Document:

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                                                                   Exhibit 10.21

                      LEASE FOR 125 SIDNEY STREET PROPERTY

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1.  PARTIES               Rizika Realty Trust (whose mailing address is: 36
                          Edgehill Road, Brookline, MA 02445), the LESSOR, which
                          expression shall include his heirs, successors, and
                          assigns where the context so admits, does hereby lease
                          to Altus Biologics Inc., the LESSEE, which expression
                          shall include his heirs, successors, executors, and
                          administrators where the context so admits, and the
                          LESSEE hereby leases the following described premises:

2.  PREMISES              All of the first floor that is cross-hatched in red on
                          the attached floor plan of the building at 125 Sidney
                          Street, Cambridge, a/k/a 16 Emily Street and/or 15
                          Tudor Street, Cambridge, comprising about 7,775 square
                          feet, together with parking spaces for fourteen (14)
                          cars, as designated by the LESSOR (the location as
                          shown on Exhibit A), and with the right to use in
                          common, with others entitled thereto, the hallways and
                          stairways necessary for access to said leased
                          premises.

3.  TERM                  The term of this lease shall be four (4) years,
                          commencing on April 15, 2002 and ending on April 14,
                          2006.

4.  RENT                  The LESSEE shall pay to the LESSOR rent at the
                          following rates:

    First Year            a. The first year's annual rent shall be three hundred
                          and twenty-two thousand six hundred and sixty-two
                          dollars and fifty cents ($322,662.50) to be paid in
                          advance in equal monthly payments of twenty-six
                          thousand eight hundred and eighty-eight dollars and
                          fifty-four cents ($26,888.54) on or before the tenth
                          day of each month by depositing the same to the
                          account of the LESSOR (Acct # 1102439611) at the
                          Citizens Bank in Boston, MA or as may otherwise be
                          directed by the LESSOR.

                          The annual rent is the gross rent and includes the
                          LESSEE's portion of real estate taxes, charges for
                          sewer and water, insurance (fire and extended coverage
                          in a minimum coverage of $2,000,000 for fire and
                          $5,000,000 public liability on the building), heat,
                          ventilation, air-conditioning, electricity, and snow
                          removal. However, if there are any substantial
                          increases in any of the forgoing due to the LESSEE's
                          actions (other than Lessee's decorative improvements
                          to the premises such as painting and carpeting, and
                          Lessee's use of the premises for ordinary office
                          purposes), the LESSEE will be billed for such charges
                          and pay them to the LESSOR at the end of each calendar
                          year.

                          Excluded from such rental payments are the costs of
                          any contents, liability, or other insurance necessary
                          to conduct the business of
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Lease for 125 Sidney Street Property                                     Page 1.
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                          the LESSEE on the Premises, all of which policies will
                          be obtained and paid for by the LESSEE. Also excluded
                          from such rental payments are the costs of cleaning
                          and other miscellaneous services supplied to the
                          LESSEE's portion of the building at Lessee's request.

    Other Years           b. At the end of each 12 months of rent, the annual
                          rent for the following 12 months will be adjusted by
                          the increase in the CPI-U ratio over the previous 12
                          months; in no event shall the annual adjusted rent be
                          less than the rent for the immediately preceding 12
                          month period. The CPI-U shall mean the Consumer Price
                          Index for Urban Consumers for the City of Boston as
                          published by the US Bureau of Labor Statistics.

5.  SECURITY DEPOSIT      Upon the execution of this lease, the LESSEE shall pay
                          to the LESSOR the amount of one hundred and seven
                          thousand and five hundred dollars ($107,500) which
                          shall be held as a security for the LESSEE's
                          performance as herein provided and refunded to the
                          LESSEE at the end of this lease subject to the
                          LESSEE's satisfactory compliance with the conditions
                          hereof.

6.  RENT ADJUSTMENTS      The LESSEE shall pay monthly in advance to the LESSOR
                          modified rent as described in Section 4.b.

7.  USE OF LEASED         The LESSEE shall use the leased premises only for the
    PREMISES              purpose of offices and/or light manufacturing and
                          quality control.

8.  COMPLIANCE WITH       The LESSEE acknowledges that no trade or occupation
    LAWS                  shall be conducted in the leased premises or use made
                          thereof which will be unlawful, improper, noisy or
                          offensive, or contrary to any law or any municipal
                          by-law or ordinance in force in the city or town in
                          which the premises are situated.

9.  FIRE INSURANCE        The LESSEE shall not permit any use (other than
                          ordinary office use) of the leased premises which will
                          make voidable any insurance on the property of which
                          the leased premises are a part, or on the contents of
                          said property or which shall be contrary to any law or
                          regulation from time to time established by the New
                          England Fire Insurance Rating Association, or any
                          similar body succeeding to its powers. The LESSEE
                          shall on demand reimburse the LESSOR, and all other
                          tenants, all extra insurance premiums caused by the
                          LESSEE's use of the premises.

10. MAINTENANCE OF        The LESSEE agrees to maintain the leased premises in
    PREMISES              the same condition as they are at the commencement of
                          the term or as they may be put in during the term of
                          this lease, reasonable wear and
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Lease for 125 Sidney Street Property                                     Page 2.
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                          tear, damage by fire and other casualty only excepted,
                          and whenever necessary, to replace plate glass and
                          other glass therein, acknowledging that the leased
                          premises are now in good order and the glass whole.
                          The LESSEE shall not permit the leased premises to be
                          overloaded, damaged, stripped or defaced, nor suffer
                          any waste. LESSEE shall obtain written consent of
                          LESSOR, not to be unreasonably withheld, before
                          erecting any sign on the premises.

                          However, the LESSOR is responsible for maintaining the
                          structural integrity of the building, including all
                          common areas, the roof, exterior walls, parking areas,
                          and all heating, ventilation, air-conditioning,
                          plumbing, utility, electric and mechanical systems in
                          good condition.

11. ALTERATIONS AND       The LESSEE shall not make structural alterations or
    ADDITIONS             additions to the leased premises, but may make
                          non-structural alterations provided the LESSOR
                          consents thereto in writing, which consent shall not
                          be unreasonably withheld or delayed. All such allowed
                          alterations shall be at LESSEE's expense and shall be
                          in. quality at least equal to the present
                          construction. LESSEE shall not permit any mechanics'
                          liens, or similar liens, to remain upon the leased
                          premises for labor and material furnished to LESSEE or
                          claimed to have been furnished to LESSEE in connection
                          with work of any character performed or claimed to
                          have been performed at the direction of LESSEE and
                          shall cause any such lien to be released of record
                          forthwith without cost to LESSOR. Any alterations or
                          improvements made by the LESSEE shall become the
                          property of the LESSOR at the termination of occupancy
                          as provided herein.

12. ASSIGNMENT AND        The LESSEE shall not assign or sublet the whole or any
    SUBLEASING            part of the leased premises without LESSOR's prior
                          written consent, which consent shall not be
                          unreasonably withheld or delayed. Notwithstanding such
                          consent, LESSEE shall remain liable to LESSOR for the
                          payment of all rent and for the full performance of
                          the covenants and conditions of this lease.

                          If over half of the space is to be sublet, the LESSOR,
                          at its option, may terminate the lease by giving the
                          LESSEE such notice in writing at least one month prior
                          to such termination date.

13. SUBORDINATION         This lease shall be subject and subordinate to any and
                          all mortgages, deeds of trust and other instruments in
                          the nature of a mortgage, now or at any time
                          hereafter, a lien or liens on the property of which
                          the leased premises are a part and the LESSEE shall,
                          when requested, promptly execute and deliver such
                          written
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Lease for 125 Sidney Street Property                                     Page 3.
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                          instruments as shall be necessary to show the
                          subordination of this lease to said mortgages, deeds
                          of trust or other such instruments in the nature of a
                          mortgage.

                          In the event that the premises are mortgaged, the
                          Lessor shall obtain from the mortgages of the building
                          a Nondisturbance Agreement in commercially reasonable
                          form which recognized the rights of the Lessee under
                          this lease.

14. LESSOR'S ACCESS       The LESSOR or agents of the LESSOR may, at reasonable
                          times, enter to view the leased premises and may
                          remove placards upon reasonable notice and signs not
                          approved and affixed as herein provided, and make
                          repairs and alterations as LESSOR should elect to do
                          and may show the leased premises to others, and at any
                          time within six (6) months before the expirations of
                          the term, may affix to any suitable part of the leased
                          premises a notice for letting or selling the leased
                          premises or property of which the leased premises are
                          a part and keep the same so affixed without hindrance
                          or molestation.

15. INDEMNIFICATION AND   The LESSEE shall save the LESSOR harmless from all
    LIABILITY             loss and damage to LESSEE's property occasioned by the
                          use or escape of LIABILITY water or by the bursting of
                          pipes, as well as from any claim or damage resulting
                          from neglect in not removing snow and ice from the
                          roof of the building or from the sidewalks bordering
                          upon the premises so leased, or by any nuisance made
                          or suffered on the leased premises, unless such loss
                          is caused by the neglect of the LESSOR. The removal of
                          snow and ice from the sidewalks bordering upon the
                          leased premises shall be the LESSOR's responsibility.

16. LESSEE'S LIABILITY    The LESSEE shall maintain with respect to the leased
    INSURANCE             premises and the property, of which the leased
                          premises are a part, comprehensive public liability
                          insurance in the amount of $2,000,000 for bodily
                          injury and with property damage insurance in limits of
                          $1,000,000 with responsible insurance companies
                          qualified to do business in Massachusetts and in good
                          standing therein insuring the LESSOR as well as LESSEE
                          against injury to persons or damage to property as
                          provided. The LESSEE shall deposit with the LESSOR
                          certificates for such insurance at or prior to the
                          commencement of the term, and thereafter within thirty
                          (30) days prior to the expiration of any such
                          policies. All such insurance certificates shall
                          provide that such policies shall not be canceled
                          without at least ten (10) days prior written notice to
                          each assured named therein.
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Lease for 125 Sidney Street Property                                     Page 4.
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17. FIRE, CASUALTY, AND   Should a substantial portion of the leased premises,
    EMINENT DOMAIN        or of the property of which they are a part, be
                          substantially damaged by fire or other casualty, or be
                          taken by eminent domain, the LESSOR may elect to
                          terminate this lease. When such fire, casualty, or
                          taking renders the leased premises substantially
                          unsuitable for their intended use, a just and
                          proportionate abatement of rent shall be made, and the
                          LESSEE may elect to terminate this lease if:

                          a. the LESSOR fails to give written notice within
                          thirty (30) days of intention to restore leased
                          premises, or

                          b. the LESSOR fails to restore the leased premises to
                          a condition substantially suitable for their intended
                          use within ninety (90) days of said fire, casualty, or
                          taking.

                          The LESSOR reserves, and the LESSEE grants to the
                          LESSOR, all rights which the LESSEE may have for
                          damages or injury to the leased premises for any
                          taking by eminent domain, except for damage to the
                          LESSEE's fixtures, property, or equipment.

18. DEFAULT AND           In the event that:
    BANKRUPTCY
                          a. the LESSEE shall default in the payment of any
                          installment of rent or other sum herein specified, and
                          such default shall continue for five (5) days after
                          written notice thereof, or

                          b. the LESSEE shall default in the observance or
                          performance of any other of the LESSEE's covenants,
                          agreements, or obligations hereunder and such default
                          shall not be corrected within thirty (30) days after
                          written notice thereof, or

                          c. the LESSEE shall be declared bankrupt or insolvent
                          according to law, or, if any assignment shall be made
                          of LESSEE's property for the benefit of creditors,

                          then the LESSOR shall have the right thereafter, while
                          such default continues, to re-enter and take complete
                          possession of the leased premises, to declare the term
                          of this lease ended, and remove the LESSEE's effects,
                          without prejudice to any remedies which might be
                          otherwise used for arrears of rent or other default.
                          The LESSEE shall indemnify the LESSOR against all loss
                          of rent and other payments which the LESSOR may incur
                          by reason of such termination during the residue of
                          the term. If the LESSEE shall default, after
                          reasonable notice thereof, in the observance or
                          performance of any conditions or covenants on LESSEE's
                          part to be observed or performed under or by virtue of
                          any of the provisions in any article of this lease,
                          the LESSOR, without being
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Lease for 125 Sidney Street Property                                     Page 5.
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                          under any obligation to do so and without thereby
                          waiving such default, may remedy such default for the
                          account and at the expense of the LESSEE. If the
                          LESSOR makes any expenditures or incurs any
                          obligations for the payment of money in connection
                          therewith, including but not limited to, reasonable
                          attorney's fees in instituting, prosecuting or
                          defending any action or proceeding, such sums paid or
                          obligations insured, with interest at the rate of ten
                          (10) per cent per annum and costs, shall be paid to
                          the LESSOR by the LESSEE as additional rent.

19. NOTICE                Any notice from the LESSOR to the LESSEE relating to
                          the leased premises or to the occupancy thereof, shall
                          be deemed duly served three days after being mailed to
                          Mr. Peter Lanciano, Altus Biologics Inc., 625 Putnam
                          Avenue, Cambridge, MA 02139 by registered or certified
                          mail, return receipt requested, postage prepaid or at
                          such other address as Lessee may from time to time
                          advise in writing. Any notice from the LESSEE to the
                          LESSOR relating to the leased premises or to the
                          occupancy thereof, shall be deemed duly served, three
                          days after being mailed to the LESSOR by registered or
                          certified mail, return receipt requested, postage
                          prepaid, addressed to the LESSOR at the address
                          provided in Clause 1 or at such address as the LESSOR
                          may from time to time advise in writing.

20. SURRENDER             The LESSEE shall at the expiration or other
                          termination of this lease remove all LESSEE's goods
                          and effects from the leased premises (including,
                          without hereby limiting the generality of the
                          foregoing, all signs and lettering affixed or painted
                          by the LESSEE, either inside or outside the leased
                          premises). LESSEE shall deliver to the LESSOR the
                          leased premises and all keys, locks thereto, and other
                          fixtures connected therewith and all alterations and
                          additions made to or upon the leased premises, in the
                          same condition as they were at the commencement of the
                          term, or as they were put in during the term hereon,
                          reasonable wear and tear and damage by fire or other
                          casualty only excepted. In the event of the LESSEE's
                          failure to remove any of LESSEE's property from the
                          premises, LESSOR is hereby authorized, without
                          liability to LESSEE for loss or damage thereto, and at
                          the sole risk of LESSEE, to remove and store any of
                          the property at LESSEE's expense, or to retain same
                          under LESSOR's control or to sell at public or private
                          sale, without notice of any or all of the property not
                          so removed and to apply the net proceeds of such sale
                          to the payment of any sum due hereunder, or to destroy
                          such property.
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Lease for 125 Sidney Street Property                                     Page 6.
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21. OTHER PROVISIONS      The following other provisions are hereby incorporated
                          as an integral part of this lease:

                          a. Smoking - There is a smoke-free environment
                          associated with this building and, as such, smoking is
                          not permitted on any part of the Premises.

                          b. Food - If food is consumed on the Premises, proper
                          care shall be exercised for its storage and any
                          residue shall be placed in a sealed container while on
                          the Premises. It is the responsibility of the LESSEE
                          to provide for its proper removal and disposal.

                          c. All additional provisions contained in the side
                          letter attached hereto as Exhibit B.

22. SEVERABILITY CLAUSE   If any provision of this lease, or any portion of any
                          provision, or the application thereof to any person or
                          circumstance is held invalid, the remainder of the
                          lease (or remainder of such provision) and the
                          application thereof to other persons or circumstances
                          shall not be affected thereby.
</TABLE>

IN WITNESS WHEREOF, the LESSOR and LESSEE have hereunto set their hands and
common seals this 4th day of April, 2002.

/s/ [Illegible]                         /s/ Peter Lanciano
-------------------------------------   ----------------------------------------
LESSOR (Rizika Realty Trust)            LESSEE (Altus Biologics Inc.)

                                        By: Peter Lanciano
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title: President & CEO

Lease for 125 Sidney Street Property                                     Page 7.
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                                    EXHIBIT B

                     LEASE FOR 125 SIDNEY STREET, CAMBRIDGE

                                   SIDE LETTER

4 April 2002

In addition to the terms and conditions stated in the lease dated 4 April, 2002,
the Rizika Realty Trust, the LESSOR, and Altus Biologics Inc., the LESSEE, agree
to the following:

     1.   Lessee will have an option to extend the term of this Lease for an
          additional period of two (2) years to be exercised by written notice
          from Lessee to Lessor no less than six (6) months prior to the lease
          expiration. All terms and covenants of the lease shall remain the same
          with the exception of rent, which shall be renegotiated.

          Lessor shall inform the Lessee of the rental rate for the extention
          term no later than ten (10) business days after receiving notice that
          Lessee desires to exercise the option. Lessee shall accept or decline
          option to extend lease no later than ten (10) business days after
          being informed of rent for the extension term.

     2.   It is understood that the Lessor shall be responsible for the one-time
          payment of the Broker's fee to CRESA Partners of $3.20 per sq ft of
          space rented-- for example, based upon 7,775 sq ft the Broker's fee
          would be $24,880. Half of this fee is to be paid at the signing of the
          lease; the remaining half is to be paid on the first day of occupancy
          by the Lessee.

          Lessor and Lessee each mutually covenant, represent and warrant to the
          other that it has had no dealings or communications with any broker or
          agent in connection with this Lease other than CRESA Partners and each
          covenants and agrees to pay, hold harmless and indemnify the other
          from and against any and all cost, expense or liability for any
          compensation commission or charges to any broker or agent claiming
          through the indemnifying party with respect hereto.

     3.   The Lessee agrees to split the cost of building a separating wall
          between it's rental area and the other section of the building. This
          cost will not exceed $12,000 for the Lessee.

     4.   If any utility bills which affect the Lessee are unpaid and remain so
          for thirty (30) days, it is agreed that the Lessee shall have the
          right to pay them directly and deduct all such payments from the rent.

     5.   Lessor and Lessee mutually agree that, with respect to any hazard
          which is covered by insurance then being carried by them,
          respectively, the one carrying such insurance and suffering such loss
          releases the other of and from any and all claims with respect to such
          loss.

Lease for 125 Sidney Street Property                                     Page 8.
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     6.   The Lessee will reasonably expect to have full use of their offices
          and space in a fair and useful manner for the period of their lease.
          Full use and enjoyment as used herein shall include, without
          limitation, the provision of the services required to be provided by
          the Lessor hereunder, and freedom from unreasonable interference with
          the Lessee's use and occupancy as a result of the construction of any
          additions to the building. Lessee shall be entitled to an equitable
          abatement of rent if they are not able to have full use of their
          offices for more than 30 days and the Lessor has not made changes to
          resolve the Lessee's full use of their office.

     7.   The Lessor shall at all times during the term of this Lease provide
          the following services to the Premises at no charge except as set
          forth in Section 4 of the Lease: heat, ventilation, air-conditioning,
          electricity, water and sewer, all in compliance with applicable laws
          and in amounts and in a manner reasonable and sufficient for the safe
          and comfortable occupancy of the Premises for the uses permitted
          hereunder. Lessor represents that all of the foregoing systems are in
          good working order,

     8.   Lessor indemnifies and holds Lessee harmless from and against all loss
          and damage suffered by Lessee on account of Lessor's negligence or
          willful misconduct, or, to the best of the Lessor's knowledge, the
          presence of hazardous materials (as defined in any applicable federal,
          state or local law, rule or regulation) or oil located in, on, under
          or at the Premises or the building as of the date of this lease.

     9.   Lessee is responsible for obtaining a valid certificate of occupancy
          for the building which permits the use of the Premises for the uses
          permitted under this lease. Lessor represents that, to the best of its
          knowledge, (a) there are no outstanding violations of law with respect
          to the Premises and (b) the Premises are vacant and free of any
          occupancy rights of any other person or entity.

Agreed and accepted:

/s/ [Illegible], Pres.                  /s/ Peter Lanciano
-------------------------------------   ----------------------------------------
LESSOR (Rizika Realty Trust)            LESSEE (Altus Biologics Inc.)

Lease for 125 Sidney Street Property                                     Page 9.
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                                    EXHIBIT B

                     LEASE FOR 125 SIDNEY STREET, CAMBRIDGE

                                   SIDE LETTER

4 April 2002

In addition to the terms and conditions stated in the lease dated 4 April, 2002,
the Rizika Realty Trust, the LESSOR, and Altus Biologics Inc., the LESSEE, agree
to the following:

     1.   Lessee will have an option to extend the term of this Lease for an
          additional period of two (2) years to be exercised by written notice
          from Lessee to Lessor no less than six (6) months prior to the lease
          expiration. All terms and covenants of the lease shall remain the same
          with the exception of rent, which shall be renegotiated.

          Lessor shall inform the Lessee of the rental rate for the extention
          term no later than ten (10) business days after receiving notice that
          Lessee desires to exercise the option. Lessee shall accept or decline
          option to extend lease no later than ten (10) business days after
          being informed of rent for the extension term.

     2.   It is understood that the Lessor shall be responsible for the one-time
          payment of the Broker's fee to CRESA Partners of. $1.60 per sq ft of
          space rented-for example, based upon 1,725 sq ft the Broker's fee
          would be $2,760. Half of this fee is to be paid at the signing of the
          lease; the remaining half is to be paid on the first day of occupancy
          by the Lessee.

          Lessor and Lessee each mutually covenant, represent and warrant to the
          other that it has had no dealings or communications with any broker or
          agent in connection with this Lease other than CRESA Partners and each
          covenants and agrees to pay, hold harmless and indemnify the other
          from and against any and all cost, expense or liability for any
          compensation commission or charges to any broker or agent claiming
          through the indemnifying party with respect hereto.

     3.   If any utility bills which affect the Lessee are unpaid and remain so
          for thirty (30) days, it is agreed that the Lessee shall have the
          right to pay them directly and deduct all such payments from the rent.

     4.   The Lessee will reasonably expect to have full use of their offices
          and space in a fair and useful manner for the period of their lease.
          Full use and enjoyment as used herein shall include, without
          limitation, the provision of the services required to be provided by
          the Lessor hereunder, and freedom from unreasonable interference with
          the Lessee's use and occupancy as a result of the construction of any
          additions to the building. Lessee shall be entitled to an equitable
          abatement of rent if they are not able to have full use of their
          offices for more than 30 days and the Lessor has not made changes to
          resolve the Lessee's full use of their office.

Lease for 125 Sidney Street Property                                     Page 8.
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     5.   The Lessor shall at all times during the term of this Lease provide
          the following services to the Premises at no charge except as set
          forth in Section 4 of the Lease: heat, ventilation, air-conditioning,
          electricity, water and sewer, all in compliance with applicable laws
          and in amounts and in a manner reasonable and. sufficient for the safe
          and comfortable occupancy of the Premises for the uses permitted
          hereunder. Lessor represents that all of the foregoing systems are in
          good working order.

     6.   Lessor indemnifies and holds Lessee harmless from and against all
          loss, and damage suffered by Lessee on account of Lessor's negligence
          or willful misconduct, or, to the best 'of the Lessor's knowledge, the
          presence of hazardous materials (as defined in any applicable federal,
          state or local law, rule or regulation) or oil located in, on, under
          or at the Premises or the building as of the date of this lease.

     7.   Lessee is responsible for obtaining a valid certificate of occupancy
          for the building which permits the use of the Premises for the uses
          permitted under this lease. Lessor represents that, to the best of its
          knowledge, (a) there are no outstanding violations of law with respect
          to the Premises and (b) the Premises are vacant and free of any
          occupancy rights of any other person or entity.

     8.   Lessor and Lessee mutually agree that, with respect to any hazard
          which is covered by insurance then being carried by them,
          respectively, the one carrying such insurance and suffering such loss
          releases the other of and from any and all claims with respect to such
          loss.

Agreed and accepted:

/s/ [Illegible]                         /s/ Peter Lanciano
-------------------------------------   ----------------------------------------
LESSOR (Rizika Realty Trust)            LESSEE (Altus Biologics Inc.)

Lease for 125 Sidney Street Property                                     Page 9.
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                AMENDMENT OF LEASE FOR 125 SIDNEY STREET PROPERTY

WHEREAS, Rizika Realty Trust (whose mailing address is: 36 Edgehill Road,
Brookline, MA 02445), the LESSOR, entered into a Lease dated April 4, 2002 (the
"Lease") with Altus Pharmaceuticals Inc., f/k/a "Altus Biologics Inc."
("LESSEE"), for approximately 7,775 square feet ("Original Premises") on the
first floor of the building located at 125 Sidney Street, Cambridge,
Massachusetts (the "Building");

WHEREAS, LESSOR and LESSEE desire to amend the Lease to temporarily add
approximately 3,000 square feet in the basement of the Building (the "Basement
Premises") to the Premises for a period of four (4) months;

NOW, LESSOR and LESSEE hereby agree to Lease the Basement Premises on the terms
and conditions contained herein:

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1.   PREMISES      Commencing on the BP Commencement Date, as defined below,
                   approximately 3,000 square feet of space in the basement of
                   the Building comprised of 10 cubicles and a conference room
                   shall be added to the Premises as defined in the Lease. The
                   demise of the Premises shall include rights of access through
                   such common areas through the Building as are necessary or
                   desirable for access thereto.

2.   TERM          The Basement Premises is leased for a term of four (4) months
                   (the "BP Term") commencing on September 7, 2004 (the "BP
                   Commencement Date") and ending on January 7, 2005. LESSOR
                   shall deliver possession of the Basement Premises to LESSEE
                   in "broom clean" condition, free of all occupants with all
                   systems serving the same in good and operational condition.

3.   RENT          In addition to the annual rent due under the Lease with
                   respect to the Original Premises, the LESSEE shall pay to the
                   LESSOR rent at the following rates for the Basement Premises
                   during the BP Term:

                   The monthly gross rent for the Basement Premises shall be
                   $10,000 a month. The rental amount is based on net rent of
                   $5,000 a month and another $5,000 a month for the LESSEE's
                   portion of real estate taxes, charges for sewer and water,
                   insurance, heat, electricity, and snow removal.
                   Notwithstanding any provision of the Lease to the contrary,
                   the rent for the Basement Premises is gross and LESSEE shall
                   not be responsible for any CPI increases in the monthly gross
                   rent or for any other expenses or additional rent, except as
                   set forth in the following paragraph.

                   Excluded from such rental payments are the costs of any
                   contents, liability, or other insurance necessary to conduct
                   the business of the LESSEE on the Premises, all of which
                   policies will be obtained and paid for by the LESSEE. The
                   LESSEE shall pay monthly on the 16th
</TABLE>

Lease for 125 Sidney Street Property                                     Page 1.
<PAGE>
<TABLE>
<S>                <C>
                   of the month for the following month's rent as part of the
                   Lease; provided, however, the first month's rent of $10,000
                   for the Basement Premises shall be paid upon execution of
                   this Amendment by the LESSOR and LESSEE.

4.   ACCESS        The LESSOR will have the right to show the Basement Premises
                   to other potential lessees during working hours provided that
                   they give a two hour advanced warning.

                   Prior to the BP Commencement Date, LESSOR will provide LESSEE
                   with 15 access key cards for the Basement Premises.

5.   OTHER TERMS   Except as set forth herein, the Basement Premises are leased
                   on the same terms and conditions of the Lease, and the term
                   Premises as used in the Lease shall include the Basement
                   Premises. Notwithstanding the foregoing, Section 2 of Exhibit
                   B to the Lease and the first sentence of Section 7 of Exhibit
                   B to the Lease shall not apply to the Basement Premises. If a
                   certificate of occupancy is required, LESSEE shall have the
                   option to terminate the lease with respect to the Basement
                   Premises upon ten (10) days' prior written notice. This
                   Amendment set forth the entire agreement between the parties.
</TABLE>

Agreed and accepted:

/s/ [Illegible]                         /s/ Peter Lanciano
-------------------------------------   ----------------------------------------
LESSOR (Rizika Realty Trust)            LESSEE (Altus Biologics, Inc.)

Lease for 125 Sidney Street Property                                     Page 2.
<PAGE>
                AMENDMENT OF LEASE FOR 125 SIDNEY STREET PROPERTY

WHEREAS, Rizika Realty Trust (whose mailing address is: 36 Edgehill Road,
Brookline, MA 02445), the LESSOR, entered into a Lease dated April 4, 2002 (the
"Lease") with Altus Pharmaceuticals Inc. (formerly known as "Altus Biologics
Inc."), the LESSEE, for approximately 7,775 square feet ("Original Premises") on
the first floor of the building located at 125 Sidney Street, Cambridge,
Massachusetts (the 'Building");

WHEREAS, LESSOR and LESSEE desire to amend the Lease to add approximately 11,000
square feet in the basement of the Building (the "Basement Premises") to the
Premises for a period of fifteen (15) months;

NOW, LESSOR and LESSEE hereby agree to Lease the Basement Premises on the terms
and conditions contained herein:

<TABLE>
<S>                <C>
1.   PREMISES      Commencing on the BP Commencement Date as defined below,
                   approximately 11,000 square feet of space (the entire
                   basement of the Building) as shown on Exhibit A hereto shall
                   be added to the Original Premises. The demise of the Basement
                   Premises shall include rights of access through such common
                   areas as are necessary for access thereto. The parking spaces
                   marked by an "*" on Exhibit B hereto shall also be included
                   in the Basement Premises.

2.   TERM          The Basement Premises is leased for a term of approximately
                   fifteen (15) months (the "BP Term") commencing on January 7,
                   2005 (the "BP Commencement Date") and ending on April 7,
                   2006. LESSOR shall deliver possession of the Basement
                   Premises to LESSEE in a "broom clean" condition, free of all
                   occupants with all systems serving the same in good and
                   operational condition. At the end of the BP Term the LESSEE
                   shall deliver possession of the Basement Premises to LESSOR
                   in the same condition it was initially received and free of
                   all occupants with all systems serving the same in good and
                   operational condition, reasonable wear and tear, damage by
                   fire or other casualty excepted.

3.   RENT          In addition to the annual rent due under the Lease with
                   respect to the Original Premises, the LESSEE shall pay to the
                   LESSOR rent at the following rates for the Basement Premises
                   during the BP Term:

                   The monthly gross rent for the Basement Premises shall be
                   $16,000 a month. This includes the LESSEE's portion of real
                   estate taxes, charges for sewer and water, insurance, heat,
                   electricity and snow removal. The rent will not increase
                   during the lease period, unless real estate taxes, charges
                   for sewer and water, insurance, heat, electricity or snow
                   removal cost increase. If an increase in rent is requested,
                   the LESSOR will share the bills for the last 24 months with
                   the LESSEE to justify the increase. Notwithstanding any
                   provision of the Lease to the contrary, the rent for the
                   Basement Premises is gross and LESSEE shall not be
                   responsible for any
</TABLE>

Lease for 125 Sidney Street Property                                     Page 1.
<PAGE>
<TABLE>
<S>                <C>
                   CPI increases in the monthly gross rent or for any other
                   expenses or additional rent, except as set forth in the
                   following paragraph.

                   Excluded from such rental payments are the costs of any
                   contents, liability, or other insurance necessary to conduct
                   the business of the LESSEE on the Premises, all of which
                   policies will be obtained and paid for by the LESSEE. The
                   LESSEE shall pay monthly on the 7th of the month for the
                   following month's rent as party of the Lease; provided,
                   however, the first month's rent of $16,000 for the Basement
                   Premises shall be paid upon execution of this Amendment by
                   the LESSOR and LESSEE.

4.   ACCESS        The LESSOR will have the right to show the Basement Premises
                   to other potential lessees during working within working
                   hours provided that they give a two-hour advanced warning.
                   The LESSEE will program access to the Basement Premises for
                   its employees. When the LESSEE moves out, the LESSOR will
                   have the option to keep the key card system as is, or have
                   the LESSEE reconfigure the key card system as it was a the
                   start of the lease.

5.   OTHER TERMS   Except as set forth herein, the Basement Premises are leased
                   on the same terms and conditions of the Lease, and the term
                   Premises as used in the Lease shall include the Basement
                   Premises. Notwithstanding the foregoing, Section 2 of Exhibit
                   B to the Lease and the first sentence of Section 7 of Exhibit
                   B to the Lease shall not apply to the Basement Premises. If a
                   certificate of occupancy is required, LESSEE shall have the
                   option to terminate the lease with respect to the Basement
                   Premises upon ten (10) days' prior written notice. This
                   Amendment set forth the entire agreement between the parties.
</TABLE>

Agreed and accepted:

/s/ [Illegible]                         /s/ Peter Lanciano
-------------------------------------   ----------------------------------------
LESSOR (Rizika Realty Trust)            LESSEE (Altus Biologics, Inc.)

Lease for 125 Sidney Street Property                                     Page 2.
<PAGE>
                                      [MAP]

Lease for 125 Sidney Street Property                                     Page 3.
<PAGE>
                                      [MAP]

Lease for 125 Sidney Street Property                                     Page 4.<PAGE>
                                                                   Exhibit 10.22

                               ASSIGNMENT OF LEASE

     This agreement of Assignment is entered into as of the 1st day of January,
2001, by and between VERTEX PHARMACEUTICALS INCORPORATED ("Vertex"), a
Massachusetts corporation having offices at 130 Waverly Street, Cambridge, MA
02139, ALTUS BIOLOGICS INC. ("Altus"), a Massachusetts corporation having
offices at 625 Putnam Avenue; Cambridge, MA 02139, and FORT WASHINGTON
ASSOCIATES LLC, a Massachusetts limited liability corporation ("Landlord").

                                    RECITALS

     A. Vertex is the Tenant under a Lease Agreement dated as of March 1, 1993,
as amended by a First Amendment dated 1 December 1996 and a Second Amendment
dated 1 February 1998 (the "Lease") with respect to the premises located at 625
Putnam Avenue, Cambridge, Massachusetts (the "Premises").

     B. Landlord is the Landlord with respect to the Lease.

     C. Altus subleases a portion of the Premises from Vertex under a Sublease
dated February 1, 1999.

     D. Vertex wishes to assign its interest as Tenant under the Lease to Altus,
and Altus wishes to assume the obligations of the Tenant under the Lease.

     E. Altus wishes to exercise the Tenant's option under the Lease to extend
the term of the Lease from 1 January 2001 through December 2003.

     F. Upon execution of this Assignment, Altus and Vertex will enter into a
Sublease under which Vertex will sublease from Altus a portion of the Premises.

     NOW THEREFORE, the parties agree as follows:

1. Vertex hereby assigns to Altus all of its right, title and interest as Tenant
under the Lease.

2. Altus hereby assumes all of Vertex's rights and obligations as Tenant under
the Lease.

3. Altus hereby exercises its option under the Lease to extend the term of the
Lease from 1 January 2001 through December 2003.

4. The Landlord hereby consents to the foregoing assignment and assumption and
agrees that Vertex shall have no further obligations under the Lease, except in
its capacity as sublessee under the Sublease between Vertex and Altus of even
date herewith.

                                       -1-
<PAGE>
     EXECUTED as of the date first set forth above.

VERTEX PHARMACEUTICALS INCORPORATED

By: /s/ Thomas G. Auchincloss, Jr.
    ---------------------------------
Name: Thomas G. Auchincloss, Jr.
      -------------------------------
Title: V.P. of Finance
       ------------------------------

ALTUS BIOLOGICS INC.

By: /s/ Peter Lanciano
    ---------------------------------
Name: Peter Lanciano
      -------------------------------
Title: President and CEO
       ------------------------------

FORT WASHINGTON ASSOCIATES LLC

By: /s/ Henry H. Koley
    ---------------------------------
Name: Henry H. Koley
      -------------------------------
Title: President
       ------------------------------

                                       -2-
<PAGE>
                                 LEASE AGREEMENT

                                 by and between

                          FORT WASHINGTON REALTY TRUST

                                       and

                          VERTEX PHARMACEUTICALS, INC.

                           Dated as of March 1, 1993.
<PAGE>
                                TABLE OF CONTENTS

<TABLE>
<S>                                                                           <C>
1.  LEASE OF PREMISES......................................................    1
      1.1     Subjects Referred To.........................................    1
      1.2     Lease of Premises............................................    2

2.  TERM...................................................................    2

3.  RENT...................................................................    2
      3.1     Rent.........................................................    2
      3.2     Late Payment.................................................    2

4.  TAXES..................................................................    3
      4.1     Real Estate Taxes............................................    3
      4.2     Other Taxing System..........................................    3
      4.3     Betterment Assessments.......................................    4
      4.4     Additional Tax Fund Payments.................................    4

5.  INSURANCE..............................................................    5
      5.1     Risk Casualty Insurance......................................    5
      5.2     Liability Insurance..........................................    5
      5.3     Sprinkler Insurance..........................................    5
      5.4     Fire Insurance...............................................    6
      5.5     Other Insurance..............................................    6
      5.6     Additional Insurance Provisions..............................    6
      5.7     Subrogation..................................................    6

6.  UTILITIES..............................................................    7

7.  TENANTS ADDITIONAL COVENANTS...........................................    8
      7.1     Affirmative Covenants........................................    8
      7.2     Negative Covenants...........................................   13

8.  CASUALTY OR TAKING.....................................................   16
      8.1     Termination by Landlord......................................   16
      8.2     Termination by Tenant........................................   17
      8.3     Restoration..................................................   17
      8.4     Award........................................................   18

9.  DEFAULTS...............................................................   19
      9.1     Events of Default............................................   19
</TABLE>

                                       -i-
<PAGE>
<TABLE>
<S>                                                                           <C>
      9.2     Remedies.....................................................   20
      9.3     Remedies Cumulative..........................................   21
      9.4     Landlord's Right to Cure Defaults............................   22
      9.5     Effect of Waivers of Default.................................   22
      9.6     No Waiver, etc...............................................   22
      9.7     No Accord and Satisfaction...................................   22

10. RIGHTS OF MORTGAGE HOLDERS.............................................   23
      10.1    Rights of Mortgage Holders...................................   23
      10.2    Lease Superior or Subordinate to Mortgages...................   24

11. MISCELLANEOUS PROVISIONS...............................................   25
      11.1    Notices from One Party to the Other..........................   25
      11.2    Quiet Enjoyment..............................................   25
      11.3    Lease not to be Recorded.....................................   26
      11.4    Limitation of Landlord's Liability...........................   26
      11.5    Acts of God..................................................   26
      11.6    Landlord's Default...........................................   27
      11.7    Brokerage....................................................   27
      11.8    Applicable Law and Construction..............................   27
      11.9    Capital Improvement Cost Recovery............................   28
      11.10   Option to Extend.............................................   29
</TABLE>

                                      -ii-
<PAGE>
                                 LEASE AGREEMENT

     THIS LEASE is made as of this 1st day of March, 1993 by and between HENRY
H. KOLM and ELIZABETH C. KOLM, Trustees of FORT WASHINGTON REALTY TRUST, Weir
Meadow, Wayland, Massachusetts 01778 and VERTEX PHARMACEUTICALS, INC, a
Massachusetts corporation with its principal place of business at 40 Allston
Street, Cambridge, Massachusetts 02139.

     1.   LEASE OF PREMISES.

     1.1 Subjects Referred To. Each reference in this Lease to any of the
following subjects shall be construed to incorporate the data stated for that
subject in this Section 1.1.

<TABLE>
<S>                        <C>
     Date of this Lease:   March 1, 1993

     Building:             One level masonry building.

     Premises:             The Building, comprising about 15,750 square feet,
                           and the approximately 27,775 square feet of land on
                           which the Building is situated, such parcel. of land
                           being described in Exhibit A attached hereto.

     Landlord:             Henry H. Kaim and Elizabeth C. Kolm, Trustees of the
                           Fort Washington Realty Trust u/d/t dated July 20,
                           1983 and filed with the Middlesex South District
                           Registry of Deeds at Book 15164, Page 520.

     Tenant:               VERTEX PHARMACEUTICALS, INCORPORATED, a Massachusetts
                           corporation with its principal place of business at
                           40 Allston Street, Cambridge, Massachusetts 02139.
</TABLE>

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 1 of 30 pages
<PAGE>
<TABLE>
<S>                        <C>
     Term:                 Three years and eleven months, commencing March 1,
                           1993 and ending January 31, 1997.

     Rent:                 Sixteen Thousand Five Hundred Ninety per month
                           ($16,590/month) (199,080 per year), triple net of all
                           taxes, insurance; utilities, and operating expenses.

     Permitted Use:        Office, research and development, and light
                           manufacturing.
</TABLE>

     1.2 Lease of Premises. Landlord hereby leases to Tenant, and Tenant hereby
leases from Landlord, subject to and with the benefit of the terms, covenants,
conditions, provisions and Exhibit A, of this Lease, the Premises.

     2. TERM.

The term of this Lease shall be for a period of three years and eleven months,
commencing on March 1, 1993 and ending on January 31, 1997, unless sooner
terminated as provided herein or further extended.

     3. RENT.

     3.1 Rent. Subject to the terms and covenants of this Lease, Tenant shall
pay to Landlord, at Landlord's office or to such other persons or at such other
places in the United States as directed by written notice to Tenant from
Landlord the Annual Rent of One Hundred Ninety-Nine Thousand and Eighty Dollars
($199,080) in equal monthly installments of Sixteen Thousand Five Hundred Ninety
Dollars ($16,590), each payable in advance on the first day of every calendar
month during the Term of the Lease and at a prorated rate for fractions of a
month if the Initial Term shall be terminated on any day other than the last day
of the month.

     3.2 Late Payment. (See also Section 9). If any installment of rent or any
sums due to Landlord under this Lease, are paid more than ten (10) days after
the date the same was due, such

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 2 of 30 pages
<PAGE>
late payment shall bear interest from the date due at the lesser of the prime
rate, so-called, of the Fleet Bank as it may be adjusted from time to time, plus
four percent per annum, or the maximum rate allowed by law.

     4.   TAXES.

     4.1 Real Estate Taxes. Tenant agrees to pay to Landlord, on a monthly basis
simultaneous with the payment of rent, one-twelfth (1/12) of all taxes levied or
assessed by, or becoming payable to the municipality or any governmental
authority having jurisdiction over the Premises, for or in respect of the
Premises, the taxes levied or assessed or becoming payable for or in respect of
the Premises for the then current tax period. If Tenant shall deem itself
aggrieved by any such tax or charge and shall elect to contest the payment
thereof, it shall have the right to so contest such charge, and Tenant agrees to
save Landlord harmless from all costs and expenses incurred on account of
Tenant's participation in such proceedings.

     4.2 Other Taxing System. If, at any time during the Term or Renewal Term of
this Lease, the present system of ad valorem taxation of real property shall be
changed so that in lieu of, or in addition to, the whole or any part thereof
there shall be assessed on Landlord a capital levy or other tax on the sums due
from Tenant to landlord under this Lease, or if there shall be assessed on
Landlord a federal, state, county, municipal, or other local, income, franchise,
excise or similar tax, assessment, levy or charge measured by or based, in whole
or in part, upon the rent and other sums payable by Tenant hereunder, then any
and all of such taxes, assessments, levies or charges, to the extent that the
same would be payable if the Premises were the only property of Landlord subject
to same, and if the income from the Premises were the only taxable income of the
Landlord in question, shall be deemed to be included in the taxes to be paid by
Tenant pursuant to this Section 4.

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 3 of 30 pages
<PAGE>
     4.3 Betterment Assessments. Tenant shall pay to Landlord each installment
of all public, special or betterment assessments levied or assessed by or
becoming payable to any municipality or other governmental authority having
jurisdiction of the Premises, for or in respect of the Premises for each
installment period partially or to be wholly included in the Initial Term or
Renewal Term, such payments to be made to the Landlord in the same manner as
provided in Section 4.1 above. Tenant may prosecute appropriate proceedings to
contest the validity or amount of any assessment with respect to which Tenant is
required to make payments as hereinabove provided, and Tenant agrees to save
Landlord harmless from all costs and expenses incurred on-account of Tenant's
participation in such proceedings. Landlord shall promptly furnish to Tenant a
copy of any notice of public, special or betterment assessments received by
Landlord concerning the Premises.

     4.4 Additional Tax Fund Payments. If the aggregate of any tax or betterment
assessments due under this Section 4 is not adequate to pay all said taxes and
assessments, Tenant shall pay to Landlord the amount by which such aggregate is
less than the amount equal to all said taxes and assessments, such payment to be
made within ten (10) days after receipt by Tenant of notice from Landlord of
such amount. If Tenant shall have made the aforesaid payments, Landlord shall on
or before-the last day on which the same may be paid without interest or
penalty, pay to the proper authority charged with the collection thereof all
taxes and assessments referred to in this Section 4 and furnish Tenant, upon
written request, with reasonable evidence of such payment. Any balance remaining
after such payment by Landlord shall be credited against future payments to be
made by Tenant pursuant to this Section 4.

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 4 of 30 pages
<PAGE>
     5. INSURANCE.

          Tenant, at its own expense, shall take out and maintain throughout the
Term of the Lease the following insurance protecting Landlord:

     5.1 Risk Casualty Insurance. All risk casualty insurance, with endorsement
for difference in conditions coverage, debris removal and demolition, in an
amount at least equal to the replacement cost of the buildings and other
improvements to the Premises, as such replacement cost may from time to time be
determined by agreement or by appraisal made at Tenant's expense by an
accredited insurance appraiser approved by Landlord which may be required by
either party after alteration or additions have been made to the Premises.

     5.2 Liability Insurance. Comprehensive liability insurance indemnifying
Landlord and Tenant against all claims and demands for death or any injury to
person or damage to property which may be claimed to have occurred on the
Premises or on any property, streets or ways adjoining the Premises, in an
amount at least equal to $1,000,000 for injury to a single person and $3,000,000
for injury to more than one person and $1,000,000 for property damage; and,
which, from time to-time, shall be for such higher limits, if any, as are
customarily carried in the area in which the Premises are located on property
similar to the Premises and used for similar purposes, and workmen's
compensation insurance with statutory limits covering all of Tenant's employees
working on the Premises.

     5.3 Sprinkler Insurance. Insurance against loss or damage from sprinklers
and from leakage or explosion or cracking of boilers, pipes carrying steam with
water, or both, pressure vessels or similar apparatus, in the so-called "broad
form" and in such amounts as Landlord may reasonably require.

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 5 of 30 pages
<PAGE>
     5.4 Fire Insurance. Fire insurance with the usual extended coverage
endorsements covering all of Tenant's furniture, furnishings, fixtures and
equipment, and any other contents or improvements not covered by the insurance
to be maintained under this Section 5.

     5.5 Other Insurance. Insurance against such other hazards, and in such
reasonable amounts, as may from time to time be required by any mortgagee of the
Premises, provided that such insurance is customarily carried in the area in
which the Premises are located on property similar to the Premises and used for
similar purposes.

     5.6 Additional Insurance Provisions. Policies for insurance required under
the provisions of this Section 5 shall, where applicable, in case of loss, be
first payable to the holders of any mortgages on the Premises under a standard
mortgagee's clause, and shall be deposited with the holder of any mortgage or
with Landlord, as Landlord or any such mortgagee may elect. All such policies
shall be obtained from responsible companies qualified to do business and in
good standing in Massachusetts, which companies and the amount of insurance
allocated thereto shall be subject to Landlord's approval. Tenant agrees to
furnish Landlord with certificates evidencing all such insurance prior to the
beginning of the term hereof and evidencing renewal thereof at least thirty (30)
days prior to the expiration of any such policy. Each such policy shall be
non-cancellable with respect to the interest of Landlord and such mortgagees
without at least ten (10) days' prior written notice thereto. In the event
provision for any such insurance is to be by a blanket insurance policy, the
policy shall allocate a specific and sufficient amount of coverage to the
Premises.

     5.7 Subrogation. All insurance which is carried by either party with
respect to the Premises or to furniture, fixtures, or equipment therein or
alterations or improvements thereto,

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 6 of 30 pages
<PAGE>
whether or not required, shall include provisions which either designate the
other party as one of the insured or deny to the insurer acquisition by
subrogation of rights of recovery against the other party to the extent such
rights have been waived by the insured party prior to the occurrence of loss or
injury, insofar as, and to the extent that, such provisions may be effective
without making it impossible to obtain insurance coverage from responsible
companies qualified to do business in Massachusetts (even though extra premiums
may result therefrom). In the event extra premium is payable by either party as
a result of this provision, the other party shall reimburse the party paying
such premium the amount of such additional premium. If, at the request of one
party, this non-subrogation provision is waived, then the obligation of
reimbursement shall cease for such period of time as such waiver shall be
effective, but nothing contained in this subsection shall derogate from or
otherwise affect releases elsewhere herein contained of either party for claims.
Each party shall be entitled to have certificates of any policies containing
such provisions. Each party hereby waives all rights of recovery against the
other for loss or injury against which the waiving party is protected by
insurance containing said provisions, reserving, however, any rights with
respect to any excess of loss or injury over the amount recovered by such
insurance. Tenant shall not acquire as insured under any insurance carried on
the Premises any right to participate in the adjustment of any loss or to
receive insurance proceeds and agrees upon request promptly to endorse and
deliver to Landlord any checks or other instruments in payment of loss in which
Tenant is named as payee.

     6. UTILITIES.

          Tenant shall pay directly to the proper authorities charged with the
collection thereof all charges for water, sewer, gas, oil, electricity,
telephone and other utilities or services used or consumed on the Premises
during the term of this lease and for all periods thereafter

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 7 of 30 pages
<PAGE>
during which Tenant is in possession of the Premises, whether designated as a
charge, tax, assessment, fee or otherwise, including, without limitation, water
and sewer use charges and taxes, if any, all such charges to be paid as the same
from time to time become due. Tenant shall make its own arrangement for the
installation or provision of all such utilities and Landlord shall bear no
obligation to furnish any utilities to the Premises and shall not be liable for
any interruption or failure in the supply of any such utilities to the Premises.
Landlord represents and warrants that the Premises are being delivered hereunder
to Tenant free of all utility liens and balances at the commencement of this
Lease.

     7. TENANTS ADDITIONAL COVENANTS.

     7.1 Affirmative Covenants. Tenant covenants that at all times during the
term and for such further time as Tenant occupies the Premises or any part
thereof:

          7.1.1 Perform Obligations. To perform promptly all of the obligations
of Tenant set forth in this Lease; and to pay when due all rent, taxes,
betterment assessments, utilities charges and all other charges, rates and other
sums which by the term of this Lease are to be paid by Tenant.

          7.1.2 Use. To use the Premises only for office, light manufacturing,
warehousing, and other uses permitted by the Landlord in writing and not then in
violation of governmental statutes, regulations, ordinances and codes; and from
time to time to procure all licenses and permits necessary therefor, at Tenant's
sole expense.

          7.1.3 Repair and Maintenance. To keep the Premises in good order,
condition and repair and at least as good order, condition and repair as they
are on the commencement date of this Lease or may be improved during the term of
this Lease, reasonable

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 8 of 30 pages
<PAGE>
use and wear only excepted; to maintain in good condition all lawns and planted
areas and to keep in good repair and clean and neat and free of snow and ice all
surfaced roadways, walks, and parking and loading areas; and to make all repairs
and replacements and to do all other work necessary for the foregoing purposes
whether the same may be extraordinary, foreseen or unforeseen, to the, extent
caused by Tenant's act and not a capital improvement. Tenant shall secure, pay
for and keep in force contracts with appropriate and reputable service companies
providing for the regular maintenance of the heating and air conditioning
systems and copies of such contracts shall be furnished to Landlord. It is
further agrees that the exception of reasonable use and wear shall not apply so
as to permit Tenant to keep the Premises in anything less than suitable,
tenantlike, and efficient and usable condition, or in less than good and
tenantlike repair.

     Subject to the foregoing, Landlord shall be responsible to maintain in good
condition the roof, foundation, and exterior walls, provided, however, that
Landlord shall not be required to make any repairs necessitated by reason of any
act or omission of Tenant, or its employees, agents, subtenants, licensees,
concessionaires, invitees or anyone claiming under Tenant, or caused by any
alteration, addition or improvement made by Tenant or anyone claiming under
Tenant. Landlord shall have no liability whatsoever to Tenant for failure to
make repairs unless and until Tenant shall give written notice to Landlord
stating the need for such repairs and Landlord shall fail to commence and
complete such repairs within a reasonable period of time following receipt of
such written notice.

     Any work done to the roof that requires penetrations of existing roof
membrane must be performed by Hi Tech Roofing, Inc., the firm which installed
the membrane roof in June 1992, in order to preserve the validity of the
guarantee.

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          7.1.4 Compliance with Law. To make all repairs, alterations,
additions, or replacements to the premises required by any law or ordinance or
any order or regulation of any public authority; to keep the Premises equipped
with all safety appliances and equipment so required; and to comply with the
orders and regulations of all governmental authorities with respect to the
zoning, building, fire, health and other codes, regulations, ordinances or laws
applicable to the Premises, except that Tenant may defer compliance so long as
the validity of .any such law, ordinance, order or regulation shall be contested
by Tenant in good faith and by appropriate legal proceedings, if Tenant first
gives Landlord appropriate assurance or security against any loss, cost or
expense on account thereof.

          7.1.5 Indemnification. To the extent covered by insurance, to save
Landlord harmless, and to exonerate and indemnify Landlord from and against any
and all claims, liabilities or penalties asserted by or on behalf of any person,
firm, corporation or public authority on account of injury, death, damage or
loss to person or property in or upon the Premises arising out of the use or
occupancy of the Premises by Tenant or by any person claiming by, through or
under Tenant (including, without limitation, all patrons, employees and
customers of Tenant), or arising out of any delivery to or service supplied to
the Premises, or on account of or based upon anything whatsoever done on the
Premises, except if the same was caused by the willful negligence, fault or
misconduct of Landlord, its agents, or employees. In respect of all of the
foregoing, Tenant shall indemnify Landlord from and against all costs, expenses
(including reasonable attorneys' fees), and liabilities incurred in or in
connection with any such claim, action or proceeding brought thereon; and, in
case of any action or proceeding brought against Landlord by reason of any such
claim, Tenant, upon notice from Landlord and at

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Tenant's expense, shall resist or defend such action or proceeding and employ
counsel therefor reasonably satisfactory to Landlord.

          7.1.6 Landlord's Right to Enter. To permit Landlord and its agents to
enter into and examine the Premises at reasonable times and to show the
Premises, and to make repairs to the Premises, and, during the last six (6)
months prior to the expiration of this Lease, to keep affixed in suitable places
notices of availability of the Premises.

          7.1.7 Personal Property at Tenant's Risk. All of the furnishings,
fixtures, equipment, effects and property of every kind, nature and description
of Tenant and of all persons claiming by, through, or under Tenant which, during
the continuance of this Lease or any occupancy of the Premises by Tenant or
anyone claiming under Tenant, may be on the Premises, shall be at the sole risk
and hazard of Tenant and 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, by theft or from any other cause, no part of
said loss or damage is to be charged or to be borne by Landlord, except that
Landlord shall in no event be indemnified or held harmless or exonerated from
any liability to Tenant or to any other person, for any injury, loss, damage or
liability to the extent prohibited by law or to the extent caused by Landlord's
gross negligence or willful misconduct.

          7.1.8 Payment of Landlord's Cost of Enforcement. To pay on demand
Landlord's expenses, including reasonable attorneys' fees, incurred in enforcing
any obligation of Tenant under this Lease or in curing any default by Tenant
under this Lease as provided in Section 9.

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          7.1.9 Yield Up. At the expiration of the term or earlier termination
of this Lease: to surrender all keys to the Premises; to remove all of its trade
fixtures and personal property in the Premises; to remove such installations
made by it as Landlord may request and all Tenant signs wherever located; to
repair all damage caused by such removal and to yield up the Premises (including
all installations and improvements made by Tenant except for trade fixtures and
such of said installations or improvements as Landlord shall request Tenant to
remove), broom-clean and in the same good order and repair in which Tenant is
obliged to keep and maintain the Premises by the provisions of this Lease,
reasonable wear and tear excepted. Any property not so removed shall be deemed
abandoned and may be removed or disposed of by Landlord in such manner as
Landlord shall reasonably determine and Tenant shall pay Landlord a reasonable
and mutually agreed cost and expense incurred by it in effecting such removal
and disposition and in making any reasonably necessary incidental repairs and
replacements to the Premises and for use and occupancy as comparable laboratory
space during the period after the expiration of the term and prior to its
performance of its obligations under this Subsection 7.1.9. Tenant shall further
indemnify Landlord against all loss, cost and damage resulting from Tenant's
failure and delay in surrendering the Premises as above provided, provided
Landlord shall use reasonable efforts to mitigate any loss.

          7.1.10 Estoppel Certificate. Upon not less than fifteen (15) days
prior written request by Landlord, to execute, acknowledge and deliver to
Landlord a reasonable statement in writing certifying that this Lease is
unmodified and in full force and effect and that Tenant has no defenses, offsets
or counterclaims against its obligations to pay the rent, taxes, utilities,
insurance and all other sums charges and to perform its covenants under this
Lease (or, if there have been any modifications, that the Lease is in full force
and effect as modified and stating the

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modifications and, if there are any defenses, offsets or counterclaims, setting
them forth in reasonable detail), and the dates to which the rent and other
charges have been paid. Any such statement delivered pursuant to this Subsection
7.1.10 may be relied upon by any prospective purchaser or mortgagee of the
Premises, or any prospective assignee of such mortgage.

     7.2 Negative Covenants. Tenant covenants at all times during the term and
such further time as tenant occupies the Premises or any part thereof:

          7.2.1 Assignment and Subletting. Not to assign, transfer, mortgage or
pledge this Lease or to sublease (which term shall be deemed to include the
granting of concessions and licenses and the like) all or any part of the
Premises or suffer or permit this Lease or the leasehold estate hereby created
or any other rights arising under this Lease to be assigned, transferred or
encumbered, in whole or in part, whether voluntarily, involuntarily or by
operation of law, or permit the occupancy of the Premises by anyone other than
the Tenant (without on each occasion obtaining the prior written consent of the
Landlord, which consent shall not be unreasonably withheld or delayed), to
assign this Lease or to make any sublease. No consent to any of the foregoing in
a specific instance shall operate as a waiver in any subsequent instance. If for
any assignment or sublease, during the initial lease period, consented to by
Landlord hereunder, Tenant receives rent or other consideration, either
initially or over the term of the assignment of sublease, in excess of the total
gross rent payable hereunder, or in case of sublease of part, in excess of such
gross rent proportionately allocable to the part, after allowing Tenant to
retain from such excess an amount equal to the reasonable and mutually agreed
expenses incurred by Tenant in connection with the assignment or sublease,
Tenant shall pay to Landlord as additional rent fifty (50) percent of such
excess attributable to each such payment or rent or

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other consideration received by Tenant promptly after its receipt, if tenant
leaves his casework, and seventy-five (75) percent if he removes such casework,
as further defined in Section 11.9.

     If, at any time during the term of this Lease, there shall be a change in
the effective control of Tenant or Guarantor, whether by sale of assets, stock
or other event, Tenant or Guarantor, as the case may be, shall immediately
notify Landlord and (whether or not Tenant or Guarantor so notifies Landlord)
Landlord may terminate this Lease by notice to Tenant given within ninety (90)
days thereafter.

          7.2.2 Overloading and Nuisance. Not to injure, overload, deface or
otherwise harm or damage the Premises, nor commit any nuisance, nor permit the
emission of any objectionable noise or odor; nor make, allow or suffer any
waste; nor make any use of the Premises which is improper or offensive or
contrary to any law or ordinance or which will invalidate any of Landlord's
insurance; nor conduct any auction, fire, "going out of business" or bankruptcy
sales.

          7.2.3 Hazardous Wastes and Materials. Unless allowed by appropriate
permit, not to dispose of any hazardous wastes, hazardous materials or oil on
the Premises, or into any of the plumbing, sewage, or drainage systems thereon,
and to indemnify and save Landlord harmless from all claims, liability, loss or
damage arising on account of the use or disposal by Tenant (and limited to
Tenant's use) of hazardous wastes, hazardous materials or oil including, without
limitation, liability under any federal, state, or local laws, requirements and
regulations, or damage to any of the aforesaid systems. Tenant shall comply with
all governmental reporting requirements with respect to hazardous wastes,
hazardous materials and oil, and shall deliver to Landlord copies of all reports
filed with governmental authorities.

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     Landlord warrants that an MGL Chapter 21E Site Investigation relative to
hazardous materials was performed by Toxic Systems Management, Inc. in January
1985, in connection with Landlord's acquisition of the premises, and no evidence
of hazardous material release was found. Test borings were made, and an
underground oil tank was pronounced clean and de-activated by permit from the
Cambridge Fire Department. A copy of the report is attached as EXHIBIT C.

     Landlord further warrants that Premises have been under his occupancy or
control from the date of the 1985 study to occupancy by Tenant, and has no
knowledge or reason to know of any release; or threat of release, of oil or
hazardous material which pre-dates Tenant's original occupancy of the Premises.

          7.2.4 Installation, Alterations or Additions. Not to make any
installations, alterations or additions in, to or on the Premises (including,
without limitation, buildings, lawns, planted areas, walks, roadways, parking
and loading areas) nor to permit the making of any holes in the walls,
partitions, ceilings or floors without on each occasion obtaining the prior
written consent of Landlord, and then only pursuant to plans specifications
approved by Landlord in advance in each instance; Tenant shall pay promptly when
due the entire cost of any work to the Premises undertaken by Tenant so that the
Premises shall at all times be free of liens for labor and materials, and at
Landlord's request Tenant shall furnish a bond or other security acceptable to
Landlord assuring that any work commenced by Tenant will be completed in
accordance with the plans and specifications theretofore approved by Landlord
and assuring that the Premises will remain free of any mechanics' lien or other
encumbrances that may arise out of such work. Tenant shall procure all necessary
licenses and permits at Tenant's sole expense before undertaking such work. All
such work shall be done in a good and workmanlike manner

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employing materials of good quality and so as to conform with all applicable
zoning, building, fire, health, and other codes, regulations, ordinances and
laws. Tenant shall save Landlord harmless and indemnified from all injury, loss,
claims or damage to any person or property occasioned by or growing out of such
work.

          7.2.5 Abandonment. Not to abandon or vacate the Premises during the
Term of the Lease.

          7.2.6 Signs. Not to place any signs on the Premises without Landlord's
written approval, which shall not be unreasonably withheld. Such signs shall be
maintained in good repair by Tenant and shall conform to applicable requirements
of public authorities.

          7.2.7 Parking and Storage. Not to permit any storage of materials
outside of the building on the Premises; to use reasonable diligence to prevent
Tenant's employees and customers and other persons visiting the Premises from
using any street abutting the Premises for parking; and, not to permit the use
of the Premises for either temporary or permanent storage of trucks or other
vehicles, or for any use for which heavy trucking to or from the site would be
customary.

     8. CASUALTY OR TAKING.

     8.1 Termination by Landlord. In the event that the Premises, or any
material part thereof, shall be taken by any public authority or for any public
use, or shall be destroyed or damaged by fire or casualty, or by the action of
any public authority, then this Lease may be terminated at the election of
Landlord or Tenant (as provided below). Such election, which may be made
notwithstanding the fact that Landlord's entire interest may have been divested,
and

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shall be made by giving of notice by Landlord to Tenant within ninety (90) days
after the date of the taking or casualty.

     8.2 Termination by Tenant. If all of the Premises, or so much thereof as to
make the balance not reasonably adequate for the conduct of Tenant's business
notwithstanding restoration by Landlord as hereinafter provided, are destroyed
or are appropriated or taken by any competent authority for any public or
quasipublic use or purpose under any statute or by right of eminent domain
(which taking shall include a sale by Landlord to any public or quasipublic
authority, whether under threat of condemnation or while condemnation
proceedings are pending), and Tenant shall within thirty (30) days from the date
of such destruction, appropriation or taking notify Landlord in writing that the
Premises are not reasonably adequate for conduct of Tenant's business, and upon
inspection by Landlord it is agreed by the parties hereto that such is the case,
then this Lease shall terminate at the time of such destruction, actual physical
taking or possession by such governmental authority, and Landlord and Tenant
shall thereupon be released from all liabilities thereafter accruing under this
Lease.

     8.3 Restoration. If the parties elect to not terminate this Lease, this
Lease shall continue in force and a just proportion of the rent reserved,
according to the nature and extent of the damages sustained by the Premises, but
not in excess of the rent otherwise payable hereunder, shall be suspended or
abated until the Premises, or what may remain thereof, shall be put by Landlord
in proper condition for use, which Landlord covenants to do with reasonable
diligence to the extent permitted by the net proceeds of insurance recovered or
damages awarded for such taking, destruction or damage and subject to zoning and
building laws or ordinances then in existence.

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     8.4 Award. Irrespective of the form in which recovery may be had by law,
all rights to damages or compensation shall belong to Landlord in all cases,
except to the extent provided herein. Tenant hereby grants to Landlord all of
Tenant's rights to such damages and covenants to deliver such further
assignments thereof as Landlord may from time to time request. Notwithstanding
the foregoing, Tenant shall be entitled to such portion of the award as is equal
to the value of any real property improvements installed on the Premises by the
Tenant as described in Exhibit "B" or agreed to by the parties as described in
Section 11.10 herein. The value of any such improvements shall be equal to the
lesser of:

     (a)  The depreciated value of such improvements as reasonably reflected (in
          accordance with generally accepted accounting principles applied on a
          consistent basis) on the books of Tenant as of the date of taking; or

     (b)  The original cost of such improvements to Tenant multiplied by a
          fraction, the numerator of which is the balance of the term of this
          Lease then remaining and the denominator of which is the balance of
          the Initial term and the Renewal Term remaining as of the date such
          improvements were made.

     On the written demand of Landlord, Tenant shall notify Landlord in writing
of the original cost of any such improvements installed by the Tenant.

     Tenant shall also be entitled to make claim in its own name to the
condemning authority for the value of any furniture, trade fixtures, trade
equipment, merchandise, or personal property of any kind belonging to Tenant and
not forming part of the real estate, or the cost of moving all of the same, and
any such award made directly to Tenant shall belong entirely to Tenant.

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     9. DEFAULTS

     9.1 Events of Default. (a) If Tenant shall default in the performance of
any of its obligations to pay the rent, taxes, betterment assessments and other
sums due hereunder and if such default shall continue for ten (10) days after
the date such sums were initially due under the provisions of this Lease, or (b)
if within thirty (30) days after written notice from Landlord to Tenant
specifying any other default or defaults Tenant has not commenced diligently, to
correct the default or defaults so specified or has not thereafter diligently
pursued such correction to completion, or (c) if any assignment shall be made by
Tenant for the benefit of creditors, or (d) if Tenant's leasehold interest shall
be taken on execution, or (e) if a lien or other involuntary encumbrance is
filed against Tenant's leasehold interest or Tenant's other property, including
said leasehold interest, and is not discharged within ten (10) days thereafter,
or (f) if a petition is filed by Tenant for liquidation, or for reorganization
or an arrangement under any provision of any bankruptcy law or code as then in
force and effect, or if Tenant is then unable to pay their liabilities as the
same become due and payable, or (g) if an involuntary petition under any of the
provisions of any bankruptcy law or code is filed against Tenant and such
involuntary petition is not dismissed within thirty (30) days thereafter, then,
and in any of such cases, Landlord and the agents and servants of Landlord
lawfully may, in addition to and not in derogation of any remedies for any
preceding breach of covenant, immediately or at any time thereafter, issue a
notice of eviction to vacate no later than six months from date of the notice,
and commence summary proceedings to repossess the same as of Landlord's former
estate and expel Tenant and those claiming through or under Tenant and remove
its and their effects without prejudice to any remedies which might otherwise be
used for arrears of rent or prior breach of covenant, and upon the determination
of a court of competent jurisdiction, Landlord, after such judgment, may store

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Tenant's effects, and those of any person claiming through or under Tenant, at
the expense and risk of Tenant, and, if Landlord so elects, may sell such
effects at public auction or private sale and apply the net proceeds to the
payment of all sums due to Landlord from Tenant, if any, and pay over the
balance, if any, to Tenant.

     9.2 Remedies. In the event that this Lease is terminated under any of the
provisions contained in Section 9.1 or shall be otherwise terminated for breach
of any obligation of Tenant, Tenant agrees to pay forthwith to Landlord, as
compensation, the excess of the total rent reserved for the residue of the term
over the rental value of the Premises for said residue of the term. In
calculating the rent reserved there shall be included, in addition to the rent
and additional sums due and owing to Landlord, the value of all other
considerations agreed to be paid or performed by Tenant for said residue. Tenant
further covenants as additional and cumulative obligations after any such
termination, to pay punctually to Landlord all the sums and to perform all the
obligations which Tenant covenants in this Lease to pay and to perform in the
same manner and to the same extent and at the same time as if this Lease had not
been terminated. In calculating the amounts to be paid by Tenant pursuant to the
next preceding sentence Tenant shall be credited with any amount paid to
Landlord as compensation as in this Section 9.2 provided and also with the net
proceeds of any rent obtained by Landlord by reletting the Premises, after
deducting all Landlord's expense in connection with such reletting, including,
without limitation, all repossession costs, brokerage commissions, fees for
legal services and reasonable expenses of preparing the Premises for such
reletting, provided that Landlord shall be obligated to use its best efforts to
relet the premises, Landlord may (i) relet the Premises or any part or parts
thereof, for a term or terms which may at Landlord's reasonable option be equal
to or less than or exceed the period which would otherwise have constituted the
balance of the term

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and may grant such concessions and free rent as Landlords reasonable judgment
considers advisable or necessary to relet the same and (ii) make such
alterations, repairs and decorations in the Premises as Landlord in its
reasonable judgment considers advisable or necessary to relet the same.

     In lieu of any other damages or indemnity and in lieu of full recovery by
Landlord of all sums payable under all the foregoing provisions of this Section
9.2, Landlord may by written notice to Tenant, at any time after this Lease is
terminated under any of the provisions contained in Section 9.1 or is otherwise
terminated for breach of any obligation of Tenant and before such full recovery,
elect to recover, and Tenant shall thereupon pay, as liquidated damages, an
amount equal to the aggregate of the rent, taxes, betterment assessments and
similar charges accrued in the twelve (12) months ended next prior to such
termination plus the amount of rent of any kind accrued and unpaid at the time
of termination and less the amount of any recovery by Landlord under the
foregoing provisions of this Section 9.2 up to the time of payment, of such
liquidated damages. Nothing contained in this Lease shall, however, limit or
prejudice the right of Landlord to prove for and obtain in proceedings for
bankruptcy or insolvency by reason of the termination of this Lease, 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, the damages are to be proved,
whether or not the amount be greater than, equal to, or less than the amount of
the loss or damages referred to above.

     9.3 Remedies Cumulative. Any and all rights and remedies which Landlord may
have under this Lease, and at law and equity, both as against Tenant and
Guarantor, shall be cumulative and shall not be deemed inconsistent with each
other, and any two or more of all such rights and remedies may be exercised at
the same time insofar as permitted by law.

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     9.4 Landlord's Right to Cure Defaults. Landlord may, but shall not be
obligated to, cure, at any time, without notice, any default by Tenant under
this Lease; and whenever Landlord so elects, all costs and expenses incurred by
Landlord, including ,attorneys' fees, in curing a default shall be paid, by
Tenant to Landlord on demand, together with lawful interest thereon from the
date of payment by Landlord to the date of Tenant's payment.

     9.5 Effect of Waivers of Default. Any consent or permission by Landlord to
any act or omission which otherwise would be a breach of any covenant or
condition herein, shall not in any way be held or construed (unless expressly so
declared) to operate so as to impair the continuing obligation of any covenant
or condition herein, or otherwise, except as to the specific instance, operate
to permit similar acts or omissions.

     9.6 No Waiver, etc. Landlord's failure to seek redress for violation of, or
to insist upon the strict performance of, any covenant or condition of this
Lease shall not be deemed a waiver of such violation nor prevent a subsequent
act, which would have originally constituted a violation, from having all the
force and effect of an original violation. The receipt by Landlord of rent with
knowledge of the breach of any covenant of this Lease shall not be deemed to
have been a waiver of such breach by Landlord. No consent or waiver, express or
implied, by Landlord to or of any breach of any agreement or duty shall be
construed as a waiver or consent to or of any other breach of the same or any
other agreement or duty.

     9.7 No Accord and Satisfaction. No acceptance by Landlord of a lesser sum
than the rent, taxes, betterment assessments or any other charge then due shall
be deemed to be other than on account of the earliest installment of such rent
or charge due, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as rent or other charge be deemed an accord
and satisfaction, and Landlord may accept such check or payment without

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prejudice to Landlord's right to recover the balance of such installment or
pursue any other remedy in this Lease provided.

     10. RIGHTS OF MORTGAGE HOLDERS

     10.1 Rights of Mortgage Holders. The word "mortgage" as used herein
includes mortgages, deeds of trust or other similar instruments evidencing other
voluntary liens or encumbrances, and modifications, consolidations, extensions,
renewals, replacements and substitutes thereof. The word "holder" shall mean a
mortgagee, and any subsequent holder or holders of a mortgage. Until the holder
of a mortgage shall enter and take possession of the Premises for the purpose of
foreclosure, such holder shall have only such rights of Landlord as are
necessary to preserve the integrity of this Lease as security. Upon entry and
taking possession of the Premises for the purpose of foreclosure, such holder
shall have all the rights of Landlord. No such holder of a mortgage shall be
liable either as mortgagee or as assignee, to perform, or be liable in damages
for failure to perform, any of the obligations of Landlord unless and until such
holder shall enter and take possession of the Premises for the purpose of
foreclosure. Upon entry for the purpose of foreclosure, such holder shall be
liable to perform all of the obligations of Landlord, subject to and with the
benefit of the provisions of Section 9.4, provided that a discontinuance of any
foreclosure proceeding shall be deemed a conveyance under said provisions to the
owner of the equity of the Premises.

     The covenants and agreements contained in this Lease with respect to the
rights, powers and benefits of a holder of a mortgage (particularly, without
limitation thereby, the covenants and agreements contained in this Section 10.1)
constitute a continuing offer to any person, corporation or other entity, which
by accepting a mortgage subject to this Lease, assumes the obligations herein
set forth with respect to such holder; such holder is hereby constituted a party

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of this Lease as an obligee hereunder to the same extent, as though its name
were written hereon as such; and such holder shall be entitled to enforce such
provisions in its own name. Tenant agrees on request of Landlord to execute and
deliver from time to time any agreement which may be necessary to implement the
provisions of this Section 10.1.

     10.2 Lease Superior or Subordinate to Mortgages. It is agreed that the
rights and interest of Tenant under this Lease shall be (i) subject or
subordinate to any present or future mortgage or mortgages and to any and all
advances to be made thereunder, and to the interest of the holder thereof in the
Premises or any property of which the Premises are a part if Landlord shall
elect by notice to Tenant to subject or subordinate the rights and interest of
Tenant under this Lease to such mortgage or (ii) prior to any present or future
mortgage or mortgages, if Landlord shall elect, by notice to Tenant, to give the
rights and interest of Tenant under this Lease priority to such mortgage; in the
event of either of such elections and upon notification by Landlord to that
effect, the rights and interest of Tenant under this Lease should be deemed to
be subordinate to, or have priority over, as the case may be, said mortgage or
mortgages, irrespective of the time of execution or time of recording of any
such mortgage or mortgages (provided that, in the case of subordination of this
Lease to any future mortgages, the holder thereof agrees not to disturb the
possession of Tenant so long as Tenant is not in default hereunder). Tenant
agrees it will, upon written request from Landlord, execute, acknowledge and
deliver any and all reasonable instruments deemed by Landlord necessary or
desirable to give effect to or notice of such subordination or priority. Tenant
also agrees that if, within 30 days of such written request, it shall fail at
any time to execute, acknowledge and deliver any such reasonable instrument
requested by Landlord, Landlord may, in addition to any other remedies available
to it, execute, acknowledge and deliver such instrument as the attorney-in-fact

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of Tenant and in Tenant's name; and Tenant does hereby make, constitute and
irrevocably appoint Landlord as its attorney-in-fact, coupled with an interest
with full power of substitution, and in its name, place and stead so to do. Any
mortgage to which this Lease shall be subordinated may contain such terms,
provisions and conditions as the holder deems usual or customary.

     11. MISCELLANEOUS PROVISIONS

     11.1 Notices from One Party to the Other. All notices required or permitted
hereunder shall be in writing and addressed, if to the Tenant, at the Original
Address of the Tenant or such other address as Tenant shall have last designated
by notice in writing to Landlord and, if to Landlord, at the Original Address of
Landlord or such other address as Landlord shall have last designated by notice
in writing to Tenant. Any notice shall be deemed duly given when mailed to such
address postage prepaid, by registered or certified mail, return receipt
requested, or when .delivered to such address by hand.

     11.2 Quiet Enjoyment. Landlord agrees that upon Tenant's paying the rent
and performing and observing the agreements, conditions and other provisions on
its part to be performed and observed, Tenant shall and may peaceably and
quietly have, hold and enjoy the Premises during the term hereof for the use
intended, without any manner of hindrance or molestation from Landlord or anyone
claiming under Landlord, subject, however, to the terms of this Lease; provided,
however, Landlord reserves the right, without the same constituting a breach of
Landlord's covenant of quiet enjoyment, to make such changes, alterations,
additions, improvements, repairs or replacements in or to the Premises as
Landlord may deem necessary or desirable, provided further, however, that there
be no unreasonable interference with Tenant's use of the premises.

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 25 of 30 pages
<PAGE>
     11.3 Lease not to be Recorded. Tenant agrees that it will not record this
Lease. Both parties shall, upon the request of either, execute and deliver a
notice or short form of this Lease in such form, if any, as may be permitted by
applicable statute.

     11.4 Limitation of Landlord's Liability. The term "Landlord" as used in
this Lease, so far as covenants or obligations to be performed by Landlord are
concerned, shall be limited to mean and include only the owner or owners at the
time in question of the Premises, and in the event of any transfer or transfers
of title to said property, the Landlord (and in case of any subsequent transfers
or conveyances, the then grantor) shall be concurrently freed and relieved from
and after the. date of such transfer or conveyance, without any further
instrument or agreement, of all liability as respects the performance of any
covenants or obligations on the part of the Landlord contained in this Lease
thereafter to be performed, it being intended hereby that the covenants and
obligations contained in this Lease on the part of Landlord, shall, subject as
aforesaid, be binding on the Landlord, its successors and assigns, only during
and in respect of their respective successive periods of ownership of said
leasehold interest or fee, as the case may be. Tenant, its successors and
assigns, shall not assert nor seek to enforce any claim for breach of this Lease
against any of Landlord's assets other than Landlord's interest in the Premises
and in the rents, issues and profits thereof, and Tenant agrees to look solely
to such interest for the satisfaction of any liability or claim against Landlord
under this Lease, it being specifically agreed that in no event whatsoever shall
Landlord (which term shall include, without limitation, any general or limited
partner, trustees, beneficiaries, officers, directors, or stockholders of
Landlord) ever be personally liable for any such liability.

     11.5 Acts of God. In any case where either party hereto is required to do
any act, delays caused by or resulting from Acts of God, war, civil commotion,
fire, flood or other

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 26 of 30 pages
<PAGE>
casualty, labor difficulties, shortages of labor, materials or equipment,
government regulations, unusually severe weather, or other causes beyond such
party's reasonable control shall not be counted in determining the time during
which work shall be completed, whether such time be designated by a fixed date,
a fixed time or a "reasonable time", and such time shall be deemed to be
extended by the period of such delay.

     11.6 Landlord's Default. Landlord shall not be deemed to be in default in
the performance of any of its obligations hereunder unless it shall fail to
perform such obligations and such failure shall continue for a period of thirty
(30) days or such additional time as is reasonably required to correct any such
default after written notice has been given by Tenant to Landlord specifying the
nature of Landlord's alleged default. Tenant shall have the right to terminate
this Lease for any default by Landlord hereunder,. and the right, for any such
default, to offset or counterclaim against any rent due hereunder.

     11.7 Brokerage. Tenant warrants and represents that it has dealt with no
brokers other than Codman Associates and Channing Real Estate in connection with
the consummation of this Lease, and in the event of any brokerage claims against
Landlord, other than the above named brokers, predicated upon prior dealings
with Tenant, Tenant agrees to defend the same and indemnify and hold Landlord
harmless against any such claim.

     11.8 Applicable Law and Construction. This Lease shall be governed by and
construed in accordance with the laws of the Commonwealth of Massachusetts and,
if any provisions of this Lease shall to any extent be invalid, the remainder of
this Lease shall not be affected thereby. There are no oral or written
agreements between Landlord and Tenant affecting this Lease. This Lease may be
amended, and the provisions hereof may be waived or modified, only by
instruments in writing executed by Landlord and Tenant. The titles of the

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 27 of 30 pages
<PAGE>
several Sections contained herein are for convenience only and shall not be
considered in construing this Lease. Unless repugnant to the context, the words
"Landlord" and "Tenant" appearing in this Lease shall be construed to mean those
named above and their respective heirs, executors, administrators, successors
and assigns, and those claiming through or under them respectively. If there be
more than one tenant the obligations imposed by this Lease upon Tenant shall be
joint and several.

     11.9 Capital Improvement Cost Recovery. The parties acknowledge that Tenant
and the prior Tenant, G&P Corporation, from whom Tenant subleased the premises
prior to the Term of the present Lease, have made certain improvements to the
Premises, some of which will be generally useful to future tenants, and that
Landlord has reimbursed G&P Corporation $71,000 for such improvements, under the
terms of the original Lease between Landlord and G&P, and will not be under
obligation to make any additional reimbursement for Capital Improvement made or
to be made by Tenant.

     Landlord and Tenant specifically agree that Tenant has installed and will
be installing certain equipment into the Premises which shall become fixtures
and may not be removed, and certain other equipment which shall not become
fixtures and which may be removed by Tenant, providing that Tenant repairs any
damage to the premises caused by removal of such equipment;

     fixtures shall include any components or fixtures of the HVAC, electric,
     lighting and plumbing systems necessary for occupancy of the building (such
     as circuit breaker boxes, sinks, fans, air conditioners, heaters, etc);

     non-fixtures shall include casework (shelving, cabinets, desks and the
     like), and special equipment related to Tenant's hoods which may be

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 28 of 30 pages
<PAGE>
     physically connected to the HVAC system (such as ventilation valves and
     associated control boxes).

Section 7.2.1 (subletting) permits the tenant to retain a higher percentage of
additional rent if he leaves casework, then if he removes it. This requires that
"casework" be distinguished from "special equipment". An inventory of each type
is to be agreed upon in separate memorandum to be attached to the present lease.

     11.10 Option to Extend

     Tenant has the option to extend the Term of this Lease for two (2)
additional periods of two (2) years each by giving Landlord notice of its
exercise at least six (6) months before the expiration of the then current Lease
Term. If no Event of Default exists when notice is given, this Lease, without
the necessity of any further writing, shall be extended and the Premises
considered to have been leased by Landlord to Tenant for an additional period of
two (2) years beginning immediately after the expiration of the current Lease
Term upon the same terms, except that (a) the Basic Rent shall be an amount
agreed upon at the time by Landlord and Tenant as the reasonable fair market
rent for the Premises; (b) after the exercise of each option to extend the
number of options to extend remaining will be reduced by one; and (c) if Tenant
exercises such option to extend and Landlord subsequently decides to develop the
Premises to a better-use, (for example a multi-story commercial or residential
structure) or if Landlord sells the Premises to a bona fide purchaser and such
purchaser wishes to terminate the Lease (after the end of the initial Lease
Term), then Tenant agrees that upon notice from the Landlord, Tenant will vacate
the Premises six months after such notice and the Lease shall thereafter
terminate.

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 29 of 30 pages
<PAGE>
     WITNESS the execution hereof under seal on the day and year first above
written.

                                        LANDLORD:

                                        FORT WASHINGTON REALTY TRUST

                                        By: /s/ Henry H. Kolm
                                            ------------------------------------
                                            Henry H. Kolm, as Trustee
                                            and not individually

                                        By: /s/ Elizabeth C. Kolm
                                            ------------------------------------
                                            Elizabeth C. Kolm, as Trustee
                                            and not individually

ATTEST:                                 TENANT:

                                        VERTEX PHARMACEUTICALS, INC.

/s/ [Illegible]                         By: /s/ Richard H. Aldrich
-------------------------------------       ------------------------------------
Director of Operations                      Vice President

Lease Agreement for 625 Putnam Ave, Cambridge
for Ft WASHINGTON _____ for VERTEX _____ page 30 of 30 pages
<PAGE>
                                    EXHIBIT A

                             DESCRIPTION OP PREMISES
<PAGE>
                                    EXHIBIT A

                             DESCRIPTION OF PREMISES

     The land in Cambridge, Middlesex County, Massachusetts, more particularly
described as follows:

Parcel One

The registered land shown on Land Court Plan No. 21188A and bounded and
described as follows:

<TABLE>
<S>              <C>
NORTHEASTERLY:   by Putnam Avenue, one hundred forty-one and no/100 (141.0)
                 feet;

SOUTHEASTERLY:   by land now or formerly of Potter-Horn Incorporated, one
                 hundred fifty and no/100 (150.00) feet;

SOUTHWESTERLY:   by lands now or formerly of North American Holding Company et
                 al. and of Melvin Frank, one hundred forty-three and no/100
                 (143.00) feet;

NORTHWESTERLY:   by said Frank land and by land now or formerly of Paul A. St.
                 Germaine, et al., being in part Parcel Two herein described,
                 one hundred fifty and 04/100 (150.04) feet;
</TABLE>

For title reference is made to Certificate of Title No. 149390, Book 877, Page
40.

Parcel Two

The unregistered land shown as Lot A on a plan entitled "Sub-division of Land in
Cambridge Belonging to Homes Inc.", dated March 24, 1948., by Edward F. Carney,
Engineer, recorded with Middlesex South District Registry of Deeds as Plan No.
624 of 1948, in Book 7292, Page 18, and bounded and described as follows:

<TABLE>
<S>              <C>
NORTHWESTERLY:   by Sidney Street, eighty-nine and no/10 (89.0) feet;

NORTHEASTERLY:   by Lot B and C as shown on said plan, seventy-five and no/10
                 (75.0) feet;

SOUTHEASTERLY:   by Parcel One hereinbefore described, eighty-nine and no/10
                 (89.0) feet; and

SOUTHWESTERLY:   by land now or formerly of Melvin Frank, seventy-five and no/10
                 (75.0) feet;
</TABLE>

Containing 6,675 square feet of land, according to said plan.

For title reference see deed from Cox Engineering Company to the Grantor herein
recorded with said Deeds in Book 13014, Page 410.
<PAGE>
                                    [PICTURE]
<PAGE>
                                    [PICTURE]
<PAGE>
                                    EXHIBIT B

                         DESCRIPTION OF TENANT'S CHANGES

                                   TO PREMISES
<PAGE>
                                    EXHIBIT C

                      CHAPTER 21E SITE INVESTIGATION REPORT

                                  JANUARY 1985
<PAGE>
TSMI                                                                617-938-7340

TOXIC SYSTEMS MANAGEMENT, INC.

                  SITE REPORT RELATIVE TO HAZARDOUS MATERIALS

                            FOR PROPERTY LOCATED AT

                               625 Putnam Avenue

                         Cambridge, Massachusetts 02139

                                January 31, 1985

Contracted for:                                                     Reported to:

Attorney Jack Mikels                                        Attorney Jack Mikels
Bank of New England                                           and Dr. Henry Kolm
2 Oliver Street                                               EML Research, Inc.
Boston, Massachusetts 02109                                    625 Putnam Avenue
                                                  Cambridge, Massachusetts 02139
<PAGE>
                                                                            TSMI

                                TABLE OF CONTENTS

<TABLE>
<S>                                                          <C>
I.     Cover page                                                         page i
II.    Table of Contents                                                 page ii
III.   Site Report Relative to Hazardous Materials                        page 1
IV.    Site Assessment Summary                               Exhibit A (7 pages)
Dated Map Showing Site Layout Information                               Figure 1
Dated Map Showing Lot A                                                 Figure 2
Area Topographic Map Showing Locus                                      Figure 3
Field Report                                                          Appendix 2
Soil Analysis                                                         Appendix 2
Analysis of Soil Samples                                              Appendix 3
Chain of Custody & Analysis Request Forms                             Appendix 4
Property Owners Affidavit                                             Appendix 5
Certificate of Oil Removal                                            Appendix 6
</TABLE>
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
page 1

                   SITE REPORT RELATIVE TO HAZARDOUS MATERIALS

This report is addressed to Attorney Jack Mikels of the Bank of New England,
with respect to the real estate situated at 625 Putnam Avenue, Cambridge, MA,
which is recorded with Middlesex Registry of Deeds South District at Book #9113,
page #582, and Registered land division at Book #423, Page #597, Document
#66275.

A.   The undersigned, based on experience and knowledge, states that:

     1. The investigations of the Site described in this Report (together with
     the "Site Assessment Summary" attached hereto as Exhibit A and incorporated
     herein by reference) were performed by Evelyn M. Butler, an Ecologist and
     Environmental Field Specialist (hereinafter the "Site Investigator") who is
     qualified to make the investigations and formulate the opinions herein set
     forth.

     2. The Site Investigator is familiar with the provisions of Massachusetts
     General Laws, Chapter 21E (as it may from time to time be amended) and the
     applicable implementing regulations under said law, including the materials
     which fall within the definitions of "oil" and "hazardous material"
     thereunder. References in this Report to oil and hazardous material refer
     to said terms as defined in MGL Chapter 21E and implementing regulations.

     3. The Site Investigator has reviewed the history of the Site and has
     considered the potential for the generation, use, treatment, storage, or
     disposal of oil or hazardous material by (a) the uses presently associated
     with the Site and (b) to the extent
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
page 2

     ascertainable by inquiry as noted in the "Site Assessment Summary", the
     uses previously associated with the Site.

     4. On December 23, 1985 the Site Investigator, accompanied by Russell M.
     Peters, an Environmental Specialist with TSMI, investigated the Site and,
     except as qualified in the "Site Assessment Summary", the areas adjacent to
     the Site to assess the possible presence of oil or hazardous material on
     the Site.

     5. The investigation, carried out December 20, 1985 to January 31, 1986,
     included the research, observations, explorations and testing described in
     the "Site Assessment Summary" attached to this Report as Exhibit A.

B. Based upon the foregoing, (including the research, observations,
explorations, and testing described in the "Site Assessment Summary") and
subject to the qualifications set forth below, the undersigned is of the
professional opinion that at the time of said investigation evidence exists that
oil or hazardous material is or has been present on the site or on areas
immediately adjacent to the site. The following summarizes this evidence:

     1. There are a number of large batteries located in the basement which
     contain lead and acid. These are received intact from the U.S. Navy and are
     sold as is when they are no longer needed. There is no visible leakage and
     the investigator was informed that there are no hazardous materials or
     wastes from these batteries to be disposed of at any time, however hydrogen
     gas may be emitted from these batteries if they are active batteries.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
page 3

     2. One-gallon containers containing cutting oil and coolant are located in
     the shop area toward the rear of the building. These are used in everyday
     operations. Since large quantities of either product are not present,
     special permits are not required.

     3. The business abutting to the east of the site, California Products
     Corporation, mixes and recans paints requiring the use of materials such as
     xylene, resin solution, solvents, and petroleum products on their property.
     Upon visiting the facility, however, no visible evidence of a release of
     hazardous materials or oil as defined in MGL Section 21E was observed.

     4. According to records with the Fire Prevention Bureau of the Cambridge
     Fire Department and testimony gathered from two other parties, a 1,000
     gallon capacity underground fuel storage tank is located on site. Fill and
     vent pipes are located in a narrow, approximately six-foot wide common
     alley between the site and California Products Corporation. According to
     official records, the last tank inspection was conducted in 1972. In 1972
     tank ownership resided with owner Cox Engineering, according to official
     records.

C. Based upon the foregoing, (including the research, observations,
explorations, and testing described in the "Site Assessment Summary") and
subject to the qualifications set forth below, the undersigned is of the
professional opinion that at the time of said investigation NO EVIDENCE
CURRENTLY EXISTS THAT OIL OR HAZARDOUS MATERIAL HAS BEEN RELEASED ON THE SITE OR
THAT SUCH A RELEASE IS IMMINENT. The following qualifies this statement:
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
page 4

     1. The underground storage tank described in Part B, Section 4, has been in
     place for at least 25 and perhaps as long as 40 years. This tank is beyond
     its life expectancy according to statistics compiled by industry and
     pollution control experts. However, based upon test results on soil samples
     taken in the area of the tank, both upgradient and downgradient, there does
     not appear to be any significant contamination from tank leakage. Also,
     prior to testing the tank had been pumped out [see Appendix 6]. See
     Conclusions and Recommendations.

     2. Based upon results of the soil analysis, the site appears to be
     relatively clean. Although trace amounts of possible fuel oil were found in
     the area of the tank this should not present any impediment to a
     transaction involving the sale of the property.

D. The following qualifications apply to the undersigned's opinion:

     1. As noted in Exhibit A borings were made and observations were made
     following the preliminary site investigation.

     2. As noted in Exhibit A soil samples were taken and chemical analyses
     performed.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
page 5

This report is dated January 31, 1986

-------------------------------------
Evelyn M. Butler, Site Investigator

Approved by:

/s/ John G. Pack
-------------------------------------
John G. Pack,
Vice President of Operations
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 1

               SITE DESCRIPTION AND ENVIRONMENTAL CHARACTERISTICS

I.   SITE OWNERSHIP AND LOCATION

1.   Site Owner: Cox Engineering/Realty Trust
                 77 Guest Street
                 Brighton, Massachusetts 02135

2.   Site Location: 625 Putnam Avenue
                    Cambridge, Massachusetts 02139
                    Middlesex County
                    USGS Quad: North Boston, Mass.

II.  SITE DESCRIPTION AND ENVIRONMENTAL CHARACTERISTICS

1. Brief Description of the Subject Site: The site lot, which is located at 625
Putnam Avenue in Cambridge, MA is comprised of two rectangular parcels which
have been consolidated into one parcel containing approximately 27,675 square
feet. The first parcel is shown as Lot A in Book #7292, page #18 and the second
parcel is shown in land registration book #423, page #597, certificate #66275 on
file with the Middlesex Registry of Deeds south district, Cambridge, MA.
Improvements on the site consist of a one story masonry building with a basement
which currently houses the offices and shop area of EML Research, Inc. To the
northwest of the building is a paved area containing a "tailboard well". Beyond
the pavement is an area covered by sand and gravel with a few weeds and
evergreens along the area bordering Sidney Street. This paved and unpaved area
serves as parking space for the facility and is surrounded by a chainlink fence.
The site borders Putnam Avenue to the northeast, California Products Corporation
to the east
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 2

and south, residential dwellings to the southwest and northern corners of the
lot and Sidney Street to the northwest, across from which lies more residential
dwellings.

2. Site Layout Information: Figure 1 shows a site plan in relation to other
properties in the immediate area. Figure 2 shows lot A which has since become a
part of the site under investigation. Figure 3 shows topographic features. The
site is served by municipal water and sewage. The site is not considered a
wetlands area as defined in MGL Chapter 131, although it was a marshland prior
to the late 1800s at which time the area was filled in, according to the
Cambridge Historical Society.

3. Site Specific Waste/Wastewater Information: The site contains no observable
pits, sumps, or lagoons on the site. According to information gathered during
interviews with the current owner, an underground tank used for the storage of
fuel oil is located between the site and abutting building to the east,
California Products Corporation. The fill and vent pipes are located in the
alleyway between the buildings. There were approximately 500 gallons of fuel oil
in the tank upon the initial investigation. On December 31, 1985, this oil was
pumped out by A.A. Waste Oil Company of Waltham, MA (See Appendix 6). According
to one fire department official, an inspection of the site revealed that this
1,000 gallon capacity tank was present in 1972. No records of the tank were on
file with the Cambridge licensing commission for the site under investigation.

Surface drainage on site is accomplished via two storm drains located in the
paved and gravel areas of the lot while drainage from the site is accomplished
via municipal storm
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 3

drains. No industrial wastewater usages are effected at this site, nor were
there observable sources of pathological wastes into the site's sewer system.

4.   Environmental Characteristics Relative to Hazardous Materials

(a)  Soil types and permeabilities are shown in Appendix 2. Soil types where
     observable, appeared to be very compact, fine to medium sand with trace
     gravel in Lot A and an approximately 4 foot layer of fill containing trace
     cinder and concrete overlying this fine to medium sand in the alleyway by
     the tank.

(b)  Subsurface geologic characteristics: The site lot lies within the area
     defined as the Boston Basin. Underlying bedrock is generally found to be
     grey argillite and minor quartzite, which are hard, fine grained
     metamorphic rocks.

(c)  After reviewing USGS Aquifer maps and topographic maps it was determined
     that the site lies with the Charles River Basin and groundwater flow is in
     the south-southeast direction. Actual site depth to groundwater was not
     determined for this project but typically ranges from twenty to thirty feet
     below grade in this region.

(d)  Ponds, streams aid wetlands: There are no ponds, streams or wetlands on the
     site or in the immediate surroundings. However, approximately 1100 feet to
     the south is the Charles River. Also, in the mid 1800s, prior to
     development, the site and surrounding properties to the southeast was
     considered marshland according to records of the Cambridge Historical
     Society.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 4

(e)  Condition of vegetation: Vegetation types noted on the site lot consist of
     evergreens and weeds along the portion of the site abutting Sidney Street.
     No visible signs of unusual plant stress as may be caused by the presence
     of certain hazardous materials was noted.

III. SITE HISTORY AND USE

1. Zoning: Present classification: The portion of the site listed as lot A is
zoned C-1 which is residential. The portion of land containing the building
along Putnam Avenue is zoned I-B which is industrial (light manufacturing and
office space), according to City of Cambridge Assessors' records.

2. Current uses of the site: The one story masonry building located on the site
houses the offices and shop area of Electromagnetic Launch Research, Inc.
According to the owner it is currently used for strobotic and other high
intensity pulsing light applications research and development projects for the
department of defense.

3. Brief Description of Former Uses of the Site: Lot A, as described in Part U.
Section 1, was acquired in March, 1958 by Cox Engineering at which time the
existing building, a residential dwelling, was razed. Prior to 1958 various
tenants owned the. property and it was strictly residential. The second parcel,
consisting of 21,000 square feet was owned by Cox Engineering for most of this
century at which time the property was used for the manufacturing of sheetmetal
ducting and some spray painting. Records were unavailable at this time defining
the time at which the original building was erected.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 5

However, the city of Cambridge building department records show several
alterations and additions from 1923 to approximately 1960.

4. Current and Former Uses of Surrounding Properties: In 1854 what is now Putnam
Avenue was known as Walnut Street. The area at and around the site consisted of
marshlands which the city filled in after 1854. Around 1870, following the
construction of the railroad, the area became industrial in nature, although
much of the area to the west and northwest of the site has continued to be
residential. To the north of the site, across Putnam Avenue is Vappi & Company,
Inc., a building and contracting company which has been in existence since
approximately 1927. A recent investigation of the Vappi G Company, Inc. site
revealed that the fill brought into the area may contain ash as tests showed low
levels of acidic materials which are generally associated with fly ash. To the
northeast, along Waverly Street, and to the south of the site is California
Products Corporation which has been in existence since approximately 1931. The
company is involved with the mixing and packaging operations of paint. Across
Putnam Avenue to the east of the site is an outdoor storage area for what
appears to be empty drums of California Products Corporation. According to
container labels, xylene, resin solutions, solvents, petroleum products and
other materials which are used in . the. company's operations were stored in the
drums. The drums appeared in satisfactory condition and were in a fenced-in area
for security. Drums were on pallets and there was no visible signs of leakage,
past or present. However, the storage area was not diked nor were the barrels
sheltered from the elements.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 6

5. List of Environmental Permits Held by Current and Former Site
Owners/Operators: There are no records on file with the Cambridge Fire
Department or the town offices showing any environmental permits for the present
or past owners. There are, however engineering plans and records showing a 1,000
gallon capacity tank at 625 Putnam Avenue listed with Cox Engineering. This
inconsistency is explained by the owner as lack of awareness that any permit was
required. Hence, no application was ever filed for the 1000 gallon tank permit.

6. Summary of Prior Citations or Fines for Violations of Environmental
Regulations: There are no records on file with the Massachusetts Department of
Environmental Quality Engineering (DEQE) northeast regional offices in Woburn.

IV.  Summary of Site Inspection and Investigations

1. On December 23, 1985 the whole site was inspected by Evelyn M. Butler, an
Ecologist and Environmental Field Specialist who was accompanied by Russell M.
Peters, an Environmental Specialist, employed by TSMI. The site boundaries were
walked down, drainage patterns were inspected and observed for contaminants.

2. Sources of information included, but were not limited to, interviews with
present owners/operators, tenants and owners of neighboring properties, and
municipal authorities.

3. On January 8, 1986, following the initial site investigation, three borings
were completed using a portable auger system and were labeled B-1, B-2 and B-3
as noted in
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 7

Figures 1 and 2. Soil samples were characterized from each boring and composite
samples were taken from each boring for analyses.

4. Composite samples taken from B-2 and B-3, located to both sides of the tank,
were tested for oil and grease. A composite sample from B-1, located in the lot
abutting Sidney Street, was tested for oil and grease, EP Toxic metals, base
neutrals and acid extractables.

5. Results and Discussion: Results of the laboratory analyses are enclosed as
Appendix 3 of this report.

Results of the oil and grease analysis, based upon Method SW 846 Method 3550,
show small amounts of what may be old fuel oil at 16.8 ppb for B-2 and 26 ppb
for B-3. No recognizable petroleum products were present as any volatiles may
have evaporated out over time.

Results of all other tests on B-1, including oil and grease, EP Toxicity, acid
extractable organics and base neutral extractable organics, show no evidence of
contaminants above the detection limit.

V.   Conclusions and Recommendations:

1. Identification of Persons Conducting the Site Inspection and Investigation:
Evelyn M. Butler, an Ecologist and Environmental Specialist was responsible for
the site investigation and inspection. Technical review of this report was
performed by John G. Pack, Vice President Operations and Technical Services of
TSMI.
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 8

2. Small amounts of what were termed "residues" (16.8 ppb and 26 ppb) were found
in B-2 and B-3, following analysis of oil and grease. These "residues" may
represent what is left of old fuel for which volatiles would have evaporated out
over time. The amount of residue found, however is within EPA guidelines and
therefore should not present any impediment to a transaction involving the sale
of the property.

3. Based upon the foregoing, it is the opinion of the Investigator that the site
poses no threat to the environment as outlined in MGL Chapter 21E and should not
be the cause for DEQE enforceable actions. TSMI bases, its opinion on the test
results attached as Appendix 3. Arrangements should be made to have it closed
out in accordance with applicable local, state and federal laws.

According to Fire Lt. Lawrence Hodgdon of the Cambridge Fire Departments Bureau
of Fire Prevention, underground fuel tanks must be closed out in an
environmentally sound manner. The city of Cambridge relies on State Fire
Marshall rules governing tank close-outs. These rules require tanks to be pumped
out and to be excavated. Lt. Hodgdon said the Department approves in-ground
close-outs on a case-by-case basis if excavation poses a threat to the
structural integrity of buildings.

At this juncture background information on federal attempts to deal with leaking
underground storage tanks is in order. Congressional amendments to the Resource
Conservation and Recovery Act (RCRA) on 11/7/84 created a new program governing
underground storage tanks (UST). Tank ownership is defined by the date of UST
enactment, 11/7/84. For tanks used but taken out of service before 11/7/84, the
owner is
<PAGE>
MGL Chapter 21E Site Investigation                                          TSMI
exhibit A
page 9

defined as "any person who owns such tank immediately before the discontinuation
of its use." However, Massachusetts is still in the process of developing its
own regulations to implement the UST program. One Federal UST section
specifically excludes heating oil tanks for consumptive use on the premises. A
note of caution: This provision may not be adopted by Massachusetts due to
severe damage caused to groundwater by leaking underground storage tanks.

VI.  LIMITATIONS

1. Usage of this report to other than the stated purpose of determining the
degree of the site having been, or the likelihood of, the site becoming a locus
where oil or hazardous materials have been, and may reasonably be expected to be
released, within the comprehension of Massachusetts General Laws, Chapter 21E is
prohibited and TSMI makes no warranty for this report's applicability for other
usage.

2. The results of this project are not transferable to subsequent
owners/prospective buyers of the site. Furthermore, TSMI makes warranty on its
findings only as of the time of actual inspections of the property, and it must
be noted that chemical constituents other than those which are described in
section IV above could be present on the site. Conclusions and/or opinions which
are based upon chemical analyses, are subject to the accuracies and precisions
of the specific analysis and method of sampling.
<PAGE>
                                      [MAP]
<PAGE>
                                      [MAP]
<PAGE>
                                      [MAP]
<PAGE>
                              [DAILY FIELD REPORT]
<PAGE>
                         [SOIL EXPLORATION CORPORATION]
<PAGE>
                                   [ANALYSIS]
<PAGE>
                          [SUMMARY OF EP TOXICITY TEST]
<PAGE>
                            [CHAIN OF CUSTODY RECORD]
<PAGE>
TSMI                                                                617-938-7340

TOXIC SYSTEMS MANAGEMENT, INC.

                    PROPERTY OWNER'S AFFIDAVIT OF SITE USAGE

INSTRUCTIONS: IN ORDER FOR TSMI TO EFFECTIVELY DETERMINE THE DEGREE OF THE SITE
DESCRIBED BELOW HAVING BEEN (OR THE LIKELIHOOD OF THE SITE BECOMING) A LOCUS
WHERE OIL OR HAZARDOUS MATERIALS HAVE BEEN (OR MAY REASONABLY BE EXPECTED TO BE)
RELEASED WITHIN THE COMPREHENSION OF MASSACHUSETTS GENERAL LAWS, CHAPTER 21E.
WE. MUST ASK CERTAIN QUESTIONS CONCERNING THE HISTORY AND USAGE OF THE SITE. ALL
THE INFORMATION WE SEEK IS NECESSARY. BE COMPLETE IN YOUR ANSWERS: IF YOUR
RESPONSE IS "NONE" OR "NOT APPLICABLE", SO INDICATE. TSMI IS AVAILABLE TO
PROVIDE ASSISTANCE IN COMPLETING THIS FORM IF REQUESTED. ALL INFORMATION
FURNISHED SHALL BE USED PURSUANT TO THE PRE-TRANSACTION ENVIRONMENTAL SITE
ASSESSMENT FOR THE PURPOSE OF THE SELLER AND/OR PROSPECTIVE BUYER OBTAINING
TITLE INSURANCE OR FINANCING AND FOR NO OTHER PURPOSES.

County of _______________________________________, Commonwealth of Massachusetts

I, John S. Desmond , having been duly sworn declare and say that I am familiar
with the premises described as follows:

LOCATION OF PROPERTY: (Give street address, exact legal description and acreage
and attach a copy of the most recent survey to this affidavit) 625 Putnam Ave.;
Cambridge, MA

I further declare and say that the answers to the following questions are
accurate to the best of my knowledge:

1. What is the current use of the premises? I do not know.
________________________________________________________________________________

________________________________________________________________________________
<PAGE>
AFFIDAVIT BY OWNER                                                          TSMI

PAGE __ OF __

2. To the best of your knowledge, are any hazardous materials or oil as
hereinafter described currently stored or used on the premises?

?    Have they been stored or used in the past?
---

No   If yes to either question explain of an additional sheet.
---

3. To the best of your knowledge has there been any disposal of oil or hazardous
materials (pursuant to licenses or otherwise) on or abutting the premises?

No   If yes, explain on an additional sheet.
---

4. Have any permits or licenses ever been issued by DEQE or the local board of
health with respect to the storage or use of oil or hazardous materials on the
premises?

No   If yes, attach copies.
---

5. To the best of your knowledge have the premises ever been investigated by
DEQE the local board of health or the media for possible illegal storage or
dumping of oil or hazardous waste?

No   If yes,. explain on an additional sheet.
---

6. Does this project involve new construction?
                                               ---

7. Have any tests been performed on the site to detect the presence of oil or
hazardous materials?

No   If yes, list tests and attach sheet interpreting the results.
---

8. Does a visual inspection of the premises reveal any possible evidence of
hazardous materials disposal [eg. discolored or foul-smelling water or soil
distressed vegetation or wildlife, barrels, etc.)?

No   If yes, explain on an additional sheet.
---

9. Are there any streams, brooks, ponds, lakes or lagoons located within or
abutting the premises?

No   If yes, to the best of your knowledge has any oil or hazardous material
---  been dumped into said water?

     If yes. explain on an additional sheet.
---

10. Were the premises ever part of or abutting a municipal dump or landfill?

No   If yes, explain on an additional sheet.
---
<PAGE>
AFFIDAVIT BY OWNER                                                          TSMI

PAGE __ OF __

11. Is the water supply for the premises provided by a private well or by the
municipality?

Municipality

12. Is there any indication in the chain of title that the premises were ever
owned by or leased to a chemical, oil, or manufacturing company or other
industrial concern?

No   If yes, explain on an additional sheet.
---

13. To the best of your knowledge, have the premises ever been used for
commercial agricultural purposes?

No   If yes, indicate on an additional sheet which types of crops were harvested
---  and what kinds of commercial herbicides and/or pesticides were applied (to
     the extent known).

**   Hazardous Materials are defined as material(s) including but not limited
     to. any material in whatever form. which, because of its quantity.
     concentration. chemical, corrosive, flammable, reactive, toxic, infectious.
     or radioactive characteristics, either separately or in combination with
     any substance or substances constitutes a present or potential threat to
     human health, safety, welfare, or to the environment, when improperly
     stored. treated, transported. disposed of, used, or otherwise managed. This
     term shall not include oil. This term [hazardous material] shall also
     include all those substances which are included under 42USCS Section
     9601(14), but it is not limited to those substances.

**   Oil is defined as insoluble or partially soluble oils of any kind or origin
     or in any form, including, without limitation, crude or fuel oils, tube oil
     or sludge, asphalt, insoluble or partially insoluble derivatives of
     mineral, animal, or vegetable oils. The term shall not include waste oil,
     and shall not include those substances which are listed in 42USCS Section
     9601(14).
<PAGE>
AFFIDAVIT BY OWNER                                                          TSMI

PAGE __ OF __

IN WITNESS WHEREOF, the undersigned have executed this AFFIDAVIT this ___ day
of ___________, 19__.

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

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

Subscribed and sworn to, before me this _____ day of _________________, 198_.

                                        ----------------------------------------
                                                      Notary Public

My Commission Expires: _______________________________
<PAGE>
December 30, 1985

This is to certify that we have removed approximately five hundred (500) gallons
of heating oil from an underground tank located adjacent to the building at 625
Putnam Avenue, Cambridge.

According to a chemical check made prior to pumping, there was no water
contamination in the tank, and the tank appears to be sound.

A. A. Waste Oil Co.,
307 Warren Street
Waltham MA 02154
617 899 3348

                                        /s/ John P. Giordano
                                        ----------------------------------------
                                        John P. Giordano, owner.
Comm. of Mass Lic. No. 77
E.P.A. I.D. MAD980584486
D.P.U. Carrier Permit No. 34012
Invoice (Receipt) No.4127
date: Dec 30, 1985.
<PAGE>
                             [A&A WASTE OIL RECEIPT]
<PAGE>
                            [APPLICATION FOR PERMIT]
<PAGE>
                                   [PICTURES]
<PAGE>
           FIRST AMENDMENT, DATED 1 DECEMBER 1996, TO LEASE AGREEMENT

  BETWEEN FORT WASHINGTON REALTY TRUST AND VERTEX PHARMACEUTICALS INCORPORATED

                               DATED 1 MARCH 1993

Fort Washington Realty Trust and Vertex Pharmaceuticals Incorporated hereby
agree to amend the current lease on 625 Putnam Avenue, Cambridge, dated 1 March
1993, as follows:

page 1, Section 1.1; page 2, Section 2; and page 2 & 3, Section 3.1: Extension
of original term:
Term: 1 February 1997 through 31 December 1998
Rent: 15,750 sq ft at $15.24/sq ft/yr = $240,000/yr = $20,000/month

page 36, Section 11.10: Option to extend beyond first extension:
Tenant's option to Extend: 1 January 1999 through 31 December 2000, at a rent of
15,750 sq ft at $18.00/sq ft/yr = $283,500/yr = $23,625/month

Triple-net of all taxes, insurance, utilities, and operating expenses.

All other provisions of said lease shall remain unchanged.

Signatories certify that they are empowered to commit their respective
organization in matters pertaining to this agreement, executed in December 1996

LESSOR:                                 LESSEE:

/s/ Henry H. Kolm
-------------------------------------

/s/ Elizabeth H. Kolm                   /s/ Richard H. Aldrich
-------------------------------------   ----------------------------------------
Fort Washington Realty Trust            Vertex Pharmaceuticals Incorporated
By: Henry H. Kolm, Trustee              By: Richard H. Aldrich
    Elizabeth C. Kolm, Trustee              Senior VP, Chief Business Officer
Date: 18 Jan 1996                       Date: 16 Dec 1996
<PAGE>
           SECOND AMENDMENT, DATED 1 FEBRUARY 1998, TO LEASE AGREEMENT

  BETWEEN FORT WASHINGTON REALTY TRUST AND VERTEX PHARMACEUTICALS INCORPORATED

                               DATED 1 MARCH 1993

Fort Washington Realty Trust and Vertex Pharmaceuticals Incorporated hereby
agree to amend the First Amendment to and the current lease on 625 Putnam
Avenue, Cambridge, dated 1 March 1993, as follows:

page 2, Section 2 & 3 of original lease and line 3 of First Amendment: Extension
of term:
Term: 1 February 1997 through 31 December 1998
Rent: 15,750 sq ft at $15.24/sq ft/yr = $240,000/yr = $20,000/month
Additional Term: 1 January 1999 through 31 December 2000
Rent: 15,750 sq ft at $18.00/sq ft/yr = $283,500/yr = $23,625/month

page 36, Section 11.10: Option to extend beyond first extension:
Tenant's option to Extend: 1 January 2001 through 31 December 2003
Rent for Option Period: 15,750 sq ft at $21.33/sq ft/yr = $336,000/yr =
$28,000/month

Triple-net of all taxes, insurance, utilities, and operating expenses.

This Second Amendment replaces the First Amendment in its entirety.

All other provisions of said lease shall remain unchanged.

Signatories certify that they are empowered to commit their respective
organizations in matters pertaining to this agreement, executed in February
1998.

LESSOR:                                 LESSEE:

/s/ Henry H. Kolm
-------------------------------------

/s/ Elizabeth H. Kolm                   /s/ Richard H. Aldrich
-------------------------------------   ----------------------------------------
Fort Washington Realty Trust            Vertex Pharmaceuticals Incorporated
By: Henry H. Kolm, Trustee              By: Richard H. Aldrich
    Elizabeth C. Kolm, Trustee              Senior VP, Chief Business Officer
Date: 30 January 1998                   Date: 2 February 1998
<PAGE>
                            THIRD AMENDMENT TO LEASE

     THIS THIRD AMENDMENT TO LEASE dated the thirty-first day of August, 2001
(this "Third Amendment") by and between FORT WASHINGTON ASSOCIATES L.L.C., a
Massachusetts limited liability company (the "Landlord") and ALTUS BIOLOGICS,
INC., a Delaware corporation (the "Tenant").

                              Preliminary Statement

     WHEREAS, by Lease Agreement dated March 1, 1993, as amended by that First
Amendment to Lease dated March 1, 1995, as further amended by that Second
Amendment to Lease dated February 1, 1998 (collectively, the "Lease"), Tenant's
predecessor-in-interest, Vertex Pharmaceuticals, Inc. ("Vertex") leased from
Landlord certain premises consisting of the land and building located at 625
Putnam Avenue, Cambridge, Massachusetts (the " Premises");

     WHEREAS, by an Assignment of Lease dated January 1, 2001 (the
"Assignment"), entered into by and between Vertex, as assignor, and Tenant, as
assignee, Vertex assigned its interest as tenant under the Lease to Tenant and
extended the term of the Lease until December 31, 2003 ("Lease Termination
Date"); and

     WHEREAS, Landlord and Tenant desire further to amend the Lease and to
provide for a five (5) year extension of the Lease.

     NOW THEREFORE, in consideration of Ten Dollars ($10.00) and other good and
valuable consideration the receipt and sufficiency of which are hereby
acknowledged, Landlord and Tenant confirm and agree as follows:

     1. TERM WITH RESPECT TO THE PREMISES. Landlord and Tenant hereby agree to
extend the term of the Lease for an additional term of five (5) years (the
"Extension Term"). Landlord and Tenant agree that the Lease Termination Date
shall be extended from December 31, 2003, to December 31, 2008. Therefore, the
parties agree that extended Lease Termination Date is now December 31, 2008
("Extended Lease Termination Date"), subject to the terms hereof.

     2. RENT PAYABLE DURING EXTENSION TERM. Landlord and Tenant agree that the
Annual Rent and monthly rent payable for the Premises, beginning on January 1,
2004 of the Extension Term shall be as follows, due and payable in equal monthly
installments on the first day of each month:

<TABLE>
<CAPTION>
Year of Extension Term   Annual Rent   Monthly Rent
----------------------   -----------   ------------
<S>                      <C>           <C>
 1/1/2004 - 12/31/2004   $349,776.00    $29,148.00
 1/1/2005 - 12/31/2005   $364,116.00    $30,343.00
 1/1/2006 - 12/31/2006   $379,044.00    $31,587.00
 1/1/2007 - 12/31/2007   $394,584.00    $32,882.00
 1/1/2008 - 12/31/2008   $410,760.00    $34,230.00
</TABLE>

Third Amendment to Lease on 625 Putnam Ave, between FtWash LLC and Altus
Biologics dated 31 Aug 01

Initials:   H Kolm   E Kolm   P Lanciano

                                                                     Page 1 of 3
<PAGE>
3. NOTICE OF LEASE. Upon either party's request, the other party shall execute a
notice of lease evidencing the Lease, as amended by this Third Amendment, which
shall be recorded at the requesting party's expense at the local registry of
deeds.

4. TERMINATION RIGHT. Landlord hereby agrees that Tenant shall have the right to
terminate this Lease by written notice given any time on or after December 31,
2003, provided that Tenant must give Landlord at least twelve (12) months prior
written notice of such termination, and provided that such notice shall set
forth the effective date of such termination which effective date shall not be
less than twelve (12) months following the date of Tenant's notice (the "Early
Termination Date"). Upon the Early Termination Date, Tenant shall vacate the
Premises and remove all of Tenant's goods and personal property from the
Premises.

5. BROKERS. Landlord and Tenant each warrants and represents to the other that
it has not dealt-with any broker in connection with the consummation of this
Third Amendment; and in the event any claim is made against one party by any
broker alleging dealings with the other party, the party against whom the broker
is alleging dealings shall defend the other party against such claim, and save
harmless and indemnify the other party on account of any loss, cost, damage and
expense (including, without limitation, attorneys' fees and court costs) which
may be suffered or incurred by such party by reason of such claim.

6. LANDLORD'S MORTGAGEE. Landlord hereby represents and warrants to Tenant that
there does not presently exist a mortgagee holding a lien or mortgage upon the
property of which the Premises is a part.

7. DEFINITIONS. All capitalized terms used herein shall have the same meaning as
set forth in the Lease, unless specifically otherwise provided herein.

8. EFFECT OF AMENDMENT. Except as set forth herein, the Lease shall remain
unchanged and in full force and effect. All references to the "Lease" shall be
deemed to be references to the Lease as amended by this Third Amendment.

Signatories hereby certify that they are authorized to commit their respective
organizations in matters pertaining to this lease agreement.

             [remaining space on this page deliberately left blank.]

Third Amendment to Lease on 625 Putnam Ave, between FtWash LLC and Altus
Biologics dated 31 Aug 01

Initials:   H Kolm   E Kolm   P Lanciano

                                                                     Page 2 of 3
<PAGE>
     EXECUTED in one or more counterparts

Signatories hereby certify that they are authorized to commit their
organizations in matters pertaining to this agreement.

WITNESS:                                LANDLORD:

                                        FORT WASHINGTON ASSOCIATES, L.L.C.

                                        By: /s/ Henry H. Kolm
                                            ------------------------------------
                                            Henry H. Kolm, President

                                        By: /s/ Elizabeth C. Kolm
                                            ------------------------------------
                                            Elizabeth C. Kolm, Trustee

                                        TENANT:

                                        ALTUS BIOLOGICS, INC.

                                        By: /s/ Peter L. Lanciano
                                            ------------------------------------
                                            Peter L. Lanciano, President

             [remaining space on this page deliberately left blank]

Third Amendment to Lease on 625 Putnam Ave, between FtWash LLC and Altus
Biologics dated 31 Aug 01

Initials:   H Kolm   E Kolm   P Lanciano

                                                                     Page 3 of 3

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