Sample Business Contracts


Massachusetts-Cambridge-281 Albany Street - Massachusetts Institute of Technology and Alkermes Inc.

Lease Forms

  • Start a state-specific lease for the rental of commercial property. Specify the term and rent due, as well as whether the landlord or tenant is responsible for property taxes, insurance, and maintenance and repairs.
  • When a tenant vacates commercial property before the lease term has expired, it may be able to rent the premises to a third party. The tenant would be the sublessor and the third party would be the sublessee. Besides preparing a sublease, both parties will want to review the provisions for assignment or subletting in the original lease agreement between the landlord and the sublessor.
  • Tenants of residential property should prepare a sublease agreement if they are seeking to sublease a room or the entire apartment or house to a third party. All parties should review the original lease agreement to see if there are any restrictions on subletting or assigning the premises.
  • Triple net leases are a type of commercial leases where the tenant has to pay for property taxes, insurance, utilities, and maintenance, in addition to the monthly rent.
  • When renting an office space, tenants should understand the amount of the rent and duration of the lease. Other important terms include whether the space can be subleased, which parties are responsible for maintenance, and whether any furniture and furnishings will be provided.

                                      LEASE

                              DATED: JULY 26, 1993

                BY MASSACHUSETTS INSTITUTE OF TECHNOLOGY, LESSOR

                            TO ALKERMES, INC., LESSEE

                   281 ALBANY STREET, CAMBRIDGE MASSACHUSETTS



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                                                                          Page i
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                                TABLE OF CONTENTS
                                -----------------


1.    Parties and Premises...................................................  1

2.    Expansion..............................................................  1

3.    Lease Term; Commencement Date; Extension Options.......................  3
      3.1      Lease Term; Commencement Date.................................  3
      3.2      Extension Option..............................................  3

4.    Rent; Determination of Fair Market Rent; Preliminary
      Entry; Net Lease.......................................................  4
      4.1      Payment of Rent...............................................  4
      4.2      Determination of Fair Market Rent.............................  5
      4.3      Preliminary Entry.............................................  7
      4.4      Net Lease.....................................................  7

5.    Permitted Use..........................................................  7

6.    Taxes..................................................................  8
      6.1      Taxes.........................................................  8
      6.2      Payment of Taxes..............................................  8
      6.3      Abatement of Taxes............................................  9

7.    Utilities and Services.................................................  9

8.    Insurance.............................................................. 11
      8.1      Public Liability Insurance.................................... 11
      8.2      Casualty Insurance............................................ 11
      8.3      Certificate of Insurance...................................... 12
      8.4      Lessor's Insurance............................................ 12
      8.5      Waiver of Subrogation......................................... 12
      8.6      Waiver of Rights.............................................. 13

9.    Assignment and Subletting.............................................. 13

10.   Parking................................................................ 17

11.   Late Payment of Rent................................................... 17

12.   Lessee's Covenants..................................................... 17

13.   Construction........................................................... 26
      13.1     Work Letter................................................... 26
      13.2     Roof Load Capacity............................................ 26
      13.3     Floor Loads................................................... 27

14.   Eminent Domain and Casualty............................................ 27
      14.1     Substantial Taking............................................ 27
      14.2     Awards........................................................ 27
      14.3     Substantial Casualty.......................................... 28
      14.4     Repair and Restoration........................................ 28
      14.5     Casualty During Last 12 Months................................ 30

                                       (i)

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                                                                         Page ii
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15.   Defaults; Events of Default; Remedies.................................. 30
      15.1     Defaults; Events of Default................................... 30
      15.2     Termination................................................... 31
      15.3     Survival of Covenants......................................... 32
      15.4     Right to Relet................................................ 33
      15.5     Right to Equitable Relief..................................... 33
      15.6     Right to Self Help............................................ 33
      15.7     Further Remedies.............................................. 34

16.   Intentionally Deleted.................................................. 34

17.   Real Estate Broker..................................................... 34

18.   Notices................................................................ 34

19.   No Waivers............................................................. 35

20.   Lessor's Obligations................................................... 35
      20.1     Generally..................................................... 35
      20.2     Lessor's Maintenance.......................................... 36

21.   Ground Leases; Mortgages............................................... 36
      21.1     Rights of Ground Lessors and Mortgagees....................... 36
      21.2     Lease Subordinate............................................. 37

22.   Notice of Lease; Estoppel Certificates................................. 38

23.   Holding Over........................................................... 38

24.   Force Majeure.......................................................... 38

25.   Signs.................................................................. 38

26.   Entire Agreement....................................................... 39

27.   Applicable Law, Severability and Construction.......................... 39

28.   Successors and Assigns................................................. 40

29.   Security Deposit....................................................... 40

30.   Authority.............................................................. 41


EXHIBIT A:  PLAN OF THE PREMISES
EXHIBIT B:  PLAN OF THE LAND
EXHIBIT C:  WORK LETTER
EXHIBIT D:  COMMENCEMENT DATE AGREEMENT


                                      (ii)

<PAGE>   4

                                      LEASE



Dated: July 26, 1993


1.   PARTIES AND PREMISES. MASSACHUSETTS INSTITUTE OF TECHNOLOGY ("Lessor")
     hereby LEASES unto ALKERMES, INC. ("Lessee"), the following premises:

          25,500 square feet of rentable area on the first floor (shown as the
          hatched area on EXHIBIT A attached hereto) (the "Premises"), of the
          building known as and numbered 281 Albany Street, Cambridge,
          Massachusetts (the "Building"), which Building contains 32,000
          rentable square feet and is located on the parcel of land (the "Land")
          identified as Assessors Plan #67, Lots 32 and 33 as shown on the plan
          attached hereto as EXHIBIT B attached hereto,

     together with the benefit of, and subject to (as the case may be) all
     rights, easements, covenants, conditions, encumbrances, encroachments and
     restrictions of record as of the date of this Lease. Lessor shall have the
     right, without the necessity of obtaining Lessee's consent thereto or
     joinder therein, to grant, permit, or enter into during the term of this
     Lease such additional rights, easements, covenants, conditions,
     encumbrances, encroachments and restrictions with respect to the Land as
     Lessor may deem appropriate, PROVIDED THAT no such rights, easements,
     covenants, conditions, encumbrances, encroachments or restrictions shall
     materially affect Lessee's use of the Premises for the Permitted Uses
     hereunder.

     Lessor hereby grants to Lessee, as appurtenant to the Premises, the right
     in common with Lessor and others to whom Lessor may have previously or may
     hereafter grant rights, to enter into the basement of the Building for the
     purpose of (i) installing an acid neutralization tank as part of "Lessee's
     Work" (as defined in the Work Letter) and maintaining, repairing, replacing
     and removing the same, and (ii) installing as part of Lessee's Work
     additional equipment intended to service the Premises and maintaining,
     repairing, replacing and removing the same, PROVIDED that such rights shall
     be exercised so as not to interfere with any Building system serving the
     second floor of the Building (whether solely or together with the first
     floor thereof).

2.   EXPANSION. Subject to the provisions of this Section, Lessee shall have the
     option (the "Expansion Option") to subject the second floor of the
     Building, containing

<PAGE>   5

     approximately 6,500 rentable square feet (the "Expansion Premises"), to all
     of the terms of this Lease (except for Basic Rent, which shall be
     calculated in the manner provided below).

     Lessee acknowledges that the Expansion Premises are currently occupied by
     another lessee ("Current Occupant") whose lease expires on or about
     December 31, 1994. Provided that both (i) an "Event of Default" (as
     hereinafter defined) has not occurred and is not then continuing as of the
     day on which Lessee purports to exercise the option herein granted, and
     (ii) as of such date the Lessee named herein is actually occupying at least
     twenty-five (25%) percent of the Premises, Lessee shall have the right to
     lease the Expansion Premises for a term commencing on the date on which
     Lessor delivers possession thereof to Lessee, and ending on the last day of
     the "Lease Term" (as hereinafter defined), by giving written notice of
     exercise to Lessor not later than July 1, 1994.

     If Lessee exercises its right under this Section to lease the Expansion
     Premises, then such space shall become subject to all of the terms of this
     Lease EXCEPT that "Basic Rent" for such space shall be in an amount equal
     to the "Fair Market Value" thereof (as these terms are hereinafter
     defined). In the event that Lessee, for any reason whatsoever, fails or
     refuses to give such notice by July 1, 1994, Lessee shall be deemed to have
     waived its rights under this Section with respect to the Expansion Premises
     for the remainder of the Lease Term.

     If Lessee exercises the Expansion Option, then Lessor shall deliver the
     Expansion Premises vacant and broom clean but otherwise in its "as is"
     condition. Lessor shall use due diligence to deliver the Expansion Premises
     to Lessee as soon as practicable, Effective upon the date on which Lessor
     delivers to Lessee possession of the Expansion Premises, such space shall
     be deemed to be part of the Premises for all purposes of this Lease, Lessee
     shall commence paying Basic Rent and "Additional Rent" on account thereof,
     and "Lessee's Share" (as these terms are hereinafter defined) shall be
     appropriately modified.

     Notwithstanding the foregoing provisions of this Section 2.0, in the event
     that Lessor learns that the Expansion Premises will become vacant prior to
     January 1, 1995, Lessor shall so notify Lessee. Provided that both (i) an
     "Event of Default" (as hereinafter defined) has not occurred and is not
     then continuing as of the day on which Lessee purports to exercise the
     right herein granted, and (ii) as of such date the Lessee named herein is
     actually occupying at least

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<PAGE>   6

     twenty-five (25%) percent of the Premises, Lessee shall have the right to
     accelerate the exercise of the Expansion Option by giving written notice of
     exercise to Lessor within twenty (20) days of receipt of Lessor's notice.
     If Lessee exercises its right to accelerate the Expansion Option, then such
     space shall become subject to all of the terms of this Lease as provided
     hereinabove in this Section as of the date on which Lessor delivers
     possession thereof to Lessee. If Lessee declines to accelerate the exercise
     of the Expansion Option, then Lessee shall be deemed to have waived all
     rights to exercise the Expansion Option at any time under this Section 2.0.

3.   Lease Term; Commencement Date; Extension Options.
     ------------------------------------------------

     3.1  LEASE TERM; COMMENCEMENT DATE. The initial term of this Lease (the
          "Initial Lease Term") shall commence on the date (the "Commencement
          Date") which is the first to occur of (i) the first day on which
          Lessee occupies any portion of the Premises for the conduct of its
          business operations, or (ii) August 15, 1993, and shall expire, unless
          sooner terminated as hereinafter provided, on the day immediately
          preceding the fifth (5th) anniversary of the Commencement Date. As
          used in this Lease, "Lease Term" means the Initial Lease Term, as the
          same may be extended pursuant to Section 3.2 below. On request of
          either party, Lessor and Lessee shall execute and deliver a
          Commencement Date Agreement in the form attached hereto as EXHIBIT D
          setting forth the Commencement Date.

     3.2  EXTENSION OPTION. Provided that both (i) an "Event of Default" (as
          hereinafter defined) has not occurred and is not then continuing as of
          either the day on which Lessee purports to give Lessor a "Lessee's
          Notice of Exercise" (as hereinafter defined) or on the first day of
          the "Extension Term" (as hereinafter defined), and (ii) the Lessee
          named herein is actually occupying at least twenty-five (25%) percent
          of the Premises as of each of said dates, Lessee shall have one (1)
          option ("Extension Option"), to extend the Lease Term of this Lease
          for a period of five (5) years ("Extension Term"), unless sooner
          terminated as hereinafter provided, subject to all the terms of this
          Lease except for the change in Basic Rent as provided in Section 4.2
          of this Lease.

          Lessee shall exercise the Extension Option, if at all, by giving
          written notice of Lessee's exercise thereof ("Lessee's Notice of
          Exercise") to Lessor not earlier than fifteen (18) months prior to,
          nor later than nine

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<PAGE>   7
          (9) months prior to, the last day of the Initial Lease Term as the
          case may be. If Lessee fails to give such Lessee's Notice of Exercise
          within such time, Lessee shall be deemed to have waived the right to
          exercise the Extension Option. The dates described in this paragraph
          are summarized in the following table:

                   Notification Dates                    Extension Term
          Not Before:                Not After:        Begins:       Ends:
          -----------                ----------        -------       -----

          5/15/1997                  11/14/1997       8/15/1998    8/14/2003

          Basic Rent shall be due and payable in the manner hereinafter provided
          in Section 4.1 below.

4.   Rent; Determination of Fair Market Rent; Preliminary Entry; Net Lease
     ---------------------------------------------------------------------

     4.1  PAYMENT OF RENT. From and after the Commencement Date, Lessee shall
          pay Lessor, without offset or deduction and without previous demand
          therefor, as items constituting rent (collectively, "Rent"):

          (a)  Basic rent ("Basic Rent") at the following rates:

               (i)  for each of the first five (5) Lease Years, $4.00 per
                    rentable square foot of the Premises ($102,000.00 per year;
                    $8,500.00 per month); and

               (ii) for each Lease Year in the Extension Term, $6.00 per
                    rentable square foot of the Premises $153,000.00 per year;
                    $12,750.00 per month).

               Basic Rent as set forth above does not include, and is in
               addition to, any Basic Rent which may become due and payable with
               respect to the Expansion Premises, calculated in the manner
               provided in Section 4.2 below. Basic Rent shall be due and
               payable in equal monthly installments, in advance, commencing on
               the Commencement Date, and continuing thereafter on the first day
               of each calendar month or portion thereof during the Lease Term.
               Basic Rent shall be PRO-RATED for partial months occurring at the
               beginning or the end of the Lease Term; and

          (b)  All other costs, charges, or expenses which Lessee in this Lease
               agrees to pay, or which Lessor pays or incurs as the result of a
               default by Lessee

                                        4





<PAGE>   8

               hereunder, including any penalty or interest which may be added
               for nonpayment or late payment thereof as provided in this Lease
               (collectively, "Additional Rent").

          As used in this Lease, "Lease Year" means the twelve (12) month period
          commencing on the Commencement Date, and each successive twelve (12)
          month period included in the Lease Term commencing on an anniversary
          of that day, but if the expiration of the Lease Term or the earlier
          termination of the Lease does not coincide with the termination of
          such a twelve (12) month period, the term "Lease Year" shall mean the
          portion of such twelve (12) month period before such expiration or
          termination.

          All payments shall be made to Lessor or such agent, and at such place,
          as Lessor shall, from time to time, in writing designate, the
          following being now so designated:

                              Meredith & Grew, Inc.
                               160 Federal Street
                              Boston, MA 02110-1701
                            Attention: Kristin Blount

     4.2  DETERMINATION OF FAIR MARKET RENT. As used in this Lease, "Fair Market
          Rent" means the fair market rent for the portion of the Building with
          respect to which "Fair Market Rent" is being determined in its "as is"
          condition, excluding the value of the improvements completed by Lessee
          therein but including the value of improvements made by Lessor, as of
          the day with respect to which such determination is being made. Fair
          Market Rent shall be based upon the rents generally in effect for
          similar premises for first-class research and development/
          manufacturing/ office uses in similar buildings in the Cambridge,
          Massachusetts area in which the Premises is located, adjusted to a
          "net" lease basis, taking into account all facts and circumstances
          customarily taken into account by prudent and commercially reasonable
          lessors and lessees (including, without limitation, concessions
          typically offered in such market to renewing tenants).

          Within twenty (20) days after Lessor receives Lessee's notice of
          exercise of the Expansion Option), Lessor shall provide to Lessee
          Lessor's good faith determination of the Fair Market Rent of the
          Expansion Premises. If Lessor and Lessee are unable to agree on such
          Fair Market Rent within twenty (20) days

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<PAGE>   9

          thereafter, then Lessor and Lessee shall, not later than sixty (60)
          days after Lessor receives Lessee's notice, each retain a real estate
          appraiser with at least ten (10) years' continuous experience in the
          business of appraising or marketing commercial real estate in the
          Cambridge, Massachusetts vicinity, who shall, within thirty (30) days
          of his or her selection, prepare a written report summarizing his or
          her conclusion as to Fair Market Rent. Lessor and Lessee shall
          simultaneously exchange such reports; PROVIDED, HOWEVER, that if one
          party has not obtained such a report within one hundred (100) days
          after Lessor receives Lessee's notice of exercise, then the
          determination set forth in the other party's report shall be final and
          binding upon the parties. If both parties receive reports within such
          time and the lesser of the two determinations is within ten (10%)
          percent of the higher determination, then the average of these
          determinations shall be deemed to be Fair Market Rent. If these
          determinations differ by more than ten (10%) percent, then Lessor and
          Lessee shall mutually select a person with the qualifications stated
          above (the "Final Appraiser") to resolve the dispute as to Fair Market
          Rent. If Lessor and Lessee cannot agree upon the designation of the
          Final Appraiser within thirty (30) days of the exchange of the first
          appraisal reports, either party may apply to the American Arbitration
          Association, the Greater Boston Real Estate Board, or any successor
          thereto for the designation of a Final Appraiser. Within ten (10) days
          of the selection of the Final Appraiser, Lessor and Lessee shall each
          submit to the Final Appraiser a copy of their respective appraiser's
          determination of Fair Market Rent. The Final Appraiser shall not
          perform his own appraisal but rather shall, within thirty (30) days
          after such submissions, select the submission which is closest to the
          determination of Fair Market Rent which the Final Appraiser would have
          made acting alone. The Final Appraiser shall give notice of his
          selection to Lessor and Lessee and such decision shall be final and
          binding upon Lessor and Lessee. Each party shall pay the fees and
          expenses of its appraiser and counsel, if any, in connection with any
          proceeding under this paragraph, and the parties shall each pay
          one-half of the fees and expenses of the Final Appraiser.

          In the event that Fair Market Rent has not been finally determined in
          the manner provided above with respect to the Expansion Premises as of
          the day on which Basic Rent commences to be due and payable on account
          of such space, then Basic Rent shall be due and payable at the

                                        6

<PAGE>   10

          rate provided by the Lessor, and Lessor and Lessee shall make such
          adjustment (and payment or credit as necessary) within thirty (30)
          days after Fair Market Rent is finally determined.

     4.3  PRELIMINARY ENTRY. Provided that an "Event of Default" (as hereinafter
          defined) has not occurred hereunder, Lessee shall have the right to
          enter upon the Premises prior to the Commencement Date to perform
          "Lessee's Work" (as defined in the Work Letter). Such entry shall be
          subject to the full and punctual performance by Lessee of all of
          Lessee's covenants hereunder with respect to the Premises from and
          after the date upon which Lessee first makes such entry except that
          Lessee shall not be required to pay any Rent. If during this time
          Lessee takes occupancy of any portion of the Premises and conducts it
          business operations therein, then the first date of such occupancy
          shall be deemed to be the Commencement Date as provided in Section 3.2
          above. The period of such preliminary entry for the purposes of
          performing Lessee's Work shall in all events end no later than the
          Commencement Date.

     4.4  NET LEASE. It is the intention of the Lessor and the Lessee that this
          is a "net" lease and that the Rent herein specified shall be paid to
          the Lessor in each month during the Lease Term, and that all costs,
          expenses, and obligations of every kind relating to the Premises
          whether usual or unusual, ordinary or extraordinary, foreseen or
          unforeseen, which may arise or become due during the Lease Term, shall
          be paid by Lessee except as otherwise specifically provided herein.

5.   PERMITTED USE. The Premises shall be occupied by Lessee and used for the
     following purposes (the "Permitted Uses") only and for no other:

          office, research and development, laboratory, manufacturing and
          distribution office uses, and ancillary uses thereto; in each case to
          the extent permitted as a matter of right under the Zoning Ordinance
          of the City of Cambridge, as amended from time to time.

     Notwithstanding anything herein contained to the contrary, provided that
     Lessee is not in default hereunder beyond the cure period provided in this
     Lease, Lessee may discontinue its occupancy of the Premises or any part
     thereof for any period of time during the Lease Term, provided that during
     any such period, Lessee shall be bound by all of the

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<PAGE>   11

     obligations of Lessee under this Lease, including without limitation, the
     obligation to pay Rent. If Lessee discontinues actual occupancy of the
     entire portion of the Premises not then subleased pursuant to this Lease
     (if any), and such discontinuance lasts for more than six (6) consecutive
     months, Lessor shall have the right, in its sole discretion, to terminate
     this Lease as to the entire portion of the Premises not so subleased (if
     any) upon thirty (30) days' written notice to Lessee and payment to Lessee
     of the "Termination Payment" (as defined in the next sentence), in which
     event the Lease shall terminate as to that portion of the Premises as if
     the date specified in such termination notice was the last day of the Lease
     Term. As used in this Lease, the term "Termination Payment" shall mean the
     unamortized portion (based on straight-line amortization over a 5-year
     period commencing on the Commencement Date) of the cost of "Lessee's Work"
     as of the effective date of such termination notice. Upon request by Lessor
     during any period that Lessee has ceased to occupy the Premises as
     aforesaid, Lessee shall provide to Lessor a reasonably detailed breakdown
     of the cost of Lessee's Work paid or incurred by Lessee to enable Lessor to
     calculate the amount of the Termination Payment.

6.   Taxes.
     -----
 
     6.1  TAXES. As used in this Lease, "Taxes" means all taxes, special or
          general assessments, water rents, rates and charges, sewer rents and
          other impositions and charges imposed by governmental authorities of
          every kind and nature whatsoever, extraordinary as well as ordinary
          and each and every installment thereof which shall or may during the
          Lease Term be charged, levied, laid, assessed, imposed, become due and
          payable or become liens upon or for or with respect to the Premises,
          the Building, the Land or any part thereof, or appurtenances or
          equipment owned by Lessor thereon or therein or any part thereof or on
          this Lease, and any tax based on a percentage fraction or capitalized
          value of the Rent (whether in lieu of or in addition to the taxes
          hereinbefore described). Taxes shall not include inheritance, estate,
          excise, succession, transfer, gift, franchise, income, gross receipt,
          or profit taxes except to the extent such are in lieu of or in
          substitution for Taxes as now imposed on the Building or the Land.

     6.2  PAYMENT OF TAXES. Lessee shall pay to Lessor, as Additional Rent, (i)
          "Lessee's Share" (which term shall mean shall be seventy-nine and
          sixty-eight hundredths percent (79.68%)) of Taxes, and (ii) Lessee's
          pro-rata

                                        8

<PAGE>   12

          share of Taxes with respect to each of the "Off-Site Lots" (as defined
          in Section 10 below) in which any of the parking spaces leased
          hereunder by Lessee are located. Lessee shall make such payment in the
          manner provided in Section 7 below. Lessee's obligations under this
          Section 6 shall be pro-rated for partial tax years at the beginning or
          end of the Lease Term.

     6.3  ABATEMENT OF TAXES. Lessor may at any time and from time to time make
          application to the appropriate governmental authority for an abatement
          of Taxes with respect to the Land and/or the Building. If Lessor files
          such an abatement application, Lessor shall pursue the same at its
          sole cost and expense (subject to potential reimbursement as provided
          below in this Section). If Lessor's application is successful and
          Lessee has made any payment in respect of Taxes pursuant to Section
          6.2 above for the period with respect to which the abatement was
          granted, Lessor shall (a) deduct from the amount of the abatement all
          expenses reasonably incurred by it in connection with the application,
          (b) pay to Lessee Lessee's Share (adjusted for any period for which
          Lessee had made a partial payment) of the abatement, with interest, if
          any, paid by the governmental authority on such abatement, and (c)
          retain the balance, if any.

          Lessee shall have the right to file an application for abatement of
          Taxes with respect to the Land and/or the Building only if (i) Lessee
          first inquires in writing to Lessor whether Lessor intends to file
          such an abatement application, and either (ii) (a) Lessor responds in
          writing that Lessor does not intend to file such an application or,
          (b) Lessee does not receive a response from Lessor within seven (7)
          business days after the day such request is made. If Lessee files such
          an abatement application, Lessee shall pursue the same at its sole
          cost and expense (subject to potential reimbursement as provided below
          in this Section) and shall keep Lessor informed of the status thereof.
          If Lessee's application is successful, Lessee shall (a) deduct from
          the amount of the abatement all expenses reasonably incurred by it in
          connection with the application, (b) retain Lessee's Share (adjusted
          for any period for which Lessee had made a partial payment) of the
          abatement, with interest, if any, paid by the governmental authority
          on such abatement, and (c) pay over the balance, if any, to Lessor.

7.   UTILITIES AND SERVICES. Lessee shall make its own arrangements for the
     provision of all utilities and

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<PAGE>   13

     services, including, without limitation, electricity, gas, heating fuels,
     trash removal, telephone service, and all maintenance and service
     agreements which are required for the Permitted Uses of the Premises, and
     shall pay when due all charges therefor directly to the company which
     provides such utility or service.

     The only services which Lessor shall provide to the Premises, the Building
     or the Land during the Lease Term (collectively, "Lessor's Services") shall
     be: (i) common area maintenance, (ii) extermination, (iii) alarm services,
     (iv) water and sewer, (v) snowplowing, paving, striping and general
     maintenance of the parking lots in which are located parking spaces leased
     by Lessee pursuant to Section 10.0 below, and (vi) such other services (if
     any) as Lessor may reasonably determine from time to time are necessary for
     the maintenance and operation of the Premises and which either are not
     provided by Lessee or cannot as a matter of law be provided to the Premises
     in the name of Lessee. It is agreed that property manager's fees shall not
     exceed seven (7%) percent of gross rental revenue of the Building. It is
     further agreed that the work performed (and the costs incurred) by Lessor
     in initially placing in serviceable condition the parking lot(s) in which
     the parking spaces are leased by Lessee pursuant to Section 10.0 below
     shall not be included in "Lessor's Services" or charged to Lessee.

     Within a reasonable time after the execution of this Lease, and thereafter
     within a reasonable time after the end of each of Lessor's fiscal years (or
     portion thereof) occurring during the Lease Term, Lessor shall deliver to
     Lessee (i) a statement of (a) the cost of Lessor's Services and (b) Taxes
     for the fiscal year just ended (the "Statement"), and (ii) a projection of
     (a) the cost of Lessor's Services and (b) Taxes for the then-current fiscal
     year. Commencing on the Commencement Date, and continuing on the first day
     of each calendar month thereafter, Lessee shall pay to Lessor, as
     Additional Rent, 1/12th of the total annualized amount of Lessee's Share of
     (a) the cost of Lessor's Services and (b) Taxes. Upon delivery to Lessee of
     the Statement for the preceding fiscal year, Lessor shall adjust Lessee's
     account accordingly. If the total amount paid by Lessee on account of the
     preceding fiscal year is less than the amount due hereunder, Lessee shall
     pay the balance due within thirty (30) days after delivery by Lessor of
     such Statement. If the total amount paid by Lessee on account of the
     preceding fiscal year exceeds the amount due hereunder, such excess shall
     be credited by Lessor against the monthly installment of Additional Rent
     next falling due or refunded to Lessee upon the expiration or termination
     of this Lease (unless such expiration or termination is the result of an
     Event of

                                       10

<PAGE>   14

     Default). Lessor's current fiscal year is July 1 - June 30, but Lessor
     reserves the right to change the fiscal year at any time during the Lease
     Term.

     Lessor shall not be held liable to anyone for the cessation of any of
     Lessor's Services due to any accident, to the making of repairs,
     alterations or improvements, or to the occurrence of an event of "Force
     Majeure" (as hereinafter defined). Lessor shall have no obligation to
     provide any services to the Premises, the Building, the Land or the Parking
     Area other than those expressly identified above in this Section. In no
     event shall Lessor be responsible for charges for any utilities or services
     consumed by Lessee or provided to Lessee at the Premises.

8.   Insurance
     ---------
 
     8.1  PUBLIC LIABILITY INSURANCE. Lessee shall take out and maintain in
          force throughout the Lease Term comprehensive public liability
          insurance naming Lessor, Lessee, and persons claiming under them, if
          any, as additional insureds against all claims and demands for any
          injury to persons or property which may be claimed to have occurred in
          the Premises, the Building, on the Land or on ways adjoining the Land,
          in an amount which at the beginning of the Lease Term shall not be
          less than $1,000,000 for injury or death of one person, $3,000,000 for
          injury or death of more than one person in a single accident and
          $500,000 for property damage, or such higher amounts as Lessor shall
          reasonably determine are required by reason of Lessee's use of the
          Premises, and which thereafter, if Lessor requires, shall be in such
          higher amounts as are then consistent with sound commercial practice
          in Cambridge, Massachusetts.

     8.2  CASUALTY INSURANCE. Lessee shall take out and maintain throughout the
          Lease Term a policy of fire, vandalism, malicious mischief, extended
          coverage and so-called all risk coverage insurance insuring all of
          "Lessee's Work", "Lessee's Property" and all "Alterations" (as these
          terms are hereinafter defined) for the benefit of Lessor and Lessee,
          as their respective interests may appear, in an amount equal to the
          replacement value thereof. Lessor shall be named as a certificate
          holder on such policy. Lessor shall, at Lessee's cost and expense,
          cooperate fully with Lessee and execute any and all consents and other
          instruments and take all other actions necessary to obtain the largest
          possible recovery. Lessor shall not carry any insurance concurrent in
          coverage and contributing in the event of

                                       11
<PAGE>   15

          loss with any insurance required to be furnished by Lessee hereunder
          if the effect of such separate insurance would be to reduce the
          protection or the payment to be made under Lessee's insurance.

          All insurance policies maintained pursuant to this Section 8.2 shall
          include insurance against payment of rents in an amount sufficient to
          pay all Rent which would otherwise be required to be paid under this
          Lease during the period of restoration.

     8.3  CERTIFICATE OF INSURANCE. All insurance required to be maintained by
          Lessee hereunder: shall be placed with insurers reasonably
          satisfactory to Lessor and authorized to do business in Massachusetts;
          shall provide that it may not be canceled without at least thirty (30)
          days prior written notice to each additional insured or certificate
          holder named therein; and shall provide that it may not be amended
          without at least ten (10) days prior written notice to each such
          person. Lessee shall furnish to Lessor certificates of insurance for
          all insurance required to be maintained by Lessee under this Lease,
          together with evidence reasonably satisfactory to Lessor of the
          payment of all premiums for such policies. Lessee, at Lessor's
          request, shall also deliver such certificates and evidence of payment
          to the holder of any mortgage affecting the Premises, the Building,
          the Land or any portion thereof.

     8.4  LESSOR'S INSURANCE. Lessor shall take out and maintain in force
          throughout the Lease Term, in a company or companies authorized to do
          business in Massachusetts, casualty insurance on the Building
          (excluding "Lessee's Work", "Lessee's Property" and all "Alterations"
          (as hereinafter defined)) in an amount equal to the full replacement
          value of the Building (exclusive of foundations and those items set
          forth in the preceding parenthetical in this sentence), covering all
          risks of direct physical loss or damage and so-called "extended
          coverage" risks. This insurance may be maintained in the form of a
          blanket policy covering the Building as well as other properties owned
          by Lessor. Notwithstanding the foregoing provisions of this Section
          8.4, Lessor shall have the right, at any time during the Lease Term,
          to self-insure all or any portion of the coverages required by this
          Section.

     8.5  WAIVER OF SUBROGATION. To the extent to which a waiver of subrogation
          clause is available, Lessor and Lessee shall obtain a provision in all
          insurance policies

                                       12

<PAGE>   16

          carried by such party covering the Premises, including but not limited
          to contents, fire and casualty insurance, expressly waiving any right
          on the part of the insurer against the other party. If extra cost is
          chargeable for such provision, then the party requesting such waiver
          shall be responsible for the payment of such extra cost.
          Notwithstanding the foregoing, with respect to such portion of the
          Lease Term during which Lessor elects to self-insure under Section 8.4
          above, then for purposes of this Section 8.5, Lessor shall be deemed
          to have maintained fire and all-risk coverage in an amount equal to
          one hundred (100%) percent of the insurable value of the Building
          (subject to the exceptions and exclusions set forth in Section 8.4
          above) with a waiver of subrogation clause contained therein.

     8.6  WAIVER OF RIGHTS. All claims, causes of action and rights of recovery
          for any damage to or destruction of persons, property or business
          which shall occur on or about the Premises, the Building or the Land,
          which result from any of the perils insured under any and all policies
          of insurance maintained by Lessor or Lessee, are waived by each party
          as against the other party, and the officers, directors, employees,
          contractors, servants and agents thereof, regardless of cause,
          including the negligence of the other party and its respective
          officers, directors, employees, contractors, servants and agents, but
          only to the extent of recovery, if any, under such policy or policies
          of insurance; PROVIDED, HOWEVER, that (i) this waiver shall be null
          and void to the extent that any such insurance shall be invalidated by
          reason of this waiver, and (ii) with respect to such portion of the
          Lease Term during which Lessor elects to self-insure under Section 8.4
          above, then for purposes of this Section 8.6, Lessor shall be deemed
          to have maintained fire and all-risk coverage in an amount equal to
          one hundred (100%) percent of the insurable value of the Building
          (subject to the exceptions and exclusions set forth in Section 8.4
          above).

9.   Assignment and Subletting.
     -------------------------
 
     (a)  Lessee shall not mortgage, pledge, hypothecate, or assign this Lease
          or sublease the Premises or any portion thereof (the term "sublease"
          shall be deemed to include any arrangement pursuant to which a third
          party is permitted by Lessee to occupy all or any portion of the
          Premises), without obtaining, on each occasion, the prior written
          consent of Lessor, which consent (in the

                                       13

<PAGE>   17

          case of a proposed assignment or sublease) shall not be unreasonably
          withheld, delayed or conditioned. Notwithstanding anything to the
          contrary contained in this Lease, Lessee shall not have more than
          three (3) subleases in effect at any one time (exclusive of subleases
          entered into pursuant to paragraph 9.0(i) below), nor shall Lessee
          have the right to assign this Lease or to sublet any portion of the
          Premises during the first twelve (12) months after the Commencement
          Date.

     (b)  If Lessee wishes to assign this Lease or sublease all or any portion
          of the Premises, Lessee shall so notify Lessor in writing and request
          Lessor's consent thereto. Such notice shall include (i) the name of
          the proposed assignee or sublessee, (ii) a general description of the
          types of business conducted by the proposed assignee or sublessee and
          a reasonably detailed description of the business operations proposed
          to be conducted in the Premises by such person or entity, (iii) such
          financial information concerning the proposed assignee or sublessee as
          Lessor may reasonably require, and (iv) all terms and provisions upon
          which such assignment or sublease is proposed to be made, including a
          copy of the assignment or sublease agreement which Lessee proposes to
          execute. Lessor shall have twenty (20) days from the day on which it
          receives Lessee's notice and such required information to give notice
          to Lessee that either (i) Lessor consents to such assignment or
          sublease, or (ii) Lessor withholds its consent to such assignment or
          sublease.

     (c)  If Lessor consents to an assignment or sublease: (i) Lessee shall
          promptly deliver to Lessor a fully executed copy of said assignment or
          sublease; (ii) Lessee shall remain primarily liable to Lessor
          hereunder (which liability shall be joint and several with the
          assignee or sublessee); and (iii) if the aggregate rent and other
          amounts payable to Lessee under or in connection with such assignment
          or sublease, after deduction of the costs reasonably incurred by
          Lessee in entering into such assignment or sublease (including,
          without limitation, reasonable attorneys' fees and expenses, brokerage
          commissions, and alteration costs amortized on a straight-line basis
          over the term of such sublease), exceeds the Rent payable hereunder,
          Lessee shall pay to Lessor immediately upon receipt thereof by Lessee,
          as Additional Rent, (i) during the Initial Term, twenty-five (25%)
          percent of such excess, and (ii) during the Extension Term, fifty
          (50%) percent of such excess.

                                       14
<PAGE>   18

     (d)  If Lessor withholds its consent to such assignment or sublease, Lessee
          shall not enter into the proposed assignment or sublease with such
          person or entity.

     (e)  Regardless of whether Lessor grants such consent, Lessee shall
          reimburse Lessor on demand, as Additional Rent, for all out of pocket
          costs and expenses (including, without limitation, attorneys' fees)
          reasonably incurred by Lessor in responding to a request for such
          consent.

     (f)  Lessee shall not be entitled to enter into any assignment or sublease,
          or to request Lessor's consent thereto, during the continuance of an
          Event of Default hereunder by Lessee.

     (g)  Any assignment or sublease entered into pursuant to this Section 9.0
          shall be subject to all of the terms and provisions of this Lease,
          including without limitation this Section 9.0. If Lessee enters into
          any such assignment or sublease, Lessor may, at any time and from time
          to time after the occurrence of a default hereunder, collect rent from
          such assignee or sublessee, and apply the net amount collected against
          Lessee's obligations hereunder, but no such assignment or sublease or
          collection shall be deemed an acceptance by Lessee of such assignee or
          sublessee as a lessee hereunder or as a release of the original named
          Lessee hereunder.

     (h)  Notwithstanding anything contained in this Lease, Lessee shall not
          enter into any assignment or sublease with any person or entity if the
          identity of the assignee or sublessee is inconsistent with the
          investment policies of Lessor as set forth in writing by the Executive
          Committee of Lessor prior to its receipt of Lessee's notice of such
          proposed assignment or sublease, and any such transaction shall be
          void AB INITIO. From time to time during the Term, Lessee may request
          in writing that Lessor deliver to it copies of all investment policies
          set forth in writing by the Executive Committee of Lessor since the
          last request made by Lessee which are relevant to the Premises or to
          this Lease, and Lessor shall provide the same within a reasonable time
          after receiving such request. Lessee shall maintain the
          confidentiality of all investment policies provided by Lessor pursuant
          to this Section, and shall not disclose the contents thereof or
          distribute copies thereof to any persons whatsoever

                                       15

<PAGE>   19

          (other than Lessee's counsel) without the prior written consent of
          Lessor.

     (i)  In the event that Lessee desires to assign this Lease or to sublease
          the Premises (or any portion thereof) to any corporation, partnership,
          association or other business organization directly or indirectly
          controlling or controlled by Lessee or under common control with
          Lessee, or to any successor by merger, consolidation or purchase of
          all or substantially all of the assets of Lessee, Lessee shall give at
          least twenty (20) days' prior written notice thereof to Lessor (unless
          Lessee is prohibited by applicable laws, codes, rules or regulations,
          or by the terms of the operative merger agreement or purchase and sale
          agreement from providing notice to Lessor at such time, in which event
          such notice shall be provided to Lessor as soon as Lessee is no longer
          subject to such prohibition). No consent of Lessor shall be required
          for any such assignment or sublease EXCEPT that Lessor shall have the
          right to withhold its consent if the identity of the assignee or
          sublessee is inconsistent with the investment policies identified in
          the foregoing paragraph (h) of this Section. Any assignee or sublessee
          which claims an interest in this Lease pursuant to a transfer of the
          type described in this paragraph (i) shall be bound by all of the
          terms and conditions of this Lease including, without limitation,
          those of the foregoing paragraph (h) of this Section, and if the
          identity of such assignee or successor is inconsistent with such
          investment policies, Lessor shall have the right to terminate this
          Lease and to exercise against such assignee or sublessee the remedies
          available to Lessor under this Lease, at law or in equity for a breach
          of the provisions hereof by Lessee. For the purpose of this Lease, the
          sale of Lessee's capital stock through any public exchange shall not
          be deemed an assignment or sublease of the Lease or of the Premises.

     (j)  Notwithstanding anything contained in this Lease, Lessee shall not,
          either voluntarily or by operation of law, make any transfer of this
          Lease or the Premises (or any portion thereof) which results in Lessee
          (or anyone claiming by, through or under Lessee) collecting in
          connection with the Premises any rental or other charge based on the
          net income or on the profits of any person so as to render any part of
          the Rent due hereunder "unrelated business taxable income" of Lessor
          as described in Section 512 of the Internal Revenue

                                       16

<PAGE>   20

          Code of 1986, as amended, and any such transfer shall be void AB
          INITIO.

10.  PARKING. During the Initial Term, Lessee shall have the right, to use a
     total of thirty-eight (38) parking spaces, subject to City of Cambridge
     parking and zoning ordinances. These spaces may be located in one or more
     parking lots located within 1,000 feet of the Land (collectively, the
     "Off-Site Lots"). Such parking spaces shall be designated for use by Lessee
     (but Lessor shall not be responsible for policing the use thereof). It is
     agreed that initially the off-site parking spaces will be located on
     Lessor's property at 252 Albany Street, but Lessor shall have the right to
     relocate such spaces to other Off-Site Lots within 1,000 feet of the Land
     from time to time during the Lease Term on thirty (30) days' prior written
     notice to Lessee.

     Lessee shall pay on account of such parking spaces, as Additional Rent, on
     the same day and in the same manner in which payments are to be made
     pursuant to Section 6.2 above, a percentage share of the Taxes assessed
     upon each of the Off-Site Lots in which any of the leased parking spaces
     are located, such percentage to be determined by dividing the number of
     parking spaces leased by Lessee pursuant to this Section in each of such
     Off-Site Lots as of the first day of the municipal fiscal year by the total
     number of parking spaces contained in each if such Off-Site Lots.

     During the Extension Term, Lessee shall pay, as Additional Rent, on the
     same day on which Basic Rent is due and payable hereunder, rent on account
     of each parking space leased at the then Fair Market Rent thereof, which
     amount may be adjusted by Lessor from year to year.

11.  LATE PAYMENT OF RENT. Lessee agrees that in the event that any payment of
     Basic Rent or Additional Rent shall remain unpaid at the close of business
     on the tenth business day after the same is due and payable hereunder,
     there shall become due to Lessor from Lessee, as Additional Rent and as
     compensation for Lessor's extra administrative costs in investigating the
     circumstances of late Rent, a late charge of two percent (2%) of the amount
     overdue. The assessment or collection of such a charge shall not be deemed
     to be a waiver by Lessor of any default by Lessee arising out of such
     failure to pay Rent when due.

12.  LESSEE'S COVENANTS. Lessee acknowledges that the Building is in good and
     satisfactory order, repair and condition, and covenants, at its sole cost
     and expense, during the Lease Term and such further time as Lessee holds
     any part of the Premises:

                                       17

<PAGE>   21

     (a)  to pay when due the Basic Rent and all Additional Rent, and all
          charges for utilities and services supplied to the Premises pursuant
          to agreements between Lessee and the appropriate utility company or
          provider of such services;

     (b)  to keep the Premises, including, without limitation, the Building
          systems (such as plumbing, heating, ventilation and air conditioning,
          and electrical) located within or serving the Premises and window
          glass and the non-structural portions of the roof (e.g., roof
          membrane) (but EXCLUDING the exterior skin of the Building, the
          structural components of the Building and the roof, and the Parking
          Area), in as good order, repair and condition as the same are in as of
          the date of this Lease or are hereafter put pursuant to the Work
          Letter, excepting only damage by fire or other casualty or taking
          which Lessee is not otherwise required by the terms of this Lease to
          repair or restore, reasonable wear and tear, and damage caused by
          other tenants of the Building;

     (c)  not to injure, overload or deface the Premises, nor to suffer or
          commit any waste therein, nor to place a load upon any floor which
          exceeds the floor load which the floor was designed to carry (Lessor
          hereby represents and warrants to Lessee that the floor load of the
          first floor of the Building is not less than 125 pounds per square
          foot), nor to connect any equipment or apparatus to any Building
          system which exceeds the capacity of such system, nor to permit on the
          Premises any auction sale or any inflammable fluids or chemicals which
          are not used, stored and disposed of in compliance with all laws,
          ordinances, codes, rules and regulations, and the provisions of any
          license, permit or other governmental consent or approval required for
          or applicable now or at any time during the Lease Term to the Premises
          or any portion thereof or Lessee's use thereof (collectively, "Legal
          Requirements"), nor to permit any nuisance or the emission from the
          Premises of any objectionable vibration, noise, or odor, nor to permit
          the use of the Premises for any purpose other than the Permitted Uses,
          nor any use thereof which is contrary to any Legal Requirements, or
          which is liable to invalidate or increase the premiums for any
          insurance on the Building or its contents, or liable to render
          necessary any alterations or additions to the Building;


                                       18

<PAGE>   22

     (d)  not to obstruct in any manner any portion of the sidewalks or
          approaches to the Building or any portion of the Parking Area;

     (e)  to comply with all Legal Requirements and all recommendations of
          Lessor's fire insurance rating organization now or hereafter in
          effect, to keep the Premises equipped with all reasonable and
          necessary safety appliances, and to procure (and maintain in full
          force and effect) all licenses, permits and other governmental
          consents and approvals required by any Legal Requirement or by the
          provisions of any applicable insurance policy because of the use made
          of the Premises by Lessee (without intending hereby to vary the
          provisions of Section 5.0 above), and, if requested by Lessor, to make
          all repairs, alterations, replacements or additions so required in and
          to the Premises, and to cooperate with Lessor in the obtaining and
          renewal by Lessor of all licenses, permits and other governmental
          consents and approvals with respect to the Premises, the Building or
          the Land which Lessor is required by applicable laws, ordinances,
          codes, rules or regulations to obtain in its own name;

     (f)  not to make any alterations, renovations, improvements and/or
          additions to the Premises (collectively, "Alterations"), without on
          each occasion obtaining prior written consent of Lessor, which consent
          may be withheld by Lessor in its reasonable discretion (taking into
          account the effect of such proposed Alterations on the structural
          integrity of the Building, whether such proposed Alterations would be
          detrimental to the Building systems as modified by Lessee's Work, and
          the effect of such proposed Alterations on the external appearance of
          the Building), (except that no such prior written consent of Lessor
          shall be required for Alterations which (i) shall not exceed $10,000
          in each instance, and (ii) do not affect the structural integrity of
          the Building, and (iii) are not detrimental to the Building systems as
          modified by Lessee's Work, and (iv) do not affect the exterior
          appearance of the Building, PROVIDED that in each such case (x) Lessee
          shall still provide advance notice to Lessor of the intended
          Alterations, and (y) such Alterations shall be subject to all of the
          provisions of this paragraph (f) other than the requirement of
          Lessor's prior consent); or to make any holes in any part of the
          Building or paint or place any signs, awnings, aerials or flagpoles,
          or the like, visible from outside of the Premises and not previously
          consented to in writing by Lessor. Prior to commencing

                                       19

<PAGE>   23

          any Alterations, Lessee shall: secure all necessary licenses, permits
          and other governmental consents and approvals; obtain the written
          approval of Lessor as to the plans and specifications for such work
          (where such approval is required under this paragraph (f)); obtain the
          written approval of Lessor as to the general contractor (not to be
          unreasonably withheld, delayed or conditioned); cause each contractor
          and subcontractor to carry worker's compensation insurance in
          statutory amounts covering all of the contractor's and subcontractor's
          employees; and cause each general contractor (or each trade contractor
          if there is no general contractor) to carry comprehensive public
          liability insurance in amounts reasonably satisfactory to Lessor (such
          insurance to be written by companies reasonably satisfactory to Lessor
          and insuring Lessee and Lessor as well as the contractors). After the
          first two (2) requests for Lessor's approval of proposed Alterations,
          Lessee shall reimburse Lessor, promptly upon demand therefor, for
          one-half (1/2) of all out-of-pocket costs and expenses reasonably
          incurred by Lessor in reviewing any plans, drawings and specifications
          submitted by Lessee pursuant to this paragraph (f) (but Lessee shall
          not be required to pay to Lessor more than $3,000.00 in connection
          with any one set of Alterations and this charge shall not apply to any
          Alterations proposed to be constructed by Lessee in the Expansion
          Premises in anticipation of the initial occupancy thereof by Lessee),
          which reimbursement shall be due and payable as Additional Rent. All
          Alterations (other than Tenant's removable personal property and trade
          fixtures) shall remain part of the Premises and shall not be removed
          upon the expiration or earlier termination of the Lease Term EXCEPT
          for those items which (i) either Lessor or Lessee designates for
          removal in a notice given to the other party at the time that Lessee
          requests Lessor's approval of such Alteration (if such approval is
          required hereunder), or (ii) Lessee designates for removal at the time
          that it notifies Lessor of its intent to make such Alteration (where
          Lessor's prior approval is not required hereunder), or (iii) Lessor
          designates for removal in a notice given to Lessee within ten (10)
          days after Lessee notifies Lessor of its intent to make such
          Alteration (where Lessor's prior approval is not required hereunder).
          Lessee shall pay promptly when due the entire cost of such work.
          Lessee shall not cause or permit any liens for labor or materials
          performed or furnished in connection therewith to attach to the Land
          or the Building, and shall discharge or bond any such liens which may
          be

                                       20

<PAGE>   24

          filed or recorded within thirty (30) days after the filing or
          recording thereof. All such work shall be performed in a good and
          workmanlike manner and in compliance with all Legal Requirements and
          the provisions of all applicable insurance policies. Promptly after
          the completion of any Alterations, Lessee shall provide an as-built
          plan (or, where appropriate in light of the nature or scope of the
          Alterations, an as-built sketch) thereof to Lessor. Lessee shall
          indemnify and hold Lessor harmless from and against any and all suits,
          demands, causes of action, claims, losses, debts, liabilities,
          damages, penalties or judgments, including, without limitation,
          reasonable attorneys' fees, arising from injury to any person or
          damage to any property occasioned by or growing out of such work
          performed prior to the last day of the Lease Term, which indemnity
          shall survive the expiration or termination of this Lease provided
          that such claim is asserted not later than three (3) years after the
          expiration or earlier termination of the Lease Term. The provisions of
          this paragraph (f) shall not apply to the performance of "Lessee's
          Work" (as defined in the Work Letter) but shall apply to any
          Alterations proposed by Lessee to be constructed in any space leased
          pursuant to Section 2.0 above);

     (g)  to save Lessor harmless and indemnified from any loss, cost and
          expense (including, without limitation, reasonable attorney's fees)
          arising out of or relating to (i) a claim of injury to any person or
          damage to any property while in the Premises, if not due to the
          negligence or willful misconduct of Lessor or its officers, agents,
          employees, servants or contractors, or the breach of Lessor's
          obligations under this Lease; or to (ii) a claim of injury to any
          person or damage to any property while in the Building (but not within
          the Premises) or on the Land or on the sidewalks or ways adjoining the
          Land, occasioned by any omission, neglect or default of Lessee or of
          anyone claiming by, through, or under Lessee, or any officer, agent,
          employee, servant, contractor or invitee of any of the foregoing. The
          provisions of this clause (g) shall survive the expiration or
          termination of this Lease with respect to any claim arising prior to
          the last day of the Lease Term regardless of whether such claim has
          been asserted by the last day of the Lease Term;

     (h)  consistent with the provisions of this paragraph (h) concerning
          Lessor's access to the Premises, to permit Lessor and Lessor's agents
          to examine the Premises at reasonable times, and if Lessor shall so
          elect (without

                                       21

<PAGE>   25

          hereby imposing any obligation on Lessor to do so), to permit Lessor
          to make any repairs or additions Lessor may deem necessary; and at
          Lessee's expense to remove any Alterations, signs, awnings, aerials or
          flagpoles, or the like, not consented to in writing; and to permit
          Lessor to show the Premises to prospective purchasers and tenants (at
          reasonable times on reasonable advance notice to Lessee) and to keep
          affixed to any suitable part of the Premises, during the nine (9)
          months preceding the expiration of the Lease Term, appropriate notices
          for letting or selling.

          Notwithstanding anything to the contrary contained herein, except in
          the event of an emergency requiring prompt attention in order to
          prevent damage to life or serious property damage, Lessor shall be
          permitted access to the Premises only upon at least twenty-four (24)
          hours' prior written notice to Dr. William Kelley or such other
          management level employee designated by Lessee, and when accompanied
          by a representative of Lessee designated by Lessee. Any such access
          shall only be permitted during Lessee's normal business hours and
          shall not unreasonably interfere with Lessee's operations. Lessor
          shall take all reasonable precautions necessary to minimize any
          disruption of Lessee's activities. All persons entering the Premises
          shall comply with all reasonable safety and security requirements of
          Lessee. No access shall be permitted into those portions of the
          Premises designated by Lessee as a "clean room" or as a secured area
          except in the event of an emergency or at other times upon the
          conditions set forth in the preceding provisions of this paragraph
          (h). In the event of an emergency which occurs during traditional
          business hours, prior to entering the Premises, Lessor shall provide
          oral notice to Lessee. In the event of an emergency which does not
          occur during traditional business hours, prior to entering the
          Premises, Lessor shall provide notice to Lessee via telephonic
          transmission to such telecopier numbers and telephonic pager numbers
          as Lessee may provide from time to time;

     (i)  that all merchandise, furniture, fixtures, effects and property of
          every kind of Lessee and of all persons claiming by, through or under
          Lessee which may be on the Premises from time to time (collectively,
          "Lessee's Property") shall be at the sole risk of Lessee, and Lessor
          shall not be liable if the whole or any part thereof shall be
          destroyed or damaged by fire, water or otherwise, or by the leakage or
          bursting of water pipes, steam pipes, or other pipes, or by theft or
          from

                                       22

<PAGE>   26

          any other cause unless caused by the negligence or willful misconduct
          of Lessor;

     (j)  to pay promptly when due, all taxes of any kind levied, imposed or
          assessed on Lessee's Property, which taxes shall be the sole
          obligation of Lessee, whether the same is assessed to Lessee or to any
          other person and whether the property on which such tax is levied,
          imposed or assessed shall be considered part of the Premises or
          personal property; PROVIDED, HOWEVER, that Lessee shall have the right
          to contest the amount of any such taxes by appropriate legal
          proceedings diligently conducted in good faith, without cost, expense,
          liability or damage to Lessor, provided in each case that: (i) no lien
          or encumbrance shall attach to the Land, Building or any equipment and
          improvements therein by reason of non-payment or otherwise by reason
          of such contest; (ii) Lessee shall indemnify Lessor against liability
          resulting from or incurred in connection with such contest; and (iii)
          Lessee shall keep Lessor regularly advised as to the status of such
          contest;

     (k)  by the end of business on the last day of the Lease Term (or the
          effective date of any earlier termination of this Lease as herein
          provided), to remove all of Lessee's Property, and those Alterations
          designated for removal as provided in paragraph (f) above, whether the
          same be permanently affixed to the Premises or not, and to repair any
          damage caused by any such removal to Lessor's reasonable satisfaction;
          and to remove the contents of all neutralization tanks installed by
          Lessee in the Premises; and peaceably to yield up the Premises clean
          and in good order, repair and condition (excepting only reasonable
          wear and tear, and damage by fire or other casualty or taking which
          Lessee is not otherwise required by the terms of this Lease to repair
          or restore); and to deliver the keys to the Premises to Lessor. Any of
          Lessee's Property or those Alterations designated for removal as
          provided in paragraph (f) above, which is not removed by such date
          shall be deemed abandoned and may be removed and disposed of by Lessor
          in such manner as Lessor may determine, and Lessee shall pay to Lessor
          on demand, as Additional Rent, the entire cost of such removal and
          disposition, together with the costs and expenses incurred by Lessor
          in making any incidental repairs and replacements to the Premises
          necessitated by Lessee's failure to remove Lessee's Property or any of
          those Alterations designated for removal as provided in paragraph (f)
          above, as required herein or by any other failure of

                                       23

<PAGE>   27

          Lessee to comply with the terms of this Lease, and for use and
          occupancy during the period after the expiration of the Lease Term and
          prior to Lessee's performance of its obligations under this paragraph
          (k). Lessee hereby acknowledges that any failure or delay on Lessee's
          part in surrendering the Premises as above provided shall subject
          Lessor to the expense of performing such work and the risk of losing a
          successor tenant;

     (l)  to pay Lessor's reasonable expenses, including reasonable attorneys'
          fees, incurred in enforcing any obligations of Lessee under this
          Lease;

     (m)  not to generate, store or use any "Hazardous Materials" (as
          hereinafter defined) in or on the Premises except those identified in
          writing to Lessor from time to time (such identification may take the
          form of delivery by Lessee to Lessor of material safety data sheets
          for such Hazardous Materials), and then only in compliance with any
          and all applicable Legal Requirements, or dispose of Hazardous
          Materials from the Premises to any other location, except a properly
          approved disposal facility and then only in compliance with any and
          all applicable Legal Requirements, nor permit any occupant of the
          Premises to do so. As used in this Lease, "Hazardous Materials" means
          and includes any chemical, substance, waste, material, gas or emission
          which is radioactive or is deemed hazardous, toxic, a pollutant, or a
          contaminant under any statute, ordinance, by-law, rule, regulation,
          executive order or other administrative order, judgment, decree,
          injunction or other judicial order of or by any governmental
          authority, now or hereafter in effect, relating to pollution or
          protection of human health or the environment, including, without
          limitation, those enumerated in the following sentence (collectively,
          "Environmental Laws"). By way of illustration and not limitation,
          "Hazardous Materials" includes "oil", "hazardous materials",
          "hazardous waste", and "hazardous substance" as defined in the
          Comprehensive Environmental Response, Compensation and Liability Act,
          42 U.S.C. Section 9601 ET SEQ., as amended, the Resource Conservation
          and Recovery Act of 1976, 42 U.S.C. Section 6902 ET SEQ., as amended,
          and the Toxic Substances Control Act, 15 U.S.C. Section 2601 ET SEQ.,
          as amended, the regulations promulgated thereunder, and Massachusetts
          General Laws, Chapter 21C and Chapter 21E and the regulations 
          promulgated thereunder. If at any time during the Lease Term, any 
          governmental authority, by reason of the use of the Premises made by 
          Lessee or

                                       24

<PAGE>   28

          anyone claiming by, through or under Lessee, requires testing to
          determine whether there has been any release of Hazardous Materials by
          Lessee, then Lessee shall reimburse Lessor upon demand, as Additional
          Rent, for the reasonable costs thereof. If, in anticipation of the
          commencement of the Lease Term or at any time during the Lease Term,
          Lessee performs any testing to determine whether there has been any
          release of Hazardous Materials onto or below the surface of the
          Premises, Lessee shall promptly provide a copy of such report to
          Lessor at no charge to Lessor. Lessee shall execute such affidavits as
          may be reasonably requested by Lessor from time to time, concerning
          Lessee's best knowledge and belief concerning the presence of
          Hazardous Materials in or on the Premises. Subject to the provisions
          of Section 12(h) above, Lessor reserves the right to enter the
          Premises at reasonable times (provided twenty-four (24) hours' notice
          is given to Lessee, except in case of emergency) to inspect the same
          for Hazardous Materials. Lessee's obligations under this paragraph (m)
          shall include, if at any time during the Lease Term Lessee uses or
          stores radioactive materials on the Premises, compliance with all
          so-called "close-out" procedures of the Nuclear Regulatory Commission
          or other federal, state or local governmental authorities having
          jurisdiction over radioactive materials, regardless of whether or not
          such procedures are completed prior to the expiration or earlier
          termination of the Lease Term. Lessee shall indemnify, defend, and
          hold harmless Lessor, and the holder of any mortgage on the Premises
          or any portion thereof, from and against any claim, cost, expense,
          liability, obligation or damage, including, without limitation,
          reasonable attorneys' fees and the cost of litigation, arising from or
          relating to the breach by Lessee of the provisions of this clause (m),
          and shall immediately discharge or cause to be discharged any lien
          imposed upon the Building or the Land in connection with any such
          claim.

          Lessee shall not be responsible for any noncompliance with
          Environmental Laws or Legal Requirements to the extent attributable to
          conditions already existing on the date hereof, or contamination
          caused by Lessor or any other tenant of Lessor (excluding Lessee and
          anyone claiming by, through or under Lessee) or their respective
          employees, agents and invitees after the date hereof. Nothing herein
          shall be deemed to create an obligation on the part of Lessee with
          respect to (1) contamination already existing before the date hereof,
          or (2) contamination caused by Lessor or any other

                                       25

<PAGE>   29

          tenant of Lessor (excluding Lessee and anyone claiming by, through or
          under Lessee) or their respective agents, employees or invitees after
          the date hereof. For purposes of this paragraph 12(m) and this Lease,
          the term "contamination" shall mean the uncontained presence of
          Hazardous Materials at the Premises, or arising from the Premises,
          which requires remediation under any applicable Environmental Law or
          Legal Requirement.

          Nothing herein shall be deemed to impair Lessee's right to contest any
          governmental agency's orders or directives with respect to
          environmental matters PROVIDED that (i) such contest is diligently
          conducted in good faith, in the name of Lessee, without cost, expense,
          liability or damage to Lessor; (ii) such contest shall not subject
          Lessor to civil or criminal penalty or to prosecution for a crime, nor
          subject the Land, the Building or any part thereof to being condemned
          or vacated, or subject to any lien or encumbrance, by reason of such
          contest; (iii) before the commencement of such contest, Lessee shall
          furnish to Lessor the bond of a surety company reasonably satisfactory
          to Lessor, in form and substance reasonably satisfactory to Lessor, or
          other security in a form reasonably acceptable to Lessor, in an amount
          equal to one hundred percent (100%) of the cost of compliance with
          such order or directive (as reasonably estimated by Landlord); (iv)
          Lessee shall indemnify Lessor against the cost of such compliance and
          liability resulting from or incurred in connection with such contest
          or non-compliance; and (v) Lessee shall keep Lessor regularly advised
          as to the status of such proceedings in good faith.

          The provisions of this clause (m) shall survive the expiration or
          termination of this Lease; and

     (n)  not to permit any officer, agent, employee, servant, contractor or
          visitor of Lessee to violate any covenant or obligation of Lessee
          hereunder.

13.  Construction
     ------------

     13.1 WORK LETTER. The Premises shall be renovated and finished in
          accordance with the provisions of the Work Letter attached hereto as
          EXHIBIT C.

     13.2 ROOF LOAD CAPACITY. Lessee shall cause its structural engineer to
          inspect the roof of the Building in those locations in which Lessee
          intends to install roof-top

                                       26


<PAGE>   30

          equipment as part of "Lessee's Work" (as defined in the Work Letter).
          If such engineer determines that the roof load capacity is less than
          30 pounds per square foot in any of such locations: (i) Lessee shall
          notify Lessor in writing; and (ii) as part of Lessee's Work, Lessee
          shall reinforce such portions of the roof as reasonably required for
          the roof-top equipment which Lessee intends to install; and (iii) upon
          completion of Lessee's Work (as evidenced by a "Certificate of
          Substantial Completion" issued by Lessee's architect) and the
          commencement of the payment of Rent by Lessee, Lessee shall be
          entitled to submit to Lessor for reimbursement paid invoices for the
          cost of such reinforcement of the roof. Provided that such invoices
          are reasonably satisfactory in form and content to Lessor, then Lessor
          shall promptly reimburse Lessee for such cost. The amount of such
          reimbursement shall be fully amortized over the portion of the Initial
          Lease Term remaining as of the date of such payment by Lessor to
          Lessee, on a straight-line basis. Lessee shall pay such amounts in
          equal monthly installments, as Additional Rent, at the same time and
          in the same manner as Basic Rent.

     13.3 FLOOR LOADS. In the event that at any time during the performance of
          Lessee's Work, Lessee's structural engineer determines that the floor
          load of the first floor of the Premises is less than 125 pounds per
          square foot, Lessee shall notify Lessor in writing. If requested by
          Lessee, Lessor shall, at its sole cost and expense and without
          reimbursement from Lessee, be responsible for reinforcing such
          portions of the first floor of the Building so as to achieve a floor
          load of at least 125 pounds per square foot.

14.  Eminent Domain and Casualty.
     ----------------------------

     14.1 SUBSTANTIAL TAKING. In the event that (i) more than fifty (50%)
          percent of the rentable area of the Premises then occupied by the
          named Lessee itself, shall be taken by any exercise of the right of
          eminent domain or other lawful power in pursuance of any public or
          other authority during the Lease Term, then this Lease shall terminate
          as of the time that possession is taken by the taking authority.

     14.2 AWARDS. Lessor reserves and excepts all rights to damage to the
          Premises, the Building, the Land and the leasehold hereby created, now
          accrued or hereafter accruing by reason of any exercise of eminent
          domain, or by reason of anything lawfully done in pursuance of

                                       27

<PAGE>   31

          any public or other authority, and by way of confirmation, Lessee
          grants to Lessor all of Lessee's rights to such damages and covenants
          to execute and deliver such further instruments of assignment thereof
          as Lessor may from time to time request. Lessee shall be entitled only
          to such award, if any, as is specifically allocated by the taking
          authority to Lessee on account of relocation expenses or other damages
          suffered by Lessee as a result of such taking.

     14.3 SUBSTANTIAL CASUALTY. If the Premises are damaged by fire or other
          casualty, Lessee shall promptly notify Lessor thereof. If the Premises
          or any part thereof shall be so damaged to the extent that more than
          fifty (50%) percent of the rentable area of the Premises then occupied
          by the named Lessee itself is rendered unusable by Lessee for the
          operation of its business in the Premises (whether by reason of direct
          or indirect damage from the casualty), or if the Building is so
          damaged (regardless of whether or not the Premises are damaged) that
          Lessee is deprived of all reasonable access to the Premises or all
          reasonable use of the Premises, then in either case either Lessor or
          Lessee may terminate this Lease by giving written notice of such
          termination to the other party within sixty (60) days after the date
          of such damage, in which event this Lease shall terminate on the date
          set forth in such notice. In the event that this Lease is terminated
          pursuant to this Section 14.3: (i) Rent shall be abated, to the extent
          the Premises are unusable for the Permitted Uses, from and after the
          date of such damage to the date of such termination of this Lease, and
          no further Rent shall accrue or be payable after the date of such
          termination; and (ii) Lessee shall turn over and assign to Lessor all
          insurance proceeds (and rights to receive the same) relating to
          Lessee's Work and any Alterations EXCEPT for the portion (if any) of
          such proceeds which is allocable to the actual cash value of the
          components thereof which had previously been designated in writing to
          by one party to the other as items to be removed upon the expiration
          of the Lease Term.

     14.4 REPAIR AND RESTORATION. In the event of a taking which does not result
          in the termination of this Lease pursuant to Section 14.1 above, or a
          casualty which does not result in the termination of this Lease
          pursuant to Section 14.3 above, the Premises shall be repaired and
          restored in the manner provided in this Section. Lessor shall
          diligently act to restore the Building and the Premises (exclusive of
          Lessee's Work,

                                       28
<PAGE>   32

          any Alterations made by Lessee, and Lessee's Property) or, in case of
          taking, what remains thereof, to substantially the condition in which
          they existed prior to the occurrence of such taking or casualty,
          provided, however, that: (i) in no event shall Lessor be required to
          spend in connection with restoring the Premises more than the amount
          of insurance proceeds or taking award actually received and allocable
          thereto (except that this limitation with respect to insurance
          proceeds shall not apply to casualties occurring during such time as
          Lessor self-insures pursuant to Section 8.4 above); (ii) Lessor shall
          not be required to restore or replace any of Lessee's Work,
          Alterations or Lessee's Property; and (iii) promptly upon completion
          of such work by Lessor, Lessee shall diligently act to restore and/or
          replace Lessee's Work, the Alterations and all of Lessee's Property to
          substantially the same condition they were in prior to the occurrence
          of such taking or casualty. All work performed by Lessor or by Lessee
          pursuant to this Section shall be performed in a good and workerlike
          manner, and in compliance with all Legal Requirements. Lessor shall
          not be liable for any inconvenience or annoyance to Lessee or injury
          to the business of Lessee resulting in any way from such taking or
          damage or the repair thereof. Rent shall be abated from and after the
          date of such taking or damage to the date on which Lessor
          substantially completes the restoration described above, to the extent
          the Premises are unusable for the Permitted Uses, but the amount of
          such abatement shall in no event exceed the amount received by Lessor
          under the rental loss insurance policy required by Section 8.2 above.

          Notwithstanding the foregoing provisions of this Section:

          (a)  in the event that Lessor has not substantially completed, within
               one (1) year after the date of such taking or damage (which
               period shall be extended by the duration of any and all events of
               Force Majeure), the restoration work which it is required by this
               Section to perform, then Lessee shall have the right to terminate
               this Lease by giving thirty (30) days' written notice to Lessor
               within thirty (30) days after the end of such 1-year period (as
               such 1-year period may be extended as provided above); and

          (b)  in the event that Lessor determines that the amount of insurance
               proceeds available for the repair and restoration work for which
               Lessor is

                                       29

<PAGE>   33

               responsible under this Section and Lessor refuses to provide the
               funds necessary to make up such deficit, Lessor shall notify
               Lessee within thirty (30) days of the occurrence of such
               casualty. Lessee shall then have the right to terminate this
               Lease by giving written notice to Lessor within fifteen (15) days
               after Lessee's receipt of Lessor's notice.

     14.5 CASUALTY DURING LAST 12 MONTHS. Notwithstanding anything to the
          contrary contained in this Lease, in the event that a material portion
          of the Premises is damaged by a fire or other casualty occurring
          during the last twelve (12) months of the Lease Term, either party may
          terminate this Lease by giving written notice to the other within
          thirty (30) days of the occurrence of such damage. If this Lease is so
          terminated, Lessee shall turn over and assign to Lessor all insurance
          proceeds (and rights to receive the same) relating to the Building
          EXCEPT as otherwise provided in the last sentence of Section 14.3
          above. However, if Lessee has exercised an Extension Option prior to
          the occurrence of such casualty, then this Section 14.5 shall not
          apply and neither party shall have the right to terminate this Lease
          pursuant to this Section 14.5.

15.  Defaults; Events of Default; Remedies.
     --------------------------------------

     15.1 DEFAULTS; EVENTS OF DEFAULT. The following shall, if any requirement
          for notice or lapse of time or both has not been met, constitute
          defaults hereunder, and, if such requirements have been met,
          constitute "Events of Default" hereunder:

          (a)  The failure of Lessee to perform or observe any of Lessee's
               covenants or agreements hereunder concerning the payment of money
               for a period of ten (10) business days after written notice
               thereof, PROVIDED, HOWEVER, that Lessee shall not be entitled to
               such notice if Lessor has given notice to Lessee of two or more
               previous such failures within a twelve-month period, in which
               event such failure shall constitute an Event of Default hereunder
               upon the expiration of ten (10) business days after such payment
               was due;

          (b)  The failure of Lessee to maintain the insurance required
               hereunder in full force and effect;

          (c)  The failure of Lessee to perform or observe any of Lessee's other
               covenants or agreements hereunder

                                       30

<PAGE>   34

               for a period of thirty (30) days after written notice thereof
               (provided that, in the case of defaults not reasonably curable in
               thirty (30) days through the exercise of reasonable diligence,
               such 30-day period shall be extended for so long as Lessee
               commences cure within such period and thereafter prosecutes such
               cure to completion continuously and with reasonable diligence);
               and

          (d)  if the leasehold hereby created shall be taken on execution, or
               by other process of law, and such taking is not vacated by a
               final order of a court of competent jurisdiction within sixty
               (60) days thereafter; or if any assignment shall be made of
               Lessee's property for the benefit of creditors; or if a receiver,
               guardian, conservator, trustee in bankruptcy or similar officer
               shall be appointed to take charge of all or any part of Lessee's
               property by a court of competent jurisdiction, and such
               appointment is not vacated by a final order of a court of
               competent jurisdiction within sixty (60) days thereafter; or if a
               petition is filed by Lessee under any bankruptcy or insolvency
               law; or if a petition is filed against Lessee under any
               bankruptcy or insolvency law and the same shall not be dismissed
               within sixty (60) days from the date upon which it is filed; or
               if a lien or other involuntary encumbrance is filed against
               Lessee's leasehold (or against the Premises, the Building or the
               Land based on a claim against Lessee) and is not discharged or
               bonded within thirty (30) days after the filing thereof.

     15.2 TERMINATION. If an Event of Default shall occur, Lessor may, at its
          option, immediately or any time thereafter and without demand or
          notice, enter upon the Premises or any part thereof in the name of the
          whole and repossess the same as of Lessor's former estate and
          dispossess Lessee and those claiming through or under Lessee and
          remove their effects, without being deemed guilty of any manner of
          trespass and without prejudice to any remedies which might otherwise
          be used for arrears of rent or preceding breach of covenant, and upon
          such entry this Lease shall terminate. In lieu of making such entry,
          Lessor may terminate this Lease upon five (5) business days' prior
          written notice to Lessee. Upon any termination of this Lease as the
          result of an Event of Default, Lessee shall quit and peacefully
          surrender the Premises to Lessor.


                                       31

<PAGE>   35

     15.3 SURVIVAL OF COVENANTS. No such termination of this Lease shall relieve
          Lessee of its liability and obligations under this Lease and such
          liability and obligations shall survive any such termination. Lessee
          shall indemnify and hold Lessor harmless from all loss, cost, expense,
          damage or liability arising out of or in connection with such
          termination.

          In the event of any such termination, Lessee shall pay to Lessor the
          Rent up to the time of such termination. Lessee shall remain liable
          for, and shall pay on the days originally fixed for such payment
          hereunder, the full amount of all Basic Rent and Additional Rent as if
          this Lease had not been terminated; PROVIDED, HOWEVER, if Lessor
          relets the Premises, there shall be credited against such obligation
          the amount actually received by Lessor each month from such lessee
          after first deducting all costs and expenses incurred by Lessor in
          connection with reletting the Premises.

          At any time within one (1) year after such termination, and regardless
          of whether Lessee has made any payments to Lessor pursuant to the
          preceding paragraph of this Section, Lessor may demand and Lessee
          agrees to pay to Lessor on such demand, as and for liquidated and
          agreed damages for Lessee's default, the present value of the amount
          by which:

          (a)  the aggregate Rent which would have been payable under this 
               Lease by Lessee from the date of such termination until what 
               would have been the last day of the Lease Term but for such 
               termination, EXCEEDS

          (b)  the greater of (i) the fair and reasonable rental value of the
               Premises for the same period, less Lessor's reasonable estimate 
               of expenses to be incurred in connection with reletting the 
               Premises, including, without limitation, all repossession costs,
               brokerage commissions, legal expenses, reasonable attorneys' 
               fees, alteration costs, and expenses of preparation for such 
               reletting, or (ii) the sum of (A) the amount actually received 
               or to be by Lessor from reletting the Premises pursuant to 
               leases which are in effect as of the date on which Lessor 
               elects to proceed under this paragraph, and (B) the amount (if 
               any) actually received by Lessor from Lessee pursuant to the 
               preceding paragraph of this Section on account of any period 
               after such termination.

                                       32

<PAGE>   36

          If the Premises or any part thereof are relet by Lessor for the period
          prior to what would have been the last day of the Lease Term but for
          such termination, or any portion thereof, the amount of rent reserved
          upon such reletting shall be, PRIMA FACIE, the fair and reasonable
          rental value for the part or the whole of the Premises so relet during
          the term of the reletting.

          In the event of the filing of a petition by or against Lessee under
          any federal bankruptcy or insolvency law now or hereafter in effect,
          nothing herein contained shall limit or prejudice the right of Lessor
          to prove and obtain as liquidated damages by reason of such
          termination, an amount equal to the maximum allowed by any statute or
          rule of law in effect at the time when, and governing the proceedings
          in which, such damages are to be proved, whether or not such amount be
          greater, equal to, or less than the amount of the difference referred
          to above.

     15.4 RIGHT TO RELET. At any time or from time to time after any such
          termination, Lessor may relet the Premises or any part thereof for
          such a term (which may be greater or less than the period which would
          otherwise have constituted the balance of the Lease Term) and on such
          conditions (which may include concessions or free rent) as Lessor, in
          its reasonable discretion, may determine, and may collect and receive
          the rents therefor. Lessor shall in no way be responsible or liable
          for any failure to relet the Premises or any part thereof, or for any
          failure to collect any rent due upon any such reletting.

     15.5 RIGHT TO EQUITABLE RELIEF. In the event of the occurrence of an Event
          of Default hereunder, Lessor shall be entitled to seek to enjoin the
          continuance thereof and shall have the right to invoke any right and
          remedy allowed at law or in equity or by statute or otherwise as
          though re-entry and other remedies were not provided for in this
          Lease.

     15.6 RIGHT TO SELF HELP. In the event of the occurrence of an Event of
          Default hereunder, Lessor shall have the right to perform such
          defaulted obligation of Lessee, including the right to enter upon the
          Premises to do so. Lessor shall, as a courtesy only, notify Lessee of
          its intention to perform such obligation. In the event of a default by
          Lessee hereunder which has not yet continued beyond the expiration of
          the applicable grace period but which Lessor determines constitutes an
          emergency threatening imminent injury to persons or

                                       33

<PAGE>   37

          damage to property, Lessor shall have the right to perform such
          defaulted obligation of Lessee (including the right to enter upon the
          Premises to do so) after giving Lessee such notice (if any) as is
          reasonable under the circumstances. In either event, the aggregate of
          (i) all sums so paid by Lessor, (ii) interest at the rate of the
          "prime" rate from time to time thereafter published in THE WALL STREET
          JOURNAL plus 1-1/2% per annum on such sum, and (iii) all necessary
          incidental costs and expenses in connection with the performance of
          any such act by Lessor, shall be deemed to be Additional Rent under
          this Lease and shall be payable to Lessor immediately upon demand.
          Lessor may exercise its rights under this Section 15.6 without waiving
          any other of its rights or releasing Lessee from any of its
          obligations under this Lease.

     15.7 FURTHER REMEDIES. Nothing in this Lease contained shall require Lessor
          to elect any remedy for an Event of Default by Lessee hereunder, and
          all rights herein provided shall be cumulative with one another and
          with any other rights and remedies which Lessor may have at law or in
          equity in the case of such Event of Default.

16.  Intentionally Deleted.
     ---------------------

17.  REAL ESTATE BROKER. Lessor and Lessee each represent to the other that they
     have dealt with no broker in connection with this Lease other than Meredith
     & Grew, Inc. ("Broker"). Lessor shall pay the Broker as part of a separate
     agreement. Lessee agrees to indemnify and hold Lessor harmless from and
     against any claims for commissions or fees by any person other than the
     Broker arising from a breach by Lessee of the foregoing representation.
     Lessor agrees to indemnify and hold Lessee harmless from and against any
     claims for commissions or fees by the Broker or any other person by reason
     of a breach by Lessor of the foregoing representation.

18.  NOTICES. Whenever by the terms of this Lease notice, demand, or other
     communication shall or may be given either to Lessor or to Lessee, the same
     shall be in writing and shall be sent by hand, or by registered or
     certified mail, postage prepaid, or by Federal Express or other similar
     overnight delivery service, to:


                                       34
<PAGE>   38

     Lessor:                  Massachusetts Institute of Technology
                              Suite 200
                              238 Main Street
                              Cambridge, Massachusetts 02142
                              Attention:  Philip A. Trussell,
                                          Director of Real Estate

     with a copy to:          Peter Friedenberg, Esquire
                              Rackemann, Sawyer & Brewster
                              One Financial Center
                              Boston, Massachusetts 02111

     Lessee:                  Alkermes, Inc.
                              64 Sidney Street
                              Cambridge, Massachusetts 02139
                              Attention:  Michael J. Landine,
                                          Chief Financial Officer

     Any notice, demand or other communication shall be effective upon receipt
     by or tender for delivery to the intended recipient thereof.

19.  NO WAIVERS. Failure of either Lessor or Lessee to complain of any act or
     omission on the part of the other, no matter how long the same may
     continue, shall not be deemed to be a waiver by such non-complaining party
     of any of its rights hereunder. No waiver by either Lessor or Lessee at any
     time, expressed or implied, of any breach of any provision of this Lease
     shall be deemed a waiver of a breach of any other provision of this Lease
     or a consent to any subsequent breach of the same or any other provision.
     No acceptance by Lessor of any partial payment shall constitute an accord
     or satisfaction but shall only be deemed a partial payment on account; nor
     shall any endorsement or statement on any check or any letter accompanying
     any check or payment be deemed an accord and satisfaction, and Lessor may
     accept such check or payment without prejudice to Lessor's right to recover
     the balance of such installment or pursue any other remedy available to
     Lessor in this Lease or at law or in equity.

20.  Lessor's Obligations.
     --------------------

     20.1 Generally. Lessor shall:
          ---------

          (a)  not obstruct in any manner any portion of the sidewalks or
               approaches to the Building or any portion of the Parking Area
               leased to Lessee hereunder;


                                       35
<PAGE>   39

          (b)  pay Lessee's reasonable expenses, including reasonable attorneys'
               fees, incurred in enforcing any obligations of Lessor under this
               Lease; and

          (c)  save Lessee harmless and indemnified from any loss, cost and
               expense (including, without limitation, reasonable attorney's
               fees) arising out of or relating to a claim of injury to any
               person or damage to any property while on the Premises, in the
               Building, on the Land or on the sidewalks or ways adjoining the
               Land occasioned by any omission, neglect or default of Lessor or
               any officer, agent, employee, servant, contractor or invitee of
               Lessor. The provisions of this paragraph (c) shall survive the
               expiration or termination of this Lease with respect to any claim
               arising prior to the last day of the Lease Term regardless of
               whether such claim is asserted prior to the last day of the Lease
               Term.

     20.2 LESSOR'S MAINTENANCE. Lessor shall maintain: (i) the structural
          components of the Building, (ii) the roof and exterior skin of the
          Building, and (iii) the Parking Area in good order, repair and
          condition, excepting only (a) damage by fire or other casualty or
          taking which Lessor is not otherwise required by the terms of this
          Lease to repair or restore, (b) reasonable wear and tear, or (c) the
          negligent acts or omissions or willful misconduct of Lessee, anyone
          claiming by, through or under Lessee, or any of the officers,
          employees, agents, servants, contractors or invitees of any of the
          foregoing. Notwithstanding the foregoing, any and all maintenance,
          repair or replacement required to be made to any of the structural
          components of the Building, or to the roof or the exterior skin of the
          Building or to the Parking Area by reason of (i) any of Lessee's Work,
          or any Alterations made by or on behalf of Lessee, or (ii) any act or
          omission of Lessee, anyone claiming by, through or under Lessee, or
          any of the officers, employees, agents, servants, contractors or
          invitees of any of the foregoing, shall be solely the responsibility
          of Lessee.

21.  Ground Leases; Mortgages.
     ------------------------

     21.1 RIGHTS OF GROUND LESSORS AND MORTGAGEES. No act or failure to act on
          the part of Lessor which would entitle Lessee under the terms of this
          Lease, or by law, to be relieved of Lessee's obligations hereunder or
          to terminate this Lease, shall result in a release

                                       36

<PAGE>   40

          or termination of such obligations or a termination of this Lease
          unless (i) Lessee shall have first given written notice to Lessor's
          ground lessors and mortgagees of record of the act or failure to act
          on the part of Lessor which Lessee claims as the basis of Lessee's
          rights; and (ii) such ground lessors and mortgagees, after receipt of
          such notice, have failed or refused to correct or cure the condition
          within a reasonable time thereafter, but nothing in this Lease shall
          be deemed to impose any obligation on any such ground lessor or
          mortgagee to correct or cure any such condition. No ground lessor
          shall be liable for the failure to perform any of the obligations of
          Lessor hereunder unless and until such ground lessor terminates its
          ground lease and takes possession of the Premises, nor shall any
          mortgagee be liable for the failure to perform any of the obligations
          of Lessor hereunder unless and until such mortgagee enters upon and
          takes possession of the Premises for purposes of foreclosure.

     21.2 LEASE SUBORDINATE. This Lease is and shall be subject and subordinate
          to any ground lease or mortgage now or hereafter on the Premises, and
          to all advances under any such mortgage and to all renewals,
          amendments, extensions and consolidations thereof, provided that the
          holder of such ground lessor's interest or mortgagee's interest enters
          into a non-disturbance and attornment agreement with Lessee which
          provides that in the event that such ground lessor or mortgagee
          succeeds to Lessor's interest hereunder, then, provided that Lessee is
          not in default hereunder beyond the cure period provided in this
          Lease, such party shall recognize and be bound by the terms of this
          Lease. In the event that any ground lessor or the holder of any
          mortgage succeeds to Lessor's interest in the Premises or any portion
          thereof, Lessee hereby agrees to attorn to such ground lessor or
          mortgagee. In confirmation of such subordination, Lessee shall execute
          and deliver promptly any certificate in recordable form that Lessor or
          any ground lessor or any mortgagee may reasonably request.
          Notwithstanding the foregoing provisions of this Section, the holder
          of any mortgage on the Premises may at any time subordinate its
          mortgage to this Lease by written notice to Lessee.

          Lessor hereby represents to Lessee that as of the date of this Lease,
          there are no mortgages or ground leases encumbering the Premises or
          any portion thereof.

                                       37

<PAGE>   41

22.  NOTICE OF LEASE; ESTOPPEL CERTIFICATES. Lessor and Lessee agree that this
     Lease shall not be recorded. However, upon the request of either party,
     Lessor and Lessee shall execute and acknowledge a Notice of Lease in
     mutually acceptable and recordable form.

     From time to time during the Lease Term, and without charge, either party
     shall, within fifteen (15) business days of request by the other, certify
     by written instrument duly executed and acknowledged, to the requesting
     party or to any person reasonably specified by the requesting party,
     regarding (a) the existence of any amendments or supplements to this Lease;
     (b) the validity and force and effect of this Lease; (c) the existence of
     any known default or Event of Default; (d) the existence of any offsets,
     counterclaims or defenses; (e) the Commencement Date and the expiration
     date of the Lease Term; (f) the amount of Rent due and payable and the date
     to which Rent has been paid; and (g) any other matter reasonably requested.

23.  HOLDING OVER. If Lessee occupies the Premises after the day on which the
     Lease Term expires (or the effective date of any earlier termination as
     herein provided) without having entered into a new lease thereof with
     Lessor, Lessee shall be a tenant-at-sufferance only, subject to all of the
     terms and provisions of this Lease at two and one-half (2 1/2) times the
     then-effective Basic Rent stated in Section 4.0 above. Such a holding over,
     even if with the consent of Lessor, shall not constitute an extension or
     renewal of this Lease. For purposes of this Section, the failure of Lessee
     to complete by the last day of the Lease Term or the effective date of any
     earlier termination as herein provided the "close-out" procedures required
     by the Nuclear Regulatory Commission or any other federal, state or local
     governmental agency having jurisdiction over the use of radioactive
     materials within the Premises shall constitute a holding over and subject
     Lessee to the provisions of this Section.

24.  FORCE MAJEURE. Neither Lessor nor Lessee shall be deemed to be in default
     hereunder (and the time for performance of any of their respective
     obligations hereunder other than the payment of money shall be postponed)
     for so long as the performance of such obligation is prevented by strike,
     lock- out, act of God, absence of materials or any other matter not
     reasonably within the control of the party which must perform the
     obligation (collectively, "Force Majeure").

25.  SIGNS. Lessee shall have the right to install up to two signs on the
     Building, identifying its name and business, provided that (i) Lessee shall
     obtain Lessor's reasonable prior written approval as to the location, size,
     shape and

                                       38

<PAGE>   42

     appearance of each sign, and as to the plans and specifications relating to
     such installation; (ii) Lessee shall install each such sign at its sole
     cost; (iii) Lessee shall, at its sole cost, obtain all licenses, permits
     and other governmental consents and approvals required by applicable Legal
     Requirements to install the signs; (iv) Lessee shall cause such
     installation to be done in a good and workmanlike manner and in accordance
     with all applicable Legal Requirements, the provisions of applicable
     insurance policies, and the requirements of all existing restrictions,
     easements and encumbrances of record affecting the Land; (v) Lessee shall,
     at its sole cost, maintain the signs in good operating condition and in
     accordance with all applicable Legal Requirements, the provisions of
     applicable insurance policies, and the requirements of all existing
     restrictions, easements and encumbrances of record affecting the Land; and
     (vi) Lessee shall, at its sole cost, remove the signs on or prior to the
     date on which the Lease Term expires or this Lease is terminated and
     restore the surface of the Land and/or the Building to the condition in
     which it was prior to the installation of the signs. Lessor shall cooperate
     with Lessee, at no cost to Lessor, in connection with the filing of any
     application with the City of Cambridge necessary to obtain approval of the
     signs as approved by Lessor.

     All work done by or on behalf of Lessee pursuant to this Section shall be
     subject to the requirements set forth in Section 12.0(f) above. Lessor may
     inspect such work at any time or times and shall promptly give notice to
     Lessee of any observed defects. Lessee shall indemnify, defend and hold
     harmless Lessor from and against any and all liability, damage, penalties
     or judgments and from and against any claims, actions, proceedings and
     expenses and costs in connection therewith, including reasonable attorneys'
     fees, resulting from any work performed by or on behalf of Lessee pursuant
     to this Section. Such signs shall be at Lessee's sole risk, and Lessor
     shall not have no responsibility to maintain any insurance on them or
     otherwise be responsible for any damage or destruction thereto.

26.  ENTIRE AGREEMENT. No oral statement or prior written matter shall have any
     force or effect. This Agreement shall not be modified or canceled except by
     writing subscribed to by all parties.

27.  APPLICABLE LAW, SEVERABILITY AND CONSTRUCTION. This Lease shall be governed
     by and construed in accordance with the laws of Massachusetts and, if any
     provisions of this Lease shall to any extent be invalid, the remainder of
     this Lease, and the application of such provisions in other

                                       39
<PAGE>   43

     circumstances, shall not be affected thereby. The titles of the several
     Sections contained herein are for convenience only and shall not be
     considered in construing this Lease. Whenever the singular is used and when
     required by the context it shall include the plural, and the neuter gender
     shall include the masculine and feminine. The Exhibits attached to this
     Lease are incorporated into this Lease by reference. This Lease may be
     executed in several counterparts, each of which shall be an original, but
     all of which shall constitute one and the same instrument. The term
     "Lessor" whenever used herein, shall mean only the owner at the time of
     Lessor's interest herein, and no covenant or agreement of Lessor, express
     or implied, shall be binding upon any person except for defaults occurring
     during such person's period of ownership nor binding individually upon any
     officer, director, employee, fiduciary, shareholder or any beneficiary
     under any trust, and the liability of Lessor, in any event, shall be
     limited to Lessor's interest in the Building. If Lessee is several persons
     or a partnership, Lessee's obligations are joint or partnership and also
     several. Unless repugnant to the context, "Lessor" and "Lessee" mean the
     person or persons, natural or corporate, named above as Lessor and as
     Lessee respectively, and their respective heirs, executors, administrators,
     successors and assigns.

28.  SUCCESSORS AND ASSIGNS. The terms, covenants and conditions of this Lease
     shall be binding upon and inure to the benefit of Lessor and Lessee and
     their respective successors and permitted assigns.

29.  SECURITY DEPOSIT. Lessee has deposited with Lessor contemporaneously with
     its delivery to Lessor of executed counterparts of this Lease $8,500.00
     (the "Security Deposit") as security for the full and faithful payment and
     performance by Lessee of its obligations under this Lease from and after
     the date of execution hereof by Lessee, and not as a prepayment of Rent.
     The Security Deposit shall be kept in a money market savings account
     separate from other funds of Lessor, and shall bear interest at the rate in
     effect from time to time on such account, which interest shall be paid to
     Lessee annually. Lessor may use the Security Deposit to cure any Event of
     Default by Lessee (whether occurring prior to the Rent Commencement Date
     hereunder or thereafter), and Lessee shall immediately pay to Lessor on
     demand, as Additional Rent, the amount so expended and such additional
     amount as is required to cause the Security Deposit to equal the amount of
     $8,500.00. Lessor shall assign the Security Deposit to any successor owner
     of the Building and thereafter Lessor shall have no further responsibility
     therefor. Upon the expiration (or

                                       40


<PAGE>   44

     earlier termination) of the Lease Term, Lessor shall inspect the Premises,
     make such deductions from the Security Deposit as may be required to cure
     any Event of Default by Lessee hereunder, and, if Lessee is not then in
     default hereunder, pay the balance of the Security Deposit, if any, to
     Lessee within thirty (30) days of such expiration or termination. If Lessee
     is in default hereunder at the time of such expiration or termination, then
     Lessor shall be entitled to retain so much of the Security Deposit as
     Lessor reasonably estimates to be Lessee's liability to Lessor hereunder
     and shall pay the balance, if any, to Lessee within such 30-day period.

30.  AUTHORITY. Lessee hereby represents and warrants to Lessor that Michael J.
     Landine has the authority to execute this Lease on behalf of Lessee. Lessee
     shall furnish to Lessor a certified copy of the resolution of the Board of
     Directors of Lessee ratifying Lessee's execution of the Lease promptly
     after the July 1993 Board meeting. Lessor shall furnish appropriate
     evidence of the authority of Lessor to enter into this Lease.

     WITNESS the execution hereof in multiple counterparts under seal the day
     and year first above written.


     LESSOR:                             MASSACHUSETTS INSTITUTE OF
                                         TECHNOLOGY


Date: July 28, 1993                      By: /s/ Philip A. Trussell
     ---------------------------------      -----------------------------------
                                            Philip A. Trussell,
                                            Director of Real Estate
                                            Hereunto duly authorized



     LESSEE:                                ALKERMES, INC.


Date: July 26, 1993                      By: /s/ Michael J. Landine
     ---------------------------------      -----------------------------------
                                            Michael J. Landine
                                             Chief Financial Officer
                                            Hereunto duly authorized

              

                                       41

<PAGE>   45



                                    EXHIBIT A

                                    PREMISES
                                    --------

                               See attached plan.





                                       A-1





<PAGE>   46







                                    EXHIBIT B

                                    THE LAND
                                    --------

                               See attached plan.






                                       B-1

<PAGE>   47

                                    EXHIBIT C

                                   WORK LETTER
                                   -----------

     This Work Letter is incorporated by reference into the Lease dated July 26,
1993 by and between Massachusetts Institute of Technology, as Lessor, and
Alkermes, Inc. as Lessee. Terms defined in or by reference in the Lease not
otherwise defined herein shall have the same meaning herein as therein.


1.   ADDITIONAL DEFINITIONS. Each of the following terms shall have the meaning
     stated immediately after it:

          CONSTRUCTION AUTHORIZATIONS. Collectively, all permits, licenses and
          other consents and approvals required from any governmental authority
          for the construction of Lessee's Work.

          LESSEE'S GENERAL CONTRACTOR. A general contractor selected by Lessee
          and approved in writing by Lessor, who will be engaged by Lessee to
          construct Lessee's Work.

          LESSEE'S WORK. All improvements, alterations and additions which
          Lessee wishes to make to the Premises as part of the initial
          preparation thereof for Lessee's occupancy.

          WORKING DRAWINGS. The working drawings and specifications for Lessee's
          Work, to be prepared by Lessee and Lessee's architect in accordance
          with this Work Letter. The Working Drawings shall be prepared in
          compliance with all applicable Legal Requirements and stamped by
          registered Massachusetts professionals, and shall consist of all
          architectural and engineering plans and specifications which are
          required to finish the Premises or to obtain any Construction
          Authorization required therefor.

2.   PREPARATION OF THE PREMISES. Lessor is leasing the Premises to Lessee in
     its "as is" condition, and Lessor shall have no obligation to perform any
     repairs or make any improvements to the Premises in anticipation of
     Lessee's occupancy thereof. Lessee shall perform Lessee's Work at Lessee's
     sole cost and expense.

     Prior to the commencement of any design work on Lessee's Work, Lessee shall
     provide to Lessor an original certificate of insurance, in customary form,
     for each architect and

                                       C-1

<PAGE>   48

     engineer retained by Lessee in connection with the design and/or
     construction of Lessee's Work, which certificate shall evidence a current
     "errors and omissions" insurance policy as in effect, in an amount
     reasonably acceptable to Lessor. Prior to the commencement of the
     construction of Lessee's Work, Lessee shall provide to Lessor an original
     certificate of insurance for the general contractor (or, if no general
     contractor is used, each trade contractor) employed by Lessee in connection
     with the construction of Lessee's Work, which certificate shall evidence a
     current general liability insurance policy as in effect, in an amount
     reasonably acceptable to Lessor, naming Lessor as an additional insured.

3.   WORKING DRAWINGS. Lessee shall be solely responsible for the preparation
     and completion of all preliminary and final Working Drawings. Lessee shall
     retain its own architects and engineers to prepare Working Drawings,
     provided that Lessor first approves such engineers and architects so
     selected by Lessee, which approval shall not be unreasonably withheld or
     delayed. Lessee shall provide copies of the preliminary Working Drawings to
     Lessor, together with a list of elements of Lessee's Work which Lessee
     intends to remove from the Premises upon the expiration or earlier
     termination of this Lease. Lessor shall provide to Lessee within ten (10)
     business days thereafter a list of corrections and modifications which
     Lessor requires to be made to the Working Drawings. Lessor shall also
     provide to Lessee within such 10-business day period a list of those
     elements of Lessee's Work which Lessee must remove at the expiration or
     earlier termination of this Lease.

     Lessee shall revise the preliminary Working Drawings to incorporate the
     corrections and modifications requested by Lessor and shall submit final
     Working Drawings to Lessor for its approval. Lessor shall review the final
     Working Drawings and, within ten (10) business days after receipt thereof,
     Lessor shall either (a) notify Lessee that Lessor has approved the final
     Working Drawings, or (b) provide to Lessee a list of corrections and
     modifications which Lessor requires to be made to the Working Drawings.
     Lessor shall also provide to Lessee within such 10-business day period a
     supplementary list of those elements of Lessee's Work which Lessee must
     remove at the expiration or earlier termination of this Lease (if any). In
     the event Lessor returns the Working Drawings to Lessee for correction or
     modification, Lessee shall diligently correct the Working Drawings and
     resubmit them to Lessor for approval pursuant to the preceding provisions
     of this paragraph. No work shall be performed until final Working Drawings
     have been approved in writing by Lessor.

                                       C-2

<PAGE>   49

     The review and/or approval by Lessor or its architect or engineers of any
     plans, sketches or Working Drawings submitted by Lessee relating to
     Lessee's Improvements shall not (i) constitute an opinion or representation
     by Lessor that the same are in compliance with all applicable Legal
     Requirements and the provisions of all applicable insurance policies or as
     to the feasibility of constructing the work shown thereon, or (ii) impose
     on Lessor any responsibility for a design defect, it being agreed that all
     such responsibility shall remain solely with Lessee.

     Lessee shall reimburse Lessor promptly upon demand therefor for all
     out-of-pocket costs and expenses reasonably incurred by Lessor in
     connection with the review by Lessor's architect, engineer or other
     consultant (but not for Lessor's "in-house" review) of any plans, drawings
     and specifications submitted by Lessee pursuant to this Work Letter, which
     reimbursement shall be due and payable as Additional Rent.

4.   LESSEE'S GENERAL CONTRACTOR. Lessee shall obtain the prior reasonable
     written approval of Lessor as to Lessee's General Contractor.

5.   LESSEE'S WORK. Lessee shall be solely responsible for obtaining all
     Construction Authorizations required for Lessee's Work. Promptly after
     receiving the same, Lessee shall cause Lessee's General Contractor to
     commence construction and diligently to proceed to completion thereof. All
     construction shall be performed in a good and workmanlike manner, using new
     materials and in compliance with the Working Drawings, the Construction
     Authorizations, all Legal Requirements, and the provisions of all
     applicable insurance policies.

6.   DELAYS. No delays in the preparation of preliminary drawings, plans or
     specifications, or in the preparation of Working Drawings, or in the
     performance and completion of Lessee's Work, regardless of the cause
     thereof, shall affect the Commencement Date or the Rent Commencement Date.

     A breach of any provision of this Work Letter shall constitute a default
     under the Lease, for which Lessor shall have all remedies therein provided.

7.   LESSOR'S AND LESSEE'S REPRESENTATIVES. Prior to the commencement of any
     design work for the Premises, each party hereto shall designate in writing
     to the other a person as "Lessor's Representative" and "Lessee's
     Representative" respectively, which person shall be available during
     ordinary business hours to review the progress of the work

                                       C-3

<PAGE>   50

     and to respond to issues which arise during construction. Each party may
     rely on the other's Representative with respect to all matters which
     pertain to this Work Letter, each party having authorized its
     Representative to make decisions binding upon such party with respect to
     such matters.




                                       C-4





<PAGE>   51






                                    EXHIBIT D

                       FORM OF COMMENCEMENT DATE AGREEMENT
                       -----------------------------------

     This Exhibit is incorporated by reference into the Lease dated July 26,
1993 by and between Massachusetts Institute of Technology, as Lessor, and
Alkermes, Inc. as Lessee.


                           COMMENCEMENT DATE AGREEMENT
                           ---------------------------
 
     THIS COMMENCEMENT DATE AGREEMENT is made this __ day of ________, 199_ by
and between MASSACHUSETTS INSTITUTE OF TECHNOLOGY ("Lessor") and ALKERMES, INC.
("Lessee"). Reference is made to a Lease between Lessor and Lessee dated July
26, 1993 (the "Lease"), pursuant to which Lessor leased to Lessee a portion of
the building located at 281 Albany Street, as more particularly described in the
Lease (the "Premises"). Capitalized terms used in this Commencement Date
Agreement which are defined in the Lease and not otherwise defined herein shall
have the same meaning herein as therein.

     For good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, Lessor and Lessee hereby agree that the Commencement
Date for all purposes of the Lease is _______________________________, and that
the last day of the Initial Lease Term is ___________________.

     WITNESS the execution hereof under seal the day and year first above
written.


     LESSOR:                             MASSACHUSETTS INSTITUTE OF
                                         TECHNOLOGY


                                         By: 
                                            ------------------------------------
                                            Philip A. Trussell,
                                            Director of Real Estate
                                            Hereunto duly authorized

                                         Date: ______________, 199_


     LESSEE:                             ALKERMES, INC.


                                         By: 
                                            ------------------------------------
                                            Name:
                                            Title:
                                            Hereunto duly authorized

                                         Date: ______________, 199_

         


                                       D-1


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