INDENTURE OF LEASE

Exhibit 10.142

33 HAYDEN AVENUE

LEXINGTON, MASSACHUSETTS

Lease Dated December 20, 2004

THIS INSTRUMENT IS AN INDENTURE OF LEASE in which the Landlord and the Tenant are the parties hereinafter named, and which relates to space in a certain building (the “Building”) known as, and with an address at, 33 Hayden Avenue, Lexington, Massachusetts.

The parties to this Indenture of Lease hereby agree with each other as follows:

ARTICLE I

REFERENCE DATA

Each reference in this Lease to any of the following subjects shall be construed to incorporate the data stated for that subject in this Article:

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There are incorporated as part of this Lease:

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ARTICLE II

THE BUILDINGS, PREMISES, TERM AND RENT

Landlord hereby demises and leases to Tenant, and Tenant hereby hires and accepts from Landlord, Tenant’s Space in the Building excluding exterior faces of exterior walls, the common stairways and stairwells, elevators and elevator wells, fan rooms, electric and telephone closets, janitor closets, and pipes, ducts, conduits, wires and appurtenant fixtures serving exclusively or in common other parts of the Building and if Tenant’s Space includes less than the entire rentable area of any floor, excluding the common corridors, elevator lobbies and toilets located on such floor.

Tenant’s Space with such exclusions is hereinafter referred to as the “Premises.” The term “Building” means the Building identified on the first page, and which is the subject of this Lease; the term “Site” means all, and also any part of the Land described in Exhibit A, plus any additions or reductions thereto resulting from the change of any abutting street line and all parking areas and structures. The term “Property” means the Building and the Site.

Subject to Landlord’s right to change or alter any of the following in Landlord’s discretion as provided in Section 2.3 hereof, Tenant shall have, as appurtenant to the Premises, the non-exclusive right to use in common with others, subject to reasonable rules of general applicability to tenants of the Building from time to time made by Landlord of which Tenant is given notice (a) the common lobbies, corridors, stairways, elevators and loading area of the Building, and the pipes, ducts, conduits, wires and appurtenant meters and equipment serving the Premises in common with others, (b) common walkways and driveways necessary for access to the Building, and (c) if the Premises include less than the entire rentable floor area of any floor, the common toilets, corridors and elevator lobby of such floor. Notwithstanding anything to the contrary herein, Landlord has no obligation to allow any particular telecommunication service provider to have access to the Building or to the Premises except as may be required by applicable law. Tenant acknowledges that it uses Verizon as its present telecommunications provider. Landlord hereby approves Tenant’s use of Verizon but any cabling, equipment and other telecommunications apparatus, wiring and other appurtenances (collectively “Equipment”) and the placement and location thereof shall be solely for Tenant’s use in the conduct of the Permitted Use and shall be first approved by Landlord prior to installation, such approval not to be unreasonably withheld. Such approval may be conditioned by Landlord on Tenant’s agreement to remove all of the same at the expiration or earlier termination of this Lease but may not be conditioned on the imposition of access

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charges. Landlord agrees not to unreasonably withhold its consent to any subsequent telecommunications service provider in replacement of, and not in addition to, Verizon. If Landlord so consents to such subsequent telecommunications service provider, Landlord may not condition such access upon the payment to Landlord by the service provider of fees assessed by Landlord. However, Landlord shall have the right to condition the same on Landlord’s prior approval of the installation, placement and location of such subsequent service provider’s Equipment and Tenant’s agreement to remove all of such subsequent service provider’s Equipment at the expiration or earlier termination of this lease. In no event shall any telecommunications provider install any equipment for sale of service to others or for anyone’s use other than Tenant in the Premises for the conduct of the Permitted Use.

In addition, Tenant shall have the right to use in the parking area the Number of Parking Spaces (referred to in Section 1.1) for the parking of automobiles by its employees and visitors, in common with use by other tenants from time to time of the Complex, provided, however, that Landlord shall not be obligated to furnish stalls or spaces in any parking area specifically designated for Tenant’s use. However, Landlord shall designate five (5) parking spaces for visitor use. Such visitor spaces shall be available to the visitors of all tenants, subtenants and other occupants from time to time of the Building and Landlord shall have no obligation to police or otherwise monitor or regulate the use thereof. Except for payment by Tenant of operating expenses as provided in Section 2.6 hereof, there shall be no charge for Tenant’s use of such parking spaces during the Original Term. Tenant covenants and agrees that it and all persons claiming by, through and under it, shall at all times abide by all reasonable rules and regulations promulgated by Landlord with respect to the use of the parking areas on the Site. The parking privileges granted herein are non-transferable except to a permitted assignee or subtenant as provided in Section 5.6 through Section 5.6.5. Further, except for the negligence or willful misconduct of Landlord and persons for whose Landlord is responsible, Landlord assumes no responsibility whatsoever for loss or damage due to fire, theft or otherwise to any automobile(s) parked on the Site or to any personal property therein, however caused, and Tenant covenants and agrees, upon request from Landlord from time to time, to notify its officers, employees, agents and invitees of such limitation of liability. Tenant acknowledges and agrees that a license only is hereby granted, and no bailment is intended or shall be created.

Landlord reserves the right from time to time, without unreasonable interference with Tenant’s use: (a) to install, use, maintain, repair, replace and relocate for service to

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the Premises and other parts of the Building, or either, pipes, ducts, conduits, wires and appurtenant fixtures, wherever located in the Premises or Building, and (b) to alter or relocate any other common facility, provided that substitutions are substantially equivalent or better. Installations, replacements and relocations referred to in clause (a) above shall be located so far as practicable in the central core area of the Building, above ceiling surfaces, below floor surfaces or within perimeter walls of the Premises. Notwithstanding the foregoing, Landlord’s right to make such alterations, additions or other changes shall not materially and adversely (i) affect Tenant’s use of the Premises, (ii) interfere with or deprive Tenant of reasonable access to and from the Premises, (iii) change the configuration of the Premises or (iv) reduce the Rentable Floor Area of the Premises. Further, except in the case of emergencies, Landlord shall give Tenant reasonable advance notice of any work and Landlord shall perform such work in a manner so as not to materially interfere with Tenant’s use of the Premises.

Tenant shall have and hold the Premises for a period commencing on the earlier of (the “Commencement Date”) (a) that date on which the Premises are “substantially complete” as provided in Section 3.1 provided, or (b) that date on which Tenant commences occupancy of any portion of the Premises for the Permitted Uses, and continuing for the Term unless sooner terminated as provided in Article VI or Article VII or unless extended as provided in Section 8.20. During Landlord’s construction of the improvements to the Premises pursuant to Article III hereof, Tenant shall have the right to install its wiring and cabling, its furniture and fixtures but only in accordance with and subject to the provisions and requirements of Section 5.14 hereof and such right and Tenant’s access shall be upon all of the terms and conditions set forth in this Lease except that such installation if prior to the date of substantial completion (as provided in Section 3.1), shall not trigger the commencement of the Lease Term as respects commencement of Annual Fixed Rent. However, whether or not Tenant exercises such rights and whether or not Tenant has completed all such installations, the Lease Term and Annual Fixed Rent shall commence on the Commencement Date.

As soon as may be convenient after the date has been determined on which the Term commences as aforesaid, Landlord and Tenant agree to join with each other in the execution of a written Declaration, in the form of Exhibit E, in which the date on which the Term commences as aforesaid and the Term of this Lease shall be stated. If Tenant fails to execute such Declaration, the Commencement Date and Lease Term shall be as reasonably determined by Visnick and Caulfield, Architects (“Visnick & Caulfield”) in accordance with the terms of this Lease.

Tenant agrees to pay to Landlord, or as directed by Landlord, at Landlord’s Original Address specified in Section 1.1 hereof, or at such other place as Landlord shall from

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time to time designate by notice, (1)(a) on the Rent Commencement Date (defined in Section 1.1 hereof) and thereafter monthly, in advance, on the first day of each and every calendar month during the Original Term, a sum equal to one twelfth (1/12 ^th ) of the Annual Fixed Rent (sometimes hereinafter referred to as “fixed rent”) and (1)(b) on the Commencement Date and thereafter monthly, in advance, on the first day of each and every calendar month during the Original Term, a sum equal to one twelfth (1/12 ^th ) of $1.00 per annum for each square foot of Rentable Floor Area of Tenant’s Space for tenant electricity subject to escalation as provided in Section 2.8 and (2) on the first day of each and every calendar month during the extension option period (if exercised), a sum equal to (a) one twelfth (1/12 ^th ) of the annual fixed rent as determined in Section 8.20 for the extension option period plus (b) then applicable monthly electricity charges (subject to escalation for electricity as provided in Section 2.8 hereof. Until notice of some other designation is given, fixed rent and all other charges for which provision is herein made shall be paid by remittance to or for the order of Boston Properties Limited Partnership at P.O. Box 3557, Boston, Massachusetts 02241-3557, and all remittances received by Boston Properties Limited Partnership, as Agents as aforesaid, or by any subsequently designated recipient, shall be treated as payment to Landlord.

Annual Fixed Rent for any partial month shall be paid by Tenant to Landlord at such rate on a pro rata basis, and, if the Rent Commencement Date is a day other than the first day of a calendar month, the first payment of Annual Fixed Rent which Tenant shall make to Landlord shall be a payment equal to a proportionate part of such monthly Annual Fixed Rent for the partial month from the Rent Commencement Date to the first day of the succeeding calendar month.

Additional Rent payable by Tenant on a monthly basis, as hereinafter provided, likewise shall be prorated, and the first payment on account thereof shall be determined in similar fashion but shall commence on the Commencement Date; and other provisions of this Lease calling for monthly payments shall be read as incorporating this undertaking by Tenant.

Notwithstanding that the payment of Annual Fixed Rent payable by Tenant to Landlord shall not commence until the Rent Commencement Date, Tenant shall be subject to, and shall comply with, all other provisions of this Lease as and at the times provided in this Lease.

The Annual Fixed Rent and all other charges for which provision is herein made shall be paid by Tenant to Landlord, without offset, deduction or abatement except as otherwise specifically set forth in this Lease.

The Rent Commencement Date in respect of the Premises (“RCD”) shall be the date which is 181 days after the Commencement Date (“Fixed Rent Abatement Period”) (i.e., Tenant shall have no obligation to pay Annual Fixed Rent during the first (1 ^st ) 180 days of the Term of the Lease in respect of the Premises (“Abated Fixed Rent”).

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Notwithstanding anything to the contrary herein contained, if Tenant defaults at any time during the Term of the Lease and fails to cure such default within the applicable cure period under this Lease, all Abated Fixed Rent shall immediately become due and payable. The payment by Tenant of the Abated Fixed Rent in the event of a default shall not limit or affect any of Landlord’s other rights, pursuant to this Lease or at law or in equity. During the Fixed Rent Abatement Period, only Annual Fixed Rent payable in respect of the Premises shall be abated, and Tax Excess, Operating Expense Excess and all other costs and charges specified in the Lease shall remain as due and payable pursuant to the provisions of the Lease. In the event that Tenant pays to Landlord the Abated Fixed Rent in accordance with this Paragraph, then the monthly installments of Annual Fixed Rent thereafter (i.e., after Tenant makes such payment) payable by Tenant during the remainder of the initial Term of the Lease shall be reduced by the Monthly Abated Fixed Rent Reduction, as hereinafter defined. The “Monthly Abated Fixed Rent Reduction” shall be defined as the amount of Abated Fixed Rent actually paid by Tenant to Landlord, amortized on a straight-line basis in equal monthly installments over the remainder of the initial Term of the Lease.

“Landlord’s Operating Expenses” means the cost of operation of the Building and the Site which shall exclude costs of special services rendered to tenants (including Tenant) for which a separate charge is made, but shall include, without limitation, the following: premiums for insurance carried with respect to the Building and the Site (including, without limitation, liability insurance, insurance against loss in case of fire or casualty and insurance of monthly installments of fixed rent and any Additional Rent which may be due under this Lease and other leases of space in the Building for not more than 12 months in the case of both fixed rent and Additional Rent and if there be any first mortgage of the Property, including such insurance as may be required by the holder of such first mortgage); compensation and all fringe benefits, worker’s compensation insurance premiums and payroll taxes paid to, for or with respect to all persons engaged in the operating, maintaining or cleaning of the Building or Site, water, sewer, electric, gas, oil and telephone charges (excluding utility charges separately chargeable to tenants for additional or special services); cost of building and cleaning supplies and equipment; cost of maintenance, cleaning and repairs (other than repairs not properly chargeable against income or reimbursed from contractors or manufacturers under guarantees or out of insurance proceeds); cost of snow removal and care of landscaping; payments under service contracts with independent contractors; any and all subsidies or other payments of any type or amount made or granted by Landlord respecting the operation of the cafeteria; management fees at reasonable rates consistent with the type of occupancy and the service rendered; and all other reasonable and necessary expenses paid in connection with the operation, cleaning and maintenance of the Building and the Site and properly chargeable against income, provided, however, there shall be included (a) depreciation for capital expenditures made by Landlord (i) to reduce Landlord’s

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Operating Expenses if Landlord shall have reasonably determined that the annual reduction in Landlord’s Operating Expenses shall exceed depreciation therefor or (ii) to comply with applicable laws, rules, regulations, requirements, statutes, ordinances, by-laws and court decisions of all public authorities which are enacted or amended after the Date of this Lease; plus (b) in the case of both (i) and (ii) an interest factor, reasonably determined by Landlord, as being the interest rate then charged for long term mortgages by institutional lenders on like properties within the locality in which the Building is located; depreciation in the case of both (i) and (ii) shall be determined by dividing the original cost of such capital expenditure by the number of years of useful life (without regard to any accelerated depreciation permitted thereunder) of the capital item acquired and the useful life shall be reasonably determined by Landlord in accordance with generally accepted accounting principles and practices (without regard to any accelerated depreciation permitted thereunder) in effect at the time of acquisition of the capital item.

Notwithstanding the foregoing, the following shall be excluded from Operating Expenses for the Property:

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“Operating Expenses Allocable to the Premises” shall mean (a) the same proportion of Landlord’s Operating Expenses for and pertaining to the Building as the Rentable Floor Area of Tenant’s Space bears to the Total Rentable Floor Area of the Building plus (b) the same proportion of Landlord’s Operating Expenses for and pertaining to the Site as the Rentable Floor Area of Tenant’s Space bears to the Total Rentable Floor Area of the Building.

“Base Operating Expenses” is hereinbefore defined in Section 1.1. Base Operating Expenses shall not include market-wide cost increases due to extraordinary circumstances, including but not limited to Force Majeure (as defined in Section 6.1), conservation surcharges, boycotts, strikes, embargoes or shortages.

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“Base Operating Expenses Allocable to the Premises” means (i) the same proportion of Base Operating Expenses for and pertaining to the Building as the Rentable Floor Area of Tenant’s Space bears to the Rentable Floor Area of the Building plus (ii) the same proportion of Base Operating Expenses for and pertaining to the Site as the Rentable Floor Area of Tenant’s Space bears to the Total Rentable Floor Area of the Building.

In the event that on the average less than ninety-five percent (95%) of the Rentable Floor Area of the Building is leased during any calendar year during the Lease Term (including, without limitation, calendar year 2005 for purposes of calculating Base Operating Expenses), then Landlord’s Operating Expenses for each such calendar year which vary based on the level of occupancy (as, for example, cleaning expenses) shall be determined by Landlord to be an amount equal to the Landlord’s Operating Expenses which so vary and which would normally be expected to have been charged had ninety-five percent (95%) of the Rentable Floor Area of the Building been leased during such calendar year. In no event shall Landlord receive on account of any extrapolation an amount in excess of actual costs incurred.

If with respect to any calendar year falling within the Term, or fraction of a calendar year falling within the Term at the beginning or end thereof, the Operating Expenses Allocable to the Premises for a full calendar year exceed Base Operating Expenses Allocable to the Premises, or for any such fraction of a calendar year exceed the corresponding fraction of Base Operating Expenses Allocable to the Premises then, Tenant shall pay to Landlord, as Additional Rent, the amount of such excess. Such payments shall be made at the times and in the manner hereinafter provided in this Section 2.6. (The Base Operating Expenses Allocable to the Premises do not include the $1.00 for tenant electricity to be paid by Tenant at the time of payment of Annual Fixed Rent and for which provision is made in Section 2.5 hereof, separate provision being made in Section 2.8 of this Lease for Tenant’s share of increases in electricity costs.)

Landlord’s Operating Expense records shall be kept on a consistent basis from year to year. Not later than one hundred and twenty (120) days after the end of the first calendar year or fraction thereof ending December 31 and of each succeeding calendar year during the Term or fraction thereof at the end of the Term, Landlord shall render Tenant a statement in reasonable detail and according to usual accounting practices certified by a representative of Landlord, showing Base Operating Expenses and Base Operating Expenses Allocable to the Premises and also showing for the preceding calendar year or fraction thereof, as the case may be, Landlord’s Operating Expenses and Operating Expenses Allocable to the Premises. Said statement shall be rendered in form substantially similar to the Operating Expenses Statement Form attached hereto as Exhibit G. Said statement to be rendered to Tenant shall also show for the preceding year or fraction thereof as the case may be the amounts of operating expenses already paid by Tenant as Additional Rent, and the amount of operating expenses remaining due from, or overpaid by,

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Tenant for the year or other period covered by the statement. Within thirty (30) days after the date of delivery of such statement, Tenant shall pay to Landlord the balance of the amounts, if any, required to be paid pursuant to the above provisions of this Section 2.6 with respect to the preceding year or fraction thereof, or Landlord shall credit any amounts due from it to Tenant pursuant to the above provisions of this Section 2.6 against (i) monthly installments of fixed rent next thereafter coming due or (ii) any sums then due from Tenant to Landlord under this Lease (or refund such portion of the overpayment as aforesaid if the Term has ended and Tenant has no further obligation to Landlord). Such refund, if any, shall survive the expiration or earlier termination of this Lease provided Tenant was not in default at the expiration or termination of this Lease and provided Tenant does not then have any further obligations to Landlord. Within ten (10) days after Landlord’s receipt of a request for explanation from Tenant, Landlord shall provide to Tenant a reasonable explanation to Tenant of questions relating to Landlord’s Operating Expenses and such reasonable documentation of expenses for the year covered by such statement as Tenant may reasonably request.

In addition, Tenant shall make payments monthly on account of Tenant’s share of increases in Landlord’s Operating Expenses anticipated for the then current year at the time and in the fashion herein provided for the payment of fixed rent. The amount to be paid to Landlord shall be an amount reasonably estimated annually by Landlord to be sufficient to cover, in the aggregate, a sum equal to Tenant’s share of such increases in operating expenses for each calendar year during the Term. Any increase in estimated annual estimated Landlord’s Operating Expenses shall be accompanied by a reasonable written explanation thereof.

Notwithstanding the foregoing provisions, no decrease in Landlord’s Operating Expenses shall result in a reduction of the amount otherwise payable by Tenant if and to the extent said decrease is attributable to vacancies in the Buildings rather than to any other causes.

Upon no less than ten (10) business days prior notice to Landlord, Tenant, at Tenant’s expense, may examine Landlord’s books and records regarding the Operating Expense statement for the year submitted at any reasonable time specified by Landlord during Landlord’s business hours at a place designated by Landlord. Tenant shall hold such books and records in confidence and not disclose the same to any other party, including, without limitation, any other tenant in the Building. As a condition precedent to the conduct of any such audit, Tenant shall execute a confidentiality agreement binding Tenant and its auditor and all of their respective employees and agents in such form as determined by Landlord. Landlord shall reasonably cooperate with any such examination and shall promptly make such records available to Tenant and Tenant’s accountant. Such audit right must be exercised within 180 days following Tenant’s receipt of Landlord’s annual reconciliation or other statement showing Landlord’s determination of the Operating Expenses for the subject calendar year. Any such review or audit shall be limited to

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the year reflected in such statement. In the event the audit shows an over-payment, or mischarged amount, then Landlord shall grant Tenant a rent credit in the amount previously paid by Tenant or if this Lease has expired or terminated Landlord shall pay to Tenant such amount (less any monies owned to Landlord under this Lease), which obligation shall survive such termination or expiration. All costs for any such audit shall be paid by Tenant, unless the amount of the discrepancy is identified to be more than five percent (5%) in which event Landlord shall pay for the costs of the audit. In no event shall Tenant employ or otherwise use or engage the services of any person, firm, consultant, accountant, advisor, agent or other representative to perform such audit whose fee or compensation is based in whole or in part on a percentage of the amount disputed or on a percentage of overpayment or savings or on any contingent basis.

If with respect to any full Tax Year or fraction of a Tax Year falling within the Term, Landlord’s Tax Expenses Allocable to the Premises as hereinafter defined for a full Tax Year exceed Base Taxes Allocable to the Premises, or for any such fraction of a Tax Year exceed the corresponding fraction of Base Taxes Allocable to the Premises then, on or before the thirtieth (30 ^th ) day following receipt by Tenant of the certified statement referred to below in this Section 2.7, then Tenant shall pay to Landlord, as Additional Rent, the amount of such excess. Not later than ninety (90) days after Landlord’s Tax Expenses Allocable to the Premises are determined for the first such Tax Year or fraction thereof and for each succeeding Tax Year or fraction thereof during the Term, Landlord shall render Tenant a statement in reasonable detail certified by a representative of Landlord showing for the preceding year or fraction thereof, as the case may be, real estate taxes on the Building and the Site and abatements and refunds of any taxes and assessments. Expenditures for legal fees and for other expenses incurred in seeking the tax refund or abatement may be charged against the tax refund or abatement before the adjustments are made for the Tax Year. Said statement to be rendered to Tenant shall include a copy of the applicable rent estate tax bill and shall also show for the preceding Tax Year or fraction thereof as the case may be the amounts of real estate taxes already paid by Tenant as Additional Rent, and the amount of real estate taxes remaining due from, or overpaid by, Tenant for the year or other period covered by the statement. Within thirty (30) days after the date of delivery of the foregoing statement, Tenant shall pay to Landlord the balance of the amounts, if any, required to be paid pursuant to the above provisions of this Section 2.7 with respect to the preceding Tax Year or fraction thereof, or Landlord shall credit any amounts due from it to Tenant pursuant to the provisions of this Section 2.7 against (i) monthly installments of fixed rent next thereafter coming due or (ii) any sums then due from Tenant to Landlord under this Lease (or refund such portion of the over-payment as aforesaid if the Term has ended and Tenant has no further obligation to Landlord). Such refund, if any, shall survive the expiration or earlier termination of this Lease provided was not then in default at the expiration or termination of this Lease and provided Tenant does not then have any further obligations to Landlord).

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In addition, payments by Tenant on account of increases in real estate taxes anticipated for the then current year shall be made monthly at the time and in the fashion herein provided for the payment of fixed rent. The amount so to be paid to Landlord shall be an amount reasonably estimated by Landlord to be sufficient to provide Landlord, in the aggregate, a sum equal to Tenant’s share of such increases, at least ten (10) days before the day on which such payments by Landlord would become delinquent.

To the extent that real estate taxes shall be payable to the taxing authority in installments with respect to periods less than a Tax Year, the foregoing statement shall be rendered and payments made on account of such installments. Notwithstanding the foregoing provisions, no decrease in Landlord’s Tax Expenses with respect to any Tax Year shall result in a reduction of the amount otherwise payable by Tenant if and to the extent said decrease is attributable to vacancies in the Building or partial completion of the Building rather than to any other causes.

Terms used herein are defined as follows:

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If with respect to any calendar year falling within the Term or fraction of a calendar year falling within the Term at the beginning or end thereof, the cost of furnishing electricity to the Premises demised to Tenant, (excluding electricity for common areas of the Building and Site and electricity for standard heating, ventilating and air-conditioning (“HVAC”), all of which shall be covered by and included in Operating Costs under Section 2.6 hereof and also excluding utility charges separately chargeable to tenants for additional or special services as, for example, for supplemental or additional HVAC services) for a full calendar year exceeds $1.00 per square foot of Rentable Floor Area of the Building, or for any such fraction of a calendar year exceeds the corresponding fraction of $1.00 per square foot of Rentable Floor Area of the Building, then Tenant shall pay to Landlord, as Additional Rent, on or before the thirtieth (30 ^th ) day following receipt by Tenant of the statement referred to below in this Section 2.8, its proportionate share of the amount of such excess (i.e.

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the same ratio of such excess as the Rentable Floor Area of Tenant’s Space bears to the Total Rentable Floor Area of the Building). Payments by Tenant on account of such excess shall be made monthly at the time and in the fashion herein provided for the payment of Annual Fixed Rent. The amount so to be paid to Landlord shall be an amount from time to time reasonably estimated by Landlord to be sufficient to cover, in the aggregate, a sum equal to such excess for each calendar year during the Term. If the Landlord shall reasonably determine that the cost of the electricity furnished to the Tenant at the Premises exceeds the amount being paid under Sections 2.5 and 2.8, then the Landlord may charge the Tenant for such excess and the Tenant shall promptly pay the same upon billing therefor.

Not later than ninety (90) days after the end of the first calendar year or fraction thereof ending December 31 and of each succeeding calendar year during the Term or fraction thereof at the end of the Term, Landlord shall render Tenant a reasonably detailed accounting certified by a representative of Landlord showing for the preceding calendar year, or fraction thereof, as the case may be, the costs of furnishing electricity to the Building. Said statement to be rendered to Tenant also shall show for the preceding year or fraction thereof, as the case may be, the amount already paid by Tenant on account of electricity, and the amount remaining due from, or overpaid by, Tenant for the year or other period covered by the statement.

From and after the date the check meter(s) for the Premises are effective and operational, then thereafter electricity thereafter used and/or consumed for the Premises shall be paid as provided in this Section 2.8.1. but a final settling up, adjustment and payment for Premises electricity used and/or consumed prior to said effective date shall be made in accordance with Section 2.5 and 2.8 hereof.

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ARTICLE III

CONDITION OF PREMISES; ALTERATIONS

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Further, Tenant shall, on or before January 14, 2005 (herein called the “Long Lead Item Release Date”), give Landlord written authorization to proceed to purchase and/or contract for the “Long Lead Items” (defined above). Notwithstanding the foregoing, Tenant acknowledges that (i) certain Long Lead Items may still delay completion of the Work and thus result in a Tenant Delay even if Tenant does authorize them on or before the Long Lead Item Release Date, and (ii) any Long Lead Items which are added as a result of a change order after the Long Lead Item Release Date may delay completion of the Work and thus result in a Tenant Delay.

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The Tenant Delays defined in clauses (a), (b) and (c) of this Section 3.1(B)(1) are sometimes hereinafter referred to as “Accelerated Rent Tenant Delays,” the Tenant Delays defined in clauses (d), (e), and (f) of this Section 3.1(B)(1) are sometimes hereinafter referred to as “Other Tenant Delays.”

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In the event of any dispute as to the date on which the Work has been substantially completed, the reasonable determination of Visnick & Caulfield, Architects as to such date shall be deemed conclusive and binding on both Landlord and Tenant.

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(A) In the event that the Work shall not be substantially completed by the sixtieth (60 ^th ) day following the Estimated Commencement Date and if such failure to substantially complete is not due, in whole or in part, to any Tenant Delay or to any Change Order, then for each day that the Commencement Date is delayed beyond the 60 ^th day following the Estimated Commencement Date, Landlord shall provide Tenant with one (1) day’s free fixed rent which shall be in addition to the free rent resulting from the Rent Commencement Date being the 181 ^st following the

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Commencement Date. The provisions of this Section 3.2(A) shall only apply if Tenant does not terminate this Lease pursuant to Section 3.2(B) below.

(B) If Landlord shall have failed substantially to complete the Work on or before the Outside Completion Date as defined in Section 1.1 hereof (which date shall be extended automatically for such periods of time as Landlord is prevented from proceeding with or completing the same by reason of Force Majeure as defined in Section 6.1 or any act or failure to act of Tenant which interferes with Landlord’s construction of the Premises, without limiting Landlord’s other rights on account thereof), Tenant shall have the right to terminate this Lease by giving notice to Landlord of Tenant’s desire to do so before such completion and within the time period from the Outside Completion Date (as so extended) until the date which is thirty (30) days subsequent to the Outside Completion Date (as so extended); and, upon the giving of such notice, the term of this Lease shall cease and come to an end without further liability or obligation on the part of either party unless, within thirty (30) days after receipt of such notice, Landlord substantially completes the Work to be performed by Landlord pursuant to Section 3.1. In the event that this Lease shall be terminated pursuant to the foregoing provisions of this Section 3.2(B), Landlord shall promptly reimburse Tenant for (a) any Tenant Plan Excess Costs previously paid by Tenant to Landlord and (b) “Tenant’s Termination Damages” (hereinafter defined). “Tenant’s Termination Damages” shall be the reasonable out of pocket costs and expenses actually paid by Tenant to third parties unaffiliated and not employed by Tenant for, on account of or respecting the following in the Premises but not to exceed $300,00.00 in the aggregate: (i) legal fees paid by Tenant in negotiating this Lease and in enforcing this Section 3.2(B) in the event Tenant terminates pursuant hereto, (ii) project management services of a third party in supervising the installation of Tenant’s telecommunications equipment; (iii) consulting services of a third party in supervising the installation of Tenant’s audio visual equipment; (iv) voice and data wiring and cabling, (v) video installations in conference rooms, (vi) wiring and cabling in Tenant’s data center in the Premises, (vii) purchase and installation of audio amplification equipment and (viii) interior and exterior signage erected by Tenant pursuant to Section 8.26 of this Lease. However, there shall be excluded from Tenant’s Termination Damages the costs and expenses of any of the foregoing items which are removed by Tenant or which are reasonably reusable in another location by Tenant. As a condition to being reimbursed for Tenant’s Termination Damages, Tenant shall be required to submit to Landlord reasonable written information evidencing actual payment of the foregoing. In no event shall Tenant be entitled to any indirect, consequential, punitive or other damages or any other remedies. Landlord and Tenant hereby agree that the foregoing right of termination and payment shall be Tenant’s sole and exclusive remedy for Landlord’s failure so to complete such Work within such time and respecting Tenant’s termination under this Section 3.2(B) or otherwise. Each day of Tenant Delay shall be deemed conclusively to cause an equivalent day of delay by Landlord in substantially completing the Work pursuant to Section 3.1, and thereby automatically extend for each such equivalent day of delay the date of the Outside Completion Date.

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All construction work required or permitted by this Lease shall be done in a good and workmanlike manner and in compliance with all applicable laws, ordinances, rules, regulations, statutes, by-laws, court decisions, and orders and requirements of all public authorities (“Legal Requirements”) and all Insurance Requirements (as defined in Section 5.14 hereof). All of Tenant’s work shall be coordinated with any work being performed by or for Landlord and in such manner as to maintain harmonious labor relations. Each party may inspect the work of the other at reasonable times and shall promptly give notice of observed defects. Each party authorizes the other to rely in connection with design and construction upon approval and other actions on the party’s behalf by any Construction Representative of the party named in Section 1.1 or any person hereafter designated in substitution or addition by notice to the party relying. Except to the extent to which Tenant shall have given Landlord notice of respects in which Landlord has not performed Landlord’s construction obligations under this Article III not later than the end of the twelfth (12 ^th ) full calendar month next beginning after the Commencement Date with respect to all of Landlord’s construction obligations under this Article III including, but not limited to, the heating, ventilating and air conditioning systems servicing the Premises, Tenant shall be deemed conclusively to have approved Landlord’s construction and shall have no claim that Landlord has failed to perform any of Landlord’s obligations under this Article III (if any). Landlord agrees to correct or repair at its expense items which are then incomplete or do not conform to the work contemplated under the Plans and as to which, in either case, Tenant shall have given notice to Landlord, as aforesaid.

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ARTICLE IV

LANDLORD’S COVENANTS; INTERRUPTIONS AND DELAYS

To furnish services, utilities, facilities and supplies set forth in Exhibit C equal to those customarily provided by landlords in high quality buildings in the Boston West Suburban Market subject to escalation reimbursement in accordance with Section 2.6.

(B) HVAC MAINTENANCE

Subject to escalation reimbursement in accordance with Section 2.6, Landlord shall maintain, repair and make replacements as necessary to operate the heating, ventilating and air-conditions system (the “HVAC System”) including periodic cleaning and maintenance of the ducts and outside components of the HVAC System.

To furnish, at Tenant’s expense, reasonable additional Building operation services which are usual and customary in similar office buildings in the Boston West Suburban Market upon reasonable advance request of Tenant at

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reasonable and equitable rates from time to time established by Landlord. Tenant agrees to pay to Landlord, as Additional Rent, the cost of any such additional Building services requested by Tenant and for the cost of any additions, alterations, improvements or other work performed by Landlord in the Premises at the request of Tenant within thirty (30) days after being billed therefor.

Except for (a) normal and reasonable wear and use and (b) damage caused by fire and casualty and by eminent domain, and except as otherwise provided in Article VI and subject to the escalation provisions of Section 2.6, (i) to make such repairs to the roof, exterior walls, floor slabs and common areas and facilities as may be necessary to keep them in serviceable condition and (ii) to maintain the Building (exclusive of Tenant’s responsibilities under this Lease) in a first class manner comparable to the maintenance of similar properties in the Boston West Suburban Market.

Landlord shall not be liable to Tenant for any compensation or reduction of rent by reason of inconvenience or annoyance or for loss of business arising from the necessity of Landlord or its agents entering the Premises for any of the purposes in this Lease authorized, or for repairing the Premises or any portion of the Building however the necessity may occur. In case Landlord is prevented or delayed from making any repairs, alterations or improvements, or furnishing any services or performing any other covenant or duty to be performed on Landlord’s part, by reason of any cause reasonably beyond Landlord’s control, including without limitation the causes set forth in Section 3.2 hereof as being reasonably beyond Landlord’s control, Landlord shall not be liable to Tenant therefor, nor, except as expressly otherwise provided in Article VI, shall Tenant be entitled to any abatement or reduction of rent by reason thereof, or right to terminate this Lease, nor shall the same give rise to a claim in Tenant’s favor that such failure constitutes actual or constructive, total or partial, eviction from the Premises.

In the event that the electrical, heating, ventilating, air conditioning, or all elevator service to the Premises shall be shut down for more than five (5) full and consecutive business days, then, Tenant shall be entitled to an abatement of Annual Fixed Rent from the date of the shutdown of such service to the date such service is restored. Tenant agrees that if and to the extent such shutdown is covered by Landlord’s loss of rents coverage, the abatement of Annual Fixed Rent shall be limited and equal to the “Insurance Amount” (hereinafter defined). However, if such shutdown of service is attributable to Landlord’s negligence or willful conduct, the abatement of Annual

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Fixed Rent shall not be limited to the Insurance Amount. The “Insurance Amount” shall be an amount equal to the payment actually received by Landlord (but only allocable to and on account of the Premises) for such shut down of service to the Premises received from Landlord’s insurance carrier providing such loss of rents insurance less the amount of any deductible contained in such loss of rents insurance coverage. Notwithstanding anything herein contained to the contrary, in no event shall any of the events referred to in this Section give rise to a claim in Tenant’s favor that such failure constitutes actual or constructive, total or partial, eviction from the Premises.

Landlord reserves the right to stop any service or utility system, when necessary by reason of accident or emergency, or until necessary repairs have been completed; provided, however, that in each instance of stoppage, Landlord shall exercise reasonable diligence to eliminate the cause thereof. Except in case of emergency repairs, Landlord will give Tenant reasonable advance notice of any contemplated stoppage and will use reasonable efforts to avoid unnecessary inconvenience to Tenant by reason thereof.

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ARTICLE V

TENANT’S COVENANTS

Tenant covenants during the Term and such further time as Tenant occupies any part of the Premises:

To pay when due all fixed rent and Additional Rent and all charges for utility services rendered to the Premises (except as otherwise provided in Exhibit C) and, as further Additional Rent, all charges for additional services rendered pursuant to Section 4.1.2.

Except as otherwise provided in Article VI and Section 4.1.3 to keep the Premises in good order, repair and condition, reasonable wear and tear only excepted, and all glass in windows (except glass in exterior walls unless the damage thereto is attributable to Tenant’s negligence or misuse) and doors of the Premises whole and in good condition with glass of the same type and quality as that injured or broken, damage by fire or taking under the power of eminent domain only excepted, and at the expiration or termination of this Lease peaceably to yield up the Premises all construction, work, improvements, and all alterations and additions thereto in good order, repair and condition, reasonable wear and tear only excepted, first removing (i) all goods and effects of Tenant except for the initial Tenant improvements constructed pursuant to Article III hereof, (ii) to the extent specified by Landlord by notice to Tenant as set forth in Section 5.14 hereof all alterations and additions made by Tenant (iii) all partitions and (iv) to the extent specified by Landlord by notice to Tenant given at least ten (10) days before such expiration or termination, the wiring for Tenant’s computer, telephone and other communication systems and equipment whether located in the Premises or in any other portion of the Building, including all risers and all alterations and additions made by Tenant, and in each case repairing any damage caused by such removal and restoring the Premises and leaving them clean and neat. Tenant shall not permit or commit any waste, and Tenant shall be responsible for the cost of repairs which may be made necessary by reason of damage to common areas in the Building, to the Site or to the other building caused by Tenant, Tenant’s agents, contractors, employees, sublessees, licensees, concessionaires or invitees.

To use and occupy the Premises for the Permitted Use only, and not to injure or deface the Premises, Building, the Site or any other part of the Complex nor to permit in the Premises or on the Site any auction sale, vending machine, or inflammable fluids or chemicals, or nuisance, or the emission from the Premises of any objectionable noise or odor, nor to permit in the Premises anything which will in any way result in the leakage of fluid or the growth of mold, and not to use or devote the Premises or any part thereof for any purpose other than the Permitted Uses, nor any use thereof which is inconsistent with the maintenance of the Building as an office building of the first class in the quality of its maintenance, use and occupancy, or which is improper, offensive, contrary to law or ordinance or liable to invalidate or increase the premiums for any insurance on the Building or its contents or liable to

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render necessary any alteration or addition to the Building. Further, (i) Tenant shall not, nor shall Tenant permit its employees, invitees, agents, independent contractors, contractors, assignees or subtenants to, keep, maintain, store or dispose of (into the sewage or waste disposal system or otherwise) or engage in any activity which might produce or generate any substance which is or may hereafter be classified as a hazardous material, waste or substance (collectively “Hazardous Materials”), under federal, state or local laws, rules and regulations, including, without limitation, 42 U.S.C. Section 6901 et seq., 42 U.S.C. Section 9601 et seq., 42 U.S.C. Section 2601 et seq., 49 U.S.C. Section 1802 et seq. and Massachusetts General Laws, Chapter 21E and the rules and regulations promulgated under any of the foregoing, as such laws, rules and regulations may be amended from time to time (collectively “Hazardous Materials Laws”), (ii) Tenant shall immediately notify Landlord of any incident in, on or about the Premises, the Building or the Site that would require the filing of a notice under any Hazardous Materials Laws, (iii) Tenant shall comply and shall cause its employees, invitees, agents, independent contractors, contractors, assignees and subtenants to comply with each of the foregoing and (iv) Landlord shall have the right to make such inspections (including testing) as Landlord shall elect from time to time to determine that Tenant is complying with the foregoing; provided, however, that if any inspection discloses a use in violation of this Section 5.3, Tenant shall pay for the Landlord’s out of pocket costs of such inspection. Notwithstanding the foregoing, Tenant may use normal amounts and types of substances typically used for office uses provided that Tenant uses such substances in the manner in which they are normally used and in compliance with all Hazardous Materials Laws and other Legal Requirements and provided further that no odors shall emanate from the Premises which are detectable in any other portion of the Building or Site.

Landlord represents to Tenant that, to the best of Landlord’s actual knowledge as of the date of this Lease, there are no Hazardous Materials in the Buildings or on the Site which are required to be removed or otherwise abated in accordance with applicable Hazardous Materials Laws. Subject to the limitations of Section 8.4 hereof if and to the extent required to be removed or abated pursuant to the requirements of Hazardous Materials Laws as set forth in any notice from applicable governmental authority having jurisdiction, which notice is not challenged but is accepted by Landlord, Landlord shall use reasonable efforts to remove or abate as required by applicable Hazardous Materials Laws Hazardous Materials in the common areas of the Buildings or the “Base Building” (as hereinafter defined), provided that the foregoing shall not apply to (i) requirements of Hazardous Materials Laws resulting from the use of, or additions, alterations or improvements in, any tenant space in the Buildings, including the Premises (except that if the initial improvements to the Premises performed by Landlord in accordance with Section 3.1 or Section 3.2 hereof triggers compliance with Hazardous Material Laws, Landlord shall be responsible for removal or abatement in accordance with such Hazardous Materials Laws) or (ii) Hazardous Materials which are in the Building or on the Site because of the action or inaction of any tenant or occupant in the Complex, including

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Tenant, or any employee, agent or contractor thereof, or (iii) any tenant space in the Building, including the Premises, and any additions, alterations and improvements therein. In addition, Landlord shall be responsible for the initiation and performance on a regular basis of an Operations and Maintenance Plan Regarding any Hazardous Materials existing in the Building or on the Site existing prior to the execution of this Lease. For purposes of this Section, the “Base Building” shall mean the structural elements of the Building and the heating, ventilating and air conditioning, electrical and plumbing systems and equipment bringing primary service to the tenant spaces in the Buildings. Subject to the limitations of Section 8.4 hereof, Landlord agrees to indemnify and save Tenant harmless from liability, loss and damage to persons or property and from any claims, actions, proceedings and expenses in connection therewith resulting from (x) the failure of Landlord to fulfill its obligations under the preceding sentence or (y) any releases of Hazardous Materials within the Buildings or on the Site that occurred prior to the Date of this Lease; provided, however, that in no event shall the foregoing indemnity render Landlord liable for any loss or damage to Tenant’s personal property, fixtures or equipment and Landlord shall in no event be liable for indirect, consequential or punitive damages.

Not to obstruct in any manner any portion of the Building not hereby leased or any portion thereof or of the Additional Building or of the Site used by Tenant in common with others; not without prior consent of Landlord to permit the painting or placing of any signs (except for such signage as is permitted pursuant to Section 8.26 hereof), curtains, blinds, shades, awnings, aerials or flagpoles, or the like, visible from outside the Premises; and to comply with all reasonable Rules and Regulations now or hereafter made by Landlord, of which Tenant has been given notice and which are applicable to all tenants generally of the Building, for the care and use of the Building and Site and their facilities and approaches; Landlord shall not be liable to Tenant for the failure of other occupants of the Buildings to conform to such Rules and Regulations.

To keep the Premises equipped with all safety appliances required by any public authority because of any use made by Tenant other than normal office use, and to procure all licenses and permits so required because of such use and, if requested by Landlord, to do any work so required because of such use, it being understood that the foregoing provisions shall not be construed to broaden in any way Tenant’s Permitted Use.

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