Document:

<PAGE>   1
                                                                    Exhibit 10.3

                       AMENDMENT TO TRANSACTION DOCUMENTS

          THIS AMENDMENT (referred to herein as this "Amendment"), dated as of
April 10, 2000, by and among PRIMARK CORPORATION, a Michigan corporation (the
"Borrower"), the Lenders party to the Revolving Credit Agreement referred to
below, the Lenders party to the Note Backup Agreement referred to below (such
agreements being referred to collectively as the "Credit Facilities"), and
MELLON BANK, N.A., a national banking association, as Agent under each such
Credit Facility.

                                   RECITALS:

          A. The Borrower has entered into (a) a Revolving Credit Agreement (as
amended, the "Revolving Credit Agreement") dated as of February 7, 1997 among
Primark Corporation (the "Borrower"), the Lenders parties thereto from time to
time, the Issuing Banks referred to therein, and Mellon Bank, N.A., as Agent,
and (b) a Note Backup Agreement (as amended, the "Note Backup Agreement") dated
as of February 7, 1997 among the Borrower, the Lenders parties thereto from
time to time, the Issuing Bank referred to therein, and Mellon Bank, N.A., as
Agent (collectively, the "Credit Facilities"). The Credit Facilities have been
amended by a letter agreement dated February 21, 1997, an Amendment to
Transactions Documents dated as of May 1, 1997, an Amendment to Transaction
Documents dated as of June 30, 1997, an Amendment to Transaction Documents dated
as of December 1, 1997, an Agreement dated as of March 6, 1998 (which restated
and superseded all such prior amendments), an Amendment to Transaction Documents
dated as of May 8, 1998, an Amendment to Transaction Documents dated as of June
15, 1998, an Amendment to Transaction Documents dated as of September 10, 1998,
a Consent and Amendment to Transaction Documents dated as of December 10, 1998,
an Amendment to Transaction Documents dated as of November 16, 1999, and an
Amendment to Transaction Documents and Waiver dated as of December 31, 1999 and
an Amendment to Transaction Documents dated as of March 28, 2000.

          B. The parties hereto desire to amend further the Credit Facilities as
set forth herein. Capitalized terms used herein and not otherwise defined shall
have the meanings given them in, or by reference in, the Collateral Agency
Agreement.

          NOW THEREFORE, the parties hereto, intending to be legally bound,
hereby agree as follows:

SECTION 1.  AMENDMENT TO FINANCIAL COVENANTS.

Section 7.09 of each Credit Facility is amended by (a) redesignating clause (h)
as clause (i); (b) changing the reference to Section 7.09(f) in such new clause
(i) to a reference to Section 7.09(i); and (c) adding the following new clause
(h):

          (h) The sale of all of the Capital Stock of Yankee Research Group,
          Inc.; provided, that the conditions set forth in the letter dated
          April 7, 2000, from the Agent to the Borrower are satisfied in
          connection with such sale; and

<PAGE>   2
SECTION 2.  EFFECTIVENESS AND EFFECT, ETC.

          (a) EFFECTIVENESS. This Amendment shall become effective on the date
when Mellon Bank, N.A., as Agent under each of the Revolving Credit Agreement
and the Note Backup Agreement, shall have received counterparts hereof duly
executed by the Borrower and by the "Required Lenders" and the "Agent" under
each of the Revolving Credit Agreement and the Note Backup Agreement.

          (b) EFFECT. The Revolving Credit Agreement and the Note Backup
Agreement, in the forms initially executed and as previously amended and as
amended hereby, are and shall continue to be in full force and effect, and are
hereby in all respects ratified and confirmed. Except to the extent expressly
set forth herein, the execution, delivery and effectiveness of this Amendment
shall not operate as a waiver of any right, power or remedy under any of the
foregoing agreements and instruments or constitute a waiver of any provision of
any of the foregoing agreements and instruments.

SECTION 3.  MISCELLANEOUS.

This Amendment may be executed in any number of counterparts and by the
different parties hereto in separate counterparts, each of which when so
executed and delivered shall be deemed to be an original and all of which taken
together shall constitute but one and the same document. Section and other
headings herein are for reference purposes only and shall not affect the
interpretation of this Amendment in any respect. This Amendment shall be
governed by and construed in accordance with the laws of the Commonwealth of
Pennsylvania, without regard to choice of law rules. This Amendment is a
requested amendment within the meaning of Section 10.06(a) of each Credit
Facility.

                  [Remainder of page intentionally left blank]

                                       2

<PAGE>   3
     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
executed by their respective officers thereunto duly authorized, as of the date
first above written.

                                        PRIMARK CORPORATION

                                        By /s/ Stephen H. Curran
                                           ----------------------
                                        Name:  Stephen H. Curran
                                        Title: Executive Vice President & CFO

                                        MELLON BANK, N.A.,
                                        individually and as Agent under each
                                        Credit Facility

                                        By /s/ R. Jane Westrich
                                           -----------------------
                                               R. Jane Westrich
                                               Vice President

CONSENTED AND AGREED:

BANKBOSTON, N.A.

By /s/ Lisa Gelfand Abrams
   -----------------------
Title: Vice President

NATIONSBANK, N.A.

By /s/ Michael R. Heredia
   ----------------------
Title: Managing Director

THE CHASE MANHATTAN BANK

By /s/ Neil Sweeny
   ----------------------
Title: Vice President

                                       3
<PAGE>   4
AMSOUTH BANK,
     Successor in interest by merger to
     First American National Bank

By /s/ Seth Butler
  -------------------
Title: Corporate Bank Officer

WACHOVIA BANK, N.A.

By /s/ John P. Rafferty
  ---------------------
Title: Senior Vice President

FLEET NATIONAL BANK

By Deanne M. Horn
  -------------------
Title: Vice President

THE HUNTINGTON NATIONAL BANK

By
  --------------------------
Title:

                                       4
<PAGE>   5
[MELLON BANK LETTERHEAD]

April 7, 2000

Primark Corporation
1000 Winter Street, Suite 4300N
Waltham, Massachusetts 02154-1248

Gentlemen:

Reference is made to (a) the Revolving Credit Agreement dated as of February 7,
1997, as amended, among Primark Corporation (the "Borrower"), the Lenders
parties thereto from time to time, the Issuing Banks referred to therein, and
Mellon Bank, N.A., as Agent, and (b) a Note Backup Agreement dated as of
February 7, 1997, as amended, among the Borrower, the Lenders parties thereto
from time to time, the Issuing Bank referred to therein, and Mellon Bank, N.A.,
as Agent (collectively, the "Credit Facilities"). The Borrower has requested
that the Lenders amend the Credit Facilities pursuant to an Amendment to
Transaction Documents dated as of April 10, 2000 (the "Proposed Amendment").
This is the letter referred to in the Section 7.09(h) of the Credit Facilities,
as proposed to be amended by the Proposed Amendment. Capitalized terms used in
this letter and not otherwise defined shall have the meanings assigned to those
terms in the Credit Facilities.

Subject to the execution and delivery of the Proposed Amendment by the Required
Lenders under the Credit Facilities, Primark Holding Corporation is permitted to
sell the Capital Stock of Yankee Research Group, Inc. ("Yankee"); provided, that
the following conditions are satisfied:

     (1)  The purchase price for the sale of the Capital Stock of Yankee is paid
          in cash on the date of the transfer of the Capital Stock to the
          purchaser thereof;

     (2)  The case purchase price received for the sale of the Capital Stock of
          Yankee is not less than $72,500,000, subject to downward adjustment
          only if and to the extent the receivables of Yankee on the closing
          date of such sale are less than $6,000,000; and

<PAGE>   6
Primark Corporation
April 7, 2000
Page 2 of 2

     (3)  The sale of the Capital Stock of Yankee is consummated on or prior to
          June 30, 2000.

Please indicate your agreement with the foregoing by signing where indicated
below and returning a signed copy of this letter to the undersigned.

                                        Very truly yours,

                                        MELLON BANK, N.A.,
                                        As Agent under the Credit Facilities

                                        By /s/ R. Jane Westrich
                                           ---------------------------------
                                           R. Jane Westrich
                                           Vice President

AGREED:
PRIMARK CORPORATION

By /s/ Stephen H. Curran
   ---------------------------------
   Stephen H. Curran
   Executive Vice President and
     Chief Financial Officer

Date: April 7, 2000

<PAGE>   7
AMSOUTH BANK,
     Successor in interest by merger to
     First American National Bank

By
  ---------------------------------
Title:

WACHOVIA BANK, N.A.

By
  ----------------------------------
Title:

FLEET NATIONAL BANK

By /s/ Deanne M. Horn
  ----------------------------------
Title: VICE PRESIDENT

THE HUNTINGTON NATIONAL BANK

By
  -----------------------------------
Title:

                                       4
<PAGE>   8
AMSOUTH BANK,
     Successor in interest by merger to
     First American National Bank

By
  ---------------------------------
Title:

WACHOVIA BANK, N.A.

By /s/ John P. Rafferty
  ---------------------------------
Title: SENIOR VICE PRESIDENT

FLEET NATIONAL BANK

By
  ---------------------------------
Title:

THE HUNTINGTON NATIONAL BANK

By
  ---------------------------------
Title:

                                       4<PAGE>   1
                                                                   EXHIBIT 10.19

                                 LEASE AGREEMENT
                                 ---------------

                LANDLORD: NEW BOSTON ALEWIFE LIMITED PARTNERSHIP

                TENANT:   NETGENESIS CORP.

                PREMISES: ONE ALEWIFE CENTER
                          CAMBRIDGE, MASSACHUSETTS

                            SUBMISSION NOT AN OPTION
                            ------------------------

THE SUBMISSION OF THIS LEASE FOR EXAMINATION AND NEGOTIATION DOES NOT CONSTITUTE
AN OFFER TO LEASE, A RESERVATION OF, OR OPTION FOR THE PREMISES AND SHALL VEST
NO RIGHT IN ANY PARTY. TENANT OR ANYONE CLAIMING UNDER OR THROUGH TENANT SHALL
HAVE THE RIGHTS TO THE PREMISES AS SET FORTH HEREIN AND THIS LEASE BECOMES
EFFECTIVE AS A LEASE ONLY UPON EXECUTION, ACKNOWLEDGMENT AND DELIVERY THEREOF BY
LANDLORD AND TENANT TO EACH OTHER, REGARDLESS OF ANY WRITTEN OR VERBAL
REPRESENTATION OF ANY AGENT, MANAGER OR EMPLOYEE OF LANDLORD TO THE CONTRARY.

                              FROM THE OFFICE OF:

                        RAPPAPORT, ASERKOFF AND RAPPAPORT
                              ONE LONGFELLOW PLACE
                                   SUITE 3611
                                BOSTON, MA 02114

<PAGE>   2
                                     LEASE

                     NEW BOSTON ALEWIFE LIMITED PARTNERSHIP
                                  ("LANDLORD")
                                       TO

                          NETGENESIS CORP. ("TENANT")

                               TABLE OF CONTENTS

SECTION I. PREMISES ........................................................  1
SECTION II. USE ............................................................  2
SECTION III. TERM ........ . ...............................................  2
SECTION IV. RENT ...........................................................  3
SECTION V. CONSTRUCTION AND PREPARATION OF THE PREMISES ....................  3
SECTION VI. BUILDING AND EQUIPMENT .........................................  5
SECTION VII. FLOOR LOAD, HEAVY MACHINERY ...................................  5
SECTION VIII. SERVICES .....................................................  6
SECTION IX. UTILITIES ......................................................  7
SECTION X. ADDITIONAL RENT AND ESCALATION ..................................  9
SECTION XI. REMOVAL OF GOODS AND TENANT'S REPAIRS .......................... 13
SECTION XII. SALES TAX ..................................................... 13
SECTION XIII. IMPROVEMENTS AND ALTERATIONS ................................. 13
SECTION XIV. INSPECTION .................................................... 14
SECTION XV. CASUALTY ....................................................... 14
SECTION XVI. EMINENT DOMAIN ................................................ 15
SECTION XVII. INDEMNIFICATION .............................................. 16
SECTION XVIII. PROPERTY OF TENANT .......................................... 17
SECTION XIX. INJURY AND DAMAGE ............................................. 17
SECTION XX. ASSIGNMENT, MORTGAGING, AND SUBLETTING ......................... 17
SECTION XXI. SIGNS, BLINDS AND WINDOW TREATMENTS ........................... 19
SECTION XXII. INSURANCE COMPLIANCE ......................................... 19
SECTION XXIII. INFLAMMABLES, ODORS ......................................... 19
SECTION XXIV. DEFAULT ...................................................... 19
SECTION XXV. SUBORDINATION AND ESTOPPEL .................................... 21
SECTION XXVI. NOTICES ...................................................... 22
SECTION XXVII. RULES AND REGULATIONS ....................................... 23
SECTION XXVIII. QUIET ENJOYMENT ............................................ 23
SECTION XXIX. BINDING AGREEMENT ............................................ 23
SECTION XXX. PARTNERSHIP ................................................... 23
SECTION XXXI. SEISIN ....................................................... 23
SECTION XXXII. INSURANCE ................................................... 23
SECTION XXXIII. SUBROGATION, INSURANCE PREMIUMS ............................ 24

                                                                               2
<PAGE>   3
SECTION XXXIV. SHORING ..................................................... 24
SECTION XXXV. REZONING ..................................................... 25
SECTION XXXVI. SEPARABILITY ................................................ 25
SECTION XXXVII. WAIVER OF TRIAL BY JURY .................................... 25
SECTION XXXVIII. NO WAIVER ................................................. 25
SECTION XXXIX. HOLDING OVER ................................................ 25
SECTION XL. CAPTIONS, PLURAL, GENDER ....................................... 25
SECTION XLI. BROKERAGE ..................................................... 25
SECTION XLII. HAZARDOUS WASTE .............................................. 26
SECTION XLIII. SECURITY DEPOSIT ............................................ 27
SECTION XLIV. LANDLORD'S RIGHT TO PERFORM FOR TENANT ....................... 29
SECTION XLV. GOVERNING LAW ................................................. 29
SECTION XLVI. FORCE MAJEURE ................................................ 29
SECTION XLVII. EXTENSION OPTION ............................................ 29
SECTION XLVIII. RIGHT OF FIRST OFFER ....................................... 30
SECTION XLIX. CONDITIONS PRECEDENT ......................................... 31
SECTION L. MULTIPLE COUNTERPARTS ........................................... 31

                                                                               3
<PAGE>   4
       THIS LEASE (the "LEASE") made and entered into as of this 4th, day of
April, 2000 by and between NEW BOSTON ALEWIFE LIMITED PARTNERSHIP, a Delaware
Limited Partnership, having a business address at One Longfellow Place, Suite
3612, Boston, Massachusetts 02114 (hereinafter called "LANDLORD") and NETGENESIS
CORP. (hereinafter called "TENANT").

       SECTION I. PREMISES. Landlord leases to Tenant, and Tenant hereby hires
and takes from Landlord the following described premises subject to the
mortgages as hereinafter provided, and to all encumbrances of record.

       The "PREMISES" are that portion of a building in the City of Cambridge,
Massachusetts, having a mailing address of One Alewife Center, Cambridge,
Massachusetts 02140 (hereinafter called the "BUILDING") (containing
approximately 89,504 square feet of space) substantially as shown cross-hatched
or outlined on the Lease Plan, Exhibit 4, hereto attached and made a part
hereof, consisting of approximately 57,948 rentable square feet of net rentable
area (the "NET RENTABLE AREA") consisting of (i) 19,228 rentable square feet on
the 1st Floor of the Building, (ii) 24,305 rentable square feet on the 3rd Floor
of the Building, (iii) 10,395 square feet on the 4th Floor of the Building (the
"ALLAIRE SPACE") all currently under lease to the Allaire Corporation
("ALLAIRE") and (iv) an additional 4,020 rentable square feet on the 4th Floor
of the Building, hereinafter known as the "TCQM SPACE", all as shown on Exhibit
A, The Building and the parcel of land on which it is located are hereinafter
referred to as the "PROPERTY".

       The parties hereto acknowledge that the TCQM Space is currently under
lease to The Center for Quality of Management ("TCQM") and this Lease as it
pertains only to the TCQM Space is contingent upon Landlord and TCQM entering
into a termination agreement for the TCQM space and the delivery of the TCQM
Space to Landlord for delivery to Tenant. The failure of Landlord to deliver the
TCQM Space shall in no way impact on the obligations of Tenant as pertains to
the remainder of the Premises. In the event that the TCQM Space is not delivered
to Tenant hereunder, all applicable provisions of this Lease shall be amended to
reflect the reduction in Net Rentable Area and Landlord shall be responsible, at
its cost and expense, for demising the Allaire Space from the TCQM Space.

       Landlord reserves and excepts all rights of ownership and use in all
respects outside the Premises, including, without limitation, the Building and
all other structures and improvements and plazas, parking areas, and common
areas on the Property, except that at all times during the term of this Lease,
Tenant shall have a reasonable means of access from the street to the Premises.
Tenant shall have, throughout the term of this Lease at no cost to Tenant, the
right to the use of 2.5 unassigned spaces per 1,000 square feet of Net Rentable
Area of the Premises then under lease to Tenant. The Premises shall be delivered
to Tenant with eight (8) existing supplemental air conditioning wall units in
place. Without limitation of the foregoing reservation of rights by Landlord, it
is understood that with regard to the Building and the Property, Landlord in its
sole discretion shall have the right to change, relocate and eliminate
facilities therein, to permit the use of or lease all or part thereof for
exhibition and displays, to sell, lease or dedicate all or part thereof to
public use; and further that Landlord shall have the

                                                                               1
<PAGE>   5
right to make changes in, additions to and eliminations from the Building, and
other structures and improvements on the Property, the Premises excepted,
provided such changes do not materially impact on Tenant's use and operation.
Notwithstanding the preceding sentence, Landlord shall have no right to
eliminate the lobby, elevators, access, loading docks or parking areas unless
the same are replaced with comparable amenities.

       SECTION II. USE. Tenant shall have the right to use, in common with
others so entitled, all common areas associated with the Building and located in
the Building or on the Property including all hallways, elevator(s), if any,
loading dock(s), access ways, walkways, nonexclusive parking areas, courtyards
and landscaped areas. Landlord reserves the right, in its sole and unfettered
discretion, to limit, relocate or diminish the non-exclusive parking area,
provided that at all times Tenant shall be entitled to the non-exclusive and
without charge use of a minimum of 2.5 parking spaces per 1,000 square feet of
Net Rentable Area of the Premises in the parking lot adjacent to the Building.
Tenant shall use the Premises for general office use and other reasonable uses
incidental and related thereto, provided that Tenant shall not use, permit nor
suffer anything to be done or anything to be brought into or kept in the
Premises or on the Property which in Landlord's sole judgment occasions
discomfort or annoyance to any other tenants or occupants of the Building and
parking area, or which may tend to impair the reputation or appearance of the
Building or the Property, or tend to interfere with the proper and economic
operation of the Building, parking area or the Property by Landlord, or which
shall violate the Certificate of Occupancy for the Building or any law or
regulation of any governmental body. If, due to Tenant's use of the Premises,
improvements or alterations to the Premises or the Building are necessary to
comply with any requirements imposed by law, Tenant shall pay the entire cost of
such improvements or alterations.

       Tenant agrees that, if it vacates the Premises, or fails to conduct its
business therein for any period of time exceeding two weeks during the term
hereof, it shall provide Landlord with prior written notice thereof.

       SECTION III. TERM. The term of this Lease shall commence upon the
vacation of the Premises by Allaire and delivery of the Premises to Tenant in a
broom clean condition, for the performance of Tenant's Work (the "COMMENCEMENT
DATE"), and shall terminate the last day of the seventy-second (72nd) calendar
month following the Rent Commencement Date as hereafter defined (the
"TERMINATION DATE"). The "RENT COMMENCEMENT DATE" shall be the earlier to occur
of thirty-seven (37) days after the Commencement Date or upon the occupancy of
the Premises by Tenant for general office use. The term "LEASE YEAR" shall mean
the twelve (12) month period commencing upon the Rent Commencement Date, and
each successive twelve (12) month period during the term hereof, provided,
however, that if the Rent Commencement Date is not the first day of the calendar
month, the Lease Year shall mean each consecutive twelve (12) calendar month
period commencing with the first day of the first full calendar month of the
term. The first Lease Year shall include any partial month between the Rent
Commencement Date and the first day of the first full calendar month immediately
following the Rent Commencement Date. In the event that the Rent Commencement
Date herein is not a date certain, at the request of either party at any time
following initial occupancy of the Premises by Tenant, Landlord and Tenant shall
execute a written memorandum reflecting the date of initial

                                                                               2
<PAGE>   6

occupancy and confirming the Commencement Date. The parties hereto acknowledge
that the Commencement Date is anticipated to be between July 1, 2000 and August
15, 2000 and will be effective upon the date which is thirty (30) days from
receipt of notice from Landlord. Landlord covenants and agrees that immediately
upon receipt of Allaire's notice of effective termination pursuant to the
Termination Agreement as hereafter defined, it shall provide Tenant with the
notice provided herein, which shall be communicated by voice, email and
facsimile transmission (which shall include a copy of the Allaire notice). In
the event that Landlord is unable to deliver the Premises to Tenant by August
15, 2000 due to Allaire's failure to vacate the Premises, the Lease shall remain
in full force and effect and Landlord shall diligently pursue any and all
remedies it may have at law to remove Allaire and all its property therein from
the Premises, provided however the Commencement Date, and the Rent Commencement
Date shall not occur until after delivery of the Premises free and clear of
Allaire in a broom clean condition.

       SECTION IV. RENT. Tenant shall pay annual "RENT" equal to the product of
the Net Rentable Area of the Premises multiplied by Annual Rent Per Square Foot
rate, as set forth below, from and after the Rent Commencement Date:

<TABLE>
<CAPTION>
                                               ANNUAL RENT
PERIOD/LEASE YEAR                           PER SQUARE FOOT
<S>                                            <C>

Lease Year One                                 $36.00
Lease Year Two                                 $36.50
Lease Year Three                               $37.00
Lease Year Four                                $37.50
Lease Year Five                                $38.00
Lease Year Six                                 $38.50

</TABLE>

       The Rent shall be paid in equal installments of one-twelfth (1/12) of the
annual Rent in advance on the first day of each calendar month.

       Tenant shall pay a proportionate share of such monthly installment for
any fraction of a calendar month at the beginning or end of the Lease term.

       Tenant shall pay the Rent and Additional Rent without demand or notice
and without deduction, abatement, counterclaim, or set-off, to the Landlord New
Boston Alewife Limited Partnership, in care of New Boston Management Services,
Inc., One Longfellow Place, Suite 3612, Boston, Massachusetts 02114, or at such
other place as designated from time to time by Landlord in writing.

       In the event that the Rent is not paid within five (5) days of when such
payment is due, Landlord shall assess and Tenant shall pay a late charge in an
amount equal to interest at the rate of one and one-half percent (1 1/2%) per
month on the unpaid balance from the date said Rent became due. All other
charges which Tenant is required to pay hereunder, together with all interest
and penalties that may accrue thereon, shall be deemed to be "ADDITIONAL RENT"
and in the event of non-payment thereof by Tenant, Landlord shall have all the
fights and remedies with respect thereto as would accrue to Landlord for
non-payment of Rent.

        SECTION V. CONSTRUCTION AND PREPARATION OF THE PREMISES.

       (a)    LANDLORD'S WORK. None. The Premises are being leased to Tenant in
its "as-is" condition as of the date of execution hereof. Landlord shall not
consent to any additions or alterations to the Premises by Allaire without
Tenant's approval. Upon the execution of the

                                                                               3
<PAGE>   7
Lease Tenant and Landlord shall inspect the Premises to verify the "as-is"
condition. The taking of possession of the Premises by Tenant shall be
conclusive evidence of the acceptance of the Premises by Tenant and that the
Premises are in good and satisfactory condition, in accordance with Landlord's
obligations hereunder.

       (b)    TENANT'S WORK. Tenant shall do the work, if any, shown on Exhibit
B (herein referred to as "TENANT'S WORK"), as the work on the part of the
Tenant, in a good and workmanlike manner in accordance with "PLANS AND
SPECIFICATIONS" (as hereinafter defined) which have Landlord's written
approval, not to be unreasonably withheld, prior to the commencement of Tenant's
Work. Tenant shall furnish and install any and all necessary trade fixtures,
equipment and other items necessary for the proper conduct of Tenant's business.
"PLANS AND SPECIFICATIONS", as used in this Section V(b) and in Section XIII,
shall mean documents and drawings sufficient for contract bidding and work
completion. All of the foregoing work and all work Tenant may undertake pursuant
to Section XIII of this Lease shall be done in accordance with all laws, rules,
regulations and ordinances applicable' thereto, including, if necessary,
compliance with the Americans With Disabilities Act, as amended from time to
time, and the acquisition by Tenant of a Building Permit from the municipal
department having jurisdiction, if required. In no event shall Landlord be
required to provide or install any trade fixtures or equipment.

       Tenant shall be entitled to receive a cash leasehold improvement
allowance in an amount not to exceed $5.00 per square foot of Net Rentable Area
of the Premises (hereinafter referred to as the "TI CONTRIBUTION"). The TI
Contribution shall be payable by Landlord to Tenant within thirty (30) days of
completion of Tenant's Work and written demand therefore, such demand to be
accompanied by copies of building permits, certificate of occupancy if required,
paid bills, lien waivers, and other evidence that Landlord reasonably requires
to satisfy itself as to the amount spent and the items for which such amount was
spent. Tenant shall be entitled to that portion of the TI Contribution equal to
the amount of approved costs actually incurred by Tenant (which may include the
actual hard and soft costs of performing leasehold improvements and
architectural and engineering costs, but not the cost of furniture or office
equipment, voice and data cabling), and shall not be entitled to any portion of
the TI Contribution in excess thereof in cash, credit or otherwise; any and all
costs incurred by Tenant in excess of the TI Contribution shall be borne by
Tenant.

       Tenant agrees to allow Landlord's contractor ("LANDLORD'S CONTRACTOR") to
submit estimates for completing Tenant's Work. In the event that Landlord's
contractor is not the lowest bidder and subject to the reasonable prior approval
of contractor by Landlord, Tenant agrees to employ for any work it may do
pursuant to Sections V(b) and XIV of this Lease, one or more responsible
contractors whose labor will work in harmony with other labor working in and
about the Building and Property and with suppliers of materials, for use in
construction in and about the Building and Property, and especially Tenant
agrees that it will not do or permit to be done anything which would cause any
labor difficulty in connection with any construction in and about the Building
and Property.

       Tenant shall require all contractors employed by Tenant to carry Worker's
Compensation Insurance in accordance with statutory requirements and to carry
Commercial General Liability

                                                                               4
<PAGE>   8
Insurance and Automobile Liability Insurance covering such contractors in or
about the Premises, Building and Property in amounts not less than Two Million
Dollars ($2,000,000) combined single limits for property damage, for injury or
death of more than one person in a single accident, and to submit certificates
of insurance evidencing such coverage to Landlord prior to commencement of such
work. Tenant agrees to indemnify and hold harmless Landlord and its management
agent from all claims, actions, demands and causes of actions occasioned by,
Tenant's contractors being on or about the Premises, or the Building or the
Property of which the same form a part and from Tenant's contractors performing
work in the Premises.

       All contractors, subcontractors, mechanics, laborers, materialmen, and
others who perform any work, labor or services, or furnish any materials, or
otherwise participate in the labor or services, or furnish any materials, or
otherwise participate in the improvement of the Premises shall be and are hereby
given notice that Tenant is not authorized to subject Landlord's interest in the
Premises, Building or Property to any claim for mechanics', laborers' and
materialmen's liens, and all persons dealing directly or indirectly with Tenant
may not look to the Premises, Building or Property as security for payment.
Tenant shall save Landlord harmless from and against all expenses, liens, claims
or damages to either property or person which may or might arise by reason of
the making of any such additions, improvements, alterations and/or
installations.

       SECTION VI. BUILDING AND EQUIPMENT. Landlord shall keep in good condition
and repair the structure and exterior of the Building as a first-class office
building, including the roof, the plumbing and electrical systems the heating,
ventilating and air conditioning systems, and elevators servicing the Building
(except the eight (8) HVAC units described in Section I, such supplemental
equipment required for Tenant's specific use and specialized equipment and
serviceable lines installed by Tenant and except otherwise provided in Section
VIII), and the exterior parking area serving the Building. The Landlord shall
comply with applicable governmental roles, regulations, laws and ordinances
affecting the Building, unless the violation is caused by Tenant or Tenant's use
of the Premises. The Landlord shall keep the sidewalks, common corridors,
stairway, elevators, and all other means of ingress and egress for the Premises
and all public portions of the Building in serviceable repair and in a
reasonably clean and safe condition. Landlord reserves the right to interrupt,
curtail, stop and suspend the furnishing of any services and operation of the
plumbing and electrical, heating and air conditioning systems when necessary by
reason of accident or emergency or for repairs, alterations, replacements or
improvements, which may become necessary or when it cannot secure supplies or
labor or by reason of any other cause beyond its control, without liability or
any abatement of Rent or additional rent being due thereby.

       SECTION VII. FLOOR LOAD, HEAVY MACHINERY. Tenant shall not place a load
upon any floor of the Premises exceeding the floor load per square foot area
which floor was designed to carry and which is allowed by law. Landlord reserves
the right to prescribe the position of all file cabinets, business machinery and
mechanical equipment (including safes) which Tenant may place in the Premises.
Business machines and mechanical equipment shall be placed and maintained by
Tenant at Tenant's expense in settings sufficient to prevent transmission of
noise and vibration to any other part of the Building in which the Premises are

                                                                               5
<PAGE>   9
located. Any moving of any machinery and/or equipment into, out of, or within
the Premises shall be done only with the prior written consent of Landlord in
each instance, which consent shall not be unreasonably withheld, and shall be at
the sole risk and hazard of Tenant and Tenant will indemnify and save Landlord
harmless against and from any liability, loss, injury, claim or, suit resulting
directly or indirectly from such moving. In the event riggers shall be required
to accomplish such moving, only persons holding a Master Rigger's License shall
perform the work. Tenant shall not in any way break, cut into, or damage the
exterior perimeter walls or insulating panels of the Building in installing,
ventilating or exhausting its equipment or in any other manner.

       SECTION VIII. SERVICES. Landlord shall provide:

       (a)    Access to the Building from the lobby Monday through Friday,
excepting legal holidays in Massachusetts, hereinafter referred to as "business
days", during normal business hours. Legal holidays in Massachusetts are shown
on Exhibit C attached hereto. Normal business hours shall mean Monday through
Friday, 8:00 AM to 6:00 PM, holidays excepted, Saturdays 8:00 AM to 1:00 PM. At
all other times Landlord shall provide limited access to the Building in
accordance with such Building standard entry system as shall from time to time
be in effect. The Landlord reserves the right to alter the Building standard
entry system as it sees fit.

       (b)    Use, in common with others, of all elevator facilities at all
times.

       (c)    Building Standard heat and air conditioning during normal business
hours which is reasonably required for reasonably comfortable occupation of the
Premises, under normal business operation at an occupancy of not more than one
person per 125 square feet of Net Rentable Area and an electrical load not
exceeding 3.0 watts per square foot of Net Rentable Area, subject to all
governmental laws, regulations or restrictions now or hereafter in force
pertaining to the furnishing or use of such heat and air conditioning. Landlord
shall maintain the Building at other than normal business hours at 55(degree) in
the winter and 80(degree) in the summer and Landlord shall provide heat and air
conditioning to Tenant at other than normal business hours in accordance with
standard Building operations, provided that Tenant pays Landlord its charges for
supplying the same. At the commencement of the term of this Lease, Landlord's
charge for supplying heat and air conditioning to Tenant at other than normal
business hours is $50.00 per hour. Landlord reserves the right to increase this
charge from time to time throughout the term of this Lease upon prior written
notice to Tenant. Tenant shall not introduce into the Premises personnel or
equipment which overloads the capacity of the Building systems or in any other
way interferes with any system's ability to perform adequately its proper
functions; provided, however, if Tenant violates the foregoing, upon notice to
Tenant Landlord may, elect to provide supplementary systems or otherwise take
steps to cure such violation, at Tenant's sole cost and expense in all respects
including, without limitation, system installation (and removal) and continuing
costs Of operation.

       (d)    Cause the Premises to be kept reasonably clean, provided the
Premises are kept in order by Tenant. The cleaning services provided hereunder
are set forth on Exhibit D attached hereto and made a part hereof which
represents the scope of the cleaning services. The cleaning services shall be
provided only Monday through Friday, legal holidays excepted. Notwithstanding
the foregoing, at no time and under no circumstances shall Landlord have any

                                                                               6
<PAGE>   10
responsibility for the storage or removal of any "medical waste", "infectious
waste", "hazardous medical waste", "hazardous waste", as such terms may from
time to time be defined in such municipal, state and federal statutes, laws,
ordinances, roles and regulations as may apply to Tenant or to the Premises
demised to Tenant because of the business, profession or activity carried on in
the Premises by Tenant, Tenant's servants, agents, employees, invitees or anyone
claiming by, through or under Tenant.

       (e)    Hot and cold running water, toilet paper, paper towels and hand
soap for common area wash rooms and lavatories.

       (f)    Electricity for normal lighting of main lobby, elevators and
stairs.

       SECTION IX. UTILITIES. As of the Commencement Date, Tenant shall pay for
all utilities furnished to the Premises by Landlord or any other supplier, which
may include electricity services, and all costs associated with the supplemental
heating, ventilating and air conditioning units serving the Premises, which
supplemental units may be check metered by Landlord and the cost of such check
meter and the electricity measured by that meter will be reimbursed as an
addition to the Electricity Charge The listing of any utility service in the
previous sentence shall not constitute a representation that such utility
service is available to the Premises. To the extent Landlord elects to
separately meter the Premises for water, gas or electricity usage, a separate
meter serving only the Premises shall be installed at Landlord's expense, and
the cost of all such utilities shall be billed directly to Tenant by the
appropriate public utility company.

       (a)    DEMAND AND USAGE. To the extent not separately metered to the
Premises, Landlord shall supply electricity, as supplied to Landlord by the
electric utility, to the Premises to meet a demand requirement (utilizing the
demand measurement standards established by the supplying utility under the rate
applicable to Landlord) not to exceed 3.0 watts per square foot of Net Rentable
Area for premises lighting and convenience outlets. Tenant agrees Tenant's use
of the Premises shall not exceed such requirements or any limits from time to
time established under applicable laws or regulations, or regulations of the
utility provider(s). In addition to the Rent set forth in Section IV of this
Lease and as part of the Additional Rent due under this Lease, Tenant shall pay
Landlord the sum of $1.00 per square foot of Net Rentable Area per annum as an
"ELECTRICITY CHARGE". The Electricity Charge shall be paid in equal installments
of one-twelfth (1/12) of the Electricity Charge each in advance on the first day
of each calendar month without deduction, demand, or set off, together with the
Rent and Additional Rent described in this Lease. If Tenant's electricity demand
exceeds the foregoing, Tenant shall pay the cost of such excess electricity
demand.

       (b)    CONSUMPTION. Landlord's supply of electricity shall allow for a
rate of consumption by Tenant of 3.0 watts per square foot of Net Rentable Area,
multiplied by sixty (60) hours of consumption per week. If Tenant's consumption
excess such allowance, Tenant shall pay the excess costs. Landlord will not
reduce the level of service or siphon off the available electric power serving
the Premises as of the date of execution hereof.

       (c)    SURVEY. From time to time during the Term or any extension
thereof, Landlord shall have the right to have an electrical consultant selected
by Landlord make a survey of Tenant's electrical usage, the result of which
survey shall be conclusive and binding upon

                                                                               7
<PAGE>   11
Landlord and Tenant. If such survey shows that Tenant has exceeded the aforesaid
requirements or standards set forth in the Lease, then, upon demand and in
addition to any other rights Landlord may have hereunder, Tenant shall reimburse
Landlord, as part of Tenant's Additional Rent, for the proportionate share of
the cost of such survey and the cost, as determined by such consultant, of
electricity usage or demand in excess of such requirements or standards.

       (d)    ESCALATION. Furthermore, it being the intention of the parties
that the Rent set forth in Section IV of this Lease be net of any cost to
Landlord of providing electric current to the Premises, if Landlord is
furnishing electric current to the Premises (i.e. Tenant's Premises is not
separately metered by the supplying utility company), Tenant shall pay, as part
of Tenant's Additional Rent, an Escalation Charge calculated and payable as
follows:

              1.     If Landlord's cost in supplying electricity to the Premises
for any Operating Year exceeds the Electricity Charge (such excess being called
"Tenant Excess Electricity Expenses"), Tenant shall pay to Landlord, as part of
Tenant's Additional Rent, an amount equal to the Tenant Excess Electricity
Expenses for such year (and at that rate for a partial year and extrapolated to
full occupancy if total Building electric current figures are used to calculate
Tenant Excess Electricity Expenses). In determining and calculating the amount
of the Tenant Excess Electricity Expenses for and in respect of any Operating
Year, Landlord may utilize electric meters, equipment surveys, engineering
estimates, electric consumption data for the entire Building, or any other
reasonable measurement, calculation and allocation devices and formulas.

              2.     Tenant shall make reasonably estimated escalation payments
on account of the Tenant Excess Electricity Expenses either in monthly
installments or in year-end lump sum, as Landlord shall elect. After the end of
each Operating Year, Landlord shall submit to Tenant an accounting of the Tenant
Excess Electricity Expenses for such Operating Year. If the estimated payments
by Tenant for such Year exceed Tenant's required payment on account of the
Tenant Excess Electricity Expenses for that Operating Year, according to such
statement, Landlord shall credit the amount of overpayment against subsequent
obligations of Tenant (or refund the overpayment if the Term has ended and
Tenant has no further obligations to Landlord). If, however, the required
payments are greater than the estimated payments made by Tenant, Tenant shall
pay to Landlord the difference within thirty (30) days after being billed
therefor by Landlord.

       (e)    SERVICE AND METERING. Landlord shall have the fight at any time
and from time to time to: (i) discontinue furnishing electricity to the Premises
upon at least thirty (30) days notice to Tenant provided Landlord shall, at
Landlord's expense, separately meter the Premises; or (ii) continue or
recommence to furnish electricity to the Premises, and install at Landlord's
expense a so-called check meter which shall measure the amount of electricity
actually used in the Premises. If Landlord exercises the right described in
clause (i), then from and after the effective date of such discontinuance,
Landlord shall not be obligated to furnish electricity to the Premises. In
either case, from and after the effective date of such new metering:

              1.     The Electricity Charge shall no longer be due from Tenant
to Landlord and Tenant shall cease making payments pursuant to Subsection (e)
above;

                                                                               8
<PAGE>   12
              2.     In the case described in clause (e)(i) above, Landlord
shall permit Landlord's existing wires, risers, conduits and other electrical
equipment to be used to supply electricity to Tenant provided that the limits
set forth in Subsection (a) shall not be exceeded; and

              3.     In the case described in clause (e)(i) above, Tenant shall
arrange for electrical service from, and make payments directly to, the
appropriate utility company; and in the case described in clause (ii) above,
Landlord may bill Tenant periodically for electricity usage as shown by such
meter.

       SECTION X. ADDITIONAL RENT AND ESCALATION.

       (a)    ADDITIONAL RENT/TAXES. In addition to the Rent set forth in
Section IV of this Lease and as part of the Rent due pursuant to the terms of
this Lease, Tenant shall pay Landlord as Additional Rent the Tax Excess as set
forth in herein. For the purposes of this Section X(a), the following words and
terms shall have the following meaning:

              (1)    "TAXES" shall mean the real estate taxes and assessments
imposed upon Landlord with respect to the Building and lot commonly known as One
Alewife Center, Cambridge, Massachusetts and its proportionate share of the
Building parking lot, as such parcel or parcels are defined in the records of
the Assessor's Office of the City of Cambridge on July 1, 1999, including all
structures located thereon, and any and all other taxes, levies, betterments,
assessments and charges arising from the ownership and/or operation of said
Building and lot and all the structures located thereon which are or shall be
imposed by a national, state or municipal or other authorities which are or may
become a lien upon Landlord and said Building and lot, but excluding any fee or
penalty levied on Landlord for late payment thereof. If, or to the extent that,
due to a future change in the method of taxation any franchise, income, profit
or other tax shall be levied against Landlord in substitution or in lieu of any
tax which would otherwise constitute a real estate tax, such franchise, income,
profit or other tax shall be deemed to constitute "Taxes" for the purposes
hereof. It is recognized and agreed by Landlord and Tenant that it is their
intention by this paragraph to include in "Taxes" that which in fiscal year 2000
was commonly known in the City of Cambridge as "real estate taxes", including
that portion covered by the school tax rate, and any type of tax or assessment
which may, throughout the term hereof be substituted, in whole or in part
therefore. If, in any fiscal year after the fiscal year 2000, the City of
Cambridge or any of its departments, shall require Landlord to pay for any
service which during the fiscal year 2000 was provided by said City of
Cambridge or any of its departments without requiring payment by Landlord, then
all such payments due on account of services rendered during any fiscal year
after the fiscal year 2000 shall, for purposes of this Section X(a)(1) be
considered and treated as real estate taxes for the fiscal year for which such
payments are due. Without in any way limiting the generality of the preceding
sentence some of the services for which the City of Cambridge or any of its
departments might require payment are: police protection, fire protection,
public schools, library services, park services, building inspections. Water and
sewer use charges are covered elsewhere in this Lease and the same shall not
enter into the calculations made under this Section X(a).

              (2)    "TAX BASE" shall mean the Taxes for the fiscal tax year
commencing July 1, 1999 and terminating June 30, 2000 as abated, if abated.

                                                                               9
<PAGE>   13

              (3)    "TENANT'S PROPORTIONATE SHARE FOR TAXES" shall be
sixty-four and seventy-four one hundredths percent (64.74%). In the event that
the Building is enlarged or diminished so as to increase or decrease the net
rentable area of the Building or in the event that the TCQM Space is not
delivered to Tenant, Tenant's Proportionate Share for Taxes shall be adjusted
to reflect accurately the portion of the net rentable area leased to Tenant.

              (4)    "TAX YEAR" shall mean the twelve-month period commencing
July 1, 2000, and each twelve-month period commencing on an anniversary of said
date during the term of the Lease.

              (5)    "TAX EXCESS" shall mean the amount, in any Tax Year by
which the Taxes for said year exceed the Tax Base, multiplied by Tenant's
Proportionate Share for Taxes. Landlord may bill Tenant annually, semi-annually,
quarterly, or monthly for such Tax Excess as may be due, and Tenant shall pay
such bills within ten (10) days after receipt of the same.

              (6)    "TAX EXCESS STATEMENT" shall mean a statement setting forth
in reasonable detail the amount payable by Tenant as Tax Excess for said Tax
Year.

              Appropriate credit against Tax Excess shall be given for any
refund obtained by reason of a reduction in any Taxes by the Courts or other
governmental agency responsible therefor. The original computation as well as
reimbursement or payments of additional charges, if any, or allowances, if any
under the provisions of this Section X shall be based on the original assessed
valuations with adjustments to be made at a later date when the tax refund, if
any, shall be paid to Landlord by the taxing authority. Reasonable expenditures
for legal fees and for other similar or dissimilar expenses incurred in
obtaining the tax refund shall be charged against the tax refund before the
adjustments are made for the Tax Year. In no event shall Tenant be entitled to
receive a credit against Tax Excess for any Tax Year in an amount greater than
Tenant's share of the Tax Excess for such Tax Year.

              (7)    If the Commencement Date or the Termination Date occurs in
the middle of a Tax Year, Tenant shall be liable for only that portion of the
Tax Excess as the case may be, in respect of said Tax Year represented by a
fraction, the numerator of which is the number of days of the herein term which
falls within Tax Year, and the denominator of which is three hundred sixty-five
(365).

              (8)    In the event of any taking of the Building or Property
whereby this Lease shall not terminate under the provisions of Section XVI, then
for the purposes of determining Tax Excess, in the event the valuation of
Building and lot is lowered to reflect the taking, the Tax Base shall be lowered
proportionately in relation to the reduced valuation. In the event the taking
includes a portion of the Premises or the Building which it is a part, Tenant's
Proportionate Share shall be adjusted pro-rata to reflect the proportion of the
Premises and/or Property remaining after such taking.

              (9)    Any obligation under this Section X(a) of Tenant which
shall not have been paid at the expiration of the term of this Lease shall
survive such obligation and shall be paid when and as the amount of same shall
be determined to be due.

       (b)    ADDITIONAL RENT/OPERATING COSTS. In addition to the Rent set forth
in Section IV of this Lease and as part of the Rent due pursuant to the terms of
this Lease, Tenant shall pay

                                                                              10
<PAGE>   14
Landlord as Additional Rent the Operating Cost Excess as set forth in this
Section X(b). For the purposes of this Section X, the following words and terms
shall have the following meaning:

              1.     "OPERATING COSTS" shall mean all costs incurred and
expenditures of whatever nature made by the Landlord in the operation,
management, repair, cleaning and, maintenance of the Building, the parking area,
related equipment and facilities and appurtenant parking and landscaped areas,
heating and cooling equipment, including but not limited to the following:

                     (a)    All costs for fire, extended coverage, casualty,
liability, workmen's compensation, rental interruption insurance, and all other
bonds and insurance as may be required by the holder or guarantor of the
mortgage upon the Building in which the Premises are located, or otherwise
reasonably required.

                     (b)    Water and sewer charges.

                     (c)    Heating, ventilating and air conditioning service
equipment contracts.

                     (d)    Rubbish removal.

                     (e)    Electricity charges except to the extent that the
same are separately metered or apportioned to tenants, including without
limitation, the cost of electric current for the operation of elevators, and
public lights inside and outside the Building, and the parking area.

                     (f)     Common area air conditioning filter service
contract.

                     (g)    Security service equipment contracts, if any.

                     (h)    Exterminating services and contracts.

                     (i)    Wages including all fringe benefits, federal and
state payroll, unemployment and old age taxes paid by Landlord on account of all
employees who are employed in, about or on account of the land, Building or
other improvements of which the premises are a part. Employees shall include
administrative and overhead personnel.

                     (j)    The cost of labor and materials used in cleaning the
Building, surrounding areaways and windows in the Building, and the parking
area.

                     (k)    Supplies.

                     (l)    Elevator service contracts.

                     (m)    All costs for permits and fees, except those
associated with work undertaken solely for an individual tenant.

                     (n)    The cost of any capital improvements or additions
made to the Building after the commencement of the term of this lease, such cost
thereof to be amortized over such improvement's or addition's useful life
together with interest on the unamortized balance at the rate two percent (2%)
above the prime rate from time to time charged by Fleet Bank, N.A., or its
successor, or such higher rate as may be paid by Landlord for funds borrowed to
construct such said capital improvements or additions, it being agreed that in
each Lease year there shall be included in Operating Costs only such years
allocable share of the amortization and interest described in this Section
X(b)(l)(n).

                     (o)    All management fees paid for the Manager of the
Building, and all asset management fees, the aggregate of which is not to exceed
five percent (5%) of the gross

                                                                              11
<PAGE>   15

receipts of the Building, provided that the management fees herein stated shall
be deemed variable expenses pursuant to Section X(b)(2) herein.

              (2)    "OPERATING COST BASE" shall mean the amount arrived at by
computing the actual costs of operation, management, repair, cleaning and
maintenance of the Building, related equipment and facilities, heating and
cooling equipment, including, without limitation, those items described in
clauses (a) through (o) inclusive of this Section X(b)(1) shown above, for the
calendar year 2000. If during the Operating Cost Base year, the Building has an
average annual occupancy rate of less than one hundred percent (100%) of the net
rentable square footage, then for the purposes of this subsection (b)(2) those
Operating Costs which are variable depending upon occupancy levels shall be
equitably adjusted as though the Building occupancy were one hundred percent
(100%).

              (3)    "COMPUTATION YEAR" shall mean each calendar year or a
portion thereof beginning with the calendar year 2001.

              (4)    "TENANT'S PROPORTIONATE SHARE FOR OPERATING COSTS" shall be
sixty-four and seventy-four one hundredths percent (64.74%). In the event that
the TCQM Space is not delivered to Tenant or the Building is enlarged or
diminished so as to increase or decrease the net rentable area of the Building,
Tenant's Proportionate Share for Operating Costs shall be adjusted to reflect
accurately the portion of the net rentable area leased by Tenant. If during a
Computation Year, the Building has an average annual occupancy rate of less than
one hundred percent (100%) of the net rentable square footage, then for the
purposes of this subsection (b)(4) those Operating Costs which are variable
depending upon occupancy levels shall be equitably adjusted as though the
Building occupancy were one hundred percent (100%).

              (5)    "OPERATING COST EXCESS" shall mean the amount, in any
Computation Year by which the Operating Costs for said year exceed the Operating
Costs Base, multiplied by Tenant's Proportionate Share for Operating Costs.

              (6)    "OPERATING COST EXCESS STATEMENT" shall mean a statement
setting forth in reasonable detail the amount payable by Tenant as Operating
Cost Excess for the Computation Year.

               Landlord may, at its sole discretion, bill Tenant monthly,
quarterly, semi-annually or annually for such Operating Cost Excess. Any bill
for a month, quarter or half-year may be rendered on an estimated basis, in
which event the estimate shall be the actual cost of the item for the next year
preceding increased by Landlord's estimate of what the increase for the current
year shall be. Any estimated bill need not include all of the items mentioned in
Section X(b). Any annual bill shall be rendered on the basis of actual Costs
only. If Landlord shall render a monthly, quarterly or semi-annual bill on
account of any calendar year, then within one hundred eighty (180) days after
the close of such calendar year, Landlord shall render an annual bill for such
year which annual bill shall make all adjustments as may be necessary to reflect
actual changes during that year including, without limitation, any refund as may
be due to Tenant. Failure of Landlord to render a bill within one hundred eighty
(180) days after the close of such calendar year shall relieve Tenant of the
obligations hereunder. All bills for the cost escalation portion of the Rent
shall be due and payable within thirty (30) days of receipt.

                                                                              12
<PAGE>   16

              (7)    If the Commencement Date or the Termination Date of the
Lease occurs in the middle of a Computation Year, Tenant shall be liable for
only that portion of the Operating Cost Excess in respect of such Computation
Year represented by a fraction, the numerator of which is the number of days of
the herein term which falls within the Computation Year, and the denominator of
which is three hundred sixty-five (365).

              (8)    In the event of any taking of the Building or the land upon
which it stands under circumstances whereby this Lease shall not terminate under
the provisions of Section XVI, the Operating Cost Base shall be adjusted
pro-rata to reflect the proportion of the Premises and/or Property remaining
after such taking.

              (9)    Any obligation under this Section X(b) of Tenant which
shall not have been paid at the expiration of the term of this Lease shall
survive such obligation and shall be paid when and as the amount of same shall
be determined to be due.

       SECTION XI. REMOVAL OF GOODS AND TENANT'S REPAIRS. At the expiration or
sooner termination of this Lease, Tenant will remove its goods and effects
(except as elsewhere provided herein) and will peaceably yield up to the
Landlord the Premises in as good order and condition as when delivered to it,
excepting ordinary wear and tear (which shall not be deemed to include holes in
walls or floors or special wiring caused by installation of Tenant's fixtures or
equipment), repairs required to be made by Landlord and damage by fire or
unavoidable casualty.

       The Tenant shall be responsible for all damages or injury to the
Premises, fixtures, appurtenances and equipment of Landlord, and to the Building
and the Property, caused by Tenant's installation or removal of furniture,
fixtures or equipment.

       SECTION XII. SALES TAX. In the event that any sales tax shall be levied
by the State of Massachusetts, or the City of Cambridge, or any other authority
having jurisdiction, upon the Rent and/or the Additional Rent received by
Landlord from Tenant, the exact amount of such tax shall be paid by Tenant to
Landlord at the same time each installment of Rent and/or Additional Rent is
paid to the Landlord.

       SECTION XIII. IMPROVEMENTS AND ALTERATIONS. The Tenant may place such
partitions, fixtures, (including light fixtures), personal property, machinery
and the like (subject to Section VII) in the Premises and may make, at its own
expense, such improvements and alterations as have the prior written approval of
Landlord, which approval shall not be unreasonably withheld or delayed, in each
instance provided that all work done by Tenant in the Premises shall be done in
accordance with all zoning, building, fire and other codes applicable thereto.
All fixtures, equipment, improvements and appurtenances paid for by Tenant and
attached to or built into the Premises prior to or during the term shall be and
remain part of the Premises as of the end of the term unless specifically
excluded elsewhere in this Lease. In the case of damage or destruction of such
items during the term, Tenant shall have the right to recover its loss from any
insurance company with which it has insured the same, notwithstanding that any
of such things might be considered part of the Premises at the end of the term.
At the option of Landlord, which option Landlord may exercise only at the time
Landlord approves any Plans and Specifications for any Tenant's Work, Tenant
shall remove any or all of Tenant's Work and alterations and improvements at the
end of the term. Landlord may not require

                                                                              13
<PAGE>   17

removal of pipes, wires and the like from the walls, ceilings or floors,
provided that the Tenant properly cuts, caps and disconnects such pipes and
wires and seals them off in a safe and lawful manner flush with the applicable
wall, floor or ceiling and redecorates the area consistent with the remainder of
the Premises. Tenant shall be responsible for any damage to the Building caused
by the malfunction of its equipment or the removal of its property as aforesaid.

       SECTION XIV. INSPECTION. The Landlord and any mortgagee of the Building
or of the Building and Property, or of Landlord's interest therein, and their
representatives shall have the right at all times to enter the Premises, upon
advance notice except in cases of emergency, to inspect the same and to make
repairs or replacements therein as required by this Lease and to introduce
conduits and pipes or ducts; provided, however, that the Landlord shall use
reasonable effort not to unduly disturb the Tenant's use and occupancy.

       SECTION XV. CASUALTY. If the Premises, the Building or Property shall be
damaged or destroyed by fire or other casualty insurable under standard coverage
insurance to the extent of less than twenty-five percent (25%) of the reasonable
replacement value thereof at the time of such damage or destruction, Landlord
shall, except as otherwise provided herein, repair and/or rebuild the same with
reasonable diligence, but Landlord's obligation hereunder shall be limited to
the condition of the Premises as of the Rent Commencement Date hereof and shall
also be subject to zoning and building laws then applicable to the Premises.
Landlord's obligation hereunder shall be limited to the proceeds received and
retained by Landlord (net of any amounts required to be paid to Landlord's
mortgagee) under the insurance policy which is allocable to the Premises and
Landlord shall not be obligated to commence such repairs and/or rebuilding until
such insurance proceeds are released to Landlord. Tenant shall repair or restore
with due diligence all trade fixtures, equipment and other installations
theretofore installed by Tenant to the extent of Tenant's obligations as set
forth in Exhibit B and damaged or destroyed by such fire or casualty.

        Within sixty (60) days after any damage to the Premises or the Property
by fire or other casualty, Landlord shall give written notice to Tenant of
Landlord's reasonable estimate of the time required to complete the restoration
of the Premises or the Property according to this Section XV (including any time
needed to collect proceeds of insurance from such damage). If the estimate of
the time to complete such restoration exceeds two hundred-ten (210) days from
the date of receipt of such notice, Tenant shall have the right to terminate
this Lease within thirty (30) days after receiving such notice from Landlord. If
the Premises shall be damaged as a result of a risk which is not required to be
covered by insurance under this Lease, or if the Premises shall be damaged or
destroyed to the extent of 25% or more of its reasonable replacement value in
the last two (2) years of the then current term of this Lease (unless Tenant
shall exercise, before or after to the date of such damage, any remaining option
to extend the term of this Lease), Landlord shall have the right to terminate
this Lease within sixty (60) days after such damage occurs.

       In any instance where Landlord or Tenant shall have an election to
terminate this Lease by reason of such damage or destruction, it shall give the
other notice of its election within sixty (60) days after such damage or
destruction, and in such event, if Landlord shall elect to restore or rebuild,
Landlord shall proceed to do so and Tenant shall replace or restore with due
diligence all

                                                                              14
<PAGE>   18
trade fixtures, equipment and other installations theretofore installed by
Tenant and damaged or destroyed by such fire or other casualty. Landlord's
obligation hereunder shall be to restore or rebuild, shall be to no greater
extent than its obligations in connection with the condition of the Premises as
of the Rent Commencement Date and shall also be subject to zoning and building
laws then applicable to the Premises. Landlord's obligation hereunder shall be
limited to the proceeds received and retained by Landlord (net of any amounts
required to be paid to Landlord's mortgagee) under the insurance policy which is
allocable to the Premises, and Landlord shall not be obligated to commence such
repairs and/or rebuilding until such insurance proceeds are released to
Landlord. Tenant shall, during any period of reconstruction or repair of the
Premises, the Building and/or of the Property, continue the operation of its
business in the Premises to the extent reasonably practicable. If the Premises
or any part thereof, or the Building shall be damaged or destroyed by fire or
other casualty not caused by the negligence or act of Tenant (irrespective of
the time when such damage or destruction shall occur, and irrespective of
whether or not Landlord shall be insured against the perils causing same) and if
as a result thereof the Premises shall be rendered untenantable to an extent
which would reasonably require the Tenant to curtail a part of its business
operation, then a just proportion of the Rent reserved hereunder shall be
suspended or abated according to the extent to which Tenant may be reasonably
required to discontinue its business in the Premises until the work of
restoration to be done by Landlord as aforesaid shall be substantially
completed.

       SECTION XVI. EMINENT DOMAIN. If the whole of the Premises, the Building,
or the Property shall be taken by condemnation or rights of eminent domain (the
words "condemnation" and "eminent domain" as used herein to include purchase in
lieu thereof) hereinafter collectively referred to as "taking", then the term
hereof shall cease as of the date of the vesting of title or as of the day
possession shall be taken thereunder, whichever is earlier. If twenty-five
percent (25%) or more of the Property shall be taken (whether or not the
Building or the Premises is within said twenty-five percent (25%) or if
twenty-five percent (25%) or more of the Premises or twenty-five percent (25%)
or more of the Building are a part shall be taken, Landlord shall be entitled to
terminate this Lease effective as of the day of vesting of title or as of the
day possession shall be taken thereunder, whichever Landlord shall elect, by
giving Tenant notice of its election within sixty (60) days of such vesting of
title or taking of possession; but if Landlord does not elect to so terminate
this Lease, it shall with due diligence restore the Premises and/or the Building
and/or the Property to an architectural unit as nearly like its condition prior
to such taking as shall be practical. If twenty-five percent (25%) or more of
the Premises shall be taken, or if twenty-five percent (25%) or more of the
Building of which the Premises are a part shall be taken, including in such
taking some portion of the Premises, Tenant shall be entitled to terminate this
Lease by giving notice to Landlord to that effect within sixty (60) days
following the taking of possession of the Premises, in which event this Lease
and the term hereof shall cease and terminate as of the end of the calendar
month in which such notice shall be given. If this Lease is not terminated as
hereinbefore provided, either by Landlord or Tenant, all of the provisions
hereof shall continue in effect, but in case there shall be a reduction of the
floor area of the Premises by reason of such taking, the Rent and Additional
Rent shall be

                                                                              15
<PAGE>   19

equitably abated to the extent of the reduction of the floor area of the
Premises from the time possession shall be taken for the balance of the term.

       During the restoration work to be done by Landlord, if any, a just
proportion of the Rent and Additional Rent herein reserved shall be suspended or
abated according to the extent that Tenant may be reasonably required to
discontinue its business in the Premises until the work shall be completed.
Tenant shall during any period of such work continue the operation of the
business in the Premises to the extent reasonably practicable. In the event of
restoration, Landlord's obligation to restore shall be limited to the
obligations of Landlord in connection with the condition of the Premises as of
the Rent Commencement Date and limited to the extent of the damages awarded for
the taking and released to Landlord (net of any mounts required to be paid to
Landlord's mortgagee). Landlord's obligations shall be subject to zoning and
building laws then applicable to the Premises. Tenant shall repair or restore
all trade fixtures or equipment and other installations theretofore installed by
Tenant. All damages awarded for any taking, whether for the whole or a part of
the Premises, the Building, or the balance of the Property, or otherwise, shall
belong to and be the property of Landlord whether such damages shall be awarded
as compensation for diminution in value to the leasehold or to any fee or
otherwise; provided, however, that Tenant shall be entitled to receive and
retain any amounts which may be specifically awarded to it by reason of the loss
of its trade fixtures or furniture. Tenant shall have the right to prosecute any
claim for its relocation or moving expenses.

       SECTION XVII. INDEMNIFICATION. Tenant shall save Landlord harmless, and
will exonerate and indemnify Landlord from and against any and all claims,
liabilities or penalties asserted by or on behalf of any person, firm or public
authority:

       (a)    on account of or based upon any injury to person, or loss of or
damage to property, sustained or occurring on the Premises on account of or
based upon the act, omission, fault, or neglect of Tenant, its servants, agents,
employees, licensees, invitees and guests;

       (b)    on account of or based upon any injury to person or loss of or
damage to property, sustained or occurring elsewhere (other than on the
Premises) in or about the Building (and, in particular, without limiting the
generality of the foregoing on or about the elevators, stairways, public
corridors, sidewalks, concourses, arcades, approaches, areaways, roof, parking
areas, or other appurtenances and facilities used in connection with the
Building or Premises) arising out of the use or occupancy of the Building,
Premises or Property by the Tenant or by any person claiming by, through or
under Tenant, except to the extent caused by or resulting from Landlord's
negligence, and in addition to and not in limitation of either of the foregoing
subdivision (a); and

       (c)    on account of or based upon (including monies due on account of)
any work or things whatsoever done (other than by Landlord or its contractors,
or agents or employees of either) on the Premises during the term of this Lease
and during the period of time, if any, prior to the Commencement Date that
Tenant may have been given access to the Premises; and, in respect of any of the
foregoing, from and against all costs, expenses (including reasonable attorney's
fees), and liabilities incurred in or in connection with any such claim, or any
action or proceeding brought thereon; and in case any action or proceeding be
brought against Landlord by reason of any such claim, Tenant, upon notice from
Landlord, shall, at Tenant's expense, resist or

                                                                              16
<PAGE>   20
defend such action or proceeding and employ counsel therefor reasonably
satisfactory to Landlord, it being agreed that such counsel as may act for
insurance underwriters of Tenant engaged in such defense shall be deemed
satisfactory.

       SECTION XVIII. PROPERTY OF TENANT. In addition to and not in limitation
of other provisions of this Lease, Tenant covenants and agrees that all of its
merchandise, furniture and property of every kind, nature and description which
may be in or upon the Premises, Building, or Property in the public corridors,
or on the sidewalks, areaways, and approaches thereto, or parking areas during
the term hereof, shall be at the sole risk and hazard of Tenant, and that if
the whole or any part thereof shall be damaged, destroyed, stolen or removed by
any cause whatsoever, no part of said damage or loss shall be charged to or
borne by Landlord. Tenant shall, at Tenant's expense, obtain and keep in force
"all risk" property insurance covering Tenant against damage to or loss of any
personal property, fixtures and equipment of Tenant, and provide for waiver of
subrogation by Tenant's insurer against Landlord and coverage for the full
replacement cost of such property.

       SECTION XIX. INJURY AND DAMAGE. Landlord shall not be liable for any
injury or damage to persons or property resulting from fire, explosion, falling
plaster, steam, gas, electricity, electrical disturbance, water, rain or snow,
or leaks from any part of the Building or parking area, or from the pipes,
appliances, or plumbing works or from the roof, street or subsurface or from any
other place or from dampness or by any other cause of whatever nature, whether
caused by other tenants or persons in the Building, or on the Property, or in
any parking area or caused by operations in construction of any private, public
or quasi-public work; nor shall Landlord be liable for any latent defect in the
Premises, in the Building, or on the Property.

       SECTION XX. ASSIGNMENT, MORTGAGING, AND SUBLETTING. Tenant covenants and
agrees that neither this Lease nor the term and estate hereby granted, nor any
interest herein or therein, will be assigned, mortgaged, pledged, encumbered or
otherwise transferred, and that neither the Premises, nor any part thereof will
be encumbered in any manner by reason of any act or omission on the part of
Tenant, or used or occupied, or utilized for desk space or for mailing
privileges, by anyone other than Tenant, or for any use or purpose other than as
stated herein, or be sublet or offered or advertised for subletting, without the
prior written consent of Landlord, which consent may not be unreasonably
withheld or delayed. Not in limitation of the foregoing, Tenant's request for
Landlord's consent to subletting or assignment shall be submitted in writing no
later than sixty (60) days in advance of the proposed effective date of such
proposed assignment or sublease, which request shall be responded to by Landlord
within thirty (30) days of receipt thereof, and which request shall be
accompanied by the following information (such information shall be collectively
referred to as the "REQUIRED INFORMATION"): (i) the name, current address and
business of the proposed assignee or sublessee; (ii) the amount and location of
the space within the Premises proposed to be so subleased; (iii) the proposed
effective date and duration of the assignment or subletting; and (iv) the
proposed rent and other consideration to be paid to Tenant by such assignee or
sublessee. Tenant also shall promptly supply Landlord with financial statements
and other information as Landlord may request, prepared in accordance with
generally accepted accounting principles not more than ninety (90) days old when
delivered to Landlord (if available), indicating the net worth, liquidity

                                                                              17
<PAGE>   21

and credit worthiness of the proposed assignee or sublessee in order to evaluate
the proposed assignment or sublease. Tenant agrees to reimburse Landlord for
reasonable legal fees and any other reasonable expenses and costs incurred by
Landlord in connection with any proposed assignment or subletting.

        Landlord's consent shall be granted only if (i) Landlord does not have
comparable space for a comparable term available for lease in the Building and
(ii) the assignee, subtenant or sublessee shall promptly execute, acknowledge,
and deliver to Landlord an agreement in form and substance satisfactory to
Landlord whereby the assignee, subtenant or sublessee shall agree to be bound
by and upon the covenants, agreements, terms, provisions and conditions set
forth in this Lease, and shall agree to pay Landlord or Tenant, as the case may
be, Rent and Additional Rent as required in the sublease. If Tenant shall sublet
the Premises, having first obtained Landlord's consent, at a rental in excess of
the Rent and Additional Rent due and payable by Tenant under the provisions of
this Lease, such excess Rent and Additional Rent shall be divided equally
between Landlord and Tenant after deducting Tenant's reasonable expenses of
subletting, including commissions paid to brokers and reasonable attorney's
fees, it being agreed, however, that Landlord shall not be responsible for any
deficiency if Tenant shall sublet the Premises at a rental less than that
provided for herein. Further, it is agreed that in lieu of withholding or
granting its consent Landlord may, within thirty (30) days of receipt of a
request for consent from Tenant, cancel this Lease as to the entire Premises or
as to so much of the Premises as Tenant has proposed for assignment or
subletting. If Landlord shall elect to cancel this Lease as to all or a portion
of the Premises, it shall give Tenant written notice of its election, which
notice shall set forth a "termination date" which shall be not less than sixty
(60) or more than one hundred twenty (120) days from the receipt by Landlord of
Tenant's request to assign or sublet, and on that "termination date" Tenant
shall surrender the Premises for which this Lease has been canceled in
accordance with the provisions of this Lease relating to the surrender of the
Premises as the expiration of the term of this Lease. If the cancellation shall
be as to a portion of the Premises only, then the Rent and the Additional Rent
shall be adjusted proportionately to reflect said cancellation, it is hereby
expressly understood and agreed, however, if Tenant is a corporation, that the
assignment, or transfer of this Lease, and the term and estate granted, to any
corporation into which Tenant is merged or with which Tenant is consolidated,
which corporation shall have a net worth at least equal to that of Tenant
immediately prior to such merger or consolidation (such corporation being
hereinafter called "ASSIGNEE"), without the prior written consent of Landlord
shall not be deemed to be prohibited hereby, if, and upon the express condition
that, Assignee and Tenant shall promptly execute, acknowledge, and deliver to
Landlord an agreement in form and substance satisfactory to Landlord whereby
Assignee shall agree to be bound by and upon the covenants, agreements, terms,
provisions and conditions set forth in this Lease on the part of Tenant to be
performed and whereby Assignee shall expressly agree that the provisions of this
Section XX shall, notwithstanding such assignment or transfer, continue to be
binding upon it with respect to all future assignments and transfers. The
listing of any name other than that of Tenant, whether on the doors of the
Premises or on the Building directory, or otherwise, shall not operate to vest
any right or interest in this Lease or in the Premises or be deemed to be the
written consent of Landlord mentioned in this Section XX, it

                                                                              18
<PAGE>   22

being expressly understood that such listing is a privilege extended by Landlord
revocable at will by written notice to Tenant.

       If this Lease is assigned, or if the Premises or any part thereof is
sublet or occupied by anybody other than Tenant, Landlord may, after default by
Tenant, collect Rent and/or Additional Rent from the Assignee, subtenant or
occupant, and apply the net amount collected to the Rent herein reserved, but no
such assignment, subletting, occupancy or collection shall be deemed a waiver of
this covenant, or the acceptance of the Assignee, subtenant or occupant as a
tenant, or a release of Tenant from the further performance by Tenant of
covenants on the part of Tenant herein contained. The consent by Landlord to an
assignment or subletting shall not in any way be construed to relieve Tenant
from obtaining the express consent in writing of Landlord to any further
assignment or subletting. No assignment, subletting or use of the Premises by an
affiliate of Tenant shall affect the purpose for which the Premises may be used
slated in Section II. Notwithstanding any permitted assignment or subletting,
Tenant shall at all times remain directly, primarily and fully responsible and
liable for the payment of all sums payable under the Lease and for compliance
with all the obligations of Tenant under the Lease.

       SECTION XXI. SIGNS, BLINDS AND WINDOW TREATMENTS. No signs or blinds may
be put on or in any window by Tenant. Tenant may install its own window
treatment, provided that the same shall not in any way interfere with the
Building standard blinds or be visible from the exterior of the Building. Any
signs or letters in the public corridors or on the doors must be submitted to
Landlord for written approval before installation, which installation shall be
at the sole expense of Tenant.

       SECTION XXII. INSURANCE COMPLIANCE. Tenant will not do or omit to do or
keep anything in, upon or about the Premises which may prevent the obtaining of
any fire, liability or other insurance upon or written in connection with the
Premises or the Building or the Property or which may make any such insurance
void or voidable, or which may create any extra premiums or increase the rate of
any such insurance over that normally applicable to office buildings unless the
Tenant pays such extra or increased premiums.

       SECTION XXIII. INFLAMMABLES, ODORS. Tenant shall not bring or permit to
be brought or kept in or on the Premises or elsewhere in the Building, any
inflammable, combustible or explosive fluids, material, chemical or substance
(other than small quantities of industrial solvents used in the normal course of
cleaning and maintenance), or cause or permit any odors of cooking or other
processes, or any unusual or other objectionable odors to emanate from or
permeate the Premises.

       SECTION XXIV. DEFAULT. Any one of the following shall be deemed to be an
"EVENT OF DEFAULT":

       (a)    Failure on the part of Tenant to pay Rent, Additional Rent or
other charges for which provision is made herein on or before the date on which
the same become due and payable and such failure continues for five (5) days
(the "MONETARY NOTICE AND CURE PERIOD") after Landlord has sent to Tenant notice
of such default. However, if: (i) Landlord shall have sent to Tenant a notice of
default, even though the same shall have been cured and this Lease not
terminated; and (ii) during the twelve (12) month period next following the date
on which said notice of default has been sent by Landlord to Tenant, Tenant
thereafter shall default in any

                                                                              19
<PAGE>   23

monetary obligation pursuant to the Lease, the same shall automatically be
deemed to be an Event of Default upon Landlord giving Tenant written notice
thereof, and there shall be no monetary notice and cure period.

       (b)    Failure on the part of Tenant to comply with any term, condition,
or requirement of this Lease and failure of Tenant to cure the same within ten
(10) days or such reasonable period of time required to cure said default, (the
"NON-MONETARY NOTICE AND CURE PERIOD") following notice from Landlord to Tenant
of a non-monetary default. Notwithstanding the non-monetary notice and cure
period provided in the preceding sentence, Tenant shall be obligated to
immediately commence, and use best efforts to complete as soon as possible, the
curing of such default. However, if: (i) Landlord shall have sent to Tenant a
notice of such default, even though the same shall have been cured and this
Lease not terminated; and (ii) during the twelve (12) month period next
following the date on which said notice of default has been sent by Landlord to
Tenant, Tenant thereafter shall default in any non-monetary obligation pursuant
to the Lease, the same shall automatically be deemed to be an Event of Default
upon Landlord giving the Tenant written notice thereof, and there shall be no
non-monetary notice and cure period.

       (c)    The commencement of any of the following proceedings: (i) the
estate hereby created being taken on execution or by other process of law; (ii)
Tenant being judicially declared bankrupt or insolvent according to law; (iii)
an assignment being made of the property of Tenant for the benefit of creditors;
(iv) a receiver, guardian, conservator, trustee in involuntary bankruptcy or
other similar officer being appointed to take charge of all or any substantial
part of Tenant's property by a court of competent jurisdiction; or (v) a
petition being filed for the reorganization of Tenant under any provisions of
the Bankruptcy Act now or hereafter enacted.

       (d)    Tenant filing a petition for reorganization or for rearrangement
under any provisions of the United States Bankruptcy Code now or hereafter
enacted, and providing a plan for a debtor to settle, satisfy or to extend the
time for the payment of debts.

       Landlord and Tenant hereby agree that, at Landlord's option, any notice
of default sent by Landlord to Tenant in accordance with Sections (a) or (b)
above, shall, without any further notice to Tenant, constitute a valid and
enforceable statutory Notice to Quit, terminating the Tenant's tenancy. The
Tenant hereby expressly waives service of any further notice to quit. However,
at Landlord's election, Landlord may, but shall not be required to, serve a
forty-eight (48) hour notice to quit in lieu of, or in addition to, any notice
of default.

       If an Event of Default shall occur, then in addition to any other remedy
Landlord may have at law or equity, Landlord may (i) apply the Security Deposit,
if any, specified in Section XLIII toward the satisfaction of such Event of
Default without waiving any of Landlord's other rights hereunder, (ii) cure
Tenant's Event of Default at Tenant's cost and expense, and/or (iii) Landlord
may lawfully enter the Premises or any part thereof and repossess the same as
the former estate of the Landlord and expel the Tenant and those claiming under
the Tenant without being deemed guilty of any manner of trespass.

       In the case of Lease termination, whether as aforesaid or otherwise, the
Tenant covenants that it will indemnify the Landlord against all losses Landlord
may incur by reason of such termination. Upon such termination, all of Tenant's
monetary obligations under the Lease shall

                                                                              20
<PAGE>   24

immediately become due and payable to Landlord, and the Tenant will immediately
be liable for, and pay to Landlord as damages, all such losses, including
without limitation; all Rent, Additional Rent and other charges due pursuant to
the Lease up until the normal expiration of the Lease term (had the Lease not
been terminated in accordance herewith) (including escalations projected on
the basis of experience under the Lease), together with all reasonable costs
Landlord may incur in obtaining possession of, or in reletting the Premises
(including without limitation reasonable attorneys fees, brokerage commissions,
prospective tenant improvements, alterations, repairs and decorations to the
Premises as Landlord in its reasonable judgment considers advisable or necessary
to relet the same), together with Tenant's proportionate share of any
unamortized capital improvements incurred during the Lease term, and any monies
owed by Tenant to Landlord for any tenant improvements to the Premises in
accordance with the Lease, together with interest at the rate of 1.5% per month
until said monies are paid in full.

       Landlord shall, to the extent required by applicable law, and not
otherwise, use reasonable efforts to relet the Premises on such terms and
conditions as Landlord in its reasonable discretion may determine (including a
term different from the term of the Lease, rental concessions, and alterations
to, and improvement of, the Premises). However, Landlord shall not be obligated
to relet the Premises at below market rates, nor shall Landlord be obligated to
relet the Premises before leasing other portions of the Building. Landlord shall
not be liable for, nor shall Tenant's obligations hereunder be diminished
because of, Landlord's failure to relet the Premises or to collect rent due for
such reletting. In the event of reletting, Landlord shall have no liability to
account to Tenant for any excess in proceeds received from such reletting.

       SECTION XXV. SUBORDINATION AND ESTOPPEL. This Lease is subject and
subordinate in all respects to all mortgages which may now or hereafter be
placed on or affect the real property of which the Premises are a part, or
Landlord's interest or estate therein, and to each advance made and/or hereafter
to be made under any such mortgages, and to all renewals, modifications,
consolidations, replacements and extensions thereof and all substitutions
therefor. This Section XXV shall be self-operative and no further instrument of
subordination shall be required. Notwithstanding the generality of the
foregoing provisions of this Section XXV, Tenant agrees that any such mortgagee
shall have the right at any time to subordinate any such mortgages or other
instruments of security to this Lease on such terms and subject to such
conditions as such mortgagee may deem appropriate in its discretion. Tenant
further covenants and agrees upon demand by Landlord's mortgagee at any time,
before or after the institution of any proceedings for the foreclosure of any
such mortgages or other instruments of security, or sale of the Building
pursuant to any such mortgages or other instruments of security (which agreement
shall survive any such foreclosure sale), to attorn to such mortgagee or such
purchaser upon any such sale and to recognize such purchaser as Landlord under
this Lease, provided that Tenant's possession shall not be disturbed except
under the terms of this Lease, and further agrees to execute any and all
documents as such mortgagee may require to confirm such attornment. In the event
Tenant fails to deliver and execute such documents within ten (10) days after
demand in writing, Tenant does hereby make, constitute and irrevocably appoints
Landlord as attorney in fact to execute said documents.

                                                                              21
<PAGE>   25
       In confirmation of the subordination herein, Tenant shall, from time to
time, within ten (10) days after request from Landlord, or from any mortgagee of
Landlord, execute, acknowledge and deliver in recordable form an estoppel
certificate ("Estoppel Certificate") certifying, to the extent true, that this
Lease is in full force and effect and unmodified (or, if there have been
modifications, that the same is in full force and effect as modified and stating
the modifications); that the term has commenced and the full amount of the Rent
and Additional Rent then accruing thereunder the dates to which the Rent has
been paid; that Tenant has accepted possession of the Premises and that any
improvements required by the terms of this Lease to be made by Landlord have
been completed to the satisfaction of Tenant; the amount, if any, that Tenant
has paid to Landlord as a security deposit; that no Rent under this Lease has
been paid more than thirty (30) days in advance of its due date; that the
address for notices to be sent to Tenant is as set forth in this Lease (or has
been changed by notice duly given and is as set forth in the Estoppel
Certificate); that Tenant, as of the date of such Estoppel Certificate, has no
charge, lien, or claim of offset under this Lease or otherwise against Rent or
Additional Rent due or to become due hereunder; that, to the knowledge of
Tenant, Landlord is not then in default under this Lease; and such other matters
as may be reasonably requested by Landlord or any mortgagee of Landlord. Any
Estoppel Certificate may be relied upon by Landlord, any successor of Landlord,
any mortgagees of Landlord or any prospective purchaser of the Building.

       SECTION XXVI. NOTICES. Any notice or demand by Tenant to Landlord shall
be served by receipted hand delivery by Sheriff, Constable or certified mail,
postage prepaid, or recognized overnight courier, addressed to Landlord as set
forth below, and any notice or demand by Landlord to Tenant shall be served by
receipted hand delivery by Sheriff, Constable or certified mail, postage
prepaid, or recognized overnight courier to the Tenant as set forth below,
except that notice of termination pursuant to Section XXIV may also be sent by
regular mail postage prepaid to Tenant at the Premises.

        To Landlord:            New Boston Alewife Limited Partnership
                                One Longfellow Place, Suite 3612
                                Boston, Massachusetts 02114

        with a copy to:         Rappaport, Aserkoff & Rappaport
                                One Longfellow Place, Suite 3611
                                Boston, Massachusetts 02114

        To Tenant:              NetGenesis Corp.
                                150 Cambridge Park Drive
                                Cambridge, Massachusetts 02140
                                Attention: Ann Tirrell

        With a copy to:         Foley, Hoag & Eliot
                                One Post Office Square
                                Boston, Massachusetts 02109
                                Attention: Sandra Shapiro

       It is agreed that certified mail shall be conclusively deemed received
one day after it is mailed, postage prepaid, and that an item sent by recognized
overnight courier shall be conclusively deemed received the day it is scheduled
to be delivered. Landlord and Tenant may each change their address, phone number
and facsimile number by providing notice of such change to the other in the
manner specified in this Section XXVI.

                                                                              22
<PAGE>   26
       SECTION XXVII. RULES AND REGULATIONS. Tenant will faithfully observe and
comply with the Rules and Regulations annexed hereto and such other further
Rules and Regulations as Landlord hereafter at any time or from time to time may
make and may communicate in writing to Tenant, which in the judgment of Landlord
shall be necessary for the reputation, operation, safety, care or appearance of
the Building, any parking garage, parking area, or the preservation of good
order in the said Building, garage or parking area, or the operation of
maintenance of the Building, or the equipment thereof, or the comfort of tenants
or others in the Building; provided, however, that in the case of any conflict
between the provisions of this Lease and any such Rules and Regulations, the
provisions of this Lease shall control; and provided further, that nothing
contained in this Lease shall be construed to impose upon Landlord any duty or
obligation to enforce the Rules and Regulations or the terms, covenants or
conditions in any other lease as against any other tenant and Landlord shall not
be liable to Tenant for violation of the same by any other tenant, or any other
tenant's servants, employees, agents, visitors, invitees or licensees.

       SECTION XXVIII. QUIET ENJOYMENT. The Tenant, on paying the said Rent and
Additional Rent and performing the covenants of this Lease on its part to be
performed shall and may peaceably and quietly have, hold and enjoy the Premises
in accordance with this Lease for the term aforesaid and any extension thereof,
free from disturbance by Landlord or anyone claiming by, through or under
Landlord.

       SECTION XXIX. BINDING AGREEMENT. This Lease shall bind and inure to the
benefit of the parties hereto and their respective heirs, representatives,
successors and assigns. This Lease contains the entire agreement of the parties
and may not be modified except by instrument in writing signed by the parties
hereto.

       SECTION XXX. PARTNERSHIP. During such time as the Landlord shall be a
limited partnership, Tenant agrees that it shall not hold any partner of
Landlord personally responsible for any of the covenants of Landlord under this
Lease, and in the event it has a claim against Landlord, Tenant shall look only
to Landlord's interest in the Building for recovery of any judgment from
Landlord; it being specifically agreed that neither the Landlord nor anyone
claiming by, through or under Landlord shall ever be personally liable for any
such judgment, or for the payment of any monetary obligation to Tenant.

       SECTION XXXI. SEISIN. In the event of a sale or other disposition of the
Building and/or land underlying it by Landlord, Landlord shall be entirely free
and relieved from the performance and observance thereafter of all covenants and
obligations of Landlord hereunder, it being understood and agreed in that the
successor to Landlord's ownership shall thereupon and thereafter assume and
perform and observe, any and all of such covenants and obligations of Landlord.

       SECTION XXXII. INSURANCE. Tenant shall maintain in full force and effect
the following insurance written by one or more responsible companies licensed to
do business in the state in which the Premises is located in form and content
reasonably satisfactory to Landlord, including, except as to (2) of this Section
XXXII at the request of Landlord, Landlord and Landlord's managing agent, New
Boston Management Services, Inc. as additional insureds, and Tenant shall keep
deposited with the Landlord copies of all policies of insurance, or certificates

                                                                              23

<PAGE>   27
thereof, with endorsements on such policies or certificates to the effect that
such insurance shall not be cancelled by the insurer without at least fifteen
(15) days prior notice to Landlord.

              (1)    Commercial General Liability insurance in the broadest form
of such coverage as is available from time to time in the jurisdiction in which
the Premises is located; applying to the use and occupancy of the Premises and
the business operated by Tenant and on an occurrence basis in an amount not less
than Three Million Dollars ($3,000,000) combined single limit for property
damage and for any personal injury, including death, to one or more than one
person arising out of any one incident. At any time during the term hereof upon
sixty (60) days notice, Landlord may require the Tenant to increase the amount
of insurance required hereunder to a greater commercially reasonable amount as
may be required by Landlord or recommended by Landlord's insurance advisor or
required by Landlord's mortgagee.

              (2)    Worker's compensation insurance in the minimum amount
required by statute covering all employees, and, if Tenant shall contract with
any independent contractor for the furnishing of labor, materials or services to
Tenant, Tenant shall require such independent contractor to maintain worker's
compensation insurance covering all its employees and all the employees of any
subcontractor.

              (3)    Personal Property - Landlord shall not be liable to Tenant
for and Tenant shall carry extended coverage property damage insurance covering
Tenant's personal property located at the Premises (furniture, fixtures and
equipment on a replacement cost basis) and Tenant improvements, if any,
including:

                     (i)    Damage to or loss of property entrusted to employees
of the Landlord.

                     (ii)   Loss of property through thefts regardless of
where the theft takes place.

                     (iii)  Damage to property regardless of where the damage
takes place.

                     (iv)   Damage to or loss of property caused by other
tenants or occupants of the building or caused by visitors to or in the
Building.

       It is specifically understood that Landlord's insurance does not cover
any personal property of Tenant and Tenant shall not make any claim for loss of
or damage to such property against Landlord or Landlord's insurance carrier and
shall not permit its insurance carrier to make any claim for loss or damage to
such property against Landlord or Landlord's insurance carrier.

       SECTION XXXIII. SUBROGATION, INSURANCE PREMIUMS. Landlord and Tenant
hereby waive any rights each may have against the other in connection with any
of the damage occasioned to Landlord or Tenant, as the case may be, their
respective property, the Building or its contents, arising from covered causes
of loss for which property insurance is carried or required to be carried
pursuant to this Lease. Each party on behalf of their respective insurance
companies insuring their respective property against any such loss, shall waive
any right of subrogation that it may have against the other party.

       SECTION XXXIV. SHORING. If an excavation shall be made upon the Property
or upon land adjacent to the Property, or shall be authorized to be made, Tenant
shall afford to the person causing or authorized to cause such excavation,
license to enter upon the Premises for the

                                                                              24

<PAGE>   28
purpose of doing such work as said person shall deem necessary to preserve the
Building from injury or damage and to support the same by proper foundations
without any claims by Tenant for damages or indemnity against Landlord, or
diminution or abatement of rent.

       SECTION XXXV. REZONING. Tenant agrees that it shall not oppose any
application for rezoning or variance instituted by Landlord, its successors or
assigns.

       SECTION XXXVI. SEPARABILITY. If any provision or any part of any
provision of this Lease, or if the application of any provision or any part of
any provision of this Lease to any person, entity, or circumstance shall be held
invalid by a court of competent jurisdiction, such invalidity shall have no
effect on any other provision or any part of any other provision of this Lease
or its application to any other person, entity, or circumstance.

       SECTION XXXVII. WAIVER OF TRIAL BY JURY. Landlord and Tenant agree that
they shall, and hereby do, waive trial by jury in any action arising out of this
Lease or Tenant's use and occupancy of the Premises.

       SECTION XXXVIII. NO WAIVER. No act or thing done by Landlord or
Landlord's agents during the term of this Lease shall constitute an eviction by
Landlord, nor shall be deemed an acceptance of a surrender of the Premises, and
no agreement to accept such surrender shall be valid unless in writing signed by
Landlord. The failure of Landlord to seek redress for violation of, or to insist
upon the strict performance of this Lease, or any of the rules and regulations
set forth in this Lease or hereafter adopted by Landlord, shall not constitute a
waiver in any respect nor prevent a subsequent act, which originally constituted
a violation from having all force and effect of an original violation. The
receipt by Landlord of Rent or Additional Rent with knowledge of the breach of
any provision of this Lease shall not be deemed a waiver of such breach. No
payment by Tenant or receipt by Landlord of a lesser amount than the monthly
Rent or Additional Rent herein stipulated shall be deemed to be other than on
account, nor shall any endorsement or statement on any check, nor any letter
accompanying any check or payment as Rent or Additional Rent be deemed an accord
and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance of such Rent or Additional
Rent or pursue any other remedy in this Lease provided.

       SECTION XXXIX. HOLDING OVER. In the event Tenant or any party claiming
by, through or under Tenant shall hold over the Premises or any part thereof
after the termination of this Lease, such holding over shall constitute and be
construed as a tenancy at sufferance only, provided that all the terms of this
Lease shall apply except that the Rent set forth in Section IV shall be
calculated at a daily rate equal to one hundred-fifty percent (150%) of the
daily Rent reserved in said Section IV. Nothing contained in this Section XXXIX
shall be construed as Landlord's consent to Tenant holding over.

       SECTION XL. CAPTIONS, PLURAL, GENDER. The captions are inserted only as a
matter of convenience and for reference and in no way define, limit or describe
the scope of this Lease nor the intent of any provisions hereof. Whenever a
masculine or singular pronoun is used in this Lease, it shall include the
feminine and plural thereof whenever the context so permits or requires.

       SECTION XLI. BROKERAGE. Tenant covenants that it has dealt with no broker
other than the broker specified at the end of this Section XLI, as Tenant's
Broker and as

                                                                              25
<PAGE>   29
Landlord's Broker, in locating the Premises demised by this Lease and in
negotiating this Lease and Tenant further covenants and agrees that it shall
hold Landlord harmless from any and all claims which may be asserted by any real
estate broker other than the broker specified at the end of this Section XLI, as
Tenant's Broker and as Landlord's Broker, who claims that it showed or referred
the Tenant to the Landlord or to the Premises for any transaction involving or
resulting in this Lease or Premises.

       Landlord covenants that it has dealt with no broker other than the broker
specified at the end of this Section XLI, as Tenant's Broker and as Landlord's
Broker, in negotiating this Lease and Landlord further covenants and agrees that
it shall hold Tenant harmless from any and all claims which may be asserted by
any real estate broker other than the broker specified at the end of this
Section XLI, as Tenant's Broker and as Landlord's Broker, who claims that it
showed or referred the Tenant to the Landlord or to the Premises for any
transaction involving or resulting in this Lease or Premises demised hereby.

       Tenant's Broker:    Curtis Cole, C.B. Richard Ellis - Whittier Partners

       Landlord's Broker:  Greg Hoffmeister, Spaulding & Slye

       In the event that Tenant and Landlord agree to renew and/or extend the
term of this Lease, in connection with any option contained herein or otherwise,
or to expand the Premises pursuant to any such provision contained herein or
otherwise, Landlord shall not be responsible for the payment of any fee or
commission to any broker or other third party, including any broker identified
herein, who is retained by Tenant in connection with such renewal, extension,
and/or expansion.

        SECTION XLII. HAZARDOUS WASTE.

       (a)    For the purpose of this Section XLII - "Hazardous Substance" shall
mean any waste, substance or other material which may be dangerous to health or
environment, including, without limitation, all "hazardous wastes", "hazardous
materials", "hazardous substance", "toxic substance", "oil", "infectious medical
waste" and "hazardous medical waste" as defined in any federal, state, or local
law, regulation or ordinance, or otherwise.

       (b)    Tenant shall not dump, flush or in any way introduce any Hazardous
Substances, which are regulated under the Resource Conservation and Recovery Act
of 1976, as amended, (42 U.S.C. Section 6901, et. seq. "RCRA") the
Comprehensive Environmental Response, Compensation and Liability Act of 1980 as
amended (42 U.S.C. 9601 et. seq. "CERCLA"), the Superfund Amendments and
Reauthorization Act of 1986 ("SARA"), Public Law 99-499, 100 Stat 1613, et seq.,
and/or any other applicable municipal, federal, state law, into the sewerage,
drainage or other waste disposal system serving the Premises, the Building or
the Property.

       (c)    Tenant shall not generate, use, store or dispose of Hazardous
Substances regulated under RCRA, CERCLA, SARA and/or any other applicable
municipal, federal or state environmental law, in or on the Premises, the
Building or the Property, nor transport Hazardous Substances from the Premises,
the Building or the Property except in compliance with RCRA, CERCLA, SARA, and
any other applicable municipal, federal or state environmental law.

                                                                              26
<PAGE>   30

       (d)    Tenant shall promptly notify Landlord in writing of any incident
in the Premises, or the Building or the Property which might require the filing
of a notice under any statute described in Section XLII(b) of this Lease.

       (e)    Tenant shall indemnify and hold Landlord harmless from any and all
cost, liabilities, demands, claims, civil or criminal actions, or causes of
action, civil or criminal penalties, fines, losses, liens, assessments, damages,
liabilities, costs, disbursements, expenses or fees of any kind or any nature
(including without limitation all clean-up costs and attorney's fees) which may
at any time be imposed upon, incurred by or asserted or awarded against Landlord
arising out of or on account of Tenant's failure to comply with the provisions
of Section XLII of this Lease, whether due to any action or non-action of
Tenant.

       SECTION XLIII. SECURITY DEPOSIT. Simultaneously with the execution and
delivery of this Lease to Landlord, Tenant shall deposit with Landlord a Letter
of Credit, in form acceptable to Landlord and its lender, in the sum of
$1,680,492.00 (the "LETTER OF CREDIT") to be held and, as applicable, presented,
drawn upon and the proceeds thereof retained and applied by Landlord as security
for the faithful payment, performance and observance by Tenant of the terms,
covenants, provisions, conditions and agreement of Tenant under and pursuant to
this Lease. It is agreed and understood that in the event of the occurrence of
an Event of Default of Tenant, Landlord may present for payment and draw upon
the Letter of Credit and Landlord may use, apply or retain the whole or any part
of the amounts available to be drawn under the Letter of Credit to the extent
required for the payment of any Rent or Additional Rent or any other sum which
Landlord may expend or be entitled to the payment of by reason of any Event of
Default of Tenant or any failure of Tenant to pay, perform or observe any term,
covenant, condition or provision of this Lease, including without limitation,
any late charges, interest payments or any damages or deficiency in the
re-letting of the Premises whether said damages or deficiency occurred before or
after summary proceedings or other re-entry by Landlord.

       If Landlord shall present, draw upon and apply or retain all or any
portion of the amounts evidenced by the Letter of Credit, Tenant shall
immediately replenish and reinstate the amount available to be drawn under the
Letter of Credit or cause a substitute Letter of Credit in the form and amount
required by this Lease to be re-issued so that at all times during the Term of
this Lease, Landlord shall be entitled to draw upon the entire dollar amount of
the Letter of Credit in the amounts required hereunder notwithstanding any prior
presentation and draw thereon.

       The Letter of Credit must at all times be an "irrevocable clean"
commercial Letter of Credit in the amount required by this Lease and payable
through a bank, acceptable to Landlord in Landlord's reasonable discretion. In
addition, the Letter of Credit shall be payable solely to the benefit of the
Landlord from time to time under this Lease and shall be automatically renewable
and, upon the direction of Landlord, transferable to and payable for the benefit
of any successor Landlord under the Lease. The Letter of Credit shall be and
remain presentable and payable for the time period beginning on the date of this
Lease through and including the date which is the last to occur of (i) the date
which is sixty (60) days after the last day of the Term of this Lease or (ii)
the date which is sixty (60) days after the date of delivery of the entire
Premises to Landlord in accordance with the terms and provisions of this Lease
or (iii) sixty (60) days after the last of Tenant's monetary obligations to
Landlord under this Lease have been satisfied in full. Tenant

                                                                              27
<PAGE>   31

shall bear all costs and expenses in connection with procuring the Letter of
Credit and maintaining it in full force and effect for the time periods required
hereunder. In the event of a sale or other transfer of the Building, Tenant
shall, at its sole cost and expense, cause the Letter of Credit, in the form
required hereunder, to be issued to and for the benefit of such transferee or
purchaser, as designated by Landlord.

       The Landlord from time to time under this Lease, shall be entitled to
receive sixty (60) days prior written notice of any cancellation of the Letter
of Credit for any reason and the Letter of Credit shall not be cancelable unless
and until Landlord shall have received such sixty (60) day advance written
notice. Upon (i) receiving notice of cancellation of the Letter of Credit or
(ii) failure of Tenant to deliver to Landlord a substitute Letter of Credit on
or before the date which is thirty (30) days prior any renewal date and whether
or not Tenant shall then be in default in the payment, performance or
observance of any term, covenant or provision of this Lease, Landlord shall be
entitled to present, draw upon and retain the entire amount of the Letter of
Credit and upon so doing, Landlord shall be entitled to hold, apply and retain
the proceeds of such payment as if it were a Cash Security Deposit under this
Lease to be applied against Defaults of Tenant from time to time arising under
this Lease.

       It is agreed and understood that any failure of Tenant to perform,
observe or comply with any term or provision contained in this Section XLII to
be performed or observed by Tenant shall entitle Landlord to the same rights and
remedies under this Lease, as a failure by Tenant to pay Rent and Additional
Rent as and when same shall be due and payable.

       Landlord may apply all or any portion of the security deposit to any
damage to the Premises or to the restoration thereof or to any Rent or
Additional Rent which may be due from Tenant to Landlord. In the event that
Landlord shall so apply all or any portion of the said security deposit, Tenant
shall immediately upon notice, restore the same to its full amount. All or any
portion of the security deposit remaining at the expiration or other termination
of this Lease which has not been so applied shall be returned to Tenant.

       Provided Tenant shall demonstrate its "Satisfactory Financial Condition"
as hereafter defined and there is no Event of Default under the Lease beyond any
applicable notice and cure period, on each of the following anniversary dates,
Landlord shall reduce the required security deposit or letter of credit on such
date:

       (i)    To six (6) months' Rent after the thirtieth (30th) calendar month
following the Rent Commencement Date;

       (ii)   To five (5) months' Rent after the thirty-sixth (36th) calendar
month following the Rent Commencement Date;

       (iii)  To four (4) months' Rent after the forty-eighth (48th) calendar
month following the Rent Commencement Date;

       (iv)   To two (2) months' Rent after the sixtieth (60th) calendar month
following the Rent Commencement Date.

       Tenant's "SATISFACTORY FINANCIAL CONDITION" shall be defined as follows:

       (a)    During the six (6) month period prior to the thirtieth (30th)
month anniversary date, Tenant shall demonstrate profitability or break even
after adding back depreciation and amortization;

                                                                              28
<PAGE>   32
       (b)    During the twelve (12) month period prior to each of the
subsequent anniversary dates defined above, Tenant shall demonstrate
profitability or break even after adding back depreciation and amortization;

       (c)    Upon each anniversary date, including month 30, Tenant shall
demonstrate positive working capital:

       (d)    Upon each anniversary date, including month 30, Tenant shall
demonstrate a net worth of at least $10 million.

       SECTION XLIV. LANDLORD'S RIGHT TO PERFORM FOR TENANT. Landlord shall have
the right, but shall not be required, to pay such sums and do any act, whether
the same requires the expenditures of monies or not, which may be necessary or
appropriate by reason of failure or neglect of the Tenant to perform any of the
provisions of this Lease, and in the event of the exercise of such right by the
Landlord, the Tenant agrees to pay to the Landlord forthwith upon demand the
cost of performing the same, plus interest at one and one-half percent (1 1/2%)
per month of such cost; and if Tenant shall default in such payment, the
Landlord shall have the same rights and remedies as the Landlord has hereunder
for the failure of the Tenant to pay the Rent or Additional Rent. Landlord may
exercise the foregoing rights without waiving any other of its rights or
releasing Tenant from any of its obligations under this Lease, and the exercise
of these rights shall not be deemed an obligation of Landlord to perform such
right in the future.

       SECTION XLV. GOVERNING LAW. This Lease shall be governed by the
provisions hereof and by the laws of the state in which the Premises are
located.

       SECTION XLVI. FORCE MAJEURE. In the event that either party shall be
delayed or hindered in or prevented from the performance of act required under
this Lease, by reason of strikes, lockouts, labor troubles, inability to procure
materials, failure of power, restrictive governmental laws or regulations,
riots, insurrection, war or other reasons of a like nature not the fault of the
party delayed in performing work or doing the acts required, then performance of
such act shall be excused for the period of the delay and the period for such
party's performance of any such act shall be extended for a period equivalent to
the period of such delay. The provisions of this Section shall in no event
operate to excuse Tenant from the prompt payment of Rent, or Additional Rent, or
excuse performance due to lack of funds. In any case where work is to be paid
for out of insurance proceeds of condemnation awards, due allowance shall be
made, both to the party required to perform such work and to the party required
to make such payments, for delays in the collection of such proceeds or awards.

     SECTION XLVII. EXTENSION OPTION. Provided the Tenant is not in default
hereunder, Tenant shall have the right to extend the term of this Lease for one
(1) additional term of five (5) years ("Extended Term") commencing upon the
expiration of the initial term. Tenant shall exercise the right to extend the
term of this Lease by written notice to Landlord no later twelve (12) months
prior to the expiration of the term. The Rent for the Extended Term shall be the
greater of the then current Rent or the Market Rent as hereafter defined. The
market rent ("Market Rent") shall be determined by Landlord based on leases then
currently under negotiation or recently executed for the Property. If no such
leases are under negotiation or have been recently executed, then Market Rent
shall be determined by Landlord based on comparable

                                                                              29
<PAGE>   33

office space in the in Alewife area (if any such space exists) taking into
account, among other factors, amenities, setting, location and demographics.
Landlord shall notify Tenant of the Market Rent within a reasonable period after
Tenant notifies Landlord that Tenant is exercising the option to extend,
provided Landlord shall not be required to set the Market Rent prior to
fourteen (14) months before the expiration of the Term. All of the covenants,
agreements, terms and conditions contained in this Lease shall apply to the
Extended Term. If Tenant is unwilling to accept Landlord's estimate of Market
Rent as set forth in Landlord's notice referred to above, and the parties are
unable to reach agreement thereon within thirty (30) days after the delivery of
such notice by Landlord, Tenant shall have no right to renew hereunder and this
Lease shall terminate on the Termination Date.

       SECTION XLVIII. RIGHT OF FIRST OFFER. Provided Tenant is not in default
of its obligations hereunder and subject to the rights of any existing Building
tenants and Landlord's right to extend the term of an existing lease, Landlord
shall provide Tenant with written notice of its intent to offer for lease
specific space located in the Building which is available or will become
available for lease ("LANDLORD'S INTENT TO LEASE NOTICE"). In the event that
Tenant desires to lease said space it shall have five (5) business days after
receipt of Landlord's Intent to Lease Notice to deliver to Landlord a notice of
its exercise of its "Right of First Offer" together with the most recent
available audited financial statements of Tenant upon which Landlord can
adequately assess the financial condition of Tenant (the "EXERCISE OF RIGHT OF
FIRST OFFER NOTICE"). In the event that Tenant fails to deliver its Exercise of
Right of First Offer Notice within said five (5) business day period, Tenant
shall have waived its right to the space and shall have no further right
pursuant to this Section XLVIII to the space offered for the remainder of the
term of this lease, as it may be extended.

       In the event Tenant timely exercises its "Right of First Offer", within
five (5) business days of receipt of Tenant's Exercise of Right of First Offer
Notice, Landlord shall deliver to Tenant a notice which shall set forth the
premises' square footage, the availability date, the term of occupancy (which
term shall be comparable to what would be offered in the market for comparable
space in a comparable building in the Alewife area), the rent, the base years
for the purpose of Tax and Operating Cost Excess, the security deposit
requirements, and the tenant improvements to be performed by Landlord, if any
(the "RIGHT OF FIRST OFFER NOTICE"). The terms and conditions contained in the
Right of First Offer Notice shall reflect Landlord's good faith determination of
the then current fair market rental terms available for comparable premises in
the Building to new tenants and shall reflect Landlord's security deposit
requirements based upon Landlord's assessment of Tenant's financial condition.
Tenant shall have ten (10) days following receipt of the Right of First Offer
Notice to accept said space on the terms and conditions offered, and if Tenant
shall fail to accept the Offer within said ten (10) day period, Tenant shall
have waived its right to the space and shall have no further right pursuant to
this Section XLVIII to the space offered for the remainder of the term of this
lease, as it may be extended. In the event Tenant accepts the offer of any space
pursuant to this Section XLVIII, Landlord and Tenant shall execute an amendment
to this Lease, setting forth the terms and conditions for the lease by Tenant of
the space so acquired.

                                                                              30
<PAGE>   34
        SECTION XLIX. CONDITIONS PRECEDENT Landlord and Tenant acknowledge and
agree that all or a portion of the Premises is presently under lease with
Allaire by virtue of a lease dated October 1, 1997, as amended by a First
Amendment of Lease dated September 28, 1998, between Allaire and Landlord's
predecessor-in-interest Robert Sorrentino and David R. Vickery, As Trustees of
One Alewife Center and Landlord does not currently have possession of the
Premises. It is a condition to the obligations of the parties under this Lease
that Landlord shall have entered into a termination agreement (the "TERMINATION
AGREEMENT") with Allaire providing for termination of the Allaire lease and
vacation of the premises demised thereby by Allaire and all persons or entities
claiming by, through or under Allaire. The anticipated termination date is
between July 1, 2000 and August 15, 2000. If Landlord has been unable to enter
into such a Termination Agreement with Allaire on or before the April 4, 2000,
then either Landlord or Tenant shall have the right to terminate this Lease by
giving notice to the other at any time prior to execution of the Termination
Agreement. Further, it is understood and agreed by Tenant that Landlord shall
have no liability if Landlord is unable to enter into a Termination Agreement or
shall be unable to deliver the Premises to Tenant as a result of Allaire's
failing or refusing to vacate the Premises after the consummation of said
Termination Agreement.

        Additionally, this lease is conditioned upon the approval of Landlord's
lender to all transaction contemplated herein.

       SECTION L. MULTIPLE COUNTERPARTS. This Lease may be executed
simultaneously in two or more counterparts, each of which shall be deemed an
original but all of which shall constitute one and the same instrument.

       IN WITNESS WHEREOF, the parties hereto have set their hands and seals as
of the day and year first above written.

                                Landlord:
                                NEW BOSTON ALEWIFE LIMITED PARTNERSHIP

                                By: New Boston Fund IV, Inc.,
                                    Its General Partner

                                By: (illegible)
                                    -------------------------------
                                    Its

                                Tenant:
                                NETGENESIS CORP.

                                By: (illegible)
                                    -------------------------------
                                    Its

                                                                              31
<PAGE>   35

                                   EXHIBIT A1

                                FIRST FLOOR PLAN

<PAGE>   36

                                   EXHIBIT A2

                                THIRD FLOOR PLAN

<PAGE>   37

                                   EXHIBIT A3

                                FOURTH FLOOR PLAN

<PAGE>   38

                                  EXHIBIT "B"

LANDLORD'S WORK:  None

TENANT'S WORK:    To be set forth under plans prepared by Tenant and submitted
                  to Landlord for approval.

                                                                      EXHIBIT B
<PAGE>   39
                                  EXHIBIT "C"

                          MASSACHUSETTS LEGAL HOLIDAYS

--------------------------------------------------------------
* January 1                    -  New Year's Day
--------------------------------------------------------------
Third Monday in January        -  Martin Luther King, Jr. Day
--------------------------------------------------------------
Third Monday in February       -  Washington's Birthday
--------------------------------------------------------------
Third Monday in April          -  Patriot's Day
--------------------------------------------------------------
Last Monday in May             -  Memorial Day
--------------------------------------------------------------
* July 4                       -  Independence Day
--------------------------------------------------------------
First Monday in September      -  Labor Day
--------------------------------------------------------------
Second Monday in October       -  Columbus Day
--------------------------------------------------------------
* November 11                  -  Veteran's Day
--------------------------------------------------------------
Fourth Thursday in November    -  Thanksgiving Day
--------------------------------------------------------------
* December 25                  -  Christmas Day
--------------------------------------------------------------

* Should any of these dates fall on a Sunday, the Holiday in observed on the
following Monday.

<PAGE>   40

                                  EXHIBIT "D"

                               SCOPE OF SERVICES

1.   CLEANING

     A.   OFFICE AREA

          DAILY: (Monday through Friday 6:00 pm -10:00 pm; holidays excepted)

          1.   Empty and clean all waste receptacles and ash trays and remove
               waste materials from the premises; wash receptacles as necessary.

          2.   Sweep and dust mop all uncarpeted areas using a dust-treated mop.

          3.   Vacuum all rugs and carpeted areas.

          4.   Wash clean all water fountains.

          5.   Wipe clean all brass and other bright work.

          6.   Upon completion of cleaning, all lights will be turned off and
               doors locked, leaving the premises in an orderly condition.

          WEEKLY:

          1.   Dust coat racks, and the like.

          2.   Remove all finger marks from private entrance, doors, light
               switches, and doorways.

          3.   Hand dust and wipe clean with treated cloths all horizontal
               surfaces including furniture, office equipment, window sills,
               door ledges, chair rails, and convector tops, within normal
               reach.

          4.   Remove and dust under all desk equipment and telephone and
               replace same.

          5.   Hand dust all grill work within normal reach.

          QUARTERLY:

          Render high dusting not reached in daily/weekly cleaning to include:

          a.   Dusting all pictures, frames, charts, graphs, and similar wall
               hangings.

          b.   Dusting all vertical surfaces, such as walls, partitions, doors,
               and ducts.

          c.   Dusting all pipes, ducts, and high moldings.

          d.   Dusting all venetian blinds.

     B.   LAVATORIES

          DAILY: (Monday through Friday, inclusive; holidays excepted)

          1.   Sweep and damp mop floors with approved germicidal detergent
               cleaning solution.

          2.   Clean all mirrors, powder shelves, dispensers and receptacles,
               bright work, flushometers, piping, and toilet seat hinges.

          3.   Wash both sides of all toilet seats.

                                                                       EXHIBIT D
<PAGE>   41
          4.   Wash all basins, bowls, and urinals with approved germicidal
               detergent cleaning solution.

          5.   Dust and clean all powder room fixtures.

          6.   Empty and clean paper towel and sanitary disposal receptacles.

          7.   Remove waste paper and refuse.

          8.   Refill tissue holders, soap dispensers, towel dispensers, vending
               sanitary dispensers; materials to be furnished to Landlord.

          9.   A sanitizing solution will be used in all lavatory cleaning.

          MONTHLY:

          1.   Machine scrub lavatory floors.

          2.   Wash all partitions and tile walls in lavatories.

     C.   MAIN LOBBY, ELEVATORS, BUILDING EXTERIOR, AND CORRIDORS.

          DAILY OR AS NEEDED: (Monday through Friday, inclusive; holidays
          excepted)

          1.   Sweep and wash all floors

          2.   Wash all rubber mats.

          3.   Clean elevators, wash or vacuum floors, wipe down walls and
               doors.

          4.   Spot clean any metal work inside lobby.

          5.   Spot clean any metal work surrounding building entrance doors.

          MONTHLY:

               All resilient tile floors in public areas to be treated
               equivalent to spray buffing.

          D.   WINDOW CLEANING

               Windows of exterior walls will be washed semi-annually.

          E.   Tenant requiring services in excess of those described above
               shall request same through Landlord, at Tenant's expense.

          F.   SNOW REMOVAL

               Clearing, sanding and salting of all snow and ice surrounding the
               building and walkways, as accumulated during storms, with special
               emphasis on the building opening at 8:00 am Monday - Friday and
               by 8:00 am on Saturday.

                                                                       EXHIBIT D

<PAGE>   42
                             RULES AND REGULATIONS

       The following Rules and Regulations constitute a part of the Lease and of
Tenant's obligations thereunder in respect of Tenant's use and occupancy of the
Premises in the Building.

                               I. BUILDING HOURS

       1.1.   The Building is accessible from 7:00 a.m. to 7:00 p.m. on Monday
through Friday except Holidays and 8:00 a.m. to 1:00 p.m. Saturdays. The
Building is closed on Sundays.

       1.2.   If you wish to use the Building during other times, please use the
authorized access-cards issued to members of your staff.

       1.3.   If you will need after-hours heating or air-conditioning services,
please notify the Building Management Office by 3:00 p.m. on the previous
working day. (These Building services are either reduced, or shut off completely
when the Building is closed.) You will be charged overtime use of the Building
services.

       1.4.   You are advised, for the protection and safety of your personnel,
to lock front doors at the end of each working day. Front doors also should be
locked whenever your receptionist leaves the area.

       1.5.   If you wish to remove fixtures or materials from your premises
after 7:00 p.m. or to have work performed after 7:00 p.m., by someone who does
not have a Building pass, the Building Management Office must be notified in
advance in writing.

                     II. ELEVATORS, DELIVERIES AND PARKING

       2.1.   If you expect delivery of any bulky material, notify the Building
Management Office reasonably in advance so that elevators may be scheduled and
elevator pads may be installed. This protects both your shipment and the
elevators. For the convenience of all, elevators may not be used for deliveries
during the peak traffic hours of 8:00 a.m. to 9:30 a.m.; 11:30 a.m. to 1:30
p.m.; and 4:30 p.m. to 6:00 p.m.

       2.2.   All large deliveries must be made from the designated Building
loading dock area. Large deliveries can be expedited by notifying the Building
Management Office 24 hours in advance. The receiving area can accommodate
certain types and sizes of vehicles. All hand trucks used for deliveries must be
equipped with rubber bumpers and tires. All deliveries are to be made/received
at the rear entrance of the Building in the designated Loading/Delivery area.

       2.3.   The loading dock may be used only for deliveries. No vehicles are
allowed to stand or park in this area after unloading nor are vehicles allowed
to park at the loading dock for service calls. You should advise your vendors
and suppliers of this rule. Any vehicles abusing the truck dock privileges are
subject to being towed at the owner's expense.

       2.4.   Building operating personnel are not authorized to receive for
shipments to or from the Building.

                   III. GENERAL USE OF BUILDING AND PREMISES

       3.1.   Tenants are not permitted to place or store property on the
sidewalks, passageways, parking areas or courtyards adjacent to the Building or
in the elevators, vestibules, stairways, or corridors (except as may be
necessary for brief periods during deliveries).

       3.2.   No animals may be brought into or kept in or about the Building or
premises. No bicycles may be brought into or kept in the Building, but must be
stored, at the sole risk of the individual storing a bicycle, in the bicycle
rack located in the underground parking area and/or the parking structure.

       3.3.   Rubbish, rags, sweepings, acid and any and all harmful or damaging
substances may not be deposited in the lavatories or in the janitor closets.
Please make arrangements with the Building Management Office for disposal of any
unusual trash.

       3.4.   If a Tenant's premises becomes infested with vermin due to
Tenant's own misuse of the premises, such tenant, at its sole cost and expense,
shall cause its premises to be

                                                                       EXHIBIT D

<PAGE>   43

exterminated by such exterminators as shall be approved by the Landlord at such
times and to such extent as the Landlord deems necessary to exterminate the
vermin.

                            IV. REPAIRS AND SERVICES

       4.1.   You are responsible for all general repairs and maintenance of
your Premises including, but not limited to, Tenant supplied supplementary air
conditioning, exterior doors, and exterior signs. All repairs, installations, or
alterations to the Building or its fixtures must first be approved and scheduled
by the Building Manager.

       4.2.   All requests for work to be done in your Premises by any of the
Building Management Staff should be directed to the Building Manager. Building
employees are not permitted to perform any work outside their regular duties
except upon special instructions from the Building Manager.

       4.3.   All schedules for the performance of your construction and repair
work must be coordinated by the Building Manager to avoid conflicts with various
building construction and maintenance schedules. Tenants must inform the
Building Manager, at least 72 hours before any work is to begin, of the nature
of the work, where and when it is to be performed, the name of the contractor or
concern doing the work, and the name of the individual who will supervise the
performance of the work. You will be required to obtain from the persons doing
work certificates of insurance coverage, signed lien waivers, and payment and
performance bond in form and substance satisfactory to the Landlord. Work may
not begin until such requirements have been satisfied.

       4.4.   Landlord shall purchase and install, at your expense, all lamps,
tubes, bulbs, starters and ballasts, at competitive prices. Tenant may elect,
upon notice to Landlord, to replace all of said items itself at its expense.

                V. ELECTRICAL SYSTEM: ENERGY CONSERVATION: WATER

       5.1.   In order to assure that the Building's electrical standards are
not exceeded and to avert possible adverse effect on the Building's electric
system, you may not, without Landlord's prior consent, connect any fixtures,
appliances or equipment to the Building's electric distribution system other
than standard office equipment.

       5.2.   Landlord reserves the right to implement policies and procedures
it deems, in its reasonable judgment, to be necessary or expedient in order to
conserve and/or preserve energy and related services, or as may be necessary or
required in order to comply with applicable government laws, rules, regulations,
codes, orders and standards.

       5.3.   If you shall use water for any purpose other than for ordinary
lavatory and drinking purposes, Landlord may assess a reasonable charge for the
additional water so used, or install a water meter and thereby measure your
water consumption for all water purposes. In the latter event, you shall pay the
cost of the meter and the cost of installation thereof and shall keep such meter
and installation equipment in good working order and repair. You agree to pay
for water consumed, as shown on such meter, together with the sewer charge based
on such meter charges, as and when bills are rendered, and in default in making
such payment Landlord may pay such charges and collect the same from you as an
additional charge.

       5.4.   The windows of the Building are designed for superior insulation
and to reduce glare. Building standard blinds or drapes present and elegant
appearance and contribute to the effectiveness of the Building's heating and
cooling systems. You should keep the blinds or drapes closed when windows are
exposed to the sun's rays in summer and keep them open when the sun is bright
enough to provide warmth during the winter months.

                           VI. SIGNS AND ADVERTISING

       Except as hereinafter provided, you may not place on the exterior of the
premises (including both interior and exterior surfaces or doors and interior
surfaces of windows) or on any part of the Building outside the premises, any
signs, symbol, advertisement or the like visible to the public view outside of
the premises. Landlord shall withhold consent for signs or lettering on the
entry doors to the premises, unless such signs conform to Building standards
adopted by Landlord. All signage must be in accordance with a plan or sketch of
the sign to be placed on such entry doors submitted to and approved by Landlord
in advance. Landlord agrees, however, to maintain a tenant directory in the
lobby of the Building in which will be placed your name and the location of the
premises in the Building. Neither Landlord's name, nor the name of the

                                                                       EXHIBIT D

<PAGE>   44
Building shall be used without Landlord's consent in any advertising material
(except on business stationery or as an address in advertising matter), nor
shall any such name, as aforesaid, be used in any undignified, confusing,
detrimental or misleading manner.

                   VII. LIFE SAFETY AND EMERGENCY PROCEDURES

       In case of emergency situations such as power failure, water leaks or
serious injury, call the Building Management Office immediately. In case of fire
or smoke, pull the nearest alarm (located on your floor) and then call the
Building Management Office

                          VIII. SMOKE FREE ENVIRONMENT

       Smoking is not permitted in the Building.

                                                                       EXHIBIT D

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