sworn, did depose and say that he resides in
                                                                    that he is 
the                                           of                           the 
corporation described in and which executed the foregoing instrument, as TENANT;
that he knows the seal of said corporation; that the seal affixed to said
instrument is such corporate seal; that it was so affixed by order of the Board
of Directors of said corporation, and that he signed his name thereto by like
order.

                                ------------------------------------------------

INDIVIDUAL TENANT
STATE OF NEW YORK,       ss.:
County of

      On this          day of          , 19    , before me personally came
to be known and known to me to be the individual described in and who, as
TENANT, executed the foregoing instrument and acknowledged to me that 
              he executed the same.

                                ------------------------------------------------

           [CLIPART OMITTED] IMPORTANT - PLEASE READ [CLIPART OMITTED]

                      RULES AND REGULATIONS ATTACHED TO AND
                               MADE A PART OF THIS
                      LEASE IN ACCORDANCE WITH ARTICLE 36.

      1. The sidewalks, entrances, driveways, passages, courts, elevators,
vestibules, stairways, corridors or halls shall not be obstructed or encumbered
by any Tenant or used for any purpose other than for ingress or egress from the
demised premises and for delivery of merchandise and equipment in a prompt and
efficient manner using elevators and passageways designated for such delivery by
Owner. There shall not be used in any space, or in the public hall of the
building, either by any Tenant or by jobbers or others in the delivery or
receipt of merchandise, any hand trucks, except those equipped with rubber tires
and sideguards. If said premises are situated on the ground floor of the
building, Tenant thereof shall further, at Tenant's expense, keep the sidewalk
and curb in front of said premises clean and free from ice, snow, dirt and
rubbish.

      2. The water and wash closets and plumbing fixtures shall not be used for
any purposes other than those for which they were designed or constructed and no
sweepings, rubbish, rags, acids or other substances shall be deposited therein,
and the expense of any breakage, stoppage, or damage resulting from the
violation of this rule shall be borne by the Tenant who, or whose clerks,
agents, employees or visitors, shall have caused it.

      3. No carpet, rug or other article shall be hung or shaken out of any
window of the building; and no Tenant shall sweep or throw or permit to be swept
or thrown from the demised premises any dirt or other substances into any of the
corridors of halls, elevators, or out of the doors or windows or stairways of
the building and Tenant shall not use, keep or permit to be used or kept any
foul or noxious gas or substance in the demised premises, or permit or suffer
the demised premises to be occupied or used in a manner offensive or
objectionable to Owner or other occupants of the buildings by reason of noise,
odors, and or vibrations, or interfere in any way, with other Tenants or those
having business therein, nor shall any bicycles, vehicles, animals, fish, or
birds be kept in or about the building. Smoking or carrying lighted cigars or
cigarettes in the elevators of the building is prohibited.

      4. No awnings or other projections shall be attached to the outside walls
of the building without the prior written consent of Owner.

      5. No sign, advertisement, notice or other lettering shall be exhibited,
inscribed, painted or affixed by any Tenant on any part of the outside of the
demised premises or the building or on the inside of the demised premises if the
same as visible from the outside of the premises without the prior written
consent of Owner, except that the name of Tenant may appear on the entrance door
of the premises. In the event of the violation of the foregoing by any Tenant,
Owner may remove same without any liability and may charge the expense incurred
by such removal to Tenant or Tenants violating this rule. Interior signs on
doors and directory tablet shall the inscribed, painted or affixed for each
Tenant by Owner at the expense of such Tenant, and shall be of a size, color and
style acceptable to Owner.

      6. No Tenant shall mark, paint, drill into, or in any way deface any part
of the demised premises or the building of which they form a part. No boring,
cutting or stringing of wires shall be permitted, except with the prior written
consent of Owner, and as Owner may direct. No Tenant shall lay linoleum, or
other similar floor covering, so that the same shall come in direct contact with
the floor of the demised premises, and, if linoleum or other similar floor
covering is desired to be used an interlining of builder's deadening felt shall
be first affixed to the floor, by a paste or other material, soluble in water,
the use of cement or other similar adhesive material being expressly prohibited.

      7. No additional locks or bolts of any kind shall be placed upon any of
the doors or windows by any Tenant, nor shall any changes be made in existing
locks or mechanism thereof. Each Tenant must, upon the termination of his
Tenancy, restore to Owner all keys of stores, offices and toilet rooms, either
furnished to, or otherwise procured by, such Tenant, and in the event of the
loss of any keys, so furnished, such Tenant shall pay to Owner the cost thereof.

      8. Freight, furniture, business equipment. merchandise and bulky matter of
any description shall be delivered to and removed from the premises only on the
freight elevators and through the service entrances and corridors, and only
during hours and in a manner approved by Owner. Owner reserves the right to
inspect all freight to be brought into the building and to exclude from the
building all freight which violates any of these Rules and Regulations of the
lease of which these Rules and Regulations are a part.

      9. No Tenant shall obtain for use upon the demised premises ice, drinking
water, towel and other similar services, or accept barbering or bootblacking
services in the demised premises, except from persons authorized by Owner, and
at hours and under regulations fixed by Owner. Canvassing, soliciting and
peddling in the building is prohibited and each Tenant shall cooperate to
prevent the same.

      10. Owner reserves the right to exclude from the building all persons who
do not present a pass to the building signed by Owner. Owner will furnish passes
to persons for whom any Tenant requests same in writing. Each Tenant shall be
responsible for all persons for whom he requests such pass and shall be liable
to Owner for all acts of such persons. Notwithstanding the foregoing, Owner
shall not be required to allow Tenant or any person to enter or remain in the
building, except on business days from 8:00 a.m. to 6:00 p.m. and on Saturdays
from 8:00 a.m. to 1:00 p.m. Tenant shall not have a claim against Owner by
reason of Owner excluding from the building any person who does not present such
pass.

      11. Owner shall have the right to prohibit any advertising by any Tenant
which in Owner's opinion, tends to impair the reputation of the building or its
desirability as a loft building, and upon written notice from Owner, Tenant
shall refrain from or discontinue such advertising.

      12. Tenant shall not bring or permit to be brought or kept in or on the
demised premises, any inflammable, combustible, or explosive, or hazardous
fluid, material, chemical or substance, or cause or permit any odors or cooking
or other processes, or any unusual or other objectionable odors to permeate in
or emanate from the demised premises.

      13. Tenant shall not use the demised premises in a manner which disturbs
or interferes with other Tenants in the beneficial use of their premises.

Address        180 Varick Street
Premises       Entire 6th and 7th floors
================================================================================

                         180 VARICK STREET CORPORATION

                                       TO

                          IMCLONE SYSTEMS INCORPORATED

================================================================================

                                STANDARD FORM OF

                               [SEAL] LOFT [SEAL]
                                      LEASE

                    The Real Estate Board of New York, Inc.

                    (c) Copyright 1994. All rights Reserved.
                  Reproduction in whole or in part prohibited.

================================================================================

Dated                        December 10, 1998

Rent Per Year
                             See Article 41 (a)(i)

Rent Per Month
                             See Article 41 (a) (i)

Term      six (6) years
From      January 1, 1999
To        December 31, 2004

Drawn by
        ------------------------------------------------------------------------
Checked by
          ----------------------------------------------------------------------
Entered by
          ----------------------------------------------------------------------
Approved by
           ---------------------------------------------------------------------

================================================================================

<PAGE>

                                                                      LS-131/177

RIDER AGREEMENT:

To be attached to and form a part of:

Lease dated December 15, 1998 Premises Entire 6th and 7th floors between 180
Varick Street Corporation c/o Olmstead Properties, Inc. 575 Eighth Avenue, NY,
NY 10018 as Landlord and Imclone Systems Incorporated, 180 Varick Street, New
York, New York 10014 as Tenant

At the commencement of the term hereof electric current shall be supplied to
Tenant at the demised premises in accordance with the provisions of clause A or
B or F of this Article, subject to the other terms and conditions of this
Article and lease. A. Submetering If electric current be supplied by Landlord,
at Landlord's option, pursuant to this clause , Tenant covenants and agrees to
purchase the same from Landlord or Landlord's designated agent, at charges,
taxes, terms and rates set by Landlord from time to time but, except as
hereinafter set forth, not more than those specified in Service Classification
No. 4 on September 7, 1970, that being the date immediately prior to which the
rates of Consolidated Edison Company of New York, Inc. were adjusted and
consolidated with respect to redistribution of electric current to commercial
buildings. Such charges, taxes, terms and rates may be revised by Landlord, at
it option, from time to time, in the same proportion as any increases after the
aforesaid date in the charges, taxes, terms or rates to Landlord in connection
with the supply of electric current to the building of which the demised
premises are a part (hereinafter referred to as the "building"). When more than
one meter measures the electric service to the demised premises, the services
rendered through each meter shall be separately computed and billed in
accordance with the charges, taxes, terms and rates stated herein. Bills shall
be rendered at such times as Landlord may elect and, commencing on the earlier
of (i) Tenant's occupancy of all or any portions of the demised premises, or
(ii) the commencement date of the term of this lease, the amounts as computed
from meter readings shall be deemed to be, and be paid as, additional rent
without set-off or deduction. B. Rent Inclusion - If electric current be
supplied by Landlord, at Landlord's option, pursuant to this clause, Tenant
covenants and agrees to have it supplied to Tenant at the demised premises based
on the method of including the use thereof within the annual rent and the annual
rent reserved herein shall be increased as hereinafter set forth, in
consideration of Landlord supplying electric current as an additional service as
hereinafter provided. At any time after Tenant is in possession of the demised
premises, a reputable electrical consultant selected by Landlord shall (but, if
this lease be a renewal or shall subsequently be extended, or if an electric
rent inclusion modification agreement is being executed in connection with this
lease, Landlord shall have the option, but not the obligation to) make a survey
of the electrical equipment, usage and powerload to ascertain the electric
current consumption and demand in the demised premises on an annual basis, and
calculate the annual rent increase resulting therefrom utilizing charges, taxes,
terms and rates as set by Landlord from time to time, but, except as hereinafter
set forth not more than those specified in Service Classification No. 2 on
September 7, 1970, that being the date immediately prior to which the rates of
Consolidated Edison Company of New York, Inc. were adjusted and consolidated
with respect to redistribution of electric current to commercial buildings. Such
charges, taxes, terms and rates may be revised by Landlord, at its option, from
time to time, in the same proportion as any increases after the aforesaid date
in the charges, taxes, terms or rates to Landlord in connection with the supply
of electric current to building. Following the making any such survey, the
parties shall execute an agreement prepared by Landlord amending this lease and
setting forth the increase in annual rent calculated as aforesaid, as of the
date of the commencement the furnishing of electric current to the demised
premises pursuant to this clause B, but such increase shall be effective from
that date even if such agreement is not executed. Landlord, its agent or
consultant, is given the right make surveys, from time to time, in the demised
premises covering the electric equipment and use of electric current. If, after
the date of such initial survey (or if subdivision "(i)" or "(ii)" above is
applicable, after the date on which the annual rent payable by Tenant was last
increased in consideration of Landlord supplying electric current to the demised
premises) there are any additions to or increases in (i) the equipment or usage
in the demised premises, or (ii) in the charges, terms and/or rates to Landlord
by the public utility corporation supplying electric current to the building, or
(iii) in any taxes thereon which Landlord is obligated to pay, or (iv) if Tenant
shall regularly remain open for business other than during those hours
incorporated in any prior electric survey, then, and in any such instance or
instances, the annual rent served herein shall be further increased in
accordance with the provisions of this Article to reflect such additions,
increases or additional use as of the effective date thereof. If Landlord and
Tenant cannot agree on the amount of any such increase, as hereinbefore
described, the same shall be determined by a reputable electric consultant
selected by the Landlord and paid equally by both parties. The parties shall
then execute an agreement prepared by Landlord amending this lease and setting
forth the new annual rent resulting from such increase and confirming the
effective date thereof, but such increase shall be effective from such date even
if such agreement is not executed. C. Landlord shall not in any way be liable or
responsible to Tenant for any loss or damage or expense which Tenant may sustain
or incur if either the quantity or character of electric service is changed or
is no longer available or suitable for Tenant's requirements. Tenant's use of
electric current in the demised premises shall not at any time exceed the
capacity of any of the electrical conductors and facilities in or otherwise
serving the demised premises. In order to insure that such capacity is not
exceeded and to avert any possible adverse effect upon the building's electric
service, Tenant shall not, without Landlord's prior written consent in each
instance, connect any fixtures, appliances of equipment (other than a reasonable
number of table or floor [ILLEGIBLE], typewriters and similar small office
machines using comparable electric current) to the building's electric
distribution system [ILLEGIBLE]make any alteration or addition to the electric
system of the demised premises. Should Landlord grant such consent, all
additional [ILLEGIBLE]or other equipment required therefor shall be provided by
Landlord, and all costs and expenses in connection therewith, including, without
limitation, those for filing and supervision, shall be paid by Tenant upon
Landlord's demand, as additional rent, without setoff or deduction. As a
condition to granting such consent, Landlord may require Tenant to agree to an
increase in the annual rent by any amount which will reflect the value to Tenant
of the additional service to be furnished by Landlord, to wit: the potential
additional electric current to be made available to Tenant based upon the
estimated initial total capacity of such additional [ILLEGIBLE] or other
equipment. If Landlord and Tenant cannot agree on the amount of such annual rent
increase, the same shall be determined by a reputable electrical consultant, to
be selected by Landlord and paid equally by both parties. The parties shall then
execute an agreement prepared by Landlord amending this lease and setting forth
the new annual rent resulting from such increase and confirming the effective
date thereof, but such increase shall be effective from such date even if such
agreement is not executed. E. Landlord reserves the right to discontinue
furnishing electric current to Tenant in the demised premises at any time upon
not less than thirty (30) days' notice to Tenant. F. If Landlord, at Landlord's
option, (i) exercises such right of discontinuance as provided in clause E, or
(ii) requires Tenant to initially obtain its electric current directly from the
public utility corporation supplying electric current to the building, this
lease shall continue in full force and effect and shall be unaffected thereby,
except only that, from and after the effective date of such discontinuance, or
the commencement of direct usage, as the case may be, Landlord shall not be
obligated to furnish electric current to Tenant and except that, if Landlord
shall have been furnishing electric current on a rent inclusion basis, from and
after the effective date of such discontinuance, the annual rent payable under
this lease shall be reduced by an amount equal to the aggregate amount of all
increases to the annual rent reserved herein pursuant to clause B of this
Article. In either aforesaid event, if Landlord is not to furnish electric
current to Tenant, Tenant shall arrange to obtain electric current directly from
the public utility corporation supplying electric current to the building; and
in any event, all risers, equipment and other facilities which may be required
for Tenant to obtain electric current directly form such public utility
corporation shall, at Tenant's expense, payable to Landlord upon demand, as
additional rent, without [ILLEGIBLE] or deduction, be installed by Landlord, if
in Landlord's judgment the same are necessary and will not cause damage or
injury to the building or any part thereof or create a hazardous condition or
entail excessive alterations, repairs or expense or [ILLEGIBLE] with or


<PAGE>

      (CONTINUED)

disturb any other building tenants or occupants; and in nay event, any such
installation shall be maintained by Tenant, at its expense, and shall be subject
to such conditions as Landlord and/or the public utility corporation may
require. If Landlord shall not furnish electric current to Tenant, it shall not
be liable to Tenant therefor and the same shall not be deemed to be a lessening
or diminution of services within the meaning of any law, rule or regulation now
or hereafter enacted, promulgated or issued. G. If any taxes or charges are or
shall be imposed upon Landlord or its agent in connection with the sale or
resale of electrical energy to Tenant, Tenant covenants and agrees that, where
permitted by law, Tenant's pro-rata share of such taxes or charges shall be
passed on to Tenant and paid by Tenant to Landlord or its agents upon demand, as
additional rent, without set-off or deduction. At all times during the term of
this lease Tenant will comply with all present and future General Rules,
Regulations, Terms and Conditions applicable to service equipment, wiring and
Requirements in accordance with the regulations of the public utility
corporation supplying electric current to the building. H. In the event that any
increased or additional rent under this article is not paid within 30 days after
a bill is rendered, Landlord may, upon at least ten (10) days' prior written
notice to Tenant without further notice and without waiving its rights to any
other remedy or remedies it may have, discontinue the service of electric
current to the demised premises without releasing Tenant by such discontinuance
of service. I. Tenant covenants and agrees that at no time will the connected
electrical load for any one full or partial floor of the demises premises exceed
6 watts per square foot of usable area unless the rent has been increased
pursuant to this Article to reflect the additional load. J. It is agreed that
Landlord, from time to time may change the method of supplying electric current
to Tenant at the demised premises in any manner referred to in this lease or
otherwise, provided that in so doing Landlord shall comply with all applicable
laws.

Notwithstanding anything to the contrary contained herein, Tenant shall be
charged for the electricity consumed by it for the Demised Premises based upon
the then current Service Classification, billed by the Utility Company servicing
the property, which is commensurate with Tenant's level of usage (including all
taxes, charges, terms, rates and other fees associated with Landlord providing
electrical service), plus fifteen percent (15%). Such taxes, charges, terms and
rates to Landlord in connection with the supply of electric current to the
Building of which the Demised Premises are a part, will be used in the
calculation of the Tenant billing.

Anything contained in subparagraph C hereof to the contrary notwithstanding,
Tenant, within twenty (20) days after receipt of the determination of Landlord's
electric consultant, may contest, at Tenant's sole cost and expense, the results
thereof by retaining a reputable electrical engineer or consultant to make a
survey of the electrical equipment, usage and powerload to ascertain the
electric current consumption and demand in the Demised Premises on an annual
basis, and to calculate the annual rent increase resulting therefrom as
hereinabove provided. Tenant shall furnish Landlord with a copy of the report
and calculation of the survey conducted by tenant's electrical engineer or
consultant, by certified or registered mail, return receipt requested, within
ten (10) days of Tenant's receipt thereof. In the event of a discrepancy between
Landlord's and Tenant's determination of the increase in annual rent resulting
from Tenant's electric equipment, usage and powerload, the Landlord and Tenant
shall cause their respective electrical engineers or consultants to confer and
resolve the discrepancy within thirty (30) days after Landlord's receipt of
Tenant's report. If the respective electrical engineers and consultants shall be
unable to reach agreement within sixty (60) days of Landlord's receipt of
Tenant's report, the two engineers or consultants shall designate a third
engineer or consultant to make the determination in accordance with the
provisions of this electric rider, and the determination of said third engineer
or consultant shall be binding and conclusive on the parties hereto. If the
parties' respective engineers or consultants shall be unable to agree upon the
designation of a third engineer or consultant by the eightieth day after
Landlord's receipt of Tenant's report, either party hereto may request the
American Arbitration Association to designate such third engineer or consultant,
whose determination shall be binding and conclusive upon the parties hereto. The
costs and expenses of any such third engineer or consultant shall be paid by the
party whose determination of the increase to annual rent due to Tenant's
electric equipment, usage and powerload was at the greatest variance from the
determination of the third engineer or consultant. Pending the resolution of any
contest pursuant to the terms hereof, Tenant shall pay the increase in the
annual rent as provided pursuant to the determination of Landlord's engineer or
consultant, and upon the resolution of any such contest, the increase to annual
rent shall be adjusted accordingly, with arrears paid to Landlord, or a refund
or credit allowed to Tenant, as the case may be, within thirty (30) days of the
date of the determination of the third engineer or consultant.


<PAGE>

ADDITIONAL  CLAUSES attached to and forming a part of lease dated as of December
15,  1998,  between  180  VARICK  STREET  CORPORATION,  Landlord,  c/o  OLMSTEAD
PROPERTIES,  INC., Suite 2400, 575 Eighth Avenue, New York, NY 10018 and IMCLONE
SYSTEMS, INCORPORATED, Tenant.

41. BASIC PROVISIONS AND  DEFINITIONS:  This Article is an integral part of this
Lease and all of the  terms  hereof  are  incorporated  into  this  Lease in all
respects.  the  following  terms,  whenever  used in this Lease,  shall have the
meanings set forth in this  Article,  and only such  meanings  unless  expressly
contradicted, limited or expanded elsewhere in this Lease.

      (a)  RENTAL:  The  payment  reserved  under this Lease for the term hereof
shall be and consist of the aggregate of:

      (i) Minimum Rent,  which shall be $720,000.00  per annum  ($60,000.00  per
month) from January 1, 1999 to and including December 31, 1999;  $741,600.00 per
annum ($61,800.00 per month) from January 1, 2000 to and including  December 31,
2000;  $763,848.00 per annum  ($63,654.00 per month) from January 1, 2001 to and
including  December 31, 2001;  $786,763.44 per annum ($65,563.62 per month) from
January  1, 2002 to and  including  December  31,  2002;  $810,366.34  per annum
($67,530.53 per month) from January 1, 2003 to and including  December 31, 2003;
and  $834,677.33  per annum  ($69,556.44  per month) from January 1, 2004 to and
including December 31, 2004.

      (ii)  Additional  Rent  consisting  of all such other sums of money  shall
become due from and  payable by Tenant to  Landlord  hereunder  (for  default in
payment of which  Landlord  shall have the same remedies as a default in payment
of Minimum Rent).

      (b) BASE TAX shall mean Taxes,  as finally  determined,  for the  calendar
year commencing January 1, 1999 through December 31, 1999.

      (c) TENANT'S SHARE shall be 13.33%.

      (d) INTENTIONALLY DELETED.

      (e) INTENTIIONALLY DELETED.

      (f) INTENTIONALLY DELETED.

      (g) BROKER shall mean OLMSTEAD PROPERTIES, INC.

      (h) USE shall mean marketing; biotechnology,  molecular modeling, computer
graphics  and  high-technology   research  facilities;   computer   programming;
manufacturing of diagnostic kits, vaccine,  therapeutics and materials therefor;
conferences and general and executive offices.

42. AS-IS POSSESSION:  Tenant acknowledges that neither Landlord,  nor any agent
of Landlord, has made any representations or promises with regard to the Demised
Premises for the term herein  demised.  The taking of  possession of the Demised
Premises by Tenant for the term herein  demised shall be conclusive  evidence as
against  Tenant  that  Tenant  accepts  the same  "as-is"  and that the  Demised
Premises were in good and satisfactory condition at the time such possession was
taken.  Landlord  shall  not be  obligated  to make  any  repairs,  alterations,
improvements or additions to the Demised Premises for Tenant's occupancy.

43. USE: (A) Subject to and in  accordance  with the rules,  regulations,  laws,
ordinances,   statutory   limitations  and   requirements  of  all  governmental
authorities  and the  fire  insurance  rating  organization  and  board  of fire
underwriters  and  any  similar  bodies  having  jurisdiction  thereof,   Tenant
covenants and agrees that it shall use the Demised  Premises  solely for the use
as provided in Article 41(h), but for no other purpose.

      (B) Tenant agrees that  Landlord  shall have the right to prohibit the use
of the Demised  Premises by Tenant for any method of operation,  advertising  or
interior display which


                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       1
<PAGE>

Landlord  deems  detrimental  to the operation or reputation of the Building and
upon notice from Landlord,  Tenant shall  forthwith  refrain from or discontinue
such activities. Landlord acknowledges that Tenant's use of the Demised Premises
for  biotechnology  purposes  shall  not,  in  and of  itself  be  deemed  to be
detrimental to the operation or reputation of the Building.

44. TENANT'S INSTALLATIONS:  All work necessary or desirable to make the Demised
Premises  suitable for Tenant's use and occupancy  (other than Landlord's  Work)
shall be  performed  by Tenant at  Tenant's  own cost and  expense  (hereinafter
called "Tenant's Work").  Tenant's Work to be performed by Tenant in the Demised
Premises shall be subject to the following conditions:

      (A)  Tenant  shall  comply  with  all  of  the  laws,  orders,  rules  and
regulations of all  governmental  authorities,  and of the fire insurance rating
organization  having  jurisdiction   thereof,   and  the  local  board  of  fire
underwriters,  or any similar body, and Tenant shall have procured and paid for,
so far as the same may be required, all governmental permits and authorizations;

      (B) Prior to  commencing  Tenant's  Work,  all  plans  and  specifications
therefor shall be submitted to Landlord for Landlord's  prior written  approval.
If, in connection with determining  whether or not to approve Tenant's plans and
specifications Landlord incurs architectural,  engineering or other professional
fees,  Tenant  shall pay such  reasonable  fees as  additional  rent  within ten
business days of submission of such bills to Tenant;

      (C) Prior to commencing  Tenant's  Work,  Tenant shall at its own cost and
expense deliver to Landlord an endorsement of Tenant's and Tenant's contractor's
policy of comprehensive general liability insurance referred to in Article 52 of
this lease, covering the risk during the course of performance of Tenant's Work,
together  with proof of payment of such  endorsement,  which  policy as endorsed
shall protect  Landlord and its managing  agent in the same amounts  against any
claims or  liability  arising  out of  Tenant's  Work,  and  Tenant or  Tenant's
contractors  shall obtain workers'  compensation  insurance to cover all persons
engaged in Tenant's Work and liability  insurance  covering Tenant's Work in the
Demised  Premises in the amounts of $1,000,000 in respect of property damage and
$1,000,000 in respect of any one person,  not less than $3,000,000 in respect of
any one occurrence, and a certificate thereof shall be furnished to the Landlord
before commencement of any work by any contractor,  subcontractor, their agents,
servants or employees.  Tenant's  contractor  shall name Landlord,  its managing
agent and any other party as Landlord may request as additional  insureds  under
said insurance policies;

      (D) Prior to  commencing  Tenant's  Work  which in  Landlord's  reasonable
judgment  will cost more than  $5,000.00,  Tenant,  at its own cost and expense,
shall  deliver to  Landlord a surety  company  performance  bond and a labor and
material and payment bond, issued by a surety company acceptable to Landlord, or
other  security  satisfactory  to  Landlord,  in an  amount  at  least  equal to
Landlord's estimated cost of Tenant's Work, guaranteeing the performance thereof
and payment  therefor  within a  reasonable  time,  free and clear of all liens,
encumbrances,  chattel  mortgages,  conditional bills of sale and other charges,
and in accordance with the plans and specifications  approved by Landlord.  Upon
completion  of all  Tenant's  Work,  the  performance  bond shall be returned to
Tenant,  provided,  however,  that all of the terms,  covenants,  conditions and
provisions of this Article have been complied with,  and further,  Tenant is not
in default of any of the terms,  covenants,  conditions  or  provisions  of this
lease;

      (E) All of  Tenant's  Work  shall  be done in such a  manner  so as not to
materially interfere with, delay, or impose any additional expense upon Landlord
in the  maintenance  of the Building.  In no event shall Landlord be required to
consent to any  Tenant's  Work  which  would  physically  affect any part of the
Building  outside of the Demised Premises or would, in Landlord's sole judgment,
affect the proper functioning of any of the mechanical,  electrical, sanitary or
other systems of the Building;

      (F)  Notwithstanding  anything  herein  contained to the contrary,  Tenant
shall make all repairs to the Demised  Premises  necessitated  by Tenant's  Work
permitted hereunder, and shall keep and maintain in good order and condition all
of the  installations  in  connection  with  Tenant's  Work,  and shall make all
necessary replacements thereto.

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       2
<PAGE>

      (G) Prior to commencing  Tenant's  Work,  Tenant shall deliver to Landlord
the names and addresses of Tenant's general contractor, subcontractors, material
supplier and laborers, and the breakdown of the aggregate total cost of Tenant's
Work. Tenant, at its sole cost and expense, shall procure written waivers of the
right to file mechanic's liens executed by contractors, subcontractors, material
suppliers and laborers  simultaneously  with payment for the labor  performed or
materials  furnished has been made to each contractor,  subcontractor,  material
supplier or laborer. Tenant shall also procure written releases of lien executed
by contractors,  subcontractors,  material suppliers and laborers simultaneously
upon  payment in full for the labor  performed  or  materials  furnished by such
contractor,  subcontractor, material supplier or laborer. Any failure or refusal
on the part of  Tenant to comply  with the  foregoing  shall be deemed a default
under this lease.

45. ELECTRICITY:  Electricity shall be supplied to Tenant in accordance with the
provisions of paragraph A of Rider A annexed hereto.

46. TAX ESCALATION: (A) As used in this lease:

      (i) "Taxes" shall mean the real estate taxes and  assessments  and special
assessments  imposed upon the Building  and/or the land on which the Building is
situated by any governmental  bodies or authorities (the "Land"). If at any time
during  the  term of this  lease  the  methods  of  taxation  prevailing  at the
commencement  of the term  hereof  shall be altered so that in lieu of, or as an
addition  to or as a  substitute  for  the  whole  or any  part  of  the  taxes,
assessments,  levies,  impositions or charges now levied, assessed or imposed on
real estate and the improvements  thereof,  there shall be levied,  assessed and
imposed  (a) a  tax,  assessment,  levy  or  otherwise  on  the  rents  received
therefrom,  or (b) a  license  fee  measured  by the rent  payable  by Tenant to
Landlord, or (c) any other such additional or substitute tax, assessment,  levy,
imposition or charge, then all such taxes, assessments,  levies,  impositions or
charges or the part  thereof so measured or based shall be deemed to be included
within the term "Taxes" for the purpose hereof.

      (ii) "Tax Year" shall mean the fiscal year commencing on July 1 and ending
on June 30 (or such other period as hereafter may be duly adopted by the City of
New York as its fiscal year for real estate tax purposes).

      (B) (i) If the  Taxes  for any Tax Year  shall be more  than the Base Tax,
Tenant  shall  pay as  Additional  Rent for such  Tax  Year an  amount  equal to
Tenant's  Share of the  amount by which the Taxes for such Tax Year are  greater
than the Base Tax (the amount payable by Tenant is  hereinafter  called the "Tax
Payment").  The Tax Payment shall be prorated, if necessary,  to correspond with
that  portion of a Tax Year  occurring  within the term of this  lease.  The Tax
Payment  shall be payable by Tenant  within ten (10) business days after receipt
of a demand  from  Landlord  therefor.  In  addition  to and  supplementing  the
foregoing, Landlord may estimate the amount of the Tax Payment which will be due
from Tenant to Landlord and notify Tenant of the amount so estimated. Thereupon,
Tenant  shall  pay the  amount  so  estimated  to  Landlord,  in  equal  monthly
installments,  in advance,  on the first day of each  calendar  month during the
applicable  Tax Year.  Within  sixty  (60) days  after the end of each Tax Year,
Landlord  shall  deliver  a copy to  Tenant  of all tax bills for such Tax Year,
together  with a statement  showing the amount of Tenant's Tax  Payment.  If the
amount of such monthly  payments  paid by Tenant  exceeds the actual amount due,
the overpayment shall be credited on Tenant's next succeeding payment or, during
the last year of the term,  Landlord  will refund  such excess to Tenant  within
thirty  (30) days  following  the  expiration  of the term,  if Tenant is not in
default  hereunder.  If the amount of such monthly payments paid by Tenant shall
be less than the actual  amount  due,  then  Tenant  shall pay to  Landlord  the
difference  between the amount  paid by Tenant and the actual  amount due within
ten (10) days after demand from Landlord.

      (ii) In the event the Base Tax is  reduced  as a result of an  appropriate
proceeding,  Landlord  shall have the right to adjust the amount of Tax  Payment
due from Tenant for any Tax Year in which  Tenant is or was  obligated  to pay a
Tax Payment hereunder, and Tenant agrees to pay the amount of said adjustment on
the  next  rental  installment  day  immediately  following  receipt  of a  rent
statement from Landlord setting forth the amount of said adjustment.

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


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<PAGE>

      (C) Only  Landlord  shall be eligible to institute  tax reduction or other
proceedings  to reduce  the  assessed  valuation  of the Land and the  Building.
Should  Landlord be successful in any such  reduction  proceedings  and obtain a
rebate for periods during which Tenant has paid its share of increases, Landlord
shall after deducting its expenses,  including attorneys' fees and disbursements
in connection therewith, return Tenant's Share of such rebate to Tenant.

      (D) With respect to any period at the expiration of the term of this lease
which shall constitute a partial Tax Year,  Landlord's statement shall apportion
the amount of the  Additional  Rent due  hereunder.  The obligation of Tenant in
respect to such Additional Rent applicable for the last year of the term of this
lease or part thereof shall survive the expiration of the term of this lease.

      (E)  Notwithstanding  the fact that the increase in rent is measured by an
increase in Taxes,  such increase is Additional Rent and shall be paid by Tenant
as provided herein regardless of the fact that Tenant may be exempt, in whole or
in part, from the payment of any taxes by reason of Tenant's diplomatic or other
tax-exempt status or for any other reason whatsoever.

47. LEASEHOLD MORTGAGE:  A. Tenant may, without Landlord's consent, from time to
time pledge, mortgage or encumber this Lease and/or the leasehold estate demised
hereunder to any institutional lender or sublease the Demised Premise to the New
York City  Industrial  Development  Agency  ("IDA") and  immediately  thereafter
sublease the Demised Premises back from the IDA ("Leaseback").  Any such pledge,
mortgage  or  encumbrance  upon  this  Lease  or the  leasehold  estate  demised
hereunder or the Leaseback,  as the same may be extended,  modified,  amended or
replaced, is referred to in this Lease as the "Leasehold Mortgage".  There shall
be no limitation or restrictions upon the principal amount or other sums secured
by any Leasehold  Mortgage and such principal amount or other sums that may also
be secured by other mortgages,  deeds of trust or security agreements.  Landlord
shall not be bound to recognize the Leasehold  Mortgagee  unless such  Leasehold
Mortgagee  or Tenant  shall have  notified  Landlord  of the  existence  of such
Leasehold  Mortgage and of the name and address of such Leasehold  Mortgagee and
furnished  Landlord  with a copy  of the  Leasehold  Mortgage  and  bond or Note
secured thereby.

      B.  Landlord  hereby  agrees  with and for the  benefit of each  Leasehold
Mortgagee  and the  heirs,  legal  representatives,  successors  and  assigns of
Leasehold Mortgagee:

      (i) When giving  notice to Tenant with  respect to any default  under this
Lease or any exercise of any right to terminate  this Lease,  Landlord will also
give a copy of such notice by  registered  or certified  mail or by a nationally
recognized  overnight courier, to the Leasehold Mortgagee at the address of such
Leasehold Mortgagee furnished to Landlord; and no such notice to Tenant shall be
deemed to have been duly given,  nor shall such notice be effective  unless such
notice is also given in said manner to the Leasehold Mortgagee.

      (ii) In case Tenant shall  default in respect of any of the  provisions of
this  Lease,  the  Leasehold  Mortgagee  shall  have  the  right,  but  not  the
obligation, to cure such default whether the same consists of the failure to pay
rent or the  failure  to  perform  any  other  matter or thing  which  Tenant is
required  to  do  or  perform  under  this  Lease,  and  Landlord  shall  accept
performance by or on behalf of Leasehold  Mortgage as though,  and with the same
effect as if it had been done or performed by Tenant.  The  Leasehold  Mortgagee
will have a period of time after the service of such notice upon it within which
it may cure the default specified in such notice, or cause it to be cured, which
is the same period for cure,  if any, as is given to Tenant  under this Lease in
respect of the specified  default after the giving of such notice to Tenant.  In
the event of a default or in the event that termination is sought by reason of a
default,  other than the non-payment of rent,  which cannot  reasonably be cured
within said period, the period of time for cure shall be extended for so long as
the Leasehold Mortgagee is diligently proceeding to cure such default,  provided
that the  Leasehold  Mortgagee  has begun to cure the  default  within  the said
period.

      (iii) If, in order to cure any default by the Tenant under the  provisions
of this Lease,  the Leasehold  Mortgagee must perform any act or acts other than
the payment of rent,  no default will be deemed to exist and the Landlord  shall
have no right,  and shall take no action,  to effect a termination of this Lease
until the  Leasehold  Mortgagee  has had a reasonable  opportunity  to cure such
default after Leasehold  Mortgagee obtains possession of the Demised Premises by

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       4
<PAGE>

appointment of a receiver,  institution or foreclosure proceedings or otherwise,
but upon condition that the Leasehold  Mortgagee  shall deliver to Landlord,  no
later than thirty (30) days after the expiration of the grace period  applicable
to the Tenant as to the particular default, an acknowledged  instrument by which
the  Leasehold  Mortgagee  undertakes  that (x) during the  pendency of any such
foreclosure or other such proceedings with respect to Tenant's  interest in this
Lease and until  the  interest  of Tenant  in this  Lease  shall  terminate  and
possession of, title to, and control over the Demised Premises shall be obtained
by  Leasehold  Mortgagee,  Leasehold  Mortgagee  will pay or cause to be paid to
Landlord,  when and as it shall  become due (but  without  giving  effect to any
right of acceleration of rentals in the event of a default), the rental provided
for in the Lease and (y) when,  as and if  possession  of, title to, and control
over the  Demised  Premises  shall be obtained by  Leasehold  Mortgagee,  or its
nominee or designee,  whether voluntarily as a result of foreclosure proceedings
or otherwise,  Leasehold  Mortgagee shall therefore perform or cause its nominee
to perform,  all the covenants of this Lease on Tenant's part to be performed to
the extent that Tenant shall have failed to perform such covenants  prior to the
date on which such title,  possession and control by Leasehold  Mortgagee shall,
upon  request of Landlord,  reimburse  Landlord for the costs of any repairs (i)
which  are the  obligation  of  Tenant  under  the  Lease  and which are made by
Landlord after default by Tenant and (ii) which corrects  dangerous or hazardous
conditions  or which are  necessary  to  prevent  deterioration  of the  Demised
Premises.  If prior to the sale in any foreclosure  proceeding instituted by the
Leasehold  Mortgagee,  or if prior to the date on which Tenant's interest in the
Lease and the Demised Premises shall otherwise be  extinguished,  the default in
respect of which  Landlord  shall have  given any  notice  contemplated  by this
paragraph  shall have been cured and  possession of the Demised  Premises  shall
have been  restored  to  Tenant,  the  undertaking  of the  Leasehold  Mortgagee
provided for in this  subparagraph  (iii) shall  automatically  terminate and be
without  further force or effect.  No Leasehold  Mortgagee  shall be required to
commence and  continue  any  foreclosure  or other  proceedings  or to obtain or
continue possession of the Demised Premises.

      (iv) The  Leasehold  Mortgagee (or its designee or nominee) may become the
legal  owner  and  holder  of the  interest  of the  Tenant  under  this  Lease,
including,  without  limitation,  the  interest  of Tenant  in all  improvements
erected by Tenant on the Demised  Premises,  by foreclosure or other enforcement
proceedings  or by obtaining an assignment of this Lease in lieu of  foreclosure
or through settlement of or arising out of any pending or threatened foreclosure
proceeding,  without Landlord's consent but subject to the Leasehold Mortgagee's
obligation to assume this Lease. In such event,  the Leasehold  Mortgage (or its
designee or nominee) shall have the right  thereafter to assign this Lease,  but
subject to the applicable terms and provisions of this Lease.

      (v) In the event of the  termination  of this  Lease,  the  Landlord  will
notify  Leasehold  Mortgagee  and certify in writing to Leasehold  Mortgagee all
amounts then due to Landlord under this Lease and the Landlord will enter into a
new lease of the Demised Premises with the Leasehold Mortgagee for the remainder
of the term, to commence as at the date of the  termination of this Lease at the
same  rental  and  upon  all of  the  other  terms,  provisions,  covenants  and
agreements  as in this  Lease  contained,  upon  condition  that  (a)  Leasehold
Mortgagee  shall make  written  request to Landlord  for such new lease no later
than  thirty  (30) days from the date such  notice by the  Landlord  is given to
Leasehold  Mortgagee;  (b) Leasehold Mortgagee shall pay to Landlord at the time
of the execution  and delivery of said new lease all sums which,  as of the date
of execution and delivery of such new lease,  were past due and owing under this
Lease,  but without giving effect to any provision  permitting  acceleration  of
rentals upon  termination  of this Lease amounts not otherwise then due; and (c)
such new lease shall require the Tenant  thereunder to perform any obligation of
Tenant under the Lease not then performed.

      (vi) Anything in this Article  contained to the contrary  notwithstanding,
the  provisions  of this Article shall only be for the benefit of the holders of
the Leasehold  Mortgage which is a first lien upon the leasehold  estate or is a
direct sublease of Tenant.

      (vii) If the Tenant  fails to observe  or perform  any of its  obligations
under this Lease,  the Leasehold  Mortgagee  may, but shall not be obligated to,
observe or perform such obligations for and on behalf of Tenant,  whether or not
Tenant shall be in default under this Lease.

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       5
<PAGE>

      C. Any notice or other  communication  which  Landlord  shall desire or is
required to give to or serve upon  Leasehold  Mortgagee  shall be in writing and
shall be served by  registered  or certified  mail or by  nationally  recognized
overnight courier addressed to such holder at its address as shall be designated
from  time to time by such  holder by notice  in  writing.  Any  notice or other
communication  which the Leasehold Mortgagee shall desire or is required to give
to or serve upon  Landlord  shall be deemed to have been duly given or served if
sent by  registered  or certified  mail or by  nationally  recognized  overnight
courier to Landlord at Landlord's  address as shall be  designated  from time to
time by Landlord by notice in writing given to Leasehold Mortgagee by registered
or certified mail or by nationally recognized overnight courier.

      D.  Landlord will not modify,  amend,  cancel or accept a surrender of the
Lease,  nor shall this Lease be  terminated  by Tenant  (including a termination
pursuant to the express  provisions  hereof),  nor shall Tenant elect any option
granted to it under this Lease,  including without  limitation to terminate this
Lease under  Article 9 hereof or any other  section of this  Lease,  without the
prior  written  consent  of the  Leasehold  Mortgagee.  Any  such  modification,
amendment,  cancellation,  surrender, termination or option election without the
written  consent  of the  Leasehold  Mortgagee  shall be void and of no force or
effect.

      E. No union of the  interests  of Landlord  and Tenant  shall  result in a
merger of this Lease and the fee  interest in the Demised  Premises  without the
prior written consent of the Leasehold Mortgagee.

      F. All notices,  statements and other communications to be given under the
terms  of this  Lease  shall  also be  given in  writing  simultaneously  to the
Leasehold Mortgagee.

      G. The  parties  agree,  at any time and from time to time,  upon not less
than ten (10) days' prior written notice from the other, to execute, acknowledge
and deliver to the  requesting  party,  a statement in writing  addressed to the
requesting  party  certifying  that this  Lease is  unmodified  and in force and
effect (or if there have been modifications,  that the same is in full force and
effect as modified  and stating the  modifications),  stating the dates to which
rent,  additional  rent and other charges have been paid, and stating whether or
not to the best  knowledge of the signer of such  certificate,  there exists any
defaults in the  performance  of any  covenant,  agreement,  term,  provision or
condition  contained in this Lease,  and if so,  specifying each such default of
which the signer may have knowledge.

48. INTENTIONALLY DELETED.

49. NON-WAIVER AND SURVIVAL OF ADDITIONAL RENT OBLIGATIONS:  Landlord's  failure
during the lease term to prepare and  deliver any of the tax bills,  statements,
notices or bills set forth in Article 46 or Landlord's  failure to make a demand
shall not in any way cause  Landlord  to  forfeit  or  surrender  its  rights to
collect any of the foregoing  items of Additional Rent which may have become due
during the term of this  lease.  Tenant's  liability  for the  amounts due under
Article 46 shall survive the expiration of the lease term.

50. ADDENDUM TO ARTICLE 6 (COMPLIANCE WITH LAWS):  Supplementing  the provisions
of Article 6 hereof,  Tenant shall give prompt  notice to Landlord of any notice
it receives of the violation of any law or requirement  of any public  authority
with respect to the Demised  Premises or the use or occupation  thereof.  Tenant
shall promptly  comply with all present and future laws,  orders and regulations
of all state, federal, municipal and local governments, departments, commissions
and boards or any  direction  of any public  officer  pursuant  to law,  and all
orders,  rules and regulations of the New York Board of Fire Underwriters or any
similar body which shall impose any  violation,  order or duty upon  Landlord or
Tenant with respect to the Demised  Premises (in which event Tenant shall effect
such  compliance  at its sole cost and expense) or the Building (in which event,
notwithstanding  anything  herein to the  contrary,  Landlord  shall effect such
compliance but Tenant shall promptly pay to Landlord  Tenant's Share of the cost
thereof).

51. WAIVER OF SUBROGATION: Each party hereby release the other party (which term
as used in this Article includes the employees,  agents,  officers and directors
of the other party) from all liability,  whether for negligence or otherwise, in
connection  with loss  covered by any fire and/or  

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       6
<PAGE>

extended coverage insurance policies, which the releasor carries with respect to
the Demised Premises, or any interest or property therein or thereon (whether or
not such insurance is required to be carried under this lease),  but only to the
extent  that such loss is  collected  under said fire and/or  extended  coverage
insurance  policies.  Such release is also conditioned upon the inclusion in the
policy or policies of a provision  whereby any such release  shall not adversely
affect  said  policies,  or  prejudice  any  right of the  releasor  to  recover
thereunder. Each party agrees that its insurance policies aforesaid will include
such a provision so long as the same shall be obtainable  without extra cost, or
if extra cost shall be charged therefor,  so long as the party for whose benefit
the clause or  endorsement  is obtained shall pay such extra cost. If extra cost
shall be  chargeable  therefor,  each party shall  advise the other of the extra
cost,  and the other party at its  election  may pay the same,  but shall not be
obligated to do so.

52. INDEMNITY-LIABILITY  INSURANCE: (A) Tenant covenants and agrees to indemnify
and  save  Landlord,  its  managing  agent  and  its  principals,  disclosed  or
undisclosed,  harmless from and against any and all claims,  losses,  damages or
expenses  (including  reasonable  attorneys'  fees) or other  liability  arising
during the term of this lease out of or in connection with (i) the construction,
possession,  use, occupancy,  management,  repair, maintenance or control of the
Demised  Premises or any part thereof or any other part of the Building  used by
Tenant,  or (ii) any act or omission of Tenant or  Tenant's  agents,  employees,
contractors,  concessionaires,  licensees, invitees, subtenants or assignees, or
(iii) any  default,  breach,  violation or  nonperformance  of this lease or any
provision hereof by Tenant,  or (iv) any injury to person or property or loss of
life sustained in or about the Demised Premises or any part thereof, except such
claims  found to be the  result  of the  negligence  of  Landlord,  its  agents,
employees or contractors.  Tenant shall, at its own cost and expense, defend any
and all actions,  suits and proceedings which may be brought against, and Tenant
shall pay, satisfy and discharge any and all judgments, orders and decrees which
may be made or entered  against,  Landlord,  its managing agent, its principals,
disclosed or  undisclosed,  with respect to, or in connection  with,  any of the
foregoing.  The comprehensive  general liability  coverage  maintained by Tenant
pursuant to this lease shall specifically insure the contractual  obligations of
Tenant as set forth in this Article and/or as provided in this lease.

      (B) Tenant covenants to provide on or before the Commencement  Date of the
term  hereof  and to keep in force  during the term  hereof  for the  benefit of
Landlord,  its  managing  agent and Tenant a  comprehensive  policy of liability
insurance  protecting  Landlord,  its  managing  agent and Tenant (and any other
parties as Landlord shall designate to be added as insured  parties) against any
liability whatsoever  occasioned by accident on or about the Demised Premises or
any  appurtenances  thereto.  Such  policy is to be written by good and  solvent
insurance  companies  licensed  to do  business  in the  State  of New  York and
satisfactory to Landlord.  The policy shall be a comprehensive General Liability
type and extended to include  personal injury liability and fire legal liability
with the amounts of liability  thereunder not less than $1,000,000.00 in respect
of any one person,  not less than  $3,000,000.00 in respect of any one accident,
and not less than  $500,000.00  in respect of  property  damages.  In  addition,
Tenant will, at Tenant's expense,  maintain (i) workers' compensation  insurance
within statutory limits covering all persons  employed,  directly or indirectly,
in connection  with any of Tenant's Work or any repair or alteration  authorized
by this lease or  consented  to by  Landlord,  and all  employees  and agents of
Tenant  with  respect to whom death or bodily  injury  claims  could be asserted
against  Landlord  or  Tenant;  (ii)  fire  and  extended  coverage,  vandalism,
malicious mischief and special extended coverage insurance in an amount adequate
to  cover  the  cost  of  replacement  of  all  fixtures  and   decorations  and
improvements in the Demised  Premises;  and (iii) rent insurance  covering those
risks  referred  to in (ii)  above in an amount  equal to all  Minimum  Rent and
Additional  Rent  payable  under this lease for a period of twelve  (12)  months
commencing  with the date of loss.  Prior to the time  such  insurance  is first
required to be carried by Tenant, and thereafter at least thirty (30) days prior
to the  expiration  of any such  policy,  Tenant  agrees to deliver to  Landlord
either  a  duplicate  or  original  of the  aforesaid  policy  or a  certificate
evidencing such  insurance,  provided said  certificate  contains an endorsement
that such  insurance may not be canceled or modified  except upon ten (10) days'
written  notice to Landlord,  together  with evidence of payment for the policy.
Tenant's failure to provide and keep in force the aforementioned insurance shall
be regarded as a material default hereunder,  entitling Landlord to exercise any
or all of the  remedies  as  provided  in this  lease in the  event of  Tenant's
default.  The minimum  limits of insurance  described  above shall be subject to
increase at any time, and from time to time, after the third  anniversary of the
commencement   date,  if  Landlord   shall  

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       7
<PAGE>

deem same  necessary  for  adequate  protection.  Within  thirty (30) days after
demand  therefor by Landlord,  Tenant shall  furnish  Landlord  with evidence of
compliance with such demand.

53. TENANT'S CERTIFICATE: Tenant shall, without charge at any time and from time
to time,  within ten (10) business  days after  request by Landlord,  certify by
written instrument, duly executed, acknowledged and delivered, to any mortgagee,
assignee of any mortgage or purchaser,  or any proposed  mortgagee,  assignee of
any mortgage or purchaser, or any other person, firm or corporation specified by
Landlord:

      (A) that this lease is  unmodified  and in full force and effect  (or,  if
there  has been  modification,  that the same is in full  force  and  effect  as
modified and stating the modifications);

      (B) whether or not there are then existing any setoffs or defenses against
the enforcement of any of the agreements,  terms, covenants or conditions hereof
upon the part of Tenant to be performed or complied with (and, if so, specifying
the same); and

      (C) the dates,  if any,  to which the rental and other  charges  hereunder
have been paid in advance.

54.  EXCULPATORY  CLAUSE:  If Landlord  shall be an  individual,  joint venture,
tenancy-in-common,   co-partnership,   unincorporated   association,   or  other
unincorporated  aggregate of  individuals  and/or  entities,  or a  corporation,
Tenant  shall look only to such  Landlord's  estate and property in the Building
and,  where  expressly  so provided in this lease,  to offset  against the rents
payable  under this lease,  for the  satisfaction  of Tenant's  remedies for the
collection of a judgment (or other  judicial  process)  requiring the payment of
money by  Landlord in the event of any  default by  Landlord  hereunder,  and no
other  property or assets of such Landlord or any of the principals of Landlord,
disclosed  or  undisclosed,  shall  be  subject  to  levy,  execution  or  other
enforcement  procedure for the  satisfaction of Tenant's  remedies under or with
respect to this lease,  the  relationship  of Landlord  and Tenant  hereunder or
Tenant's use or occupancy of the Demised Premises.

55. BROKER:  Tenant covenants,  warrants and represents that there was no broker
instrumental in  consummating  this lease and no  conversations  or negotiations
were had with any broker other than Broker concerning the renting of the Demised
Premises. Tenant agrees to indemnify, defend and hold and save Landlord harmless
against any and all  liability  from any claims of any broker  other than Broker
who claims to have dealt with Tenant (including, without limitation, the cost of
counsel  fees in  connection  with the defense of any such claims in  connection
with the  renting of the  Demised  Premises).  Based  upon such  representation,
Landlord has agreed to enter into this leasing agreement with Tenant.

56. CONFLICT OF TERMS: In the event any term,  covenant,  condition or agreement
contained in this rider to the lease shall conflict or be inconsistent  with any
term, covenant,  condition or agreement contained in the printed portion of this
lease, then the parties agree that the rider provision shall prevail.

57.  TENANT'S  REMEDIES:  With  respect to any  provision  of this  lease  which
provides,   in  effect,  that  Landlord  shall  not  unreasonably   withhold  or
unreasonably  delay any  consent or any  approval,  Tenant in no event  shall be
entitled to make, nor shall Tenant make, any claim, and Tenant hereby waives any
claim,  for money  damages;  nor shall Tenant claim any money  damages by way of
setoff,  counterclaim  or defense,  based upon any claim or  assertion by Tenant
that Landlord has unreasonably  withheld or unreasonably  delayed any consent or
approval;  but Tenant's  sole remedy shall be an action or proceeding to enforce
any such  provision,  or for specific  performance,  injunction  or  declaratory
judgment.

58. TENANT'S OPERATING OBLIGATIONS:  Tenant covenants and agrees that during the
term of this lease:

      (A) If any governmental license or permit shall be required for the proper
and lawful  conduct of Tenant's  business in the Demised  Premises,  or any part
thereof, and if failure to secure such license or permit would in any way affect
Landlord,  then  Tenant,  at its sole cost and  

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       8
<PAGE>

expense,  shall duly procure and thereafter  maintain such license or permit and
submit the same to inspection by Landlord. Tenant shall at all times comply with
the terms and conditions of each such license or permit.

      (B) Tenant shall maintain any sanitary  lines in the Demised  Premises and
shall not  misuse  plumbing  facilities  or  dispose  of any  foreign  substance
therein. Tenant shall not permit any food, waste, or other foreign substances to
be thrown or drawn into the pipes.  Tenant shall  maintain the plumbing  that it
installs in good order,  repair and condition,  and repair any damage  resulting
from any violation of this Paragraph. Tenant shall make any repairs to the other
plumbing in the Building,  if damage results from Tenant's  improper use of such
plumbing.

      (C) Tenant will retain a licensed professional exterminating service which
will service the Demised  Premises on a regular basis  throughout the term so as
to keep the Demised Premises free of vermin.  Tenant shall furnish Landlord with
a copy of said contract within seven (7) days of Landlord's request therefor.

      (D) Tenant shall install  chemical  extinguishing  devices approved by the
Fire Insurance Rating  Organization and shall keep such devices under service as
required by such  organization.  If gas is used in the Demised Premises,  Tenant
shall install gas cutoff devices (manual and automatic).

      (E) Tenant will not  encumber or  obstruct or permit to be  encumbered  or
obstructed  any  hallway,  service  elevator,  stairway  or  passageway  in  the
Building.

      (F) Tenant  covenants  and agrees that  throughout  the term, it shall not
suffer,  allow or permit any offensive or obnoxious  vibration,  noise,  odor or
other undesirable effect to emanate from the Demised Premises, or any machine or
other  installation  therein,  or  otherwise  suffer,  allow or permit  any such
obnoxious  vibration,  noise, odor or other  undesirable  effect to constitute a
nuisance or  otherwise  interfere  with the safety,  comfort or  convenience  of
Landlord,  or other tenants,  occupants,  customers,  agents, or invitees or any
others lawfully in or upon the Building and upon Landlord's notice, Tenant shall
within  five (5) days  thereof  remove  or  control  the  same,  and if any such
condition is not so remedied, then Landlord may, at its discretion,  either: (i)
cure such condition and add any cost and expense  incurred by Landlord  therefor
to the next  installment of rent due under this lease, and Tenant shall then pay
said amount,  as Additional  Rent  hereunder;  or (ii) treat such failure on the
part of Tenant to remedy such  condition as a material  default of this lease on
the part of Tenant hereunder, entitling Landlord to any of its remedies pursuant
to the terms of this lease.

      (G) Tenant  shall not  subject  any  fixtures  or  equipment  in or on the
Demised  Premises  which are  affixed to the  realty,  to any  mortgage,  liens,
conditions, sales agreements, security interests or encumbrances.

      (H) Tenant  shall not perform any act or carry on any  practice  which may
damage, mar or deface the Demised Premises or any other part of the Building.

      (I) Tenant shall not permit window cleaning or other exterior  maintenance
and janitorial  services in and for the demised  premises to be performed except
by such person(s) as shall be approved by Landlord, and except during reasonable
hours designated for such purposes by Landlord.

      (J) Tenant shall not install,  operate or maintain in the Demised Premises
any electrical  equipment which will overload the electrical system therein,  or
any part thereof,  beyond its reasonable capacity for proper and safe operation,
as  determined  by  Landlord,  in light of the overall  system and  requirements
therefor in the Building, or which does not bear underwriters' approval.

      (K) Tenant  shall not use or occupy the Demised  Premises  for any purpose
calculated to injure the reputation of the Demised Premises, and/or the Building
or of the  neighborhood in which the same are located or to, presently or in the
future,  impair the value of the Demised Premises and/or the Building.  Landlord
acknowledges  that the use of the Demised  

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                                                        Tenant__________________
                                                        Landlord________________

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Premises for  biotechnology  purposes shall not, in and of itself,  be deemed to
injure the reputation of the Demised Premises, the Building or the neighborhood,
nor impair the value of the Demised Premises or the Building.

      (L) Tenant  shall not permit any  business  to be  operated in or from the
Demised  Premises by any  concessionaire  or licensee  without the prior written
consent of Landlord in each instance.

      (M)  There  shall be no  cooking  or food  preparation  whatsoever  in the
Demised Premises.

59. LABOR REGULATIONS:  Tenant covenants and agrees that prior to and throughout
the demised term,  it shall not take any action which would  violate  Landlord's
union contract,  if any,  affecting the Building,  nor create any work stoppage,
picketing, labor disruption or dispute, or any interference with the business of
Landlord or any other  tenant or occupant in the Building or with the rights and
privileges  of any  person(s)  lawfully in the  Building.  Any default by Tenant
under this  Article  shall be deemed a material  default  entitling  Landlord to
exercise  any or all of the  remedies as  provided in this lease  subject to the
notice provisions provided in Article 17 hereof.

60. INTENTIONALLY DELETED.

61.  ADDENDUM  TO  ARTICLE  22  (END  OF  TERM):  If  Tenant  shall  default  in
surrendering  the Demised  Premises upon the  expiration or  termination  of the
term, Tenant's occupancy  subsequent to such expiration or termination,  whether
or not with the consent or acquiescence of Landlord,  shall be deemed to be that
of a tenancy  at will and in no event  from month to month or from year to year,
and it shall be subject to all the terms, covenants and conditions of this lease
applicable  thereto,  except the Minimum Rent shall be one hundred fifty percent
(150%) of the amount  payable in the last year of the term,  and no extension or
renewal of this lease shall be deemed to have  occurred by such holding over. In
the event Landlord shall commence  proceedings to dispossess Tenant by reason of
Tenant's  default,  Tenant  shall pay, in  addition to costs and  disbursements,
minimum legal fees of $500.00 for each proceeding as Additional Rent hereunder.

62.  ADDENDUM TO ARTICLE 18  (LANDLORD'S  REMEDIES):  Should  Tenant fail to pay
within five (5) days after same  becomes due any  installment  of Minimum  Rent,
Additional  Rent,  or any other sum payable to Landlord  under the terms of this
lease,  then interest shall accrue from and after the date on which any such sum
shall be due and payable, and such interest, together with a late charge of five
cents for each dollar  overdue to cover the extra  expense  involved in handling
such  delinquency  shall be paid by Tenant to Landlord at the time of payment of
the delinquent sum. Anything  contained herein to the contrary  notwithstanding,
including  but not  limited to Article 17  hereof,  Landlord  shall give  Tenant
written notice of its monetary defaults under this Lease, but no more often than
twice in a twelve  consecutive  month  period.  If Tenant shall issue a check to
Landlord which is returnable unpaid for any reason, Tenant shall pay Landlord an
additional charge of $100.00 for Landlord's expenses in connection therewith. If
Tenant  shall be late in making any payment due under this lease more than three
(3) times in any Lease  Year,  Landlord  shall be entitled to demand from Tenant
and Tenant agrees to tender to Landlord additional security in the amount of one
month's  current Minimum Rent to be held in accordance with the terms of Article
32 hereof.

63.  INTEREST:  Whenever this lease refers to "interest"  (except in relation to
Tenant's security deposit), same shall be computed at a rate equal to the "Prime
Rate" (as hereinafter defined) plus three (3%) percent except where otherwise in
this lease a different rate is specifically set forth.  If, however,  payment of
interest at any such rate by Tenant (or by the tenant then in possession  having
succeeded  to  Tenant's  interest  in  accordance  with the terms of this lease)
should be unlawful,  i.e.,  violative of the usury  statutes or otherwise,  then
"interest"  shall, as against such party, be computed at the maximum lawful rate
payable by such party.  "Prime  Rate" shall mean the rate being  reported at the
time in question by The Wall Street Journal.

64.  ARBITRATION:  Either party may request arbitration of any matter in dispute
wherein  arbitration  is  expressly  provided  in this lease as the  appropriate
remedy. All such  controversies  

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                                                        Landlord________________

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shall be settled by  decision of the  Chairman  of the Real Estate  Board of New
York,  Inc. whose decision shall be final and conclusive upon the parties hereto
and a judgment  may be  obtained  thereon in any court  having  jurisdiction  in
accordance with the procedural  rules then obtaining of the Real Estate Board of
New York, Inc. or any successor thereto. The arbitrator or arbitrators may grant
injunctions or other relief in such  controversies or claims.  The parties agree
that the  unsuccessful  party  shall pay the  entire  cost and  expense  of such
arbitration,  and each  shall  separately  pay for its own  attorneys'  fees and
expenses.

65. ENTIRE  AGREEMENT:  No earlier  statement or prior written matter shall have
any force or effect. Tenant agrees that it is not relying on any representations
or agreements other than those contained in this lease. This agreement shall not
be  modified  or  canceled  except by writing  subscribed  by all of the parties
hereto.

66. SAVINGS PROVISION:  If any provision of this lease or its application to any
situation shall be invalid or unenforceable to any extent, the remainder of this
lease, or the application  thereof to situations  other than that as to which it
is invalid or unenforceable  shall not be affected thereby,  and every provision
of this lease shall be valid and enforceable to the fullest extent  permitted by
law.

67.  LEASE NOT BINDING  UNLESS  EXECUTED:  Submission  by Landlord of the within
lease for execution by Tenant shall confer no rights nor impose any  obligations
on either  party unless and until both  Landlord and Tenant shall have  executed
this lease and  duplicate  originals  thereof  shall have been  delivered to the
respective parties.

68. MECHANIC'S LIENS: (A) Notwithstanding  anything to the contrary contained in
this lease,  Tenant,  its  successors  and  assigns,  warrant and  guarantee  to
Landlord, its successors and assigns, that if any mechanic's lien shall be filed
against  the  Building  of which the  Demised  Premises  forms a part,  for work
claimed to have been done for, or materials  claimed to have been  furnished to,
Tenant (i) the same shall be discharged by Tenant, by either payment, by bond or
otherwise,  at the sole cost and expense of Tenant,  within fifteen (15) days of
the  giving  of  notice  thereof  by  Landlord,  (ii)  either  a  release  or  a
satisfaction  of lien,  as the case may be, shall be filed with the County Clerk
of the county in which the  Building  is situate  within such  fifteen  (15) day
period,  and (iii) a copy of such release or  satisfaction,  as the case may be,
certified to by such County  Clerk shall be  delivered to Landlord  within three
(3) days after such filing.

      (B) In the  event  such  mechanic's  lien  is not  discharged  timely,  as
aforesaid,  Landlord may discharge same for the account of and at the expense of
Tenant  by  payment,  bonding  or  otherwise,  without  investigation  as to the
validity  thereof  or of any  offsets or  defenses  thereto,  and  Tenant  shall
promptly reimburse Landlord,  as Additional Rent, for all costs,  disbursements,
fees and  expenses,  including,  without  limitation,  legal  fees,  incurred in
connection  with so discharging  said  mechanic's  lien,  together with interest
thereon from the time or times of payment until reimbursement by Tenant.  Tenant
shall,  within five (5) days of demand therefor by Landlord,  pay to Landlord as
Additional  Rent,  the  sum of One  Thousand  ($1,000)  Dollars  on  account  of
Landlord's legal fees and  disbursements,  but the foregoing shall not limit the
extent of Tenant's liability as set forth above.

      (C) In the  event  such  mechanic's  lien  is not  discharged  timely,  as
aforesaid, Landlord, in addition to all other rights granted to Landlord in this
lease and without  limitation,  may  institute a dispossess  summary  proceeding
based upon such failure to discharge any such lien. In the event Tenant fails to
deliver to Landlord the certified copy of the release or  satisfaction  required
hereunder  within the time period provided for the delivery thereof to Landlord,
Landlord shall have the right to assume that such  mechanic's  lien has not been
discharged and Landlord  shall have all of the rights and remedies  provided for
herein based upon Tenant's failure to discharge any such lien.

      (D) It is further  expressly  understood  and agreed  between  the parties
hereto that Landlord may expend all or a portion of the security deposit made by
Tenant  hereunder  toward  discharging  any such  mechanic's  lien and the cost,
expenses, fees and disbursements,  including, without limitation, legal fees, in
connection therewith. Upon notification by Landlord of the 

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                                                        Landlord________________

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application  of all or a portion of the  security  deposited  by Tenant,  Tenant
shall,  within five (5) days after receipt of said notice,  restore the security
deposit to such amount held by Landlord prior to Landlord's application thereof.
Tenant's  failure to do so within said five (5) day period  shall  constitute  a
material default under this lease.

      (E) Tenant, at its sole cost and expense, shall procure written waivers of
the right to file  mechanic's  liens  executed by  contractors,  subcontractors,
material  suppliers  and  laborers  simultaneously  with  payment  for the labor
performed   or   materials   furnished   has  been  made  to  each   contractor,
subcontractor,  material supplier or laborer.  Tenant shall also procure written
releases of lien executed by contractors, subcontractors, material suppliers and
laborers  simultaneously  upon  payment  in full  for  the  labor  performed  or
materials  furnished  by such  contractor,  material  supplier or  laborer.  Any
failure or refusal on the part of Tenant to comply with the  foregoing  shall be
deemed a default under this lease.

69. LANDLORD'S  CONSENT:  If Tenant requests  Landlord's  consent or approval to
alterations,  assignment,  subletting  or any other  matter  or thing  requiring
Landlord's  consent or approval under this lease, and if in connection with such
request  Landlord seeks the advice of its attorneys,  architect and/or engineer,
then Landlord, as a condition precedent to granting its consent or approval, may
require (in addition to any other  requirements  of Landlord in connection  with
such request) that Tenant pay the fee of Landlord's attorneys,  architect and/or
engineer  in  connection  with the  consideration  of such  request  and/or  the
preparation of any documents pertaining thereto.

70. ENTRANCE DOORS: Tenant shall,  throughout the term of this lease,  maintain,
repair,  service and replace when  necessary,  all doors leading into and out of
the Demised Premises and all hardware  appurtenant thereto,  including,  but not
limited to,  locks,  hinges,  silencers,  door stops,  door jams,  door closets,
latchsets,  flashbulbs,  door frames,  thresholds and door knobs. Landlord shall
have no liability or obligation  whatsoever  regarding the maintenance,  repair,
service and replacement of the foregoing.

71.  FINANCING  REQUIREMENTS:  If, in  connection  with  obtaining  financing or
refinancing  for the  Building  of which the  Demised  Premises  form a part,  a
banking,  insurance  or other  institutional  lender  shall  request  reasonable
modifications  to this lease as a condition to such  financing  or  refinancing,
Tenant  shall not  unreasonably  withhold,  delay or defer its consent  thereto;
provided,  however,  that such  modifications do not increase the obligations of
Tenant hereunder (except,  perhaps, to the extent that Tenant may be required to
give notices of any defaults by Landlord to such lender and/or permit the curing
of such defaults by such lender  together  with the granting of such  additional
time for such curing as may be required for such lender to get possession of the
Building) or materially  adversely affect the leasehold interest hereby created.
In no event shall a requirement that the consent of any such lender be given for
any  modification  of this lease or subject to the  provisions of this lease for
any  assignment  or  sublease,  be deemed to  materially  adversely  affect  the
leasehold interest hereby created.

72.  WAIVER OF  COUNTERCLAIM:  Tenant  hereby  waives the right to interpose any
offset or counterclaim (except for a "compulsory" counterclaim) in any action or
proceeding  brought by the  Landlord  against the Tenant,  or to enjoin any such
action or proceeding  brought by the Landlord  against the Tenant and the Tenant
further waives the right to consolidate with, or try together in any such action
or  proceeding so  instituted  by the  Landlord,  any action or proceeding  then
pending or thereafter instituted by the Tenant against the Landlord.

73. PERMITS AND FEES:

      (A) Tenant covenants and agrees that, upon request of Landlord,  it shall,
within  ten (10) days from the date of the  request,  furnish  Landlord  with an
up-to-date  copy of any  permit or  license  required  by any  authority  having
jurisdiction therein for Tenant to conduct business at the Demised Premises.

      (B) In addition, Tenant further covenants and agrees that, upon request of
Landlord,  it shall, within ten (10) days from the date of the request,  furnish
Landlord  with a copy of the  canceled  check,  paid bill or any other  evidence
which supports payment of current tax, 

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                                                        Tenant__________________
                                                        Landlord________________

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assessment  or fee, for personal  property,  fees or other  imposition  which is
imposed upon Tenant, other than the Real Estate Tax.

      (C) In the event  Tenant fails to submit to Landlord,  upon  request,  the
items called for under either subparagraphs (A) or (B) above, such failure shall
be a default under the terms of this lease.

74. FORCE MAJEURE:  Except for the payment of Minimum Rent and Additional  Rent,
neither Landlord nor Tenant shall be deemed in default in the performance of any
obligation  or  undertaking  provided  herein in the event and/or so long as the
performance of any such obligation is prevented or delayed, retarded or hindered
by act of God, fire, earthquake, floods, explosion, action of the elements, war,
hostilities,  invasion, insurrection, riot, mob violence, sabotage, inability to
procure  or  general  shortage  of labor  equipment,  facilities,  materials  or
supplies  in the open  market,  failure of  transportation,  strikes,  lockouts,
action of labor unions, condemnation, requisition, laws, orders of government or
civil or military or naval  authorities,  act or failure to act of either  party
which  causes  the other  party to be  delayed  in the  performance  of any such
obligation or undertaking,  or any other cause, whether similar or dissimilar to
the foregoing, not within the reasonable control of the non-performing party.

75. ATTORNMENT: At the option of Landlord or any successor landlord or holder of
any mortgage  affecting  the demised  premises,  Tenant  agrees that neither the
cancellation  nor  termination  of any ground or underlying  lease to which this
lease is now or may hereafter become subject or subordinate, nor any foreclosure
of a mortgage  affecting the demised premises,  nor the institution of any suit,
action,  summary or other proceeding against Landlord or any successor landlord,
or any  foreclosure  proceedings  brought by the holder of any such  mortgage to
recover  possession  of the  demised  premises,  shall  by  operation  of law or
otherwise  result  in the  cancellation  or  termination  of this  lease  or the
obligations  of Tenant  hereunder,  and upon the request of Landlord,  successor
landlord or mortgagee,  Tenant covenants and agrees to attorn to the Landlord or
to any successor to the Landlord's  interest in the demised premises,  or to the
mortgagee or to the purchaser of the mortgaged premises in foreclosure.

76. SORTING AND SEPARATION OF REFUSE AND TRASH:

      Tenant covenants and agrees, at its sole cost and expense,  to comply with
all present  and future  laws,  orders and  regulations  of all state,  federal,
municipal and local governments,  departments,  commissions and boards regarding
the collection,  sorting,  separation and recycling of waste products,  garbage,
refuse and trash.  Tenant shall sort and separate such waste products,  garbage,
refuse and trash into such categories as provided by law. Each separately sorted
category  of waste  products,  garbage  and trash  shall be  placed in  separate
receptacles  reasonably approved by Landlord.  Such separate  receptacles may at
Landlord's  option,  be removed from the demised  premises in accordance  with a
collection  schedule prescribed by law. Landlord reserves the right to refuse to
collect or accept from Tenant any waste products, garbage, refuse or trash which
is not separated and sorted as required by law and to require  Tenant to arrange
for such  collection,  at Tenant's sole cost and expense  utilizing a contractor
satisfactory to Landlord. Tenant shall pay all costs, expenses, fines, penalties
or  damages  which may be imposed on  Landlord  or Tenant by reason of  Tenant's
failure to comply with the  provisions  of this  article,  and, at Tenant's sole
cost and expense, shall indemnify,  defend and hold Landlord harmless (including
legal fees and expenses) from and against any actions,  claims and suits arising
from such non-compliance, utilizing counsel reasonably satisfactory to Landlord.

77. ASSIGNMENT,  SUBLETTING, MORTGAGING. A. Tenant will not, by operation of law
or otherwise,  assign, mortgage or encumber this Lease, nor sublet or permit the
Demised  Premises  or any part  thereof  to be used by  others.  The  consent by
Landlord to any assignment or subletting shall not in any manner be construed to
relieve Tenant from obtaining Landlord's express written consent to any other or
further assignment or subletting nor shall any such consent by Landlord serve to
relieve or release Tenant from its  obligations to fully and faithfully  observe
and perform all of the terms, covenants and conditions of this Lease on Tenant's
part to be observed and performed.

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                                                        Tenant__________________
                                                        Landlord________________

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      B.  Upon   obtaining  a  proposed   assignee  or  sublessee,   upon  terms
satisfactory to Tenant,  Tenant shall submit to Landlord in writing (w) the name
of the  proposed  assignee or  subtenant;  (x) the terms and  conditions  of the
proposed assignment or subletting;  (y) the nature and character of the business
and  credit  of the  proposed  assignee  or  subtenant;  (z)  current  financial
statements,   banking  references  and  any  other  references  and  information
reasonably  requested by the Landlord.  Landlord's  consent to any such proposed
assignment or subletting  shall not be unreasonably  withheld or unduly delayed,
provided, however, that Landlord may withhold consent thereto if in the exercise
of its sole judgment it determines that:

      (i)  The  financial  condition  and  general  reputation  of the  proposed
assignee  or  subtenant  are not  consistent  with the extent of the  obligation
undertaken  by the proposed  assignment  or sublease or with the  character  and
reputation of the Building.

      (ii) The proposed use of the Demised  Premises is not  appropriate for the
Building or in keeping with the character of the existing tenancies or permitted
by the  Lease  or with  the  dignity  and  character  of the  Building  (but the
foregoing  shall not be deemed to enlarge  the  purposes  for which the  Demised
Premises are  permitted  to be used as set forth in this Lease).  The use of the
Demised  Premises for  biotechnology  purposes  shall not, in and of itself,  be
deemed to be  inappropriate  for the Building or not in keeping with the dignity
and character of the Building.

      (iii) The nature of the  occupancy of the  proposed  assignee or subtenant
will cause an  excessive  density  of  employees  or  traffic or make  excessive
demands on the Building's services or facilities or in any other way will lessen
the dignity or character of the Building.

      (iv) The Tenant proposes to assign or sublet to one who, at the time, is a
tenant or occupant of the Building,  or a  subsidiary,  division or affiliate of
any such tenant or  occupant of the  Building,(except,  however,  a  subsidiary,
division or affiliate of Tenant), or to one with whom Landlord or its agents are
actively negotiating for space in the Building, or to one who, at the time, is a
tenant or occupant of  premises in any other  building  then owned or managed by
Landlord or its affiliates.

      (v) The Tenant  offers or  advertises to assign or sublet all or a portion
of the Demised  Premises at a rental rate less than the rental rate  Landlord is
then asking for other space in the Building.

      C. Further,  and as a condition of Landlord's consent to any assignment or
subletting:

      (i) Tenant at the time of  requesting  Landlord's  consent shall not be in
material default under this Lease;

      (ii) Each assignee of this Lease shall assume in writing all of the terms,
covenants  and  conditions  of this Lease on the part of Tenant  hereunder to be
performed and observed;

      (iii) An original or duplicate  original of the  instrument  of assignment
and  assumption  or of the  sublease  agreement  shall be  delivered to Landlord
within (5) days following the making thereof;

      (iv) Any  instrument  of  sublease  shall  specifically  state  that  each
sublease is subject to all of the terms, covenants and conditions of this Lease;

      (v)  Landlord  may bill and  Tenant  shall pay all  charges  estimated  by
Landlord  (such estimate shall be subject to adjustment for underage and overage
upon  ascertation  of actual  charges) to be due through the date of  assignment
(without  relieving  Tenant or its assignee of the obligation to pay any balance
due when the actual charges are computed);

      (vi) Each assignee  shall deposit with Landlord and each  sublessee  shall
deposit with  sublessor a sum equal to one month  Minimum Rent as an  additional
security deposit under the Lease;

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                                                        Landlord________________

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      (vii) Any  portion  of the  Demised  Premises  to be sublet  shall  have a
configuration  which does not  adversely  impact on the remainder of the Demised
Premises and has direct access to the public corridor on the floor; and

      (viii)  In the  event  that  this  Lease  shall be  terminated,  then,  at
Landlord's  option,  sublessee  shall  attorn to  Landlord  pursuant to the then
executory terms and conditions of this sublease,  except that Landlord shall not
(1) be liable for any previous  act or omission of Tenant  under such  sublease,
(2) be subject to any offset,  not  expressly  provided in such  sublease,  that
theretofore  accrued  to such  subtenant  against  Tenant or (3) be bound by any
previous  modification  of such  sublease or by any previous  prepayment of more
than one month's fixed rent or any additional rent then due.

      If Tenant shall duly comply with all of the foregoing  then, as aforesaid,
Landlord  shall not  unreasonably  withhold  its consent to such  assignment  or
subletting.

      Notwithstanding  anything  contained  in  this  Article  to the  contrary,
Landlord  shall not be  obligated to entertain or consider any request by Tenant
to assign this Lease,  or sublet all or a part of the  Demised  Premises  unless
each  request  by Tenant is  accompanied  by a  non-refundable  fee  payable  to
Landlord in the amount of Seven Hundred  Fifty  ($750.00)  Dollars  representing
Landlord's  administrative  costs and  expenses in  processing  each of Tenant's
requests.

      D. It is agreed  that if  Landlord  shall  consent to such  assignment  or
subletting,  and Tenant  thereupon  assigns  this  Lease or  sublets  all or any
portion of the  Demised  Premises,  then and in that event  Tenant  shall pay to
Landlord, as Additional Rent, (i) in the event of an assignment during the first
two years of the term  hereof,  the amount of all monies  received  by Tenant in
excess of the Minimum Rent and  additional  rent  payable by Tenant  pursuant to
this Lease for the corresponding period of such assignment and thereafter, fifty
(50%) percent of such amount;  and (ii) in the event of a subletting  during the
first two years of the term  hereof,  the  amount,  if any, by which the Minimum
Rent and  Additional  Rent  payable by the  sublessee to Tenant shall exceed the
Minimum Rent plus Additional Rent allocable to that part of the Demised Premises
affected by such  sublease,  pursuant to the  provisions  of this Lease plus the
amounts,  if any,  payable  by such  sublessee  to Tenant  pursuant  to any side
agreement  as  consideration  (partial  or  otherwise)  for Tenant  making  such
subletting, and thereafter,  fifty (50%) percent of such amount. Such Additional
Rent payments  shall be made monthly within five (5) business days after receipt
of the same by Tenant or within five (5) business  days after Tenant is credited
with the same by the  assignee  or  sublessee.  At the  time of  submitting  the
proposed assignment or sublease to Landlord, Tenant shall certify to Landlord in
writing whether or not the assignee or sublessee has agreed to pay any monies to
Tenant in  consideration  of the making of the assignment or sublease other than
as specified and set forth in such  instruments,  and if so Tenant shall certify
the amounts and time of payment thereof in reasonable detail.

      E. If this Lease shall be assigned, or if the Demised Premises or any part
thereof  be sublet or  occupied  by any person or  persons  other  than  Tenant,
Landlord may, after default by Tenant, collect rent from the assignee, subtenant
or occupant and apply the net amount collected (which may be treated by Landlord
as rent or as use and occupancy) to the Minimum Rent and Additional  Rent herein
reserved but no such  assignment,  subletting,  occupancy or  collection of rent
shall be  deemed a waiver  of the  covenants  in this  Article,  nor shall it be
deemed an acceptance of the assignee,  subtenant or occupant as a tenant,  nor a
release  of  Tenant  from the  full  performance  by  Tenant  of all the  terms,
conditions and covenants of this Lease.

      F. Each permitted assignee shall assume and be deemed to have assumed this
Lease and shall be and remain liable  jointly and severally  with Tenant for the
payment of the Minimum Rent and Additional  Rent and for the due  performance of
all the terms, covenants, conditions and agreements herein contained on Tenant's
part  to be  performed  for  the  term  of  this  Lease  and  any  renewals  and
modifications  hereof.  No assignment  shall be binding on Landlord  unless,  as
hereinbefore  provided,  such  assignee  or Tenant  shall  deliver to Landlord a
duplicate  original of the instrument of assignment which contains a covenant of
assumption by the assignee of all of the obligations  aforesaid and shall obtain
from  Landlord the aforesaid  written  consent prior  thereto.  Any  assignment,
sublease or agreement  permitting the use and occupancy of the Demised  Premises
or any portion thereof,  to which Landlord shall not have expressly consented in
writing shall be deemed null and void and of no force or effect.

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


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<PAGE>

      G.  Tenant  agrees  that  notwithstanding  any  subletting  or  assignment
permitted  by  Landlord,  no  other  or  further  assignment  of this  Lease  or
subletting of all or any part of the Demised Premises by Tenant or any person or
entity claiming  through or under Tenant (except as provided in subparagraph (B)
herein)  shall or will be made  except upon  compliance  with and subject to the
provisions of this Article.

      H. No acceptance of rent by Landlord from a third party shall constitute a
consent to any assignment or subletting.

      I. In lieu of  consenting  to any  subletting  or  assignment  as detailed
above,  the landlord shall have the option to cancel this Lease by giving Tenant
written notice of its intention to do so, in which event such cancellation shall
become  effective  on  the  effective  date  of  such  proposed   subletting  or
assignment, with the same force and effect as if said cancellation date were the
date originally set forth as the expiration date of the term of this Lease.

      J. It is specifically understood and agreed that if Tenant shall utilize a
broker, it shall designate Olmstead Properties, Inc. as its exclusive agent.

78. NEW YORK STATE LAW: This Lease shall be construed and enforced in accordance
with the laws of the State of New York.

79.  TRANSFER PLUS  ADDITIONAL  SECURITY:  Of the security herein referred to in
Paragraph  32, Tenant now has on deposit with the Landlord the sum of $35,000.00
under the terms and  conditions  of a lease dated as of October 18, 1973 between
Landlord  and  Footlight  Parade,  Inc. as tenant,  which lease was  assigned to
Imclone  Systems  Incorporated  as of October 26, 1981 and further amended by an
agreement  dated  October  8,  1985 and an  Additional  Space  and  Modification
Agreement  dated  as of May  13,  1989  respectively  (hereinafter  collectively
referred  to as the  "Lease")  covering  the  entire 6th and 7th  floors,  which
security shall be  transferred to the within Lease.  The Tenant agrees that upon
the execution hereof to pay to Landlord an additional sum of $119,445.50, making
the total security deposit pursuant to Article 32 of the Lease $154,445.50.  The
parties  agree  that at all times  during the term of the  Lease,  Tenant  shall
maintain a security  deposit with Landlord  equal to twice the total of the then
current monthly installment of basic annual rent and average monthly electricity
charges  payable by Tenant.  It is  expressly  understood  and agreed that on or
before the date of any  increase in Minimum Rent as provided in Paragraph 41 (a)
(i), the Tenant shall deposit with the Landlord  additional  security  required.
Any failure or refusal on the part of Tenant to timely make any such  additional
security  deposit  may be  deemed by  Landlord  as a default  under  this  Lease
equivalent to the non-payment of rent.

80. AIR CONDITIONING: Tenant agrees that any air conditioning installed shall be
installed in accordance with any applicable laws, rules and regulations.  Tenant
specifically  agrees  that  under  no  circumstances  shall it  install  any air
conditioning units that extend beyond the building property line. Tenant further
agrees that any air  conditioning  installed shall be installed in such a manner
as to prevent any condensation  waste or water from dripping outside the window.
Failure to comply  with the above shall be deemed a material  default  under the
terms of this Lease. In addition,  Tenant agrees that if there currently  exists
any air conditioning units that extend beyond the Building property line, Tenant
shall be fully  responsible for any and all costs associated with the relocation
of said units to ensure that nothing is extending  beyond the Building  property
line.  In the event  Tenant  fails to  relocate  any air  conditioning  units as
aforesaid,  Landlord may relocate  same for the account of and at the expense of
Tenant by payment or otherwise, without investigation as to the validity thereof
or any offsets or defenses thereto, and Tenant shall promptly reimburse Landlord
as Additional  Rent for all costs,  disbursements,  fees and expenses  including
without limitation, legal fees incurred in connection with the aforesaid.

81. THE OTHER LEASE: It is understood and agreed between the parties hereto that
there exists a lease dated as of October 18, 1973 between Landlord and Footlight
Parade, Inc. as tenant, which lease was assigned to Imclone Systems Incorporated
on October  26, 1981 and which  lease was  amended by an  agreement  dated as of
October 8, 1985 and which lease was further  amended  pursuant to an  Additional
Space and  Modification  Agreement  dated as of May 13, 1989 covering the entire
6th and 7th floors in the Building.  Said lease as amended shall  hereinafter be
referred to as 

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/26/99


                                       16
<PAGE>

the "Other Lease".  Provided and on condition  there exists no monetary  arrears
beyond any applicable notice and cure periods, the term of the Other Lease shall
cease and  expire as of  December  31,  1998 and such date  shall be deemed  the
expiration  date of the Other  Lease,  provided,  however,  Tenant  shall pay to
Landlord all unpaid rents and additional rents up to said expiration date of the
Other Lease although subsequently billed.

82. OVERTIME  ELEVATOR  SERVICE:  The Landlord agrees that the Tenant shall have
access to the building and to at least one (1) elevator to the Demised  Premises
on a  twenty-four  (24) hour a day basis,  seven days a week.  It is agreed that
during  non-business hours if the elevators  malfunction then the Landlord shall
not be responsible to arrange for the  commencement of repairs and restoring the
elevator to service until normal business begins.  Nothing herein shall obligate
the Landlord to provide any additional  services (i.e.  heat,  freight  elevator
service etc.) other than specifically  contained in this Lease. Tenant agrees to
fully cooperate with any and all after hours access systems or requirements that
the Landlord may impose.

      IN WITNESS  WHEREOF,  the parties have  hereunto set their hands and seals
(or in the case of a  corporation,  have had  their  proper  corporate  officers
execute this lease and affix their  corporate seals hereto) as of the date first
above written.

                                    LANDLORD:

                                    180 VARICK STREET CORPORATION

                                    By:_________________________________________
                                             Vice President

                                    TENANT:

                                    IMCLONE SYSTEMS INCORPORATED

                                    By:_________________________________________

                                                                 Please Initial:
                                                        Tenant__________________
                                                        Landlord________________

                                                                Revised: 3/16/99


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