EXHIBIT 10.37.1



                               OFFICE SPACE LEASE

                                       for

                            826 NEWTOWN YARDLEY ROAD
                              NEWTOWN, PENNSYLVANIA

                                 by and between

                          YARDLEY ROAD ASSOCIATES, L.P.
                                  (as Landlord)

                                       and

                         AXCELL BIOSCIENCES CORPORATION
                                   (as Tenant)


                               Date: July 23, 1999



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         THIS LEASE (the "Lease") is made the ____ day of July, 1999 between
YARDLEY ROAD ASSOCIATES, L.P. (herein referred to as "Landlord'1) whose address
1101 West DeKalb Pike, Wayne, PA 19087 and AXCELL BIOSCIENCES CORPORATION
(herein referred to as "Tenant") whose address is.

                                    PREAMBLE

                     BASIC LEASE PROVISIONS AND DEFINITIONS

         In addition to other terms elsewhere defined in this Lease, the
following terms whenever used in this Lease shall have only the meanings set
forth in this section, unless such meanings are expressly modified, limited or
expanded elsewhere herein.

1. ADDITIONAL RENT shall mean all sums in addition to Fixed Basic rent payable
by Tenant to Landlord or to third parties pursuant to the provisions of the
Lease.

2. BROKER(S) shall mean Kelley & Associates, Inc. and Julien J. Studley, Inc.


3.  BUILDING  shall mean 826  Newtown-Yardley  Road,  Newtown,  Pennsylvania  as
described on Exhibit A hereto.


4. BUILDING HOLIDAYS shall be those shown on Exhibit D.


5. DEMISED PREMISES OR PREMISES shall be approximately nine thousand one hundred
forty six (9,146) gross rentable square feet on the lower level of the Building
as designated on Exhibit A- 1 which includes an allocable share of the Common
Facilities as defined in Section 2.

6.  EXHIBITS  shall be the  following,  attached to this Lease and  incorporated
herein and made a part hereof:


            Rider A                            Option to Renew
            Exhibit A                          Location of Building
            Exhibit A-1                        Demised Premises
            Exhibit B                          Rules and Regulations
            Exhibit C                          Landlord's Work
            Exhibit D                          Building Holidays
            Exhibit E                          Tenant Estoppel Certificate
            Exhibit F                          Lease Guaranty








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7. FIXED BASIC RENT shall be calculated and payable as follows:

                   Rate per rentable
        Years     square foot (net of         Monthly            Yearly
        -----       Additional Rent         Installment           Rate
                     and utilities)         -----------           ----
                     --------------
         1               $21.85              $16,653.34        $199,840.10
         2               $22.35              $17,034.43        $204,413.10
         3               $22.85              $17,415.51        $208,986.10
         4               $23.35              $17,796.59        $213,559.10
         5               $23.85              $18,177.68        $218,132.10


8. OFFICE BULDING AREA is set forth on Exhibit A-1


9.  PERMITTED USE shall be general  office and  laboratory  use and for no other
purpose.



10. PROPORTIONATE SHARE shall mean ______ percent.


11. SECURITY DEPOSIT shall be two (2) months Fixed Basic Rent.


12. TARGET DATE shall be October 1, 1999.


13. TERM shall mean five (5) years from the Commencement Date (as defined in
Section 4 of the Lease) unless terminated or extended pursuant to any option or
provision contained herein.






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                                TABLE OF CONTENTS

  Section                                                                Page
  -------                                                                ----
    1.     Definitions....................................................1
    2.     Premises.......................................................1
    3.     Completion of Premises.........................................1
    4.     Term...........................................................2
    5.     Use of Premises................................................2
    6.     Rent...........................................................3
    7.     Insurance......................................................6
    8.     Repairs and Maintenance........................................7
    9.     Utilities and Services.........................................7
    10.    Governmental Regulations.......................................9
    11.    Signs..........................................................9
    12.    Alterations, Additions and Fixtures...........................10
    13.    Mechanic's Liens..............................................11
    14.    Landlord's Right of Entry.....................................11
    15.    Damage by Fire or Other Casualty..............................12
    16.    Non-Abatement of Rent.........................................13
    17.    Indemnification...............................................13
    18.    Condemnation..................................................14
    19.    Quiet Enjoyment...............................................15
    20.    Rules and Regulations.........................................15
    21.    Assignment and Subletting.....................................16
    22.    Tenant's Expansion/Relocation.................................18
    23.    Subordination.................................................18
    24.    Curing Tenant's Defaults......................................19
    25.    Surrender.....................................................19
    26.    Defaults-Remedies.............................................23
    27.    Condition of Premises.........................................23
    28.    Hazardous Substances..........................................24
    29.    Recording.....................................................25
    30.    Broker's Commission...........................................25
    31.    Notices.......................................................26
    32.    Irrevocable Offer, No Option..................................26
    33.    Landlord Inability to Perform.................................26
    34.    Survival......................................................26
    35.    Corporate Tenants.............................................26
    36.    Tenant Representations and Warranties.........................26
    37.    Waiver of Invalidity of Lease.................................26
    38.    Security Deposit..............................................27
    39.    Estoppel Certificate..........................................27
    40.    Rights Reserved by Landlord...................................27
    41.    Miscellaneous.................................................28
    42.    Additional Definitions........................................30
    43.    Guaranty of Lease.............................................31


<PAGE>




         For and in consideration of the covenants herein contained, and upon
the terms and conditions herein set forth, Landlord and Tenant, intending to be
legally bound, agree as follows:

         1. Definitions.  The definitions set forth in the preceding Preamble
shall apply to the same capitalized terms appearing  in  this  Lease  Agreement.
Additional definitions are contained in Section 42 and throughout this Lease.

         2. Premises. Landlord hereby demises and leases the Premises to Tenant
and Tenant hereby leases and takes the Premises from Landlord for the Term (as
defined in Section 4) and upon the terms, covenants, conditions, and provisions
set forth in this Lease Agreement, including the Preamble (this "Lease"). The
Tenant's interest in the Premises as tenant shall include the right, in common
with Landlord and other occupants of the Building, to use driveways, sidewalks,
loading and parking areas, lobbies, hallways and other facilities which are
located within the Property (defined in Section 6) and which are designated by
Landlord from time to time for the use of all of the tenants of the Building
(the "Common Facilities").

         3. Completion of Premises. The Premises shall be completed by Landlord
in accordance with the plans and specifications attached hereto as Exhibit C
(herein called the "Plans") at Landlord's expense provided, however, Tenant
shall pay the sum of Fifty Thousand Dollars ($50,000.00) to Landlord on account
of the tenant improvements to be constructed (the "Tenant's Share"). All
necessary construction shall be commenced promptly following Landlord's
execution and acceptance of this Lease and Tenant's delivery of the Security
Deposit to Landlord and shall be substantially completed and ready for use and
occupancy by Tenant on the Target Date set forth in the Preamble; provided,
however, that the time for substantial completion of the Premises and the
Outside Date (as defined below) shall be extended for additional periods of time
equal to the time lost by Landlord or Landlord's contractors, subcontractors or
suppliers due to strikes or other labor troubles; delays in Tenant's selection
of materials, plans or specifications; modifications or amendments to the plans
or specifications prepared by Tenant; governmental restrictions and limitations;
unavailability or delays in obtaining fuel, labor or materials; war or other
national emergency; accidents; floods; defective materials; fire damage or other
casualties; adverse weather conditions; the inability to obtain building or use
and occupancy permits; or any cause similar or dissimilar to the foregoing which
is beyond the reasonable control of Landlord or Landlord's contractors,
subcontractors or suppliers. The Premises shall be deemed substantially
completed when Tenant is in receipt of a Certificate of Occupancy or Temporary
Certificate of Occupancy (punch list items excepted) and Tenant can use and
occupy the Premises for the Permitted Purpose without unreasonable interference.
Upon substantial completion, Tenant shall immediately pay to Landlord the
Tenant's Share. All construction shall be done in a good and workmanlike manner
and shall comply at the time of completion with all applicable and lawful laws,
ordinances, regulations and orders of the federal, state, county or other
governmental authorities having jurisdiction thereof. Tenant and its authorized
agents, employees and contractors shall have the right, at their own risk,
expense and responsibility, at all reasonable times prior to the Target Date as
hereinafter defined, to


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enter the Premises for the purpose of taking measurements and installing its
furnishings and equipment; provided that Tenant, in so doing, shall not
interfere with or delay the work to be performed hereunder by Landlord, and
Tenant shall use contractors and workmen compatible with the contractors and
workmen engaged in the work to be performed hereunder by Landlord, and Tenant
shall have obtained Landlord's written consent to installing any furnishings or
equipment. If Landlord shall fail to deliver possession of the Premises by the
Target Date for any reason, whether or not within Landlord's control, Landlord
shall not be subject to any liability to Tenant. No failure to deliver the
Premises by the Target Date or any other date shall in any respect affect the
validity or continuance of this Lease of any obligation of Tenant hereunder or
extend the Term of the Lease. Notwithstanding the foregoing, in the event
Landlord fails to substantially complete the Premises (as defined above) on or
before December 1, 1999 (the "Outside Date"), then Tenant shall be entitled to
terminate this Lease upon three (3) days prior written notice given on or before
December 15, 1999.

         4. Term. The Term of this Lease shall commence on the date (the
"Commencement Date") which is the first to occur of (a) the date the Premises
are deemed substantially completed as provided in Section 3 and ready for
occupancy as evidenced by a certificate of occupancy or temporary certificate of
occupancy above and (b) the date on which the Premises are actually occupied by
Tenant. Following the Commencement Date, the Term of this Lease, unless sooner
terminated as expressly provided in this Lease, shall continue until the date of
expiration of the term specified as the Term of Lease in the Preamble plus the
number of days which remain in the calendar month in which such term expires
(the "Term"). Notwithstanding the foregoing, in the event Tenant is not in
default of its obligations hereunder, Tenant shall have the one time right to
terminate this Lease as if such termination date were the date of the expiration
of the Lease subject to the following conditions: (i) Landlord has received
thirty six (36) months of Fixed Basic Rent and Additional Rent; (ii) Tenant give
Landlord in writing at least twelve (12) months prior written notice of such
termination; (iii) Tenant reimburses Landlord for all costs of: (x) unamortized
tenant improvements completed in accordance with Section 3 of this Lease; and
(y) unamortized brokerage commissions paid by Landlord on account of this Lease
the sum of which unamortized tenant improvements and brokerage commissions
Landlord and Tenant acknowledge will be One Hundred Thirty Eight Thousand Three
Hundred Seventy Two and 8/100 Dollars ($138,372.84); and (iv) Tenant pay to
Landlord a termination fee equal to Sixty Five Thousand Five Hundred Forty Six
and 33/100 Dollars ($65,546.33) plus the sum of four (4) months of Additional
Rent. In the event Tenant does not exercise the termination right provided
herein effective as of the end of the thirty sixth (36> month of the Term, the
Tenant shall be deemed to have waived such right. Upon request of Landlord,
Tenant shall enter into a memorandum agreement stipulating the actual
Commencement Date of the Term.

         5. Use of Premises. Tenant shall occupy the Premises throughout the
Term and shall use the same for, and only for, the Permitted Use specified in
the Preamble. The Building is designed to normal building standards for
floor-loading capacity. Tenant shall not use the Premises in such ways which, in
Landlord's judgment, exceed such load limits.


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<PAGE>

         6. Rent. Unless otherwise specifically requested by Landlord at any
time, Fixed Basic Rent, Additional Rent and any other rent or other sums due
under this Lease (hereunder collectively referred to as Rent) shall be paid and
delivered to Landlord's property manager, if any, as agent for Landlord, in the
amounts, time and manner more particularly provided in this Lease.

                  a. Fixed Basic Rent. Commencing on the Commencement Date,
Tenant shall pay, throughout the Term, Fixed Basic Rent in the amount specified
in the Preamble, without notice or demand and without setoff or deduction, in
equal monthly installments equal to one-twelfth of the Fixed Basic Rent
(specified as Monthly Installments in the Preamble), in advance, on the first
day of each calendar month during the Term. If the Commencement Date falls on a
day other than the first day of a calendar month, the fixed Basic Rent shall be
apportioned on a per diem basis for the period between the Commencement Date and
the first day of the first full calendar month in the Term and such apportioned
sum shall be paid on the Commencement Date.

                  b. Additional Rent. Commencing on the Commencement Date,
Tenant shall pay to Landlord, as Additional Rent, in the manner more
particularly set forth below, Tenant's Proportionate Share of Annual Operating
Costs (as defined below) for the Property to the extent same exceeds the sum of
Four and 25/100 Dollars ($4.25) (the "Expense Stop") per rentable square foot of
the Premises:

                    i) Annual Operating Costs. The term "Annual Operating Costs"
shall mean all costs Landlord incurs from owning, operating and maintaining the
Building and the lot or tract of land on which it is situated (the "Property").
Annual Operating Costs shall include, by way of example rather than limitation:
insurance costs, including premiums; fees; Impositions (defined below); costs
for repairs, maintenance and service contracts (including HVAC service contracts
for base Building standard HVAC systems); management fees (reasonably consistent
with market rates); landscaping; snow removal; governmental permits fees; costs
of compliance with governmental orders and regulations; administrative and
overhead expenses; costs of furnishing water, sewer, electricity, gas, fuel, and
other utility services, for use in Common Facilities of the Building and
Property; and the cost of janitorial service and trash removal; excluding,
however, from Annual Operating Costs the following: costs which are treated as
capital expenditures (except as provided in Sections 9(d) andl0(b)) under
generally accepted accounting principles; mortgage debt or ground rents incurred
by Landlord as owner of the Property; income, excess profits, corporate capital
stock or franchise tax imposed or assessed upon Landlord, unless such tax or any
similar tax is levied or assessed, in lieu of all or any part of any currently
existing Imposition or an increase in any currently existing Imposition; leasing
commissions, accountants', consultants' or attorneys' fees, costs and
disbursement and other expenses incurred in connection with negotiations or
disputes with tenants or prospective tenants or associated with the enforcement
of any leases or the defense of Landlord's title to or interest in the Building
in connection with any proceedings involving real property taxes other than
disputes regarding tax assessment and reduction of real property taxes; costs of


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construction of the Building and related facilities and correction of defects in
construction of the Building (including permit, license and inspection fees);
costs of any items or services sold or provided to tenants (including Tenant)
for which Landlord is entitled to be reimbursed by such tenants or which are not
generally provided to all tenants of the Building at the same level of service;
fees and higher interest charges caused by Landlord's refinancing the Building;
all repairs to the interior of the Building of a structural nature (not made
necessary by unusual use by Tenant); costs incurred due to violation by Landlord
or any tenant of the terms and conditions of any lease; overhead and profit
increment paid to subsidiaries or affiliates of Landlord, or to any party as a
result of a noncompetitive selection process, for management or other services
on or to the Building or for supplies or other materials, to the extent that the
costs of such services, supplies or materials exceed the costs that would have
been paid had the services, supplies or materials been provided by unaffiliated
parties on a competitive basis; general overhead and administrative expenses
except salaries of on-site property manager, management secretary and
maintenance man; any compensation paid to clerks, attendants or other persons in
commercial concessions operated by Landlord, rentals and other related expenses
incurred in leasing air conditioning systems, elevators or other equipment
ordinarily considered to be for a capital nature, except equipment which is used
in providing janitorial services and which is not affixed to the Building; all
items and services for which Tenant reimburses Landlord or pays third persons or
which Landlord provides selectively to one or more tenants or occupants of the
Building (other than Tenant) without reimbursement; commissions, advertising,
and promotional expenditures. "Impositions" shall mean all levies, taxes,
assessments, charges, imposts, and burdens, of whatever kind and nature,
ordinary and extraordinary, which are assessed or imposed during the Term by any
federal, state or municipal government or public authority or under any law,
ordinance or regulation thereof or pursuant to any recorded covenants or
agreements upon or with respect to the Property or any part thereof, any
improvements thereto, any personal property necessary to the operation thereof
and owned by Landlord or this Lease. If under the requirements of any state or
local law, a new Imposition is imposed upon Landlord which Tenant is prohibited
by law from paying, Landlord may, as its election, terminate this Lease by
giving written notice thereof to Tenant provided the effect of such imposition
is material and adverse to Landlord's ownership and economic interest in the
Building and Tenant and Landlord are not otherwise able to remedy such adverse
impact on Landlord's interest in the Building.

                    ii)   Estimated Payments - Expense Statement and
Reconciliation.

                       (1)   Landlord shall submit to Tenant as soon as
reasonably possible after the beginning of each calendar year of the Term, but
no greater than 120, days the following:

                         (a) a statement  setting forth (i) the Annual Operating
Costs for the previous calendar year of the Term and (ii) acalculation of
Tenant's Proportionate Share of the increase in the Annual Operating Costs over
the Expense Stop for the previous calendar year (the "Expense Statement"); and


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                         (b) a statement of Landlord's good faith estimate of
the Annual Operating Costs for the current calendar year and a calculation of
Tenant's Proportionate Share of the increase in the Annual Operating Costs over
the Expense Stop for the current calendar year ("Tenant's Estimated
Share").

                  (2)   Beginning with the next installment of Fixed Basic Rent
due thirty (30) days after the delivery of the aforesaid statements to Tenant,
Tenant shall pay to Landlord, on account of its Proportionate Share of the
increase in the Annual Operating Costs over the Expense Stop, a sum equal to the
product of one-twelfth (1/12) of Tenant's Estimated Share and the number of
calendar months elapsed during the current calendar year up to and including the
month payment is made, plus any amounts due from Tenant to Landlord on account
of Annual Operating Costs for any prior period(s) of time.

                  (3)   In the event the Expense Statement indicates the sum of
all payments made by Tenant to Landlord on account of Annual Operating Costs for
the previous calendar year exceed those actually specified in the Expense
Statement, then such credit shall be applied to the next following installments
of Additional Rent due to Landlord until such credit is exhausted.

                  (4)   On the first day of each succeeding calendar month
until such time as Tenant receives a new Expense Statement and statement of
Tenant's Estimated Share, Tenant shall pay to Landlord, on account of its
Proportionate Share of Annual Operating Costs, one-twelfth (1/12) of the then
current Tenant's Estimated Share. Any payment due from Tenant to Landlord, or
any refund due from Landlord to Tenant, on account of Annual Operating Costs not
yet determined as of the expiration of the Term shall be made within thirty (30)
days after submission to Tenant of the next Expense Statement.

               c)  Disputes. Unless Tenant, within thirty (30) days
after any statement of Additional Rent is furnished, shall give notice to
Landlord that Tenant disputes said statement, specifying the basis for such
dispute, each statement furnished to Tenant by Landlord under any provision of
this Section shall be conclusively binding upon Tenant as to the particular
Additional Rent due from Tenant for the period represented thereby. Tenant shall
have the right at reasonable times to examine the records used in making the
aforestated determinations, upon written notice in advance; provided, however,
such disputed amount shall have been paid by Tenant to Landlord. In the event
any such examination shall reveal an adverse variance in excess of 5% of the
total operating expenses of which Tenant is required to pay their Proportionate
Share, Landlord shall reimburse Tenant for the reasonable cost of such
examination within thirty (30) days after demand and the amount of disputed
item(s) overpaid by Tenant. Tenant shall make all payments of Additional Rent
without delay and regardless of any pending dispute over the amount of
Additional Rent that is due in accordance with the statements furnished by
Landlord. Landlord shall have the right to retain Tenant's security deposit
until all Additional Rent payable by Tenant is determined and paid.


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               d)  Independent Covenant; Survival. Tenant's covenant to pay
Rent is independent of any other covenant, agreement, term or condition of this
Lease except as provided in Sections 9(d), 15 and 18 below. Without limitation
of any obligation of Tenant under this Lease which shall survive the expiration
of the Term, the obligation of Tenant to pay Rent shall survive the expiration
of the Term.

         7.  Insurance.

                  a)  Liability. Tenant, at Tenant's sole cost and expense,
shall maintain and keep insurance in effect throughout the Term against
liability for bodily injury (including death) and property damage in or about
the Premises or the Property under a policy of comprehensive general public
liability insurance, with such limits as to each as may be reasonably required
by Landlord from time to time, but not less than $2,000,000.00 for each person
and $5,000,000.00 in the aggregate for bodily injury (including death) to more
than one (1) person and $2,000,000.00 for property damage. The policies of
comprehensive general public liability insurance shall name Landlord (and if
requested, any mortgagee of Landlord) as an additional party. Each such policy
shall provide that it shall not be cancelable without at least thirty (30) days
prior written notice to Landlord and to any mortgagee named in an endorsement
thereto and shall be issued by an insurer and in a form satisfactory to
Landlord. At least ten (10) days prior to the Commencement Date, and thereafter
upon Landlord's request, a certificate of insurance shall be delivered to
Landlord proving compliance with the foregoing requirements. If Tenant shall
fail, refuse or neglect to obtain or to maintain any insurance that it is
required to provide or to furnish Landlord with satisfactory evidence of
coverage on any such policy upon demand, Landlord shall have the right to
purchase such insurance. All payments made by Landlord for such insurance shall
be recoverable by Landlord from Tenant, together with interest thereon, as
Additional Rent promptly upon demand. Notwithstanding anything contained herein
to the contrary, Tenant may self-insure all of its personal property situated
within the Premises against property damage and destruction.

                  b)  Waiver of Subrogation. The parties to this Lease each
release the other, to the extent of the releasing party's insurance coverage,
from any and all liability for any loss or damage covered by such insurance
which may be inflicted upon the property of such party even if such loss or
damage shall be brought about by the fault or negligence of the other party, its
agents or employees. If any policy does not permit such a release of liability
and a waiver of subrogation, and if the party to benefit therefrom requests that
such a waiver be obtained, the other party agrees to obtain an endorsement to
its insurance policies permitting such waiver of subrogation if it is available.
If an additional premium is charged for such waiver, the party benefiting
therefrom agrees to pay the amount of such additional premium promptly upon
demand. In the event a party is unable to obtain such a waiver, it shall
immediately notify the other party of its inability. In the absence of such
notifications, each party shall be deemed to have obtained such waiver of
subrogation.

                  c)  Increase of Premiums. Tenant will not do anything or
fail to do anything or permit anything to be done which will cause the cost of
Landlord's insurance


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to increase or which will prevent Landlord from procuring insurance (including
but not limited to public liability insurance) from companies, and in a form,
satisfactory to Landlord. If any breach of this subsection (c) by Tenant shall
cause the rate of fire or other insurance to be increased, Tenant shall pay the
amount of such increase as Additional Rent promptly upon demand. If Tenant does
anything or fails to do anything or permits anything to be done for which
insurance cannot be obtained, Landlord may terminate this Lease upon written
notice to Tenant.

         8.   Repairs and Maintenance.

                  a)   Tenant shall, throughout the Term and at Tenant's
sole cost and expense, keep and maintain the Premises in a neat and orderly
condition; and, upon expiration of the Term, Tenant shall leave the Premises in
good order and condition, ordinary wear and tear, damage by fire or other
casualty alone excepted, and for that purpose and except as stated, Tenant will
make all necessary repairs and replacements. Tenant shall not permit any waste,
damage or injury to the Premises. Tenant shall not use or permit the use of any
portion of the Common Facilities for other than their intended use as specified
by the Landlord from time to time.

                  b)   Landlord shall, throughout the Term, make all
necessary repairs to the structural elements of the Premises and other
improvements located on the Property; provided, however, that Landlord shall
have no responsibility to make any repairs unless and until Landlord receives
written notice of the need for such repair or otherwise has actual knowledge of
the need for such repair. Landlord shall keep and maintain all Common Facilities
of the Property and any sidewalks, parking areas, curbs and access ways
adjoining the Property in a clean and orderly condition, free of accumulation of
dirt and rubbish and shall keep and maintain all landscaped areas within the
Property in a neat and orderly condition.

                  c)   Notwithstanding the foregoing, repairs and
replacements to the Premises and the Property arising out of or caused by
Tenant's use, manner of use or occupancy of the Premises, by Tenant's
installation of alterations, additions, improvements, trade fixtures or
equipment in or upon the Premises or by any act or omission of Tenant or any
employee, agent, contractor or invitee of Tenant shall be made at Tenant's sole
cost and expense and Tenant shall pay Landlord the cost of any such repair or
replacement, as Additional Rent, upon demand.

         9.   Utilities and Services.

                  a)   Landlord shall furnish the Premises with electricity,
heating and air conditioning for the normal use and occupancy of the Premises as
general offices and labs 24 hours per day 7 days per week throughout the Term.
Tenant agrees to pay as Additional Rent all charges for electricity, light, heat
or other utility used by Tenant at the Premises. Tenant shall pay for the
consumption of such gas and electricity based upon its metered usage. If no
meter is installed, Tenant shall pay its Proportionate Share of any utility
charges covering the Demised Premises and the remainder of the Building.



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    Landlord shall have the right to make an equitable allocation of the utility
charges for utilities which are not separately submetered based upon a utility
survey or meters. Tenant shall pay all bills for separately metered utility
usage within thirty (30) days after receipt thereof, and any non-payment or late
payment of such utility bills shall be deemed a default under the terms of this
Lease. All charges for installation and repairs of any meters servicing the
Premises shall be payable by Tenant as Additional Rent and shall be paid when
the same shall become due.

                  b)   Within the Common Facilities of the Building,
Landlord shall furnish reasonably: (i) adequate electricity, (ii) hot and cold
water, (iii) lavatory supplies, (iv) automatically operated elevator service,
(v) normal and customary cleaning services (on a five-day a week basis) after
business hours, (vi) heat and air conditioning in season, (vii) landscaping,
(viii) parking lot maintenance, (ix) common area maintenance and (x) snow and
ice removal. Tenant shall be responsible for its Proportionate Share of the cost
of such services in accordance with Section 6(b) hereof. Landlord shall provide
janitorial service to the Premises, five days per week, after regular business
hours, and the costs of such service will be passed through to Tenant as set
forth in Section 6. Tenant shall be permitted to contract for its own janitorial
services in which event Tenant shall receive a credit against Fixed Basic Rent
in the amount of $0.90 per rentable square foot of the Premises and the Expense
Stop shall be reduced to $3.35 per rentable square foot of the Premises.

                  c)   Landlord shall not be liable for any damages to
Tenant resulting from the quality, quantity, failure, unavailability or
disruption of any services beyond the reasonable control of Landlord and the
same shall not constitute a termination of this Lease or an actual or
constructive eviction or entitle Tenant to an abatement of rent. Landlord shall
not be responsible for providing any services not specifically provided for in
this Lease.

                  d)   Landlord's services shall be provided in a manner
consistent with the operation of comparable buildings in the competitive area of
the Building. Notwithstanding anything to the contrary contained in this Lease,
if (i) Landlord ceases to furnish any service in the Building, and Tenant
notifies Landlord of such cessation in writing (the "Interruption Notice"), (ii)
such cessation does not arise as a result of the gross negligence of Tenant
(iii) such cessation is not caused by a fire or other casualty (in which case
Section 15 shall control), (iv) the repair or restoration of such service is
reasonably within the control of Landlord, and (v) as a result of such
cessation, the Premises or material portion thereof, is rendered untenatable
(meaning that Tenant is unable to use the Premises or a substantial portion
thereof in the normal course of its business) and Tenant, in fact ceases to use
the Premises, or material portion thereof, then, commencing on the fifth (5")
Business Day after the later to occur of the date the Premises (or material
portion thereof) becomes untenatable, the date Tenant ceases to use such space
and the date Tenant provides Landlord with an Interruption Notice, all rent
hereunder shall be abated on a per diem basis for each day of such interruption
based upon the percentage of the Premises so rendered untenantable and not used
by Tenant and such abatement shall continue until the date the Premises becomes
tenantable again. In making all repairs and restorations hereunder, and in
fulfilling its obligations under this



                                       8
<PAGE>


     Lease, Landlord shall use reasonable efforts to minimize the disruption of
Tenant's use and enjoyment of the Premises.


         10.   Governmental Regulations.

                  a)   Landlord and Tenant shall comply with all laws,
ordinances, notices, orders, rules, regulations and requirements of all federal,
state and municipal government or any department, commission, board of officer
thereof, or of the National Board of Fire Underwriters or any other body
exercising similar functions, relating to the Premises or to the use or manner
of use of the Property. Tenant shall not knowingly do or commit, or suffer to be
done or committed anywhere in the Building, any act or thing contrary to any of
the laws, ordinances, regulations and requirements referred to in this Section.
Tenant shall give Landlord prompt written notice of any accident in the Premises
and of any breakage, defect or failure in any of the systems or equipment
servicing the Premises or any portion of the Premises.

                  b)   Tenant shall pay its Proportionate Share of the cost
of capital improvements which Landlord shall install or construct in compliance
with governmental requirements which take effect after the commencement of the
Term hereof. Tenant's Proportionate Share shall be determined based upon the
estimated life of the capital investment item, determined by Landlord in
accordance with generally accepted accounting principles, and shall include a
cost of capital funds adjustment equal to the rate of Interest on the
unamortized portion of all such costs. Tenant shall only have to pay for the
portion of the useful life of the capital improvement which falls within the
Term. Tenant shall thus make payments in equal annual installments for such
capital improvements until the Term expires or until the cost of the improvement
has been fully paid for, whichever first occurs; such payments shall be computed
by Landlord at the time of installation of the capital improvement in the same
manner as Landlord makes computations of Tenant's share of the Annual Operating
Costs pursuant to Section 6(b) (ii).

                  c)   Tenant shall pay all taxes imposed upon Tenant's
furnishings, trade fixtures, equipment or other personal property.

         11.   Signs. Except for signs which are located wholly within the
interior of the Premises and which are not visible from the exterior of the
Premises, Tenant shall not place, erect, maintain or paint any signs upon the
Premises or the Property unless the design of such signs are approved by
Landlord in writing which approval may be withheld in Landlord's sole
discretion. Tenant shall be solely responsible for all costs and expenses
associated with the erection of any signs upon the Premises and shall be
obligated to obtain and provide to Landlord any and all necessary permits prior
to the placement or erection of such signs. Notwithstanding the foregoing,
Tenant shall be permitted (at its sole cost and expense) to place its name (as
directed by Landlord) on any Building monument sign erected at the Building by
Landlord which contains the names of tenants in the Building. In addition,
Tenant may place its name and logo on the door



                                       9
<PAGE>


to its Premises such signage to be generally consistent with the Building
standard signage.





                                       10
<PAGE>


          12.   Alterations, Additions and Fixtures.

                  a)   Tenant shall have the right to install in the
Premises any trade fixtures; provided, however, that no such installation and no
removal thereof shall be permitted which affects any structural component of the
Building or Premises and that Tenant shall repair and restore any damage or
injury to the Premises or the Property caused by installation or removal.

                  b)   Tenant shall not make or permit to be made any
alterations, improvements or additions to the Premises or Property without on
each occasion first presenting plans and specifications to Landlord and
obtaining Landlord's prior written consent, which shall not be unreasonably
withheld or delayed, but may be conditioned upon compliance with reasonable
requirements of Landlord including, without limitation, the filing of mechanics'
lien waivers by Tenant's contractors and the submission of written evidence of
adequate insurance coverage naming Landlord as an additional insured thereunder.
If Landlord consents to any proposed alterations, improvements or additions or
Tenant's contractor performs any of the work identified in Section 3 of this
Lease Agreement, then Tenant shall make the proposed alterations, improvements
and additions at Tenant's sole cost and expense provided that: (i) Tenant
supplies any necessary permits; (ii) such alterations and improvements do not,
in Landlord's judgment, impair the structural strength of the Building or any
other improvements or reduce the value of the Property; (iii) Tenant takes or
causes to be taken all steps that are otherwise required by Section 13 of this
Lease and that are required or permitted by law in order to avoid the imposition
of any mechanic's, laborer's or materialman's lien upon the Premises or the
Property; (iv) Tenant uses a contractor approved by Landlord; (v) the occupants
of the Building and of any adjoining real estate owned by Landlord are not
unreasonably annoyed or disturbed by such work; (vi) the alterations,
improvements or additions shall be installed in accordance with the approved
plans and specifications and completed according to a construction schedule
approved by Landlord; and (vii) Tenant provides insurance of the types and
coverage amounts required by Landlord. Any and all alterations, improvements and
additions to the Premises which are constructed, installed or otherwise made by
Tenant shall be the property of Tenant until the expiration or sooner
termination of this Lease; at that time all such alterations and additions shall
remain on the Premises and become the property of Landlord without payment by
Landlord unless, upon approval, Landlord instructs Tenant to remove the same at
the termination of the Lease in which event Tenant will remove such alterations,
improvements and additions, and repair and restore any damage to the Property
caused by the installation or removal. Notwithstanding the foregoing, Tenant,
without Landlord's consent, may make alterations, improvements and additions to
the Premises which are non structural, non adverse, do not affect the base
Building systems and which do not cost in the aggregate (per project) more than
$50,000.00. Notwithstanding anything to the contrary contained in this Lease,
Landlord may withhold its approval to any proposed alterations, additions or
improvements to the Premises in its absolute and sole discretion with respect to
any such alteration, addition or improvement which Landlord determines involves
any modification to the Building's exterior or its structural, electrical,



                                       11

<PAGE>


mechanical or plumbing systems, or any components thereof.

         13.    Mechanic's Liens. Tenant shall promptly pay any contractors and
materialmen who supply labor, work or materials to Tenant at the Premises or the
Property so as to minimize the possibility of a lien attaching to the Premises
or the Property. Tenant shall take all steps permitted by law in order to avoid
the imposition of any mechanic's, laborer's or materialman's lien upon the
Premises or the Property. Should any such lien or notice of lien be filed for
work performed for Tenant other than by Landlord, Tenant shall cause such lien
or notice of lien to be discharged of record by payment, deposit, bond or
otherwise within fifteen (15) days after the filing thereof or after Tenant's
receipt of notice thereof, whichever is earlier, regardless of the validity of
such lien or claim. If Tenant shall fail to cause such lien or claim to be
discharged and removed from record within such fifteen (15) day period, then,
without obligation to investigate the validity thereof and in addition to any
other right or remedy Landlord may have, Landlord may, but shall not be
obligated to, contest the lien or claim or discharge it by payment, deposit,
bond or otherwise; and Landlord shall be entitled to compel the prosecution of
an action for the foreclosure of such lien by the lienor and to pay the amount
of the judgment in favor of the lienor with interest and costs. Any amounts so
paid by Landlord and all costs and expenses including, without limitation,
attorneys' fees incurred by Landlord in connection therewith, together with
Interest from the respective dates of Landlord's making such payment or
incurring such cost or expense, which shall constitute Additional Rent payable
hereunder promptly upon demand therefore. Nothing in this Lease is intended to
authorize Tenant to do or cause any work or labor to be done or any materials to
be supplied for the account of Landlord, all of the same to be solely for
Tenant's account and at Tenant's risk and expense. Further, notwithstanding
anything to the contrary contained in this Lease, nothing contained in or
contemplated by this Lease shall be deemed or construed in any way to constitute
the consent or request by Landlord for the performance of any work or services
or the furnishing of any materials for which any lien could be filed against the
Premises or the Building or the Property or any part of any thereof, nor as
giving Tenant any right, power or authority to contract or permit the
performance of any work or services or the furnishing of any materials for which
any lien could be filed against the Premises, the Building, the Property or any
part of any thereof. Throughout this Lease the term "mechanic's lien" is used to
include any lien, encumbrance or charge levied or imposed upon the Premises or
the Property or any interest therein or income therefrom on account of any
mechanic's, laborer's or materialman's lien or arising out of any debt or
liability to or any claim or demand of any contractor, mechanic, supplier,
materialman or laborer and shall include without limitation any mechanic's
notice of intention given to Landlord or Tenant, any stop order given to
Landlord or Tenant, any notice of refusal to pay naming Landlord or Tenant and
any injunctive or equitable action brought by any person entitled to any
mechanic's lien.

         14.   Landlord's Right of Entry.

                  a)   Tenant shall permit Landlord and the authorized
representatives of Landlord and of any mortgagee or any prospective mortgagee to
enter the Premises at all reasonable times, with 24 hour notice to Tenant
(except in the event of an emergency), for



                                       12
<PAGE>


the purpose of (i) inspecting the Premises or (ii) making any necessary repairs
to the Premises or to the Building and performing any work therein. In all
events Landlord shall comply, to the extent practical under the conditions, with
all reasonable safety precautions Tenant may establish from time to time. During
the progress of any work on the Premises or the Building, Landlord shall use its
reasonable best efforts not to inconvenience Tenant, but shall not be liable for
inconvenience, annoyance, disturbance, loss of business or other damage to
Tenant by reason of making any repair or by bringing or storing materials,
supplies, tools and equipment in the Premises during the performance of any
work, and the obligations of Tenant under this Lease shall not be thereby
affected in any manner whatsoever.

                  b)   Landlord shall have the right at all reasonable times
to, with prior notice to Tenant, enter and to exhibit the Premises for the
purpose of inspection or showing the Premises in connection with a sale or
mortgage and, during the last six (6) months of the Term, to enter upon and to
exhibit the Premises to any prospective tenant.

         15.   Damage by Fire or Other Casualty.

                  a)   If the Premises or Building is damaged or destroyed
by fire or other casualty, Tenant shall promptly notify Landlord whereupon
Landlord shall, subject to the consent of Landlord's present or future mortgagee
and to the conditions set forth in this Section 15, repair, rebuild or replace
such damage and restore the Premises to substantially the same condition as the
Premises were in immediately prior to such damage or destruction; provided,
however, that Landlord shall only be obligated to restore such damage or
destruction to the extent of the proceeds of fire and other extended coverage
insurance policies. Notwithstanding the foregoing, if the Premises is destroyed
or damaged to the extent that in Landlord's sole judgment the Premises cannot be
repaired or restored within one hundred eighty (180) days after such casualty,
Landlord or Tenant may, subject to the rights of Landlord's mortgagee, terminate
this Lease by written notice to Tenant within sixty (60) days after the date of
such casualty. In the event such restoration or repair cannot be completed prior
to eighteen (18) months prior to the last day of the Term, Landlord may
terminate this Lease upon written notice to Tenant, except that Tenant may cause
Landlord to withdraw its notice of termination (provided in this sentence only)
by electing to extend the Term of this Lease pursuant to any option to extend
the Term.

                  b)   The repair, rebuilding or replacement work shall be
commenced promptly and completed with due diligence, taking into account the
time required by Landlord to effect a settlement with, and procure insurance
proceeds from, the insurer, and for delays beyond Landlord's reasonable control.

                  c)   The net amount of any insurance proceeds recovered by
reason of the damage or destruction of the Building (meaning the gross insurance
proceeds excluding proceeds received pursuant to a rental coverage endorsement
and the cost of adjusting the insurance claim and collecting the insurance
proceeds) shall be applied towards the cost of restoration. Notwithstanding
anything to the contrary in this Lease Agreement, if in



                                       13
<PAGE>


Landlord's sole opinion the net insurance proceeds will not be adequate to
complete such restoration, Landlord shall have the right to terminate this Lease
and all the unaccrued obligations of the parties hereto by sending a written
notice of such termination to Tenant specifying a termination date no less than
ten (10) days after its transmission; provided, however, that Tenant may require
Landlord, except during the last two (2) years of the Term, to withdraw the
notice of termination by agreeing to pay the cost of restoration in excess of
the net insurance proceeds and by giving Landlord adequate security for such
payment prior to the termination date specified in Landlord's notice of
termination. If the net insurance proceeds are more than adequate, the amount by
which the net insurance proceeds exceed the cost of restoration will be retained
by Landlord or applied to repayment of any mortgage secured by the Premises.

                  d)   Landlord's obligation or election to restore the
Premises under this Section shall be subject to the terms of any present or
future mortgage affecting the Premises and to the mortgagee's consent if
required in the mortgage and shall not, in any event, include the repair,
restoration or replacement of the fixtures, improvements, alterations, furniture
or any other property owned, installed, made by, or in the possession of Tenant.

                  e)   Landlord shall maintain insurance against loss or
damage to the Building by fire and such other casualties as may be included
within fire and extended coverage insurance or all-risk insurance, together with
a rental coverage endorsement or other comparable form of coverage. If Tenant is
dispossessed of the Premises due to fire or other casualty, Tenant will receive
an abatement of its Fixed Basic Rent during the period Tenant is dispossessed to
the extent of payments received by Landlord from the carrier providing the
rental coverage endorsement.

         16.   Non-Abatement of Rent. Except as otherwise expressly provided in
subsection 9(d), subsection 15(e) and as to condemnation in subsections 18(a)
and (b) there shall be no abatement or reduction of the Fixed Basic Rent,
Additional Rent or other sums payable hereunder for any cause whatsoever and
this Lease shall not terminate, nor shall Tenant be entitled to surrender the
Premises, in the event of fire, casualty or condemnation or any default by
Landlord under this Lease.

         17.   Indemnification

                  a)   Unless such loss, costs or damages were caused by
negligence of Landlord, its employees, agents or contractors, Tenant hereby
agrees to indemnify, defend and hold the Landlord and its employees, agents and
contractors harmless from any loss, costs and damages (including reasonable
attorney's fees and costs) suffered by Landlord, its agents, employees or
contractors, as a result of any claim by a third party, its agents, employees or
contractors arising from Tenant's occupancy of the Premises. Tenant shall have
the right to designate counsel acceptable to Landlord, such approval not be
unreasonably withheld, to assume the defense of any such third party claim on
behalf of itself and Landlord. Landlord shall not have the right to settle any
claim without the consent of Tenant. This indemnity shall survive the expiration
or termination of this Lease.



                                       14
<PAGE>

                  b)   Unless such loss, costs or damages were caused by
negligence of Tenant, its employees, agents or contractors, Landlord hereby
agrees to indemnify, defend and hold the Tenant and its employees, agents and
contractors harmless from any loss, costs and damages (including reasonable
attorney's fees and costs) suffered by Tenant, its agents, employees or
contractors, as a result of any claim by a third party, its agents, employees or
contractors arising from Landlord's ownership of the Property. Landlord shall
have the right to designate counsel acceptable to Tenant, such approval not be
unreasonably withheld, to assume the defense of any such third party claim on
behalf of itself and Tenant. Tenant shall not have the right to settle any claim
without the consent of Landlord. This indemnity shall survive the expiration or
termination of this Lease.

                  b)   If Landlord brings any action under this Lease
Agreement, Tenant agrees in each case to pay Landlord's reasonable attorney's
fees and other costs and expenses incurred by Landlord in connection therewith;
provided, however, the Landlord prevails in such action.

         18.   Condemnation.

                  a)Termination. If (i) all of the Premises are covered
by a condemnation; or (ii) any of the Premises is covered by a condemnation and
the remaining part is insufficient for the reasonable operation therein of
Tenant's business; or (iii) subject to the provisions of subsection 1 8(b)(i)
hereof, any of the Property is covered by a condemnation and, in Landlord's sole
opinion, it would be impractical or the condemnation proceeds are insufficient
to restore the remainder of the Property; then, in any such event, this Lease
shall terminate and all obligations hereunder shall cease as of the date upon
which possession is taken by the condemnor. Upon such termination the Fixed
Basic Rent and all Additional Rent herein reserved shall be apportioned and paid
in full by Tenant to Landlord to that date and all such rent prep aid for
periods beyond that date shall forthwith be repaid by Landlord to Tenant. In the
event such restoration cannot be completed prior to eighteen (18) months prior
to the last day of the Term, Landlord may terminate this Lease upon written
notice to Tenant, except that Tenant may cause Landlord to withdraw its notice
of termination provided in this sentence only) by electing to extend the Term of
this Lease pursuant to any option to extend the Term.


                  b)   Partial Condemnation.

                     i)  If there is a partial condemnation and Landlord decides
to terminate pursuant to subsection 18(a) (iii) hereof then Tenant may require
Landlord, except during the last two (2) years of the Term, to withdraw its
notice of termination by: [A] giving Landlord written notice thereof within ten
(10) days from transmission of Landlord's notice to Tenant of Landlord's
intention to terminate, [B] agreeing to pay the cost of restoration in excess of
the condemnation proceeds reduced by those sums


                                       15
<PAGE>

expended by Landlord in collecting the condemnation proceeds, and [C] giving
Landlord adequate security for such payment within such ten (10) day period.

                    ii)  If there is a partial condemnation and this Lease has
not been terminated pursuant to subsection (a) hereof, Landlord shall restore
the Building and the improvements which are part of the Premises to a condition
and size as nearly comparable as reasonably possible to the condition and size
thereof immediately prior to the date upon which possession shall have been
taken by the condemnor; provided, however, that Landlord shall only be obligated
to restore such damage from condemnation to the extent possible with the award
damage. If the condemnation proceeds are more than adequate to cover the cost of
restoration and the Landlord's expenses in collecting the condemnation proceeds,
any excess proceeds shall be retained by Landlord or applied to repayment of any
mortgage secured by the Premises.

                    iii) If there is a partial condemnation and this Lease has
not been terminated by the date upon which the condemnor obtains possession, the
obligations of Landlord and Tenant under this Lease shall be unaffected by such
condemnation except that there shall be an equitable abatement for the balance
of the Term of the Fixed Basic Rent according to the value of the Premises
before and after the date upon which the condemnor takes possession. In the
event that the parties are unable to agree upon the amount of such abatement,
either party may submit the issue to arbitration.

                  c)   Award. In the event of a condemnation affecting
Tenant, Tenant shall have the right to make a claim against the condemnor for
removal expenses and moving expenses, loss of business and any other claims
Tenant may have; provided and to the extent, however, that such claims or
payments do not reduce the sums otherwise payable by the condemnor to Landlord.
Except as aforesaid, Tenant hereby waives all claims against Landlord and
against the condemnor, and Tenant hereby assigns to Landlord all claims against
the condemnor including, without limitation, all claims for leasehold damages
and diminution in value of Tenant's leasehold interest.

         19.  Quiet Enjoyment. Tenant, upon paying the Fixed Basic Rent,
Additional Rent and other charges herein required and observing and keeping all
covenants, agreements and conditions of this Lease, shall quietly have and enjoy
the Premises during the Term without hindrance or molestation by anyone claiming
by or through Landlord, subject, however, to the exceptions, reservations and
conditions of this Lease.

         20.  Rules and Regulations. The Landlord hereby reserves the right to
prescribe, from time to time, at its sole discretion, reasonable rules and
regulations (herein called the "Rules and Regulations") attached hereto as
Exhibit B governing the use and enjoyment of the Premises and the remainder of
the Property. The Rules and Regulations shall not materially interfere with the
Tenant's use and enjoyment of the Premises in accordance with the provisions of
this Lease for the Permitted Use and shall not increase or modify Tenant's
obligations under this Lease. In the event of a conflict between the Lease
Agreement and such rules and regulations, the Lease Agreement shall control. The
Tenant shall comply at all times with the Rules and Regulations and shall cause
its



                                       16
<PAGE>

agents, employees, invitees, visitors, and guests to do so.

         21.   Assignment and Sublease. Tenant may assign or sublease the within
Lease to any party subject to the following:

                  a)   In the event Tenant desires to assign this Lease or
sublease seventy percent (70%) or more of the Premises to any other party,
Tenant shall provide written notice of the terms and conditions of such
assignment or sublease to Landlord prior to the effective date of any such
sublease or assignment, and, prior to such effective date, the Landlord shall
have the option, exercisable by written notice to Tenant within ten (10)
business days of Landlord's receipt of written notice from Tenant, to: (i)
sublease such space from Tenant at the lower rate of (a) the rental rate per
rentable square foot of Fixed Basic Rent and Additional Rent then payable
pursuant to this Lease or (b) the terms set forth in the proposed sublease (ii)
recapture (in the case of subletting) that portion of the Premises to be sublet
or all of the Premises (in the case of an assignment) ("Recapture Space") so
that such prospective subtenant or assignee shall then become the sole Tenant of
Landlord hereunder, or (iii) recapture the Recapture Space for Landlord's own
use, whereupon Tenant shall be fully released from any and all obligations
hereunder with respect to the Recapture Space.

                  b)   In the event that the Landlord elects not to
recapture the Lease as hereinabove provided, the Tenant may nevertheless assign
this Lease or sublet the whole or any portion of the Premises, subject to the
Landlord's prior written consent, on the basis of the following terms and
conditions:

                    i)  The Tenant shall provide to the Landlord the name and
address of the assignee or subtenant.

                    ii) The assignee or subtenant shall assume, by written
instrument, all of the obligations of this Lease, and a copy of such assumption
agreement shall be furnished to the Landlord within ten (10) days of its
execution. Any sublease shall expressly acknowledge that said subtenant's rights
against Landlord shall be no greater than those of Tenant.

                    iii) The Tenant and each assignee shall be and remain liable
for the observance of all the covenants and provisions of this Lease, including,
but not limited to, the payment of Fixed Basic Rent and Additional Rent reserved
herein, through the entire Term of this Lease, as the same may be renewed,
extended or otherwise modified.

                    iv)  The Tenant and any assignee shall promptly pay to
Landlord fifty percent (50%) of the net profit received from such subleasing or
assignment. Net profit will be calculated after deducting the Tenant's direct
costs of implementing the sublease or assignment.

                    v)   In any event, the acceptance by the Landlord of any
rent from the assignee or from any of the subtenants or the failure of the
Landlord to insist upon a strict



                                       17
<PAGE>


performance of any of the terms, conditions and covenants herein shall not
release the Tenant herein, nor any assignee assuming this Lease, from any and
all of the obligations herein during and for the entire Term of this Lease.

                    vi)  Tenant acknowledges that its sole remedy with respect
to any assertion that Landlord's failure to consent to any sublet or assignment
is unreasonable shall be the remedy of specific performance and Tenant shall
have no other claim or cause of action against Landlord as a result of
Landlord's actions in refusing to consent thereto.

                  c)   If Tenant is a corporation other than a corporation
whose stock is listed and traded on a nationally recognized stock exchange, the
provisions of subsection a hereof shall apply to a transfer (however
accomplished, whether in a single transaction or in a series of related or
unrelated transactions) of stock (or any other mechanism such as, by way of
example, the issuance of additional stock, a stock voting agreement or change in
class(es) of stock) which results in a change of control of Tenant as if such
transfer of stock (or other mechanism) which results in a change of control of
Tenant were an assignment of this Lease, and if Tenant is a partnership or joint
venture, said provisions shall apply with respect to a transfer (by one or more
transfers) of an interest in the distributions of profits and losses of such
partnership or joint venture (or other mechanism, such as, by way of example,
the creation of additional general partnership or limited partnership interests)
which results in a change of control of such a partnership or joint venture, as
if such transfer of an interest in the distributions of profits and losses of
such partnership or joint venture which results in a change of control of such
partnership or joint venture were an assignment of this Lease; but said
provisions shall not apply to transactions with a corporation into or with which
Tenant is merged or consolidated or to which all or substantially all of
Tenant's assets are transferred or to any corporation which controls or is
controlled by Tenant or is under common control with Tenant, provided that in
the event of such merger, consolidation or transfer of all or substantially all
of Tenant's assets (i) the successor to Tenant has a net worth computed in
accordance with generally accepted accounting principles at least equal to the
greater of (1) the net worth of Tenant immediately prior to such merger,
consolidation or transfer, or (2) the net worth of Tenant herein named on the
date of this Lease, and (ii) proof satisfactory to Landlord of such net worth
shall have been delivered to Landlord at least ten (10) days prior to the
effective date of any such transaction. Notwithstanding the foregoing, Tenant
may assign its rights under this lease to an entity which is in common control
with Tenant, is controlled by Tenant or controls Tenant as well as to an entity
in which Tenant or any of the foregoing is a principal investor provided,
however, no such assignment shall relieve Tenant or Guarantor of its obligations
hereunder.

                  d)   In the event that any or all of Tenant1s interest in
the Premises and/or this Lease is transferred by operation of law to any
trustee, receiver, or other representative or agent of Tenant, or to Tenant as a
debtor in possession, and subsequently any or all of Tenant's interest in the
Premises and/or this Lease is offered or to be offered by Tenant or any trustee,
receiver, or other representative or agent of Tenant as to its estate or
property (such person, firm or entity being hereinafter referred to as the
"Grantor", for assignment, conveyance, lease, or other disposition to a person,
firm or entity other than Landlord (each



                                       18
<PAGE>


such transaction being hereinafter referred to as a "Disposition"), it is agreed
that Landlord has and shall have a right of first refusal to purchase, take, or
otherwise acquire, the same upon the same terms and conditions as the Grantor
thereof shall accept upon such Disposition to such other person, firm, or
entity; and as to each such Disposition the Grantor shall give written notice to
Landlord in reasonable detail of all of the terms and conditions of such
Disposition within twenty (20) days next following its determination to accept
the same but prior to accepting the same, and Grantor shall not make the
Disposition until and unless Landlord has failed or refused to accept such right
of first refusal as to the Disposition, as set forth herein. Landlord shall have
sixty (60) days next following its receipt of the written notice as to such
Disposition in which to exercise the option to acquire Tenant's interest by such
Disposition, and the exercise of the option by Landlord shall be effected by
notice to that effect sent to the Grantor; but nothing herein shall require
Landlord to accept a particular Disposition or any Disposition, nor does the
rejection of any one such offer of first refusal constitute a waiver or release
of the obligation of the Grantor to submit other offers hereunder to Landlord.
In the event Landlord accept such offer of first refusal, the transaction shall
be consummated pursuant to the terms and conditions of the Disposition described
in the notice to Landlord. In the event Landlord rejects such offer of first
refusal, Grantor may consummate the Disposition with such other person, firm, or
entity; but any decrease in price of more than two percent (2%) of the price
sought from Landlord or any change in the terms of payment for such Disposition
shall constitute a new transaction requiring a further option of first refusal
to be given to Landlord hereunder.

                  e)   Without limiting any of the provisions of this
Section 21, if pursuant to the Federal Bankruptcy Code (herein referred to as
the "Code"), or any similar law hereafter enacted having the same general
purpose, Tenant is permitted to assign this Lease notwithstanding the
restrictions contained in this Lease, adequate assurance of future performance
by an assignee expressly permitted under such Code shall be deemed to mean the
deposit of cash security in an amount equal to the sum of one year's Fixed Basic
Rent plus an amount equal to the Additional Rent for the calendar year preceding
the year in which such assignment is intended to become effective, which deposit
shall be held by Landlord for the balance of the Term, without interest, as
security for the full performance of all of Tenant's obligations under this
Lease, to be held and applied in the manner specified for any security deposit
required hereunder.

                  f)   Except as specifically set forth above, no portion of
the Premises or of Tenant's interest in this Lease may be acquired by any other
person or entity, whether by assignment, mortgage, sublease, transfer, operation
of law or act of the Tenant, nor shall Tenant pledge its interest in this Lease
or in any security deposit required hereunder.

         22.   Tenant's Relocation. [Intentionally Deleted]

         23. Subordination. This Lease and Tenant's rights hereunder shall be
subject and subordinate at all times in lien and priority to any first mortgage
or other primary encumbrance now or hereafter placed upon or affecting the
Property or the Premises, and to any second mortgage or encumbrance with the
consent of the first mortgagee, and to all renewals, modifications,
consolidations and extensions thereof, without the necessity



                                       19
<PAGE>


of any further instrument or act on the part of Tenant. Tenant shall execute and
deliver upon demand any further instrument or instruments confirming the
subordination of this Lease to the lien of any such first mortgage or to the
lien of any other mortgage, if requested to do so by Landlord with the consent
of the first mortgagee, and any further instrument or instruments of attorument
that may be desired by any such mortgagee or Landlord, provided, however, that
any holder of such lien or mortgage agrees not to disturb the use and occupancy
of the Premises in accordance with the terms of this Lease Agreement upon any
foreclosure. Notwithstanding the foregoing, any mortgagee may at any time
subordinate its mortgage to this Lease, without Tenant's consent, by giving
notice in writing to Tenant and thereupon this Lease shall be deemed prior to
such mortgage without regard to their respective dates of execution and
delivery. In that event such mortgagee shall have the same rights with respect
to this Lease as though this Lease had been executed prior to the execution and
delivery of the mortgage and had been assigned to such mortgagee. Landlord
agrees that it will use best efforts to obtain and deliver to Tenant a
subordination, non-disturbance and attornment agreement from the holder(s) of
any mortgage or other security interest affecting the Premises of Building.

         24.  Curing Tenant's Defaults. If Tenant defaults in the performance of
any of its obligations hereunder, Landlord may, without any obligation to do so
and in addition to any other rights it may have in law or equity, elect to cure
such default on behalf of Tenant after reasonable prior written notice (except
in the case of emergency) to Tenant. Tenant shall reimburse Landlord upon demand
for any sums paid or costs incurred by Landlord in curing such default,
including interest thereon from the respective dates of Landlord's making the
payments and incurring such costs, which sums and costs together with interest
thereon shall be deemed Additional Rent payable within ten (10) days of demand.

         25.  Surrender.

                  a)   At the expiration or earlier termination of the Term
Tenant shall promptly yield up the Premises and all improvements, alterations
and additions thereto, and all fixtures and equipment including all hoods and
casework (excluding Tenant's personalty) servicing the Premises in a condition
which is clean of garbage and debris and broom clean and in the same condition,
order and repair in which they are required to be kept throughout the Term,
ordinary wear and tear excepted.

                  b)   If Tenant, or any person claiming through Tenant,
continues to occupy the Premises after the expiration or earlier termination of
the Term or any renewal thereof without prior written consent of Landlord, the
tenancy under this Lease shall become, at the option of Landlord, expressed in a
written notice to Tenant and not otherwise, either from month-to-month or for a
period of one (1) year, terminable by Landlord on thirty (30) days prior notice,
under the same terms and conditions set forth in this Lease; except, however,
that the Fixed Basic Rent during such continued occupancy shall be 150% of the
amount set forth in subsection 6(a) and Tenant shall indemnify Landlord for any
actual loss or damage incurred by reason of Tenant's failure to surrender the
Premises. Anything to the contrary notwithstanding, any holding over by Tenant
without Landlord's




                                       20
<PAGE>


prior written consent shall constitute a default hereunder and shall be subject
to all the remedies set forth in subsection 26(b) hereof.

         26.   Defaults-Remedies.

                  a)   Defaults. It shall be an event of default (an "Event
of Default") under this Lease if any one or more of the following events occurs:

                     i)  Tenant fails to pay in full, after five (5) days prior
written notice from Landlord, any and all installments of Fixed Basic Rent or
Additional Rent or any other charges or payments due and payable under this
Lease whether or not herein included as rent.

                     ii) Tenant violates or fails to perform or otherwise
breaches any agreement, term, covenant or condition contained in this Lease,
within fifteen (15) days after prior written notice from Landlord.

                     iii)Tenant abandons or vacates the Premises without notice
without having first paid to Landlord in full all Fixed Basic Rent, Additional
Rent and other charges that have become due as well as all which will become due
thereafter through the end of the Term.

                     iv) Tenant becomes insolvent or bankrupt in any sense or
makes an assignment for the benefit of creditors or if a petition in bankruptcy
or for reorganization or for an arrangement with creditors under any federal or
state law is filed by or against Tenant, or a bill in equity or other proceeding
for the appointment of a receiver or similar official for any of Tenant's assets
is commenced, or if any of the real or personal property of Tenant shall be
levied upon by any sheriff, marshal or constable; provided, however, that any
proceeding brought by anyone other than the parties to this Lease under any
bankruptcy, reorganization arrangement, insolvency, readjustment, receivership
or similar law shall not constitute an event of default until such proceeding,
decree, judgment or order has continued unstayed for more than sixty (60)
consecutive days.

                     v)  Any of the events enumerated in subsections (a) (i)
through (a) (iv) of this Section happen to any guarantor of this Lease.

                  b)   Remedies. Upon the occurrence of an Event of Default
under this Lease, Landlord shall have all of the following rights:

                     i)  Landlord may charge a late payment charge of five (5%)
percent of any amount owed to Landlord pursuant to this Lease which is not paid
within five (5) days of the due date which is set forth in the Lease or, if a
due date is not specified in this Lease, within thirty (30) days of the mailing
of a bill therefor by Landlord. If Landlord incurs a late charge in connection
with any payment which Tenant has failed to make within the times required in
this Lease, Tenant shall pay Landlord, in addition to such



                                       21
<PAGE>


payment due, the full amount of such late charge incurred by Landlord. Nothing
in this Lease shall be construed as waiving any rights of Landlord arising out
of any default of Tenant, by reason of Landlord's imposing or accepting any such
late charge(s) and/or interest; the right to collect such late charge(s) and/or
interest is separate and apart from any rights relating to remedies of Landlord
after default by Tenant including, without limitation, the rights and remedies
of Landlord provided herein.

                    ii)  Landlord may accelerate the whole or any part of the
Fixed Basic Rent and all Additional Rent for the entire unexpired balance of the
Term of this Lease, as well as all other charges, payments, costs and expenses
herein agreed to be paid by Tenant, and any Fixed Basic Rent or other charges,
payments, costs and expenses so accelerated shall, in addition to any and all
installments of rent already due and payable and in arrears and any other charge
or payment herein reserved, included or agreed to be treated or collected as
rent and any other charge, expense or cost herein agreed to be paid by Tenant
which may be due and payable and in arrears, be deemed due and payable as if,
by the terms and provisions of this Lease, such accelerated rent and other
charges, payments, costs and expenses were on that date payable in advance.

                    iii) Landlord may re-enter the Premises and, at the option
of Landlord, remove all persons and all or any property therefrom, either by
summary dispossess proceedings or by any suitable action or proceeding at law or
otherwise, without being liable for prosecution or damages therefor, and
Landlord may repossess and enjoy the Premises. Upon recovering possession of the
Premises by reason of or based upon or arising out of a default on the part of
Tenant, Landlord may, at Landlord's option, either terminate this Lease or make
such alterations and repairs as may be necessary in order to relet the Premises
and may relet the Premises or any part or parts thereof, either in Landlord's
name or otherwise, for a term or terms which may, at Landlord's option, be less
than or exceed the period which would otherwise have constituted the balance of
the Term of this Lease and at such rent or rents and upon such other terms and
conditions as in Landlord's sole discretion may seem advisable and to such
person or persons as may in Landlord's discretion seem best; upon each such
reletting all rents received by Landlord from such reletting shall be applied as
follows: first, to the payment of any costs and expenses of such reletting,
including all costs of alterations and repairs; second, to the payment of any
indebtedness other than Fixed Basic Rent, Additional Rent or other charges due
hereunder from Tenant to Landlord; third, to the payment of Fixed Basic Rent,
Additional Rent and other charges due and unpaid hereunder; and the residue, if
any, shall be held by Landlord and applied in payment of future rent as it may
become due and payable hereunder. If rentals received from reletting during any
month are less than that to be paid during that month by Tenant, Tenant shall
pay any such deficiency to Landlord. Such deficiency shall be calculated and
paid monthly. No such re-entry or taking possession of the Premises or the
making of alterations or improvements thereto or the reletting thereof shall be
construed as an election on the part of Landlord to terminate this Lease unless
written notice of termination is given to Tenant. Landlord shall in no event be
liable in any way whatsoever for failure to relet the Premises or, in the event
that the Premises or any part or parts thereof are relet, for failure to collect
the rent thereof under such releffing.



                                       22
<PAGE>


Notwithstanding any such reletting without termination, Landlord may at any time
thereafter elect to terminate this Lease for such previous breach.

                    iv)  Landlord may terminate this Lease and the Term without
any nght on the part of Tenant to waive the forfeiture by payment of any sum due
or by other performance of any condition, term or covenant broken. Upon such
termination, Landlord shall be entitled to recover, in addition to any and all
sums and damages for violation of Tenant's obligations hereunder in existence at
the time of such termination, damages for Tenant's default in an amount equal to
the amount of the Fixed Basic Rent and Additional Rent reserved for the balance
of the Term, as well as all other charges, payments, costs and expenses herein
agreed to be paid by Tenant all of which amount shall be immediately due and
payable from Tenant to Landlord upon demand therefor.

                    v)       WHEN THIS LEASE AND THE TERM OR ANY
EXTENS ION OR RENEWAL THEREOF SHALL HAVE BEEN TERMINATED ON ACCOUNT OF ANY
DEFAULT BY TENANT, OR WHEN THE TERM HAS EXPIRED, IT SHALL BE LAWFUL FOR ANY
ATTORNEY OF ANY COURT OF RECORD TO APPEAR AS ATTORNEY FOR TENANT AS WELL AS FOR
ALL PERSONS CLAIMING BY, THROUGH OR UNDER TENANT, AND TO FILE AN AGREEMENT FOR
ENTERING IN ANY COMPETENT COURT AN ACTION FOR JUDGMENT IN EJECTMENT AGAINST
TENANT AND ALL PERSONS CLAIMING BY, THROUGH OR UNDER TENANT FOR THE RECOVERY BY
LANDLORD OF POSSESSION OF THE PREMISES, FOR WHICH THIS LEASE SHALL BE A
SUFFICIENT WARRANT; WHEREUPON, IF LANDLORD SO DESIRES, AN APPROPRIATE WRIT OF
POSSESSION MAY ISSUE FORTHWITH, WITHOUT ANY PRIOR WRIT OR PROCEEDING WHATSOEVER,
AND PROVIDED THAT IS FOR ANY REASON AFTER SUCH ACTION SHALL HAVE BEEN COMMENCED
IT SHALL BE DETERMINED AND POSSESSION OF THE PREMISES REMAIN IN OR BE RESTORED
TO TENANT, LANDLORD SHALL HAVE THE RIGHT FOR THE SAME DEFAULT AND UPON ANY
SUBSEQUENT DEFAULT OR DEFAULTS, OR UPON THE TERMINATION OF THIS LEASE OR
TENANT'S RIGHT OF POSSESSION AS HEREINBEFORE SET FORTH, TO BRING ONE OR MORE
FURTHER ACTIONS IN EJECTMENT AS HEREINBEF ORE SET FORTH TO CONFESS JUDGMENT FOR
THE RECOVERY OF POSSESSION OF THE PREMISES.


                  c)   Waiver of Jury Trial. IT IS MUTUALLY AGREED BY AND
BETWEEN LANDLORD AND TENANT THAT (A) THEY HEREBY WAIVE TRIAL BY JURY IN ANY
ACTION, PROCEEDING OR COUNTER-CLAIM BROUGHT BY EITHER OF THE PARTIES HERETO
AGAINST THE OTHER ON ANY MATTER WHATSOEVER ARISING OUT OF OR IN ANY WAY
CONNECTED WITH THIS LEASE, THE RELATIONSHIP OF LANDLORD AND TENANT, TENANT'S USE
OF OCCUPANCY OF THE PREMISES OR CLAIM OF INJURY OR DAMAGE, AND (B) IN ANY ACTION
BY LANDLORD AGAINST TENANT, THE LEGAL FEES OF THE



                                       23
<PAGE>

PREVAILING PARTY WILL BE PAID BY THE OTHER PARTY TO THE ACTION.

                  d)   Non-Waiver. No waiver by Landlord of any breach by
Tenant of any of Tenant's obligations, agreements or covenants herein shall be a
waiver of any subsequent breach or of any other obligation, agreement or
covenant, nor shall any forbearance by Landlord to seek a remedy for any event
of default by Tenant be a waiver by Landlord of any rights and remedies with
respect to such or any subsequent event of default.

                  e)   Rights and Remedies Cumulative. No right or remedy
herein conferred upon or reserved to Landlord is intended to be exclusive of any
other right or remedy provided herein or by law, but each shall be cumulative
and in addition to every other right or remedy given herein or now or hereafier
existing at law or in equity or by statute.

                  f)   Duty to Mitigate. In the event of an Event of
Default, Landlord shall undertake commercially reasonable efforts to mitigate
its damages.

         27.  Condition of Premises. Tenant represents that the zoning of the
Property, the street or streets, sidewalks, parking areas, curbs and access ways
adjoining them, any surface conditions thereof, and the present uses and
non-uses thereof, have been examined by Tenant and Tenant accepts them in the
condition or state in which they now are, or any of them now is, without relying
on any representation, covenant or warranty, express or implied, in fact or in
law, by Landlord and without recourse to Landlord, the nature, condition or
usability thereof or the use or uses to which the Premises and the Property or
any part thereof may be put under present zoning ordinances or otherwise, except
as to work to be performed by Landlord pursuant to Section 3 and except as to
latent defects in such work. Tenant's occupancy of the Premises shall constitute
acceptance of the Work performed by Landlord pursuant to Section 3.

         28.  Hazardous Substances.

                  a)   Landlord and Tenant shall not cause or allow the
generation, treatment, storage or disposal of Hazardous Substances on or near
the Premises or Property. "Hazardous Substances" shall mean (i) any hazardous
substance as that term is defined in the Comprehensive Environmental Response,
Compensation and Liability Act ("CERCLA"), 42 U.S.C. 9601 et seq., as amended,
(ii) any hazardous waste or hazardous substance as those terms are defined in
any local, state or Federal law, regulation or ordinance not inapplicable to the
Premises and Property, or (iii) petroleum including crude oil or any fraction
thereof. In the event Landlord or Tenant uses any Hazardous Substances, Landlord
or Tenant shall dispose of such substances in accordance with all applicable
Federal, state and local laws, regulations and ordinances.

                  b)   Landlord and Tenant agree to indemnify, defend and
hold harmless the other, its employees, agents, successors, and assigns, from
and against any and all damage, claim, liability, or loss, including reasonable
attorneys' and other fees, arising



                                       24
<PAGE>


out of or in any way connected to the generation, treatment, storage or disposal
of Hazardous Substances by Landlord or Tenant, its employees, agents,
contractors, or invitees, on or near the Premises or Property. Such duty of
indemnification shall include, but not be limited to damage, liability, or loss
pursuant to all Federal, state and local environmental laws, rules and
ordinances, strict liability and common law.

                  c)   Landlord and Tenant agree to notify each other
immediately of any disposal of Hazardous Substances in the Premises or Property,
of any discovery of Hazardous Substances in the Premises, or of any notice by a
governmental authority or private party alleging or suggesting that a disposal
of Hazardous Substances on or near the Premises or Property may have occurred.
Furthermore, Landlord and Tenant agree to provide the other with full and
complete access to any documents or information in its possession or control
relevant to the question of the generation, treatment, storage, or disposal of
Hazardous Substances on or near the Premises.

                  d)   Landlord represents and warrants that, to the best of
its knowledge, there are no Hazardous Substances in, under or about the
Building.

                  e)   Tenant and Landlord acknowledge that Tenant will be
storing and using chemicals and biologicals in connection with the conduct of
its business. Tenant shall use, store and dispose of all such substances in
accordance with all applicable law. In addition, Tenant shall promptly provide
Landlord with all reasonable information Landlord requests concerning the
substances which Tenant is using or storing at the Premises including, but not
limited to MSDS sheets. Tenant further acknowledges that Landlord's architect
has prepared the Premises plans in accordance with Tenant's direction and
utilizing all relevant information Tenant has provided to it. In the event
Landlord is unable to obtain a building permit due to an objection to the
Premises plans which were prepared in conformity with Tenant's design
specifications, Tenant shall be liable for all costs associated with redesigning
the Premises, including architectural costs, base Building modifications, and
such other costs Landlord incurs due to required changes in the Premises Plans.

         29.  Recording. Neither this Lease nor a memorandum of this Lease shall
be recorded in any public records without the written consent of Landlord.

         30.  Brokers' Commission. Tenant represents and warrants to Landlord
that the Brokers (as defined in the Preamble) are the sole brokers with whom
Tenant has negotiated in bringing about this Lease and Tenant agrees to
indemnify and hold Landlord and its mortgagee(s) harmless from any and all
claims of other brokers and expenses in connection therewith arising out of or
in connection with the negotiation of or the entering into this Lease by
Landlord and Tenant. In no event shall Landlord's mortgagee(s) have any
obligation to any broker involved in this transaction. In the event that no
broker was involved as aforesaid, then Tenant represents and warrants to the
Landlord that no broker brought about this transaction, and Tenant agrees to
indemnify and hold Landlord harmless from any and all claims of any broker
arising out of or in connection with the negotiations of, or entering into of,
this Lease by Tenant and Landlord.



                                       25
<PAGE>

         31.  Notices. All notices, demands, requests, consents, certificates,
and waivers required or permitted hereunder from either party to the other shall
be in writing and sent by United States certified mail, return receipt
requested, postage prep aid, or by recognized overnight courier, addressed as
follows:

                  If to Tenant:

                  at the Premises
                  Atten:...President


                  with a copy to:

                  Donald F. Crane, Jr.
                  Vice President, General Counsel
                  Cytogen Corporation
                  600 College Road East
                  .CN5308
                  Princeton, NJ 08540-5308

                  If to Landlord:

                  Yardley Road Associates, L.P.
                  c/o O'Neill Properties Group, L.P.
                  1101 West DeKalb Pike
                  Suite 200
                  Wayne,PA 19087
                  Attn:....President

                  with a copy to:

                  Kevin W. Walsh, Esquire
                  Adelman Lavine Gold and Levin
                  Suite 1900, Two Penn Center Plaza
                  Philadelphia, PA 19102-1799


Either party may at any time, in the manner set forth for giving notices to the
other, specify a different address to which notices to it shall thereafter be
sent.

         32.  Irrevocable Offer: No Option. Although Tenant's execution of this
Lease shall be deemed an offer irrevocable by Tenant,  the submission of this
Lease by Landlord to Tenant for  examination  shall not  constitute a
reservation  of or option for the Premises.  This Lease shall become  effective
only upon execution thereof by an authorized  officer of the general  partner of
the Landlord and by an authorized officer of Tenant.



                                       26
<PAGE>


         33.  Inability to Perform. If Landlord is delayed or prevented from
performing any of its obligations under this Lease by reason of strike, labor
troubles, or any cause whatsoever beyond Landlord's control, the period of such
delay or such prevention shall be deemed added to the time herein provided for
the performance of any such obligation by Landlord.

         34.  Survival. Notwithstanding anything to the contrary contained in
this Lease, the expiration of the Term of this Lease, whether by lapse of time
or otherwise, shall not relieve Tenant from its obligations accruing prior to
the expiration of the Term.

         35.  Corporate Tenants. If Tenant is a corporation, the person(s)
executing this Lease on behalf of Tenant hereby covenant(s) and warrant(s) that:
Tenant is a duly formed corporation qualified to do business in the state in
which the Property is located; Tenant will remain qualified to do business in
said state throughout the Term and any renewals thereof, and such persons are
duly authorized by such corporation to execute and deliver this Lease on behalf
of the corporation.

         36.  Tenant Representations and Warranties. Tenant hereby represents
and warrants to Landlord (i) that Tenant's most recent financial statements
delivered to Landlord in connection with the execution of this Lease are true in
all material respects and no material adverse changes have occurred with respect
thereto, (ii) that on each anniversary of the Commencement Date, Tenant will
deliver to Landlord current financial statements which shall be prepared in
accordance with generally accepted accounting principles consistently applied,
and (iii) during the Term of the Lease, no material adverse change shall occur
with respect to Tenant's financial condition.

         37.  Waiver of Invalidity of Lease. Each party agrees that it will not
raise or assert as a defense to any obligation under the Lease or make any claim
that the Lease is invalid or unenforceable due to any failure of this document
to comply with ministerial requirements including, without limitation,
requirements for corporate seals, attestations, witnesses, notarizations or
other similar requirements and each party hereby waives the right to assert any
such defenses or make any claim of invalidity or unenforceability due to any of
the foregoing.

         38.  Security Deposit. As additional security for the full and prompt
performance by Tenant of the terms and covenants of this Lease, Tenant has
deposited with Landlord the Security Deposit, as set forth in the Preamble. The
Security Deposit shall not constitute rent for any month (unless so applied by
Landlord on account of Tenant's default hereunder). Tenant shall, upon demand,
restore any portion of the Security Deposit which may be applied by Landlord to
cure any default by Tenant hereunder. To the extent that Landlord has not
applied the Security Deposit or any portion thereof on account of a default, the
Security Deposit, or such remaining portion of the Security Deposit, shall be
returned to Tenant, without interest, promptly following the termination of this
Lease.



                                       27
<PAGE>


         39. Tenant Estoppel Certificate. Tenant shall from time to time, within
fifteen (15) days after Landlord's request or that of any mortgagee of Landlord,
execute, acknowledge and deliver to Landlord a written instrument in recordable
form, substantially in the form attached hereto as Exhibit E (a "Tenant Estoppel
Certificate"), certifying (i) that this Lease is in full force and effect and
has not been modified, supplemented or amended (or, if there have been
modifications, supplements or amendments, that it is in full force and effect as
modified, supplemented or amended, and stating such modifications, supplements
and amendments); (ii) the dates to which Fixed Basic Rent and Additional Rent
and any other charges arising hereunder have been paid; (iii) the amount of any
prepaid rents or credits due Tenant, if any; (iv) if applicable, that Tenant has
accepted possession and has entered into occupancy of the Premises, and
certifying the Commencement Date and the Termination Date; (v) whether or not,
to the best of the Tenant's knowledge, all conditions under the Lease to be
performed by Landlord prior thereto have been satisfied and whether or not
Landlord is then in default in the performance of any covenant, agreement or
condition contained in this Lease and specifying each, if any, unsatisfied
condition and each, if any, default of which Tenant may have knowledge; and (vi)
any other fact or condition related to the Lease or the Tenant reasonably
requested. Any certification delivered pursuant to the provisions of this
Article shall be intended to be relied upon by Landlord and any mortgagee or
prospective mortgagee or purchaser of the Property or of any interest therein.
Notwithstanding the foregoing, Tenant's failure to furnish a Tenant Estoppel
Certificate within said fifteen (15) day period shall constitute an Event of
Default under this Lease.

         40.  Rights Reserved by Landlord. Landlord waives no rights, except
those that may be specifically waived herein, and explicitly retains all other
rights including, without limitation, the following rights, each of which
Landlord may exercise without notice to Tenant and without liability to Tenant
for damage or injury to property, person or business on account of the exercise
thereof, and the exercise of any such rights shall not be deemed to constitute
an eviction or disturbance of Tenant's use or possession of the Premises and
shall not give rise to any claim for set-off or abatement of Rent or any other
claim:

                  a)   To change the name or street address of the Building.

                  b)   To install, affix and maintain any and all signs on
the exterior and on the interior of the Building (excluding the interior of the
Premises).

                  c)   To decorate or to make repairs, alterations,
additions, or improvements, whether structural or otherwise, in and about the
Building, or any part thereof, and for such purposes to enter upon the Premises
and during the continuance of any of such work, to temporarily close doors,
entry ways, public space and corridors in the Building and to interrupt or
temporarily suspend services or use of facilities, all without affecting any of
Tenant's obligations hereunder, so long as the Premises are reasonably
accessible and usable.

                  d)   To furnish door keys for the entry door(s) in the
Premises on the



                                       28
<PAGE>



Commencement Date and to retain at all times, and to use in appropriate
instances, keys to all doors within and into the Premises. Tenant agrees to
purchase only from Landlord additional duplicate keys as required, to change no
locks, and not to affix locks on doors without the prior written consent of the
Landlord. Upon the expiration of the Term or Tenant's right to possession,
Tenant shall return all keys to Landlord and shall disclose to Landlord the
combination of any safes, cabinets or vaults left in the Premises.

                  e)   To designate and approve all window coverings used in
the Building.

                  f)   To approve the weight, size and location of safes,
vaults and other heavy equipment and articles in and about the Premises and the
Building so as not to exceed the legal load per square foot designated by the
structural engineers for the Building, and to require all such items and
furniture and similar items to be moved into or out of the Building and Premises
only at such times and in such manner as Landlord shall direct in writing.
Tenant shall not install or operate machinery or any mechanical devices of a
nature not directly related to Tenant's ordinary use, as limited by the
Permitted Use, of the Premises without the prior written consent of Landlord.
The movement of Tenant's property into or out of the Building or the Premises
and within the Building are entirely at the risk and responsibility of Tenant,
and Landlord reserves the right to require written authorization from Tenant, in
form and content satisfactory to Landlord, before allowing any property to be
moved into or out of the Building or Premises.

                  g)   To regulate delivery of supplies and the usage of the
loading docks, receiving areas and freight elevators.

                  h)   To enter the Premises in accordance with Section 14,
and, if vacated or abandoned, to show the Premises at any time and to prepare
the Premises for re- occupancy.

                  i)   To erect, use and maintain pipes, ducts, wiring and
conduits, and appurtenances thereto, in and through the Premises.

                  j)   To grant to any person or to reserve unto itself the
exclusive right to conduct any business or render any service in the Building.

                  k)   To alter the layout, design and/or use of the
Building in such manner as Landlord, in its sole discretion, deems appropriate,
so long as the character of the Building as a first class office building is
maintained.

         41.  Miscellaneous.

                  a)   Entire Agreement. This Lease represents the entire
agreement between the parties hereto and there are no collateral or oral
agreements or understandings between Landlord and Tenant with respect to the
Premises or the Property. No rights, easements or licenses are acquired in the
Property or any land adjacent to the Property by Tenant by implication or
otherwise except as expressly set orth in the provisions of this Lease.



                                       29
<PAGE>

                  b)   Modification. This Lease shall not be modified in any
manner except by an instrument in writing executed by the parties. In addition,
Tenant agrees to make such changes to this Lease as are required by any
mortgagee, provided such changes do not substantially affect Tenant's rights and
obligation hereunder.

                  c)   Interpretation. The masculine (or neuter) pronoun,
singular number, shall include the masculine, feminine and neuter genders and
the singular and plural number.

                  d)   Exhibits. Each writing or plan referred to herein as
being attached as an Exhibit or otherwise designated herein as an Exhibit hereto
is hereby made a part hereof.

                  e)   Captions and Headings. The captions and headings of
sections, subsections and the table of contents herein are for convenience only
and are not intended to indicate all of the subject matter in the text and they
shall not be deemed to limit, construe, affect or alter the meaning of any
provisions of this Lease and are not to be used in interpreting this Lease or
for any other purpose in the event of any controversy.

                  f)   Interest. Wherever interest is required to be paid
hereunder, such interest shall be at the highest rate permitted under law but
not in excess of the prime rate (as set forth in the Wall Street Journal plus
two percentage points per annum).

                  g)   Severability. If any term or provision of this Lease,
or the application thereof to any person or circumstance shall, to any extent,
be invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those as to which
it is held invalid or unenforceable, shall not be affected thereby, and each
term and provision of this Lease shall be valid and be enforced to the fullest
extent permitted by law.

                  h)   Joint and Several Liability. If two or more
individuals, corporations, partnerships or other persons (or any combination of
two or more thereof) shall sign this Lease as Tenant, the liability of each such
individual, corporation, partnership or other persons to pay the Rent and
perform all other obligations hereunder shall be deemed to be joint and several,
and all notices, payments and agreements given or made by, with or to any one of
such individuals, corporations, partnerships or other persons shall be deemed to
have been given or made by, with or to all of them. In like manner, if Tenant
shall be a partnership or other legal entity, the members of which are, by
virtue of any applicable law or regulation, subject to personal liability, the
liability of each such member shall be joint and several.

                  i)   No Representations by Landlord. Landlord and
Landlord's agents have made no representations, agreements, conditions,
warranties, understandings or promises, either oral or written, other than as
expressly set forth herein, with respect to this Lease, the Premises and/or the
Building.



                                       30
<PAGE>

                  j)   Relationship of Parties. This Lease shall not create
any relationship between the parties other than that of Landlord and Tenant.

                  k)   Choice of Law. The terms of this Lease shall be
construed under the laws of the Commonwealth of Pennsylvania, and that exclusive
jurisdiction and venue shall be in the Court of Common Pleas of the County in
which the Property is located.

         42.  Additional Definitions.

                  a)   "Date of this Lease" or "date of this Lease" shall
mean the date of acceptance of this Lease by the Landlord, following execution
and delivery thereof to Landlord by Tenant and that date shall be inserted in
the space provided in the Preamble.

                  b)  "Landlord" as used herein includes the Landlord named
above as well as its successors and assigns, each of whom shall have the same
rights, remedies, powers, authorities and privileges as it would have had it
originally signed this lease as Landlord. Any such person, whether or not named
herein, shall have no liability hereunder after ceasing to hold title to the
Premises. Neither Landlord nor any principal of Landlord nor any owner of the
Building or the Lot, whether disclosed or undisclosed, shall have any personal
liability with respect to any of the provisions of this Lease or the Premises,
and if Landlord is in breach or default with respect to Landlord's obligations
under this Lease or otherwise, Tenant shall look solely to the equity of
Landlord in the Premises for the satisfaction of Tenant's remedies.

                  c)   "Tenant" as used herein includes the Tenant named
above as well as its heirs, successors and assigns, each of which shall be under
the same obligations, liabilities and disabilities and each of which shall have
the same rights, privileges and powers as it would have possessed had it
originally signed this Lease as Tenant. Each and every person named above as
Tenant shall be bound formally and severally by the terms, covenants and
agreements contained herein. However, no such rights, privileges or powers shall
inure to the benefit of any assignee of Tenant, immediate or remote, unless the
assignment to such assignee is permitted or has been approved in writing by
Landlord. Any notice required or permiffed by the terms of this Lease may be
given by or to any one of the persons named above as Tenant, and shall have the
same force and effect as if given by or to all of them.

                  d)   "Mortgage" and "Mortgagee" as used herein includes
any lien or encumbrance on the Premises or the Property or on any part of or
interest in or appurtenance to any of the foregoing, including without
limitation any ground rent or ground lease if Landlord's interest is or becomes
a leasehold estate. The word "mortgagee" is used herein to include the holder of
any mortgage, including any ground Landlord if Landlord's interest is or becomes
a leasehold estate. Wherever any right is given to a mortgagee, that right may
be exercised on behalf of such mortgagee by any representative or servicing
agent of such mortgagee.



                                       31
<PAGE>


                  e)   "Person" as used herein includes a natural person, a
partnership, a corporation, an association3 and any other form of business
association or entity.

                  f)   "Property" as used herein shall mean the Building and
the lot, tract or parcel of land on which the Building is situated.

                  g)   "Rent" or "rent" as used herein shall mean all Fixed
Basic Rent and Additional Rent reserved under this Lease.

         43.  Guaranty of Lease. The obligations of Tenant under and pursuant to
this Lease are subject to that certain Guaranty of Lease ("Guaranty") of even
date herewith between Cytogen Corporation as Guarantor and Landlord which
Guaranty is attached hereto as Exhibit F.

         SECTION 26(b) HEREOF SETS FORTH A WAAAANT OR AUTHORITY FOR AS ATTORNEY
TO CONFESS JUDGMENT AGAINST TENANT. IN GRANTING THIS WAAAANT OF ATTORNEY TO
CONFESS JUDGMENT AGAINST TENANT, TENANT HEREBY KNOWINGLY, INTENTIONALLY AND
VOLUNTARILY, AND (ON THE ADVICE OF THE SEPARATE COUNSEL OF TENANT, IF TENANT HAS
USED COUNSEL IN REGARD TO ENTERING INTO THIS LEASE) UNCONDITIONALLY WAIVES ANY
AND ALL RIGHTS TENANT HAS OR MAY HAVE TO PRIOR NOTICE AND AN OPPORTUNITY FOR
HEARING UNDER THE CONSTITUTIONS AND LAWS OF THE UNITED STATES AND THE
COMMONWEALTH OF PENNSYLVANIA.



               [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]




                                       32
<PAGE>

 IN WITNESS WHEREOF, and in consideration of the mutual entry into this Lease
and for other good and valuable consideration, and intending to be legally
bound, each party hereto has caused this agreement to be duly executed under
seal.

Landlord:
---------

Date Signed:      7/23/99                      YARDLEY ROAD ASSOCIATES, L.P.
                                               By:      YARDLEY ROAD ASSOCIATES
                                                        ACQUISITION CORPORATION


                                                By:  /s/ Stephen Spaeder
                                                   -----------------------------
                                                    Name:  Stephen Spaeder
                                                         -----------------------
                                                    Title:    Vice President
                                                         -----------------------
                                                Attest:  /s/
                                                       -------------------------


Tenant:
-------

Date Signed:      07/15/99                     AXCELL BIOSCIENCES CORPORATION,
                                               a Delaware corporation


                                               By:  /s/ John D. Rodwell
                                                  ------------------------------
                                                   Name:  John D. Rodwell
                                                        ------------------------
                                                   Title:    President
                                                        ------------------------
                                               Attest:   /s/ Joan I. Breece
                                                       -------------------------





                                       33
<PAGE>


                                     RIDER A


RENEWAL OPTION: Tenant is hereby granted two (2) options to renew this Lease
upon the following terms and conditions:

At the time of the exercise of each option to renew and at the time of the said
renewal, the Tenant shall not be in default in accordance with the terms and
provisions of this Lease, and shall be in possession of the Premises pursuant to
this Lease.

Notice of the exercise of the option shall be sent to the Landlord in writing at
{east nine (9) months but not more than twelve (12) months before the expiration
of the term of this Lease.

Each renewal term shall be for a period of five (5) years3 to commence at the
expiration of the Term of this Lease, and all of the terms and conditions of
this Lease, other than the Fixed Basic Rent, shall apply during any such renewal
term.

The annual fixed basic rent to be paid during the first renewal term shall not
be less than Twenty Two Dollars ($22.00) per rentable square foot of the
Premises. The annual fixed basic rent to be paid during the second renewal term
shall not be less than the Fixed Basic Rent paid during the last year of the
first renewal term. However, if the fair rental value per square foot at the
commencement of either renewal term shall exceed the rent as established in the
preceding sentences, the Tenant shall pay such fair rental value. In determining
the fair rental value, the Landlord shall noh~ Tenant of the fair rental value
as established by Landlord. Should Tenant dispute Landlord's determination, then
the Tenant shall be free to, at the Tenant's sole cost and expense, employ the
services of an appraiser familiar with office buildings located within the
metropolitan Philadelphia, Pennsylvania area comparable to the Building, who
shall be a member of MAI and who shall render an appraisal. If the Landlord and
the Tenant's appraiser cannot agree on the fair rental value, or in such case,
on an independent appraiser acceptable to both, either party may request the
American Arbitration Association to appoint such independent appraiser who shall
be a member of MAI farniliar with office buildings in the area of the Building
who shall render an appraisal, and in such event the judgment of a majority of
the three appraisers shall be final and binding upon the parties. The parties
shall share equally in the cost of any such independent appraiser. Pending
resolution of the issue of fair rental value, the Tenant shall pay the Landlord
as of commencement of the renewal term, the Fixed Basic Rent as established by
Landlord, subject to retroactive adjustment upon final determination of this
issue.







                                       34

<PAGE>


                                    EXHIBIT A

Premises "A"

ALL THAT CERTAIN tract, piece or parcel of land, Situate in Newtown Township,
Bucks County, Commonwealth of Pennsylvania, according to an ALTA/ACSM Land Title
Survey for O'Neill Properties by Pickering, Corts & Summerson, Inc., Consulting
Engineers & Land Surveyors, Newtown, PA, beign dated August 27, 1997, as
follows, to wit:

BEGINNING at an iron pin set on the northerly right-of-way line of Friends Lane
(50' wide), said point being the common corner between tax parcels 29-10-88 and
29-10-86;

Thence, along the common property line between Tax Parcel 29-10-86 and Parcels
29-10-88, 29-10-87 and 29-10-40, crossing over an iron pin found and a concrete
monument found along the aforesaid line, N. 09(degree)17' 15" W, a distance of
1064.19' to an iron pin set for a corner; thence, N. 04(degree)02' 45" W. a
distance of 13.50' to an iron pin set for a corner; thence, extending easterly
along the bed of Newtown-Yardley Road, S.R. 6332, (variable width right-of-way),
N. 86 12' 00" E. a distance of 103.27 to a P.K. Nail set for a corner; thence,
S. 03(degree)58' 15" E, a distance of 4.69' to an iron pin set for a corner;
thence, S. 83(degree)20' 29" E a distance of 97.58 to an iron pin set for a
corner; thence, along the aforesaid right-of-way line of Newtown-Yardley Road,
S. 85(degree)13' 33" E. a distance of 207.45' to an iron pin set on the westerly
side of a 150' wide Transmission Line right-of-way for PECO Energy (formerly
Philadelphia Electric Company); thence, extending along aforesaid Transmission
Line right-of-way S. 31(degree)04' 00" E. a distance of 968.25' to an iron pin
set for a corner, said point beginning the common rear corner of Tax Parcels
29-10-86 and 29-10-91; thence, extending along the common property line between
the aforesaid two parcels, S. 70(degree)03' 30" W. a distance of 239.21' to an
iron pin set on the right-of-way line of Friends Lane; thence, along the arc of
a circle curving to the left, having a radius of 75.00' and a length of 184.34'
with a chord bearing of S. 89(degree)38' 50" W. and a chord distance of 141.32'
to an iron pin set for a corner, said point being a point of reverse curve along
the aforesaid right-of-way line of Friends Lane; thence, continuing along the
aforesaid right-of-way line of Friends Lane along the arc of a circle curving to
the right and having a radius of 50.00' and a length of 46.37', with a chord
bearing of S. 45 48' 04" W. and a chord distance of 44.72' to an iron pin set
for a corner at the terminus of said curve; thence,




                                       35
<PAGE>

along the right-of-way of Friends Lane (50' wide in this area), S. 72(degree)22'
00" W. a distance of 131.09' to an iron pin set at the point of curvature;
thence, continuing along the aforesaid right-of-way line along the arc of a
circle curving to the right and having a radius of 2000.00' and a length of
217.86' with a chord bearing of S. 75(degree)29' 14" W. and a chord distance of
217.75' to an iron pin set for a corner, said point being the point and place of
beginning.













                                       36
<PAGE>


                                   EXHIBIT A-1


                          [DIAGRAM OF DEMISED PREMISES]











                                       37
<PAGE>


                                    EXHIBIT B

                              RULES AND REGULATIONS


1. OBSTRUCTION OF PASSAGEWAYS: The sidewalks, entrance, passages, courts,
elevators, vestibules, stairways, corridors and public parts of the Building
shall not be obstructed or encumbered by Tenant or used by Tenant for any
purpose other than ingress and egress. If the Premises are situated on the
ground floor with direct access to the street, then Landlord shall, at
Landlord's expense, keep the sidewalks and curbs directly in front of the
Premises clean and free from ice, snow and refuse.

2. WINDOWS: Windows in the Premises shall not be covered or obstructed by
Tenant. No boffles, parcels or other articles shall be placed on the window
sills, in the halls, or in any other part of the Building other than the
Premises. No article shall be thrown out of the doors or windows of the
Premises.

3. PROJECTIONS FROM BUILDING: No awnings, air-conditioning units, or other
fixtures shall be attached to the outside walls or the window sills of the
Building or otherwise affixed so as to project from the Building, without prior
written consent of Landlord.

4. SIGNS: No sign or lettering shall be affixed by Tenant to any part of the
outside of the Premises, or any part of the inside of the Premises so as to be
clearly visible from the outside of the Premises, without the prior wriff en
consent of Landlord. However, Tenant shall have the right to place its name on
any door leading into the Premises the size, color and style thereof to be
subject to the Landlord's approval. Tenant shall not have the right to have
additional names placed on the Building directory without Landlord's prior
written consent.

5. FLOOR COVERING: Tenant shall not lay linoleum or other similar floor covering
so that the same shall come in direct contact with the floor of the Premises. If
linoleum or other similar floor covering is desired to be used, an interlimng of
builder's deadening felt shall first be fixed to the floor by a paste or other
material that may easily be removed with water, the use of cement or other
similar adhesive material being expressly prohibited.

6. INTEREERENCE WITH OCCUPANTS OF BUILDING: Tenant shall not make, or permit to
be made, any unseemly or disturbing noises or odors and shall not interfere with
other tenants or those having business with them. Tenant will keep all
mechanical apparatus in the Premises free of vibration and noise which may be
transmitted beyond the limits of the Premises.

7. LOCK KEYS: No additional locks or bolts of any kind shall be placed on any of
the doors or windows by Tenant without allowing Landlord access. Tenant shall,
on the termination of Tenant's tenancy, deliver to Landlord all keys to any
space within the



                                       38
<PAGE>


Building either furnished to or otherwise procured by Tenant, and in the event
of the loss of any keys furnished, Tenant shall pay to Landlord the cost
thereof. Tenant, before closing and leaving the Premises, shall ensure that all
windows are closed and entrance doors locked. Nothing in this Paragraph 7 shall
be deemed to prohibit Tenant from installing a burglar alarm within the
Premises, provided: (1) Tenant obtains Landlord's consent which will not be
unreasonably withheld or delayed; (2) Tenant supplies Landlord with copies of
the plans and specifications of the system; (3) such installation shall not
damage the Building; and (4) all costs of installation shall be borne solely by
Tenant.

8. CONTRACTORS: No contract of any kind with any supplier of towels, water,
toilet articles, waxing, rug shampooing, venetian blind washing, furniture
polishing, lamp servicing, cleaning of electrical fixtures, removal of waste
paper, rubbish, garbage, or other like service shall be entered into by Tenant
without the prior written consent of the Landlord. Tenant shall not employ any
persons other than Landlord's janitors for the purpose of cleaning the Premises
without prior written consent of Landlord. Landlord shall not be responsible to
Tenant for any loss of property from the Premises however occurring, or for any
damage to the effects of Tenant by suchjanitors or any of its employees, or by
any other person or any other cause.

9. PROHIBITED ON PREMISES: Tenant shall not conduct, or permit any other person
to conduct, any auction upon the Premises, manufacture or store goods, wares or
merchandise upon the Premises without the prior written approval of Landlord,
except the storage of usual supplies and inventory to be used by Tenant in the
conduct of its business, permit the Premises to be used for gambling, make any
unusual noises in the Building, permit to be played musical instrument on the
Premises, permit any radio to be played, or television, recorded or wired music
in such loud manner as to disturb or annoy other tenants, or permit any unusual
odors to be produced on the Premises. Tenant shall not permit any portion of the
Premises to be occupied as an office for a public stenographer or typewriter, or
for the storage, manufacture, or sale of intoxicating beverages, narcotics,
tobacco in any form or as a barber or manicure shop. Canvassing, soliciting and
peddling in the Building and the Office Building Area are prohibited and Tenant
shall cooperate to prevent the same. No vehicles or animals (other than lab
animals used in the normal course of Tenant's business) of any kind shall be
brought into or kept in or about the Premises.

10. PLUMBING, ELECTRIC AND TELEPHONE WORK: Plumbing facilities shall not be used
for any purpose other than those for which they were constructed; and no
sweepings, rubbish, ashes, newspaper or other substances of any kind shall be
thrown into them. Waste and excessive or unusual amounts of electricity or water
is prohibited. When electric wiring of any kind is introduced, it must be
connected as directed by Landlord, and no stringing or cutting of wires will be
allowed, except by prior written consent of Landlord, and shall be done by
contractors approved by Landlord. The number and locations of telephones,
telegraph instruments, electrical appliances, call boxes, etc. shall be subject
to Landlord's approval.





                                       39
<PAGE>

11. MOVEMENT OF FURNITURE, FREIGHT OR BULKY MATTER: The carrying in or out of
freight, furniture or bulky matter of any description must take place during
such hours as Landlord may from time to time reasonably determine and only after
advance notice to the superintendent of the Building. There shall not be used in
the Building or Premises, either by Tenant or by others in the delivery or
receipt of merchandise, any hand trucks except those equipped with rubber tires
and side guards, and no hand trucks will be allowed in the elevators without the
consent of the superintendent of the Building.

12. SAFES AND OTHER HEAVY EQUIPMENT: Landlord reserves the right to prescribe
the weight and position of all safes and other heavy equipment so as to
distribute properly the weight thereof and to prevent any unsafe condition from
arising.

13. ADVERTISING: Landlord shall have the right to prohibit any advertising by
Tenant which in Landlord's reasonable opimon tends to impair the reputation of
the Building or its desirability as a building for offices, and upon written
notice from Landlord, Tenant shall refrain from or discontinue such advertising.

14.      NON-OBSERVANCE OR VIOLATION OF RULES BY OTHER TENANTS:
Landlord shall not be responsible to Tenant for non-observance or violation of
any of these rules and regulations by any other tenant.

15. AFTER HOURS USE: Landlord reserves the right to exclude from the Building
between the hours of 6:00 p.m. and 8:00 am. and at all hours on Saturdays,
Sundays and Building Holidays, all persons who do not present a pass to the
Building signed by the Tenant. Each Tenant shall be responsible for all persons
for whom such a pass is issued and shall be liable to the Landlord for the acts
of such persons.

16. PARKING: Tenant and its employees shall park their cars only in those
portions of the parking area designated by Landlord.

17. RESERVATION OF RIGHTS: Landlord hereby reserves to itself any and all rights
not granted to Tenant hereunder, including, but not limited to, the following
rights which are reserved to Landlord for its purposes in operating the
Building:

         a.     the exclusive right to the use of the name of the Building for
all purposes, except that Tenant may use the name as its business address and
for no other purposes; and

         b.     the right to change the name or address of the Building, without
incurring any liability to Tenant for doing so; and

         c.     the right to install and maintain a sign on the exterior of the
Building; and

         d.     the exclusive right to use or dispose of the use of the roof of
the Building; and

         e.     the right to limit the space on the directory of the Building to
be allotted to Tenant; and




                                       40
<PAGE>


         - the right  to grant to anyone the right to conduct any particular
business or understanding in the Building.

18.  HEALTH AND SAFETY: The Tenant shall be responsible for initiating,
maintaining and supervising all health and safety precautions and /or programs
required by Law in connection with the Tenant's use and occupancy of the
Premises.

19. HAZZARDOUS MATERIALS:. The Tenant shall not store, introduce or otherwise
permit any material known to be hazardous within the Premises. Any material
within the Premises which is determined to be hazardous shall be removed and
properly disposed of by the Tenant at the Tenant's sole expense.





                                     --END--


                                       41
<PAGE>


                                    EXHIBIT C
                                 LANDLORD'S WORK



A & E Construction, Inc.
P.O. Box 370
Drexel Hill, PA 19026
(610) 449-3152
(610)449-6325 (Fax)                                          General Contracting
--------------------------------------------------------------------------------

July 9,1999
Mr. John Shclly
KELLET & ASSOCIATES, Inc.
580 Virginia Drive - Suite 201
Fort Washington, PA 19034


RE:      AXCELL - BlOSCIENCES                                Proposal #1139-99R2
         --------------------
         826 Newtown Yardley Road - First Floor
         Newtown, PA 18940

The following is a proposal for work at the above referenced location. The scope
of work is based upon Thomas E. Hall. Architects space plan #SK-1, dated
5/24/99. There are NO specifications or details.


GENERAL REQUIREMENTS, DEMOLITION & SITE MANAGEMENT
--------------------------------------------------
     -   Licenses & permits.
     -   Project supervision.
     -   Properly dispose of all demolition / construction related debris.
     -   Ongoing site maintenance.

DRYWALL / FRAMING
-----------------
         182-Linear feet of one hour rated, demised partition.
         189-Linear feet of perimeter.
         124 -Linear feet of existing masonary partition to be laminated with
              1/2" GWB.
         678 -Linear feet of full height partition. Extend to underside of deck.
             -Patch and repair existing walls as required to achieve smooth
              finish.


DOORS & HARDWARE
----------------
           21 -3'-0" x 7'-0" Birch stain grade door with hollow metal frame.
            4 -5'-0" x 7'-0" Birch stain grade door with hollow metal frame.
            4 -3'-0" x 7'-0" Fire rated birch stain grade door with labeled
               hollow metal frame.
            1 -6'-0- x 7'-0" stain/paint grade bi-fold doors
              -All new doors to receive building standard hardware.




                                       42
<PAGE>


                                                Axcell- Biosciences- Page 2 of 4

CARPENTRY / MILLWORK
--------------------
         1 -Closet rod and shelf
         9 Linear feet of white MCP base cabinetry.
         9 Linear feet of while MCP wail cabinetry.
         9 -Linear feet of plastic laminate counter top (24" deep) with cut out
           for sink. -Additional blocking for Breakroom cabinets and fixtures.

ACOUSTIC CEILINGS
-----------------
         8200 - Square feet of 2 x 4' exposed grid system with Celotex #BET-197
         fissured, non directional tiles.


SPRINKLER SYSTEM
----------------
      Furnish and install in accordance with all stale and local fire codes.
Provide sprinkler drawings for township.


ELECTRICAL
----------
          1 -60 amp, 277 volt, lighting panel, including feeder breaker,
feeders, and branch circuit breakcr.
          1 -75 KVA transformer; 480/277 - 208/120 - 3 phase.
          3 -200 amp. 208/120 volt 3 phase, 42 circuit panel for general power
requirements and furniture teeds.  Includes feeder breaker, feeder, and branch
circuit breakers.
           -All existing electrical main distribution equipment to remain for
         reuse.
         103 -2' x 4' fluorescent lay-in fixture with magnetic ballast and
prismatic lens.
          21 -20 amp, 120 volt, dedicated duplex receptacle.
          10 -20 amp, 120 volt designated outlets (for PC's and other equipment
that may need separate circuitry).
         195 -20 amp, 120 volt duplex receptacle.
           1 -20 amp, 120 volt, G.F.I. receptacle
           3 -20 amp, 220 volt, dedicated power feed and connection.
          22 -20  amp, single pole switch.
          60 -Linear feet of Plugmold in Chemistry Lab (receptacle every 4').
           6 - 20 amp, 3-way switch.
           7 - Emergency light.
          11 - Exit Light.
             - HVAC connections (Computer Room).
           1 - Power feed for electric water heater.
           2 - Power feeds tar exhaust hood fans.
           8 - 120 volt furniture feed.





                                       43
<PAGE>


                                              Axcell - Biosciences - Page 3 of 4

FIRE ALARM SYSTEM
-----------------
         -Furnish and install devices as required by code.
         -Provide shop drawings for township.

HVAC
----
         - HVAC equipment to be in place as part of base building improvements.
This includes units controls, thermostats, duct drops and start-up.
         - Start-up of equipment by others.
         - Furnish and install new hard duct. flex duct, dampers and diffusers
as required to accommodate ceiling and floor plan.
         - Furnish and install one (1) 4-ton A/C unit in Computer Room.
Includes all necessary controls/ductwork


PLUMBING
--------
Furnish and install the following:
---------------------------------
         4 -Stainless steel sinks (22" x 25') with faucet.
         2 -Electric hot water heater to support Breakroom and Lab plumbing
            fixtures.
           -All hot and cold water supply line rough-ins.
           -All drain line rough-ins.

PAINTING
--------
        -Walls 10 be painted as per building standard. One color throughout.
        -Paint door frames and stain doors.

FLOOR COVERING
--------------
          564 -Square yards of building standard level loop carpet - 28 oz.
         3360 -Square feet of building standard vinyl floor tile. VCT to be used
in the MB & HTS Lab. Flammable Storage, Equipment Freezer, Chemistry Lab,
Breakroom, Computer Room & Telephone Room.
         1850 -Linear feet of 4' vinyl cove base.
            1 - Walk-off mat at `New Vestibule'.  To be 'Hercules' brand.

GLASS / GLAZING
---------------
         -Furnish and install two (2) -3'-0' wide x 4'-0" high x 1/4 ` tempered
           glass windows at Computer room.
         -Furnish and install one (1) 4'-0" wide x 4'-0" high x 1/4 tempered
           glass windows at Chemistry Lab.
         -Furnish and install new interior Vestibule doors and sidelight.
           Exterior vestibule doors and windows to be installed as part of base
           building renovations and are not included in this bid.




                                       44
<PAGE>

                                              Axcell - Biosciences - Page 4 of 4


CONCRETE / MASONRY
------------------
        - Trench floor for plumbing and electrical feeds in Labs.
        1 -$4,000,000 allowance for floor repairs.


MISCELLANEOUS
-------------
         4  -Wall mounted 5# ABC fire extinguisher.
         2  -Roof penetrations for exhaust hoods.
         -Final construction cleaning.


                    Cost of Construction as Specified Above:
                    ----------------------------------------


EXCLUSIONS
----------
        Exterior renovations.
        Restroom Construction
        Public Vestibule / Corridor Construction
        Data & Telephone.
        Sub floor preparation.
        Security Alarms.
        New HVAC equipment.
        Backflow preventers/flow meters/flow switches for sprinkler system. Lab
        millwork. Non-Corrosive plumbing pipes or specialized plumbing fixtures.
        Gas lines for Lab (if required).
        Compressed air lines (if required).
        Exhaust hoods. To be furnished and installed by Others.
        Reception Desk.
        Roof drain relocation.


Thank you for the opportunity to present our proposal. We hope It meets with
your approval. If you have any questions or require additional information1
please contact our office at (610) 449-3152.





                                       45
<PAGE>


                                    EXHIBIT D

                                BUILDING HOLIDAYS


BULDING CLOSED ON:


* NEW YEAR'S DAY *


* MEMORIAL DAY *


* INDEPENDENCE DAY *



* LABORDAY *


* THANKSGIVING DAY *


* CHRISTMAS DAY *







                                       46
<PAGE>


                                    EXHIBIT E

                           TENANT ESTOPPEL CERTIFICATE

TO:_________________ ("_____") pursuant to that certain ________________
Agreement (the "Agreement") dated ________, 199__, by and by and between _______
and  ______________ ("Lessor").

         1. The undersigned ("Lessee") is the lessee under that certain Lease
dated __________, 19__ by and between __________________________________ as
lessor, and ___________________________________________,as lessee (the "Lease"),
covering a portion of those certain premises commonly known and designated as
_________________________________________________,Pennsylvania, consisting of
approximately _________ square feet (the "Premises"). A true, complete and
correct copy of the Lease is attached hereto as Exhibit "A".

         2. The Lease has not been modified, changed, altered or amended in any
respect (except as indicated following this sentence) and is the only lease or
agreement between the undersigned and the Lessor affecting the Premises. If
none, state "none

         3. The undersigned has made no agreements with Lessor or its agents or
employees, which are not described in the Lease concerning free rent, partial
rent, rebate of rental payments or any other type of rental concession with
respect to the Lease (except as indicated following this sentence). If none,
state "none

         4. The undersigned accepted possession of the Premises on _________,
19__ currently occupies the Premises and has been open for business since
____________ , 19__ The current term of the Lease began on __________, 19__ The
current term of the Lease will expire on ___________, 19__ and Lessee has no
present right to cancel or terminate the Lease under the terms thereof, or
otherwise. No rent payable pursuant to the Lease has been prepaid for more than
two (2) months, and no monies otherwise payable to Lessor under the Lease have
been paid in advance of the due date therefor as set forth in the Lease. The
fixed minimum rent currently being paid under the Lease is $________ per month.
Future changes to the fixed minimum rental are as set forth in the Lease. The
undersigned also pays amounts for percentage rent, insurance and property tax
escalations based upon the square footage of the Premises subject to the Lease,
as set forth in the Lease, which amounts have been paid to and including
__________, 199__.

         5. The Lease is fully valid and enforceable and is currently in full
force and effect. Neither Lessor or Lessee is in default thereunder, and all
conditions and obligations on the part of Lessor to be fulfilled under the terms
of the Lease have been




                                       47
<PAGE>


satisfied or fully performed including, without limitation, all required tenant
improvements, allowances, alterations, installations and construction, and
payment therefor has been made in full. Lessee has no offset, claim, defense or
counterclaim against any rent or other sum payable by Lessee under the Lease or
against any other obligation of Lessee under the Lease. No condition exists
which with the giving of notice or the passage of time, or both, would
constitute a default under the Lease.

         6. Lessee has not suffered any assignment of the Lease or sublet the
Premises or any portion thereof, and no person or entity, other than Lessee, has
any possessory interest in the Premises or right to occupy the Premises or any
portion thereof, except as permitted under the Lease.

         7. Lessee claims no right, title or interest in or to the Premises or
right to possession of the Premises, except as lessee under the terms of the
Lease. The Lease does not contain and the undersigned does not have any
outstanding options or rights of first refusal to purchase the Premises or any
portion thereof or the real property of which the Premises are a part, except as
otherwise set forth below. If none, state "none".

         8. No actions, whether voluntary or otherwise, are pending against the
undersigned under the bankruptcy laws of the United States or any state thereof,
and Lessee knows of no fact or pending or threatened claim or litigation that
might result in the insolvency or bankruptcy of Lessee.

         9. Lessee is a [corporation] [limited partnership] [general
partnership] duly organized and validly existing and in good standing under the
laws of the State of __________ [and qualified to do business in the State where
the Premises is located]. [________ a ________,owns and holds all of the issued
and outstanding stock in and of Lessee, and is a separate and distinct entity
from Lessee].

         10. Lessee's occupancy of the Premises complies fully with all local,
state and federal laws, ordinances, codes, rules, regulations and orders
including, without limitation, those concerning hazardous wastes, hazardous
materials, asbestos, oil and underground storage tanks. In addition, no such
hazardous wastes, hazardous materials, asbestos, oil or underground storage
tanks have been or are incorporated in, stored on or under, released from,
treated on, transported to or from or disposed of, on or from the Premises or
any portion thereof.

         11. All inspections, licenses, permits, consents, permissions,
approvals and certificates required, whether by law, regulation or insurance
standards, to be made or issued with respect to the conduct of Lessee's
business, the Premises and the use and occupancy of the Premises by Lessee have
been made by or issued by all necessary private parties, the appropriate
governmental or quasi-governmental authorities or other authorities having
jurisdiction over the Premises and/or Lessee's business, are in full force and
effect, and Lessee has not received notification from any such authority that




                                       48
<PAGE>
Lessee or the Premises is in material noncompliance with such laws, regulations
or standards, that the Premises is being used, operated or occupied unlawfully
or that Lessee has failed to obtain such inspections, permits, consents,
permissions, approvals, licenses or certificates, as the case may be. Lessee has
not received notice of any violation or failure to conform with any such law,
ordinance, regulation, standard, license, permit, consent, permission, approval
or certificate.

         12. All insurance policies required to be maintained by Lessee under
the Lease have been maintained, are in full force and effect and all premiums
with respect thereto have been paid in full.

         13. Upon receipt of notice of the closing of the purchase and sale of
the Premises as set forth in the Agreement, Lessee shall recognize ______ as
lessor under the Lease, and all payments of rent and other sums due to Lessor
under the Lease and all communications permitted or required under the Lease
shall be directed to ______ c/o

-------------------------------------------------------------------------------,
and all communications permitted or required under the Lease shall be directed
to Lessee at the address for Lessee set forth in the Lease (except as otherwise
indicated following this sentence), unless and until otherwise specified in
written notice by the party to whom notice is to be given at such address. If
none, state "none".

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

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

         14. This certification is made to induce _____________________ [to
enter into the Agreement] [to provide financing to Lessor] knowing that
_______________________ is relying upon the truth of this Tenant Estoppel
Certificate in [entering into the Agreement,] [providing such financing] and
that [the acquisition of the Premises by __________________________ pursuant to
the Agreement] [the financing provided to Lessor] shall be deemed good and
valuable consideration to Lessee for the foregoing representations made by
Lessee.

Dated this ____ day of_________ , 199_.
                                               LESSEE:

                                               --------------------------------,

                                               a -------------------------------




                                               BY: -----------------------------
                                                   Name:
                                                        ------------------------
                                                   Title:
                                                        ------------------------




                                       49

<PAGE>


                                    EXHIBIT F

                                 LEASE GUARANTY

         FOR VALUE RECEIVED, and in consideration for and as an inducement to
Yardley Road Associates, L.P. ("Landlord") to enter in an Office Space Lease
dated _____________ (the "Lease"), with AxCell Biosciences Corporation
("Tenant"), the undersigned (whether one or more, "Guarantor") hereby
absolutely, unconditionally, and irrevocably guarantees to Landlord, its
successors and assign, subject to any grace period set forth in the Lease as
applicable to Tenant and further subject to any rights or defenses applicable to
the obligations of Tenant (excluding a discharge or release in bankruptcy or
other similar proceedings), the prompt and full payment of all rent and other
amounts payable by Tenant (including, without limitation, Fixed Basic Rent and
Additional Rent) and the performance of all other modifications thereof and any
holdover term (collectively, "Lease Obligations"). If Tenant defaults in the
performance of the Lease Obligations, upon Landlord's request, Guarantor will
perform the Lease Obligations. Guarantor also agrees to pay Landlord's
reasonable costs and attorney's fees in enforcing this Guaranty.

         Guarantor hereby waives any notice of the acceptance hereof, of any
action taken or omitted in reliance hereon, or of any nonpayment,
nonperformance, or default of Tenant. With the exception of full payment and
performance, no act or thing which but for this provision could act as a release
shall in any way terminate, affect, or impair the liability of Guarantor
hereunder, whether or not notice is given to Guarantor, including without
limitation: (1) any extension, renewal, modification, sublease, transfer, or
assignment of the Lease; (2) a discharge or release in bankruptcy or other
proceedings of any of the Lease Obligations or any defenses otherwise available
to a surety or guarantor; (3) any waiver, indulgence, or consent granted to
Tenant, any delay or lack of diligence in the enforcement of the Lease
Obligations; (4) any receipt, application, or release of any security for the
Lease Obligations. Until full payment and performance of the Lease Obligations,
Guarantor: shall have no right of subrogation against Tenant by reason of any
payment or performance by Guarantor; waives any right to enforce any remedy
which Guarantor now or hereafter shall have against Tenant by reason of any
payment or performance hereunder; and subordinates any liability or indebtedness
of Tenant now or hereafter held by Guarantor to the Lease Obligations. Each of
Landlord's rights under the Lease, this Guaranty, or any other agreement
securing Lease is separate and may be exercised and enforced one at a time or
all at once, in any order and against Tenant, Guarantor, or any other person
liable for any of the Lease Obligations separately or against all of them
together. A waiver by Land~rd of any right in a specific instance, or any delay
or failure to act, shall not operate as a waiver of the right itself or prevent
the future exercise or enforcement of the right. This Guaranty shall be governed
in all respects by the laws of the Commonwealth of Pennsylvania and may not be
modified, revoked or terminated except in writing signed by Guarantor and
Landlord.





                                       50
<PAGE>

         This Guaranty shall be binding upon each person signing below, and such
person's heirs or successors and assigns, whether or not signed by any other
person. If this Guaranty is signed by more than one person, their liability
shall be joint and several. For purposes of this Guaranty, the terms "Tenant"
shall also include the successors and permitted assigns of Tenant. Unless
otherwise specifically defined in this Guaranty, all capitalized terms used
herein shall have the same meanings as are given to such terms in the Lease.


Guarantor:

CYTOGEN CORPORATION:
--------------------



By:  /s/ Jane M. Maida
     --------------------
      Name: Jane M.Maida
            -------------
      Title: Chief Accounting Officer
             ------------------------


State of New Jersey:

COUNTY OF

         On the 14 day of July 1999, before me, the subscriber, a Notary Public
in and for the State and County aforesaid, personally appeared Jane M. Maida
known to me or satisfactorily proven to be the person who executed the foregoing
instrument for the purposes therein contained and desired that this instrument
be recorded as such.

         WITNESS my hand and seal the day and year aforesaid.

                                            /s/ Theresa Eamello
                                            -------------------

                                            NOTARY PUBLIC

                                            My commission expires:


                                                  THERE8A EAMELLO
                                        Notery Public, State of New Jersey
                                                  ID No. 2217405
                                           Qualified in Middlesex County
                                       Commission expires September 1, 2003





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