Document:

<PAGE>
                                                                   Exhibit 10.19

                  ASSIGNMENT, ASSUMPTION AND AMENDMENT OF LEASE

         This ASSIGNMENT, ASSUMPTION AND AMENDMENT OF LEASE (this "Agreement")
made this 10th day of April, 2002, by and among Central Plaza/Wells Avenue LLC,
with an address at c/o Wight & Company, 10 Cedar Street, Woburn, MA 01801
("Landlord"), TolerRx, Inc., with an address at 675 Massachusetts Avenue,
Cambridge, MA ("Original Tenant") and Critical Therapeutics, Inc., with an
address at PMB #461, One Kendall Square, Building 600, Cambridge, MA 02139 ("New
Tenant").

                                    RECITALS:

         A.       Landlord and Original Tenant entered into that certain Lease
dated October 25, 2000 (the "Lease"), whereby Original Tenant leases 7,533
square feet of office and laboratory space on the fourteenth and fifteenth
floors of the building known as Central Plaza I (the "Premises"). A true,
correct and complete copy of the Lease is attached hereto as Exhibit A. All
capitalized terms used herein without definition shall have the same meaning
herein as in the Lease. The Lease is in full force and effect and there are no
defaults thereunder.

         B.       Original Tenant desires to assign the Lease to New Tenant, and
the New Tenant desires to accept such assignment and, as of the Effective Date
(as defined below), to assume all of the Original Tenant's obligations under the
Lease, as amended by this Agreement, all upon the terms and conditions set forth
herein.

         NOW, THEREFORE, effective as of the Effective Date (as defined below),
the parties agree as follows:

         1.       Amendment of Lease. The Lease is amended by deleting the
definition of Rent in Section 1.2 and substituting the following therefore:

         Rent:    The rent shall be at the rate of:
<TABLE>
<CAPTION>
                                                                   Monthly
        Period                                  Annual Rent         Rent
        ------                                  -----------         ----
<S>                                             <C>               <C>
        11/01/2000 - the date                    $233,523.00     $19,460.25
        immediately preceding the
        Effective Date

        Effective Date - 10/31/05               $301,320.000     $25,110.00
</TABLE>

         2.       Assignment of Lease. Original Tenant transfers, assigns and
sets over unto the New Tenant all of its right, title and interest under the
Lease and the Landlord hereby consents to this assignment.

         The "Effective Date" shall mean [5] days after notice from Original
Tenant stating that Original Tenant has vacated the Premises; provided, however,
that Original Tenant will have vacated the Premises no later than July 1, 2002.
The estimated Effective Date is July 1, 2002.
<PAGE>
         3.       Assumption of Lease/Condition of Premises. New Tenant will
accept the Premises in their "As-Is" condition with no representation or
warranty by Landlord or Original Tenant as to the condition of the Premises or
the suitability therefore for New Tenant's use. New Tenant shall have the right
to use the laboratory benches currently located within the Premises. At the end
of the Term, New Tenant shall be responsible for the removal of the laboratory
benches in accordance with the terms of the Lease.

                  New Tenant covenants promises and agrees that New Tenant shall
unconditionally assume and be bound by all terms, provisions and covenants of
the Lease and this Agreement, from and after the Effective Date. New Tenant
shall pay all sums to be paid, and perform each and every obligation to be
performed by, Original Tenant under and in accordance with the terms and
conditions of the Lease and this Agreement from and after the Effective Date.
New Tenant indemnifies and agrees to hold Original Tenant harmless from and
against any and all claims or liabilities on account of or based upon the
performance or observance of any obligations of the Tenant under the Lease first
occurring on or after the Effective Date. Original Tenant indemnified and agrees
to hold New Tenant harmless from and against any and all claims or liabilities
on account of or based upon the performance or observance of any obligations of
the Tenant under the Lease occurring prior to the Effective Date.

         4.       Reservation by Original Tenant. Original Tenant reserves the
rights to any refund due Original Tenant from Landlord arising out of any
overpayment by Original Tenant of amounts due for either real estate taxes or
operating expenses pursuant to the terms of Articles VIII and IX of the Lease
pertaining to the period prior to the Effective Date.

                  Notwithstanding anything herein to the contrary, Original
Tenant shall remain liable to Landlord for any amounts owed by Original Tenant
to Landlord under Articles VII and IX of the Lease for the period prior to the
Effective Date.

         5.       Security Deposit. Upon execution of this Agreement by all
parties, New Tenant shall pay to Original Tenant the sum of $38,920.50 as
reimbursement to Original Tenant of the Security Deposit paid by Original Tenant
under the Lease. Upon receipt of the $38,920.50 payment, Original Tenant assigns
to New Tenant all interest Original Tenant has in the Security Deposit under the
Lease and Landlord acknowledges New Tenant's right, title and interest to the
Security Deposit.

         6.       Release of Original Tenant. Landlord releases Original Tenant
from any and all obligations under the Lease and further assures that there are
no outstanding defaults against or by the Original Tenant.

         7.       Miscellaneous.

         a)       This Agreement shall be binding upon and shall inure to the
                  benefit of the parties to the Agreement and their respective
                  heirs, successors and permitted assigns.

         b)       Except as expressly modified by this Agreement, the Lease
                  shall be unchanged and remain in full force and effect, and is
                  hereby expressly approved, ratified and confirmed. No
                  provision of this Agreement that is held to be inoperative,
<PAGE>
                  unenforceable or invalid shall affect the remaining
                  provisions, and to this end all provisions of this Agreement
                  are declared to be severable.

         c)       Time is of the essence of this Agreement.

         d)       This Agreement may not be changed orally, but only by an
                  agreement in writing, signed by the party against whom
                  enforcement of any waiver, change, modification or discharge
                  is sought.

         e)       This Agreement shall be construed in accordance with the laws
                  of the Commonwealth of Massachusetts.

         f)       This Agreement may be executed in counterparts, each of which
                  shall be deemed an original, but all of which together shall
                  constitute one and the same document.

         g)       All notices given pursuant to the Agreement must be in writing
                  and will be effectively given if personally delivered or, if
                  mailed, postage prepaid, certified or registered mail, receipt
                  requested to the address of the parties set forth above or to
                  such other address as any party subsequently may designate in
                  writing.
<PAGE>
         IN WITNESS WHEREOF, the parties have executed this Agreement under seal
as of the date set forth above.

LANDLORD:                             ORIGINAL TENANT:

CENTRAL PLAZA/WELLS AVENUE LLC        TOLERX, INC.

By: /s/ Raymond C. Lee                By: /s/ Douglas J. Ringler
    ------------------------------        -------------------------------------
    Its Manager                           Douglas J. Ringler, V.M.D., President

NEW TENANT:

CRITICAL THERAPEUTICS, INC.

By: /s/ Christopher Mirabelli
    ------------------------------
Name:  Christopher Mirabelli
Title: Acting President
<PAGE>
                                    EXHIBIT A

                                      Lease
<PAGE>
                                    ARTICLE I
                             BASIC LEASE PROVISIONS

1.1.     INTRODUCTION                  The following sets forth basic data and,
                                       where appropriate, constitutes
                                       definitions of the terms hereinafter
                                       listed.

1.2.     BASIC DATA

         Date:                         October 25, 2000

         Landlord:                     Central Plaza/Wells Avenue, LLC

         Mailing                       c/o Wight & Company, Incorporated
         Address of                    10 Cedar Street
         Landlord:                     Woburn, MA  01801

         Tenant:                       TolerRx, Inc.

         Mailing Address               675 Massachusetts Avenue
         of Tenant:                    Cambridge, MA  02139

         Lease Term:                   Five (5) Years

         Commencement Date:            November 1, 2000

         Rent:                         The rent shall be at the rate of:

<TABLE>
<CAPTION>
                                                              MONTHLY
         PERIOD                        ANNUAL RENT            RENT
         ------                        -----------            ----
<S>                                    <C>                    <C>
         11/01/2000 - 10/31/2003       $233,523.00            $19,460.25
         11/01/2003 - 10/31/2005       $248,589.00            $20,715.75
</TABLE>

         Use:                          Tenant shall use the Premises for general
                                       office and laboratory purposes only and
                                       for no other use without the Landlord's
                                       written consent which shall not be
                                       unreasonably withheld or delayed. For the
                                       purpose of this Lease, the term
                                       laboratory shall mean an area entirely
                                       segregated and operating independently
                                       from the HVAC system of the Building to
                                       be used for pharmaceutical research
                                       activities. The function of said
                                       laboratory is further described in
                                       Exhibit E attached hereto.
<PAGE>
         Building:                     Central Plaza I
                                       675 Massachusetts Avenue
                                       Cambridge,MA  02139

                                       Said building consists of 130,550
                                       rentable square feet.

         Premises:                     The area located within the Building
                                       outlined on the attached Plans (Exhibit
                                       A-1 - 14th Floor Space and Exhibit A-2 -
                                       15th Floor Space). The area is deemed to
                                       be 7533 rentable square feet of office
                                       and laboratory space on the fourteenth
                                       and fifteenth floors of Central Plaza I
                                       (hereinafter "the Premises").

         Tenant's
         Percentage:                   5.77% (7533/130,550)

         Base Taxes:                   Fiscal Year 2001

         Base Operating
         Expense:                      Calendar Year 2000

         Guarantor of Tenant's
         Obligations:                  N/A

         Tenant Plan Delivery
         Date:                         N/A

         Security Deposit:             $38,920.50

         Broker:                       Wight & Company, Incorporated and
                                       Trammell Crow Company

         Mortgagees of
         Record:                       Salomon Brothers Realty Corp.

                                   ARTICLE II
                             DESCRIPTION OF PREMISES
                   AND APPURTENANT RIGHTS; TERM AND EXTENSIONS

2.1.     LOCATION OF PREMISES - Landlord hereby demises and leases to Tenant, an
         Tenant hereby accepts from Landlord, the Premises.

2.2.     APPURTENANT RIGHTS AND RESERVATION - Tenant shall have, as appurtenant
         to the Premises, the non-exclusive right to use, and permit its
         invitees to use in common with others, public or common lobbies,
         hallways, stairways, passenger elevators and sanitary facilities in the
         building, but such rights shall always be subject to reasonable rules
         and
<PAGE>
         regulations from time to time established by Landlord by suitable
         notice, and to the right by Landlord to designate and change from time
         to time areas arid facilities so to be used.

         Excepted and excluded from the Premises are the roof or ceiling, the
         floor and all perimeter walls of the Premises, except the inner
         surfaces thereof, but the entry doors to the Premises are not excluded
         from the Premises and are a part thereof for all purposes. Tenant
         agrees that Landlord shall have the right to place in the Premises
         utility lines, pipes and the like, to serve premises other than the
         Premises, and to replace and maintain and repair such utility lines,
         pipes and the like, in, over and upon the Premises.

         During the hours of 8:00 a.m. to 6:00 p.m., Monday through Friday,
         legal holidays in all cases excepted (hereinafter referred to as
         "Normal Building Operating Hours"), the Building shall be open and
         access to the Premises shall be freely available, subject to
         interruption due to causes beyond Landlord's reasonable control. During
         periods other than Normal Building Operating Hours, Landlord shall
         endeavor, on the reasonable prior request of Tenant, to provide means
         of access to the Premises, but access to the Premises during Normal
         Building Operating Hours and at other times shall always be subject to
         reasonable rules and regulations established by Landlord. Tenant
         acknowledges that, in all events, Tenant is responsible for providing
         security to the Premises and its own personnel.

         Tenant acknowledges and agrees to provide access within the Premises to
         the locations identified on Exhibit A-I to Landlord or their designee
         at all times in case of emergency and otherwise during normal operating
         hours as defined herein.

2.3.     TERM - The initial Term of this Lease is as set forth in Section 1.2
         hereof. The Term shall begin at 12:01 a.m. on November 1, 2000 and
         shall end at 12:00 midnight on October 31, 2005.

                                   ARTICLE III
                                      RENT

3.1.     RENT - Tenant agrees to pay the Landlord or as directed by Landlord on
         the Commencement Date, and thereafter, monthly, in advance, on the
         first day of each and every calendar month during the term of this
         Lease, at the address from time to time designated by Landlord, the
         Rent specified in Section 1.2 hereof. Until notice of some other
         designation is given, Rent and all other charges for which provision is
         herein made, including without limitation increases in rent, increases
         in Operating Expenses payable pursuant to Article IX hereof, and
         increases in real estate and other taxes payable pursuant to Article
         VIII hereof, shall be paid by remittance to or to the order of
         Landlord, at Landlord's mailing address.

                                   ARTICLE IV
                                 USE OF PREMISES

4.1.     PERMITTED USE - Tenant agrees that the Premises shall be used and
         occupied by Tenant only for the purpose specified as the use thereof in
         Section 1.2 of this Lease, and for no other purpose or purposes.
<PAGE>
         Tenant further agrees to conform to the following provisions during the
         entire Lease Term.

         (a)      Tenant shall cause all freight to be delivered to or removed
                  from the Building and the Premises in accordance with
                  reasonable rules and regulations established by Landlord
                  therefore;

         (b)      Tenant shall not place on the exterior or exterior walls
                  (including both interior and exterior surfaces of windows and
                  doors) or on any part of the Building outside the Premises,
                  any sign, symbol, advertisement or the like visible to public
                  view outside of the Premises without the prior consent of
                  Landlord, except for signs or lettering on the entry doors to
                  the Premises of the type commonly and customarily found in
                  first-class office buildings for the purpose of identifying
                  and locating the Premises. Where Landlord establishes
                  reasonable standards for such signs, Tenant agrees to conform
                  to the same and to submit for Landlord' s prior approval a
                  plan or sketch of the sign to be placed on such entry doors.

         (c)      Tenant shall not perform any act or carry on any practice
                  which may injure the Premises, or any other part of the
                  Building, or cause any offensive odors or loud noise, or
                  constitute a nuisance or menace to any other tenant or tenants
                  or other persons in the Building, or be detrimental to the
                  reputation or appearance of the Building.

4.2      ALTERATIONS - Tenant shall not alter or add to the Premises, except
         upon and in accordance with written consent from Landlord. All
         alterations made by Tenant shall be made in accordance with all
         applicable laws and in a first-class manner. All work performed by
         Tenant in the Premises shall remain therein and, at termination, shall
         be surrendered as a part thereof, except for Tenant's usual trade
         furniture and equipment (laboratory benches and furniture), which trade
         furniture and equipment Tenant may remove upon the termination of this
         Lease provided that Tenant is not then in default hereunder. Tenant
         agrees to repair any and all damage to the Premises resulting from such
         removal or, if Landlord so elects, to pay Landlord for the cost of any
         such repairs. Notwithstanding the foregoing, Tenant will comply with
         the requirements of Section 14.24 for the initial alteration of the
         Premises.

4.3      RESTORATION CLAUSE - At the termination of this Lease, the Tenant will
         vacate and surrender possession of the entire Premises ordinary wear
         and tear excepted. At Landlords sole option, Tenant will restore all
         space used as laboratories to an office standard which shall be defined
         as - 24 ounce direct glue down nylon carpet throughout, clean wall
         surfaces with any laboratory like apparatus removed, a clean ceiling
         that matches the other space used as offices with adequate lighting for
         office use. The Tenant shall remove all personal property and office
         trade fixtures that may be readily removed without damage to the
         Premises.

         For spaces to be utilized by Tenant as laboratory space, the Tenant
         will, at the termination of this Lease, return the space to its
         original condition, ordinary wear and tear excepted, provided that
         improvements to floors, walls, electrical service, lighting, ceiling,
<PAGE>
         and HVAC will remain in the space and will become the property of the
         Landlord. While the benches, hoods, equipment, attached and unattached
         laboratory furniture, and other laboratory relating items, whether
         attached or unattached (Laboratory Improvements) will remain the
         property of the Tenant. Tenant shall repair any damage to the Premises
         caused by Tenant's removal of Laboratory Improvements to the condition
         they were in when first occupied by Tenant, normal wear and tear
         excepted. For the restoration of the intended lab space on the 15th
         floor (Temple Street side of the building), the Tenant will return the
         space to an "empty shell" status with three existing office units on
         the Massachusetts Avenue side of the building, while repairing all open
         plumbing pipes, electrical conduits, or any damage to walls or floors
         incurred by Tenant during the renovation and restoration. At the
         Landlord's discretion and before Tenant's departure, the Landlord may
         ask Tenant to leave the space "as is" without subjecting Tenant to any
         restoration efforts.

                                    ARTICLE V
                            ASSIGNMENT AND SUBLETTING

5.1      PROHIBITION - Notwithstanding any other provisions of this Lease,
         Tenant covenants and agrees that it will not assign this Lease or
         sublet the whole or any part of the Premises without the express
         written consent of Landlord which consent shall not be unreasonably
         withheld, conditioned, or delayed. Without limiting the generality of
         the foregoing, if Landlord shall consent to any such assignment or
         sublet, it shall be a condition of any such consent i) that any excess
         in the amount of rent paid by any sublessee or assignee over the Rent
         payable hereunder less reasonable leasing commissions shall be entirely
         the property of the Landlord; and ii) the Tenant shall not in any way
         be excused from its obligations hereunder because of such assignment or
         sublease.

                                   ARTICLE VI
                           RESPONSIBILITY FOR REPAIRS
                            AND CONDITION OF PREMISES

6.1      REPAIRS TO BE MADE BY LANDLORD - Except as otherwise provided in this
         Lease, Landlord agrees to keep in good order, condition and repair the
         Building, including the utility systems therein, insofar as such
         systems service the Premises. Landlord shall in no event be responsible
         to Tenant for the condition of glass in and about the Premises or for
         the doors leading to the Premises, or for any condition in the Premises
         or the Building caused by any act of neglect of Tenant or any
         contractor, agent, employee or invitee of Tenant, or anyone claiming
         by, through or under Tenant.

6.2      TENANT'S AGREEMENT - Tenant acknowledges that, as of the date hereof,
         the Premises are in good order, condition and repair and as represented
         to Tenant, and that, from and after the date hereof, and until the end
         of the Term, condition and repair the Premises and every part thereof,
         excepting only those repairs for which Landlord is responsible under
         the terms of the Lease or damage by fire or other casualty and as a
         consequence of the exercise of the power of eminent domain and
         excepting ordinary wear and tear; and shall surrender the Premises, at
         the end of the term, in such condition.
<PAGE>
6.3      FLOOR LOAD-HEAVY MACHINERY - Tenant shall not place a load upon any
         floor in the Premises exceeding the floor load per square foot of area
         which such floor was designed to carry and which is allowed by law.
         Landlord reserves the right to prescribe the weight and position of all
         business machines and mechanical equipment, including safes, which
         shall be placed so as to distribute the weight. Business machines and
         mechanical equipment shall be placed and maintained by Tenant at
         Tenant's expense in settings sufficient, in Landlord's judgment, to
         absorb and prevent vibration, noise and annoyance. Tenant shall not
         move any safe, heavy machinery, heavy equipment, freight, bulky matter
         or fixtures into or out of the Building without Landlord's prior
         consent.

                                   ARTICLE VII
                      SERVICES TO BE FURNISHED BY LANDLORD

7.1      ELECTRIC CURRENT - Landlord will furnish to Tenant during Normal
         Building Operating Hours electric current for the operation of lighting
         fixtures and the electrical outlets located in the Premises for normal
         lighting requirements and normal light business office equipment (as
         distinguished from special items such as computer installations; such
         electricity shall be paid for by the Tenant). If an electric meter
         serves the Building, or a portion of the Building which includes the
         Premises, but the Premises are not separately metered, Tenant shall pay
         monthly to the Landlord an estimated amount based upon its
         proportionate share (determined by its portion of the total rentable
         area metered on a per rentable square foot basis) of the estimated
         usage, to be adjusted by the Landlord upon receipt of the electric
         bill. If an electric meter serves the Premises, the electric service
         shall be billed directly to and paid by the Tenant.

         No special installations or facilities shall be permitted in the
         Premises unless Tenant has represented the type of equipment and
         electrical energy requirements on account thereof, and Landlord has
         approved such installation in writing and the Tenant pays the
         additional cost of the energy used.

7.2      WATER - Landlord shall furnish hot and cold water for ordinary toilet,
         lavatory and drinking purposes to those plumbing fixtures presently
         installed within the Building. If Tenant requires water for any other
         purpose, Tenant shall pay to Landlord an appropriate charge stipulated
         by Landlord to reimburse Landlord for the cost of such water and
         related sewer use charge (including a charge to reimburse Landlord for
         the cost of metering Tenant's usage).

7.3      OTHER SERVICES - Landlord shall:

         (a)      provide automatically operated elevators in such number as
                  Landlord shall from time to time determine to be necessary in
                  Landlord's sole discretion, and maintain the same in
                  operation, available for the non-exclusive use thereof by
                  Tenant, in common with others having business in the Building,
                  during Normal Building Operating Hours;

         (b)      provide routine cleaning service specified in the schedule
                  attached hereto to the Premises outside of Normal Building
                  Operating Hours;
<PAGE>
         (c)      provide cleaning services to public areas, including
                  lavatories in the Building so that the same are in reasonably
                  neat and clean condition; and

         (d)      furnish air conditioning and heat to the Premises during
                  normal seasons therefor and during Normal Building Operating
                  Hours by means of equipment presently installed in the
                  Premises. If such air conditioning and/or heat is generated
                  electrically, or by gas and if an electric or gas meter serves
                  the Premises, the cost thereof shall be billed directly to and
                  paid by the Tenant in addition to which Tenant shall pay its
                  proportionate share of the cost of the heating the common
                  areas of the Building. If electricity or gas is not metered to
                  the Premises, the Tenant shall pay such electricity or gas
                  monthly in advance based upon its proportionate share
                  (determined by its portion of the total rented area metered on
                  a per rentable square foot basis) of the estimated usage, to
                  be adjusted promptly by the Landlord upon its receipt of the
                  electricity or gas bill.

                                  ARTICLE VIII
                           REAL ESTATE AND OTHER TAXES

8.1      TENANT'S SHARE OF REAL ESTATE TAXES - In addition to the Rent to be
         paid by Tenant, Tenant shall pay to Landlord its proportionate share
         (determined by its portion of the total rentable area on a per rentable
         square foot basis) of the amount by which real estate taxes for any tax
         period or part thereof during the term of this lease on the Building
         and the land on which the Building is located, exceeds the taxes for
         the Base Tax Year specified in Section 1.2 (prorated for less than a
         full year).

         Payments by Tenant on account of Tenant's share of such taxes shall be
         made monthly and at the time and in the fashion herein provided for the
         payment of Rent. The amount so to be paid to Landlord shall be an
         amount form time to time estimated by Landlord to be sufficient to
         provide Landlord, in the aggregate, a sum equal to Tenant's share of
         each payment by Landlord on account of such taxes, ten (10) days at
         least before the day on which such payments by Landlord would become
         delinquent.

         Promptly after receipt by Landlord of bills for such taxes, Landlord
         shall advise Tenant of the amount thereof, and the computation of
         Tenant's' share on account thereof for the tax period included within
         the term of this Lease covered by such bill. If payments theretofore
         made for such period by Tenant exceed such share, Landlord shall credit
         the amount of overpayment against subsequent obligations of Tenant;
         but, if such share is greater than payments theretofore made on account
         for such period, Tenant shall make suitable payable to Landlord within
         ten (10) days after being so advised by Landlord.

         Landlord shall have the same rights and remedies for the non-payment by
         Tenant of any amounts due on account of such taxes as Landlord has
         hereunder for the failure of Tenant to pay Rent.

         Payments by the Tenant to the Landlord on account of such taxes shall
         not be considered as being held in trust, in escrow, or the like, by
         the Landlord; it being the express intent of the Landlord and the
         Tenant that the Tenant shall in no event be entitled to receive
<PAGE>
         interest upon, or any payments on account of earnings or profits
         derived from, such payments by the Tenant to the Landlord.

                                   ARTICLE IX
                               OPERATING EXPENSES

9.1      TENANT'S SHARE OF OPERATING COSTS - In addition to the Rent to be paid
         by Tenant, Tenant shall pay to Landlord its proportionate share
         (determined by its portion of the total rented area on a per rentable
         square foot basis) of the amount by which "Operating Costs (as
         hereinafter defined) for any calendar year or part thereof during the
         term of this Lease, exceed the Operating Costs for the Base Operating
         Year specified in Section 1.2 (prorated for less than a full year).

         Payments by Tenant on account of Tenant's share of such excess shall be
         made monthly and at the time and in the fashion herein provided for the
         payment of Rent. The amount so to be paid to Landlord shall be an
         amount from time to time estimated by Landlord to be sufficient to
         provide Landlord, in the aggregate, a sum equal to Tenant's share of
         such excess for each calendar year during the Term of this Lease.

         Promptly after the end of each calendar year during the Term of this
         Lease, Landlord shall submit to Tenant an accounting of costs for such
         calendar year, and Landlord shall certify to the substantial accuracy
         thereof. If payments theretofore made for such calendar year by Tenant
         exceed Tenant's share of Operating Costs according to such statement,
         Landlord shall credit the amount of overpayment against subsequent
         obligations of Tenant; but, if the Tenant's share of Operating Costs is
         greater than payments theretofore made on account for such period,
         Tenant shall make suitable payment to Landlord within ten (10) days
         after being so advised by Landlord.

         Landlord shall have the same rights and remedies for the non-payment by
         Tenant of any amounts due on account of such Operating Costs as
         Landlord has hereunder for the failure of Tenant to pay the Rent.

         Payments by the Tenant to the Landlord on account of such Operating
         Costs shall not be considered as being held in trust, in escrow, or the
         like, by the Landlord; it being the express intent of the Landlord and
         the Tenant that the Tenant shall in no event be entitled to receive
         interest upon, or any payments on account of earnings or profits
         derived from, such payments by the Tenant to the Landlord.

9.2      DEFINITION OF "OPERATING COSTS" - The term "Operating Costs" means all
         expenses reasonably incurred in the operation, management, cleaning and
         maintenance of the Building and the land on which the same is located,
         including, without limitation, expenses reasonably incurred in the
         cleaning and maintenance of all public areas, elevators, cooling and
         heating equipment for the Building, wages to Landlord's employees or
         independent contractors providing cleaning and maintenance services to
         the Building, taxes on such wages, charges for water and sewerage, fuel
         expense, and electric current utilized for the Building, not otherwise
         paid by the Tenant pursuant to Section 7.1 and 7.3 hereof, premiums for
         fire, casualty, liability and such other insurance as may
<PAGE>
         from time to time customarily be maintained on first-class office
         buildings in the city or town where the Building is located, the cost
         of any installations, alterations, and the like in and to the Building
         made necessary by amendment of governmental building codes or other
         regulations occurring after the date of this lease, the costs incurred
         in complying with the requirements of the insurers of the Building or
         with the requirements of any applicable Board of Fire Underwriters and
         the cost (or portion thereof allocable to the Building) of any capital
         improvement that reduces other operating costs chargeable to Tenant
         (amortized over such reasonable period as Landlord shall determine,
         together with interest at the rate of Prime (as per Fleet Bank) plus 2
         % per annum on the unamortized balance), management fee in amounts
         customarily charged for similar properties and such other services as
         Landlord, in its sole discretion, may, from time to time, deem
         necessary for the maintenance, operation and/or security of the
         Building.

                                    ARTICLE X
                    INDEMNITY AND PUBLIC LIABILITY INSURANCE

10.1     TENANT'S INDEMNITY - To the maximum extent this agreement may be made
         effective according to law, Tenant agrees to indemnify and save
         harmless Landlord from and against all claims of whatever nature
         arising from any act, omission or negligence of Tenant, or Tenant's
         contractors, licensees, invitees, agents, servants or employees, or
         arising from any accident, injury or damage whatsoever caused to any
         person, or to the property of any person, occurring after the
         commencement of the Lease Term and until the end of the Lease Term and
         thereafter, so long as Tenant is in occupancy of any part of the
         Premises.

         This indemnity and hold harmless agreement shall include indemnity
         against all costs, expenses and liabilities incurred in or in
         connection with any such claim or proceeding brought thereon, and the
         defense thereof, by counsel satisfactory to Landlord.

10.2     PUBLIC LIABILITY INSURANCE - Tenant agrees to maintain in full force
         from the date on which Tenant first enters the Premises for any reason,
         throughout the Lease Term, and thereafter so long as Tenant is in
         occupancy of any part of the Premises, a policy of Comprehensive
         General Liability insurance in accordance with the broadest form of
         such coverage as is available from time to time in the jurisdiction in
         which the Premises are located. The minimum limits of liability of such
         insurance shall be $1 million per occurrence,

         Bodily Injury Liability (including death) and $250,000 per occurrence,
         Property Damage Liability. Such minimum limits shall be increased from
         time to time as specified by the Landlord provided such increases are
         consistent with sound practice.

         Tenant further agrees to maintain a Worker's Compensation and
         Employer's Liability Insurance policy. The limit of liability as
         respects Employers' Liability coverage shall be no less than $100,000
         per accident.

         Except for Workers' Compensation and Employers' Liability coverage, the
         Tenant agrees that the Landlord (and such other persons as are in
         privity of the estate with Landlord as
<PAGE>
         may be set out in notice from time to time) are named as additional
         insureds. Further, all policies shall be noncancellable and
         non-amendable with respect to Landlord and Landlord's said designees
         without 30 days' prior notice to Landlord. A duplicate original or a
         Certificate of Insurance evidencing the above agreements shall be
         delivered to Landlord.

10.3     TENANT'S RISK - To the maximum extent this agreement may be made
         effective according to law, Tenant agrees to use and occupy the
         Premises and to use such other portions of the Tenant's own risk; and
         Landlord shall have no responsibility or liability for any loss of or
         damage to fixtures or other personal property of Tenant for any reason,
         unless Landlord is proven to have sole liability for negligence by a
         court of competent jurisdiction. The provisions of this Section shall
         be applicable from and after the execution of this Lease and until the
         end of the Lease Term, and during such further period as Tenant may use
         or be in occupancy of any part of the Premises or of the Building.
         Tenant shall comply with any loss prevention or safety recommendations
         made by Landlord's insurance companies when such recommendations arise
         from the operation of the Tenant. The cost of compliance, if any, shall
         be paid by the Tenant.

10.4     INJURY CAUSED BY THIRD PARTIES - To the maximum extent this agreement
         may be made effective according to law, Tenant agrees that Landlord
         shall not be responsible or liable to Tenant, unless Landlord is proven
         to have sole liability for negligence by a court of competent
         jurisdiction, or to those claiming by, through or under Tenant, for any
         loss or damage that may be occasioned by or through the acts or
         omissions of third persons for any loss or damage resulting to Tenant
         or those claiming by, through or under Tenant, or its or their
         property, from the breaking, bursting, stopping or leaking of electric
         cables and wires, water, gas, sewer or steam pipes, and from roof leaks
         and the like.

                                   ARTICLE XI
                          LANDLORD'S ACCESS TO PREMISES

11.1.    LANDLORD'S RIGHT OF ACCESS - Landlord shall have the right to enter the
         premises at all reasonable hours, and upon reasonable advance notice
         and accompanied by a representative of Tenant, and at all hours in the
         event of an emergency, for the purpose of inspecting or of making
         repairs to the same, and Landlord shall also have the right to make
         access available at all reasonable hours to prospective or existing
         mortgagees or purchasers of the Building.

11.2     EXHIBITION OF SPACE TO PROSPECTIVE TENANTS - For a period commencing
         six (6) months prior to the expiration of the Lease Term, Landlord may
         have reasonable access to the Premises at all hours and upon reasonable
         advance notice and accompanied by a representative of Tenant, and upon
         reasonable advance notice and accompanied by a representative of Tenant
         for the purpose of exhibiting the same to prospective tenants, and may
         post suitable notices on the Premises advertising the same for rent.
<PAGE>
                                   ARTICLE XII
                           FIRE, EMINENT DOMAIN, ETC.

12.1.    ABATEMENT OF RENT - If the Premises shall be damaged by fire or
         casualty, the Rent and the charges payable by Tenant hereunder shall
         abate or be reduced proportionately for the period in which, by reason
         of such damage, there is substantial interference with the operation of
         Tenant's use of the Premises, having regard to the extent to which
         Tenant may be required to discontinue Tenant's use of the Premises.
         Such abatement or reduction shall end if and when Landlord shall have
         restored the Premises (exclusive of any of Tenant's fixtures,
         furnishings, equipment and the like) to substantially the condition in
         which the Premises were in prior to such damage.

         If any part of the Building is taken by any exercise of the power of
         eminent domain, as a result of which there is substantial interference
         with the operation of Tenant's use of the Premises, then the rent and
         the charges payable by Tenant hereunder shall be justly and equitably
         abated and reduced according to the nature and extent of the loss of
         use thereof suffered by Tenant.

12.2.    RIGHT OF TERMINATION - If the Premises or the Building are
         substantially damaged by fire or casualty (the term "substantially
         damaged" meaning damage of such a character that the same can not, in
         ordinary course, reasonably be expected to be repaired within ninety
         (90) days from the time that repair work would commence), or any part
         of the Building is taken by any exercise of the right of eminent
         domain, then Landlord or Tenant shall have the right to terminate this
         Lease by giving notice of either such party's election to do so,
         whereupon this Lease shall terminate as of the date of such notice with
         the same force and effect as if such date were the date originally
         established as the expiration date hereof.

12.3.    AWARD - Landlord shall have and hereby reserves and accepts, and Tenant
         hereby grants and assigns to Landlord, all rights to recover for
         damages to the Building, the land on which the same is located, as
         aforesaid, and the leasehold interest hereby created, and to
         compensation accrued or hereafter to accrue by reason of such taking,
         damage or destruction, as aforesaid, and by way of confirming the
         foregoing, Tenant hereby grants and assigns, and covenants with
         Landlord to grant and assign, to Landlord all rights to such damages or
         compensation. Nothing contained herein shall be construed to prevent
         Tenant from prosecuting in any condemnation proceedings a claim for the
         value of any of Tenant's movable trade fixtures installed in the
         Premises by Tenant at Tenant's expense and for relocation expenses,
         provided that such action shall not affect the amount of compensation
         otherwise recoverable by Landlord from the taking of authority.

                                  ARTICLE XIII
                                     DEFAULT

13.1     TENANT'S DEFAULT - If

         (a)      Tenant shall fail to pay the rent or other charges for which
                  'provision is made herein on or before the date on which the
                  same become due and payable, or
<PAGE>
         (b)      shall fail to perform or observe any other term or condition
                  contained in this Lease, and such failure is not cured within
                  twenty (20) days after written notice form Landlord thereof,
                  or, if cure may not be completed within twenty (20) days, such
                  cure has been commenced within twenty (20) days and is
                  thereafter completed in a reasonably prompt manner, or

         (c)      if the estate hereby created shall be taken on execution or by
                  other process of law, or if Tenant shall be judicially
                  declared bankrupt or insolvent according to law, or if any
                  assignment shall be made of the property of Tenant for the
                  benefit of creditors, or if a receiver, guardian, conservator,
                  trustee in involuntary bankruptcy or other similar officer
                  shall be appointed to take charge of all or any substantial
                  part of Tenant's property by a court of competent
                  jurisdiction, or if a petition shall be filed for the
                  reorganization of Tenant under any provisions of any
                  Bankruptcy Act now or hereafter enacted, or if Tenant shall
                  file a petition for such reorganization, or for arrangements
                  under any provision of any Bankruptcy Act now or hereafter
                  enacted and providing a plan for a debtor to settle, satisfy
                  or extend the time for payment of debt (references herein to
                  Tenant shall include any guarantor of Tenant's obligations
                  hereunder), then, and in any of said cases Landlord lawfully
                  may, immediately or at any time thereafter, and without demand
                  or notice, enter into and upon he Premises or any part thereof
                  in the name of the whole and repossess the same, and expel
                  Tenant and those claiming through or under Tenant and remove
                  its or their effects (forcibly, if necessary) without being
                  guilty of any manner of trespass, and without prejudice to any
                  remedies which might otherwise be used for arrears of rent or
                  breach of covenant. Upon entry as aforesaid, Landlord shall
                  have the right, by suitable notice to Tenant, forthwith to
                  terminate this Lease. Tenant covenants and agrees,
                  notwithstanding any entry or re-entry by Landlord, whether by
                  summary proceedings, termination, or otherwise, to pay and be
                  liable for, on the days originally fixed herein for the
                  payment thereof, amounts equal to the several installments of
                  Rent and other charges reserved a they would, under the terms
                  of this Lease, become due if this Lease had not been
                  terminated or if Landlord had not entered or reentered, as
                  aforesaid, and whether the Premises be relet or remain vacant,
                  in whole or in part, or for a period less than the remainder
                  of the Term, and for the whole thereof. In the event the
                  Premises be relet by Landlord, Tenant shall be entitled to a
                  credit in the net amount of Rent and other charges received by
                  Landlord in reletting, after deduction of all expenses
                  incurred in reletting the Premises (including, without
                  limitation, remodeling costs, brokerage fees, attorney's fees,
                  and the like).

                  Without limiting any of Landlord's rights and remedies
                  hereunder, and in addition to all other amounts Tenant is
                  otherwise obligated to pay, it is expressly agreed that
                  Landlord shall be entitled to recover from Tenant all costs
                  and expenses, including reasonable attorney's fees, and court
                  costs incurred by Landlord in enforcing this Lease from and
                  after Tenant's default and all of Landlord's reasonable
                  expenses in connection with reletting the brokerage
                  commissions, fees for legal services, expenses of preparing
                  the Premises for reletting and the like ("Reletting
                  Expenses"). It is agreed by Tenant that Landlord may (i) relet
                  the
<PAGE>
                  Premises or any part or parts thereof for a term or terms
                  which may at Landlord's option be equal to or less than or
                  exceed the period which would otherwise have constituted the
                  balance of the Term, and may grant such tenant inducements as
                  Landlord in its sole judgment considers advisable, and (ii)
                  make such alterations, repairs and decorations in the Premises
                  as Landlord in its sole discretion considers advisable, and no
                  action of Landlord in accordance with the foregoing nor any
                  failure to relet or to collect rent under any reletting shall
                  operate or be construed to release or reduce Tenant's
                  liability. Landlord's Reletting Expenses together with all
                  sums otherwise provided for in this Lease, whether incurred
                  prior to or after such termination, shall be due and payable
                  immediately from time to time upon notice from Landlord. If
                  this Lease is terminated for default, then Tenant covenants,
                  as an additional cumulative obligation after termination, to
                  pay forthwith to Landlord, at Landlord's election made by
                  written notice to Tenant at any time after termination, as
                  liquidated damages a single lump sum payment equal to the sum
                  of (i) all sums provided for in this Lease to be paid by
                  Tenant and not then paid at the time of such election, plus
                  (ii) the excess of all of the rent reserved for the residue of
                  the Term (with additional rent on account of Landlord's Taxes
                  and Operating Expenses deemed to increase 10 % in each year on
                  a compounding basis) over all of the rent actually received
                  (or which rent received), on account of the Premises during
                  such period, which rent from reletting shall be reduced by
                  reasonable projections of vacancies and by Landlord's
                  Reletting Expenses described above to extent not theretofore
                  paid to Landlord.

13.2     LANDLORD'S DEFAULT - Landlord shall in no event be in default in the
         performance of any of Landlord's obligations hereunder unless and until
         Landlord shall have failed to perform such obligations within thirty
         (30) days, or such additional time as is reasonably required to correct
         any such default, after written notice by Tenant to Landlord properly
         specifying wherein Landlord has failed to perform any such obligation.

                                   ARTICLE XIV
                            MISCELLANEOUS PROVISIONS

14.1.    EXTRA HAZARDOUS USE - Tenant covenants and agrees that Tenant will not
         do or permit anything to be done in or upon the Premises, or bring in
         anything or keep anything therein, which shall increase the rate of
         insurance on the Premises or on the Building above the standard rate
         applicable to premises being occupied for the use to which Tenant has
         agreed to devote the Premises; and Tenant further agrees that, in the
         event that Tenant shall do any of the foregoing, Tenant will promptly
         pay to Landlord, on demand, any such increase resulting therefrom,
         which shall be due and payable as additional rent hereunder.

14.2     WAIVER - Failure on the part of the Landlord or Tenant to complain of
         any action or non-action on the part of the other, no matter how long
         the same may continue, shall never be a waiver by Tenant or Landlord,
         respectively, of any of the other's rights hereunder. Further, no
         waiver at any
<PAGE>
         time of any of the provisions hereof by Landlord or Tenant shall be
         construed as waiver of any of the other provisions hereof, and a waiver
         at any time of any of the provisions hereof shall not be construed as a
         waiver at any subsequent item of the same provisions. The consent or
         approval of Landlord or Tenant to or of any action by the other
         requiring such consent or approval shall not be construed to waive or
         render unnecessary Landlord's or Tenant's consent or approval to or of
         any subsequent similar act by the other.

         No payment by Tenant, or acceptance by Landlord, of a lesser amount
         than shall be due from Tenant to Landlord shall be treated otherwise
         than as a payment on account. The acceptance by Landlord of a check for
         a lesser amount with an endorsement or statement thereon, or upon any
         payment in full, shall be given no effect, and Landlord may accept such
         check without prejudice to any other rights or remedies which Landlord
         may have against Tenant.

14.3     COVENANT OF QUIET ENJOYMENT - Tenant, subject to the terms and
         provisions of this Lease on payment of the Rent and observing, keeping
         and performing all of the terms and provisions of this Lease on
         Tenant's part to be observed, kept and performed, shall lawfully,
         peaceably and quietly have, hold, occupy and enjoy the Premises during
         the Term hereof, without hindrance or ejection by any persons lawfully
         claiming under Landlord to have title to the Premises superior to
         Tenant. The foregoing covenant of quiet enjoyment is in lieu of any
         other covenant, express or implied; and it is understood and agreed
         that this covenant and any and all other covenants of Landlord
         contained in this Lease shall be binding upon Landlord and Landlord's
         successors only with respect to breaches occurring during Landlord's
         and Landlord's successors' respective ownership of Landlord's interest
         hereunder.

         With respect to any services, including, without limitation, electric
         current or water, to be furnished by Landlord to Tenant, or obligations
         to be performed by Landlord hereunder, Landlord shall in no event be
         liable for failure to furnish or perform the same when (and the date
         for performance of the same shall be postponed so long as Landlord is)
         prevented from doing so by strike, lockout, breakdown, accident, order
         or regulation of or by any governmental authority, or failure of
         supply, or inability by the exercise of reasonable diligence to obtain
         supplies, parts, or employees necessary to furnish such services, or
         perform such obligations, or because of war or other emergency, or for
         any cause beyond Landlord's' reasonable control, or for any cause due
         to any act or neglect of Tenant or Tenant's servants, agents,
         employees, licensees, invitees or any person claiming by, through or
         under Tenant. Landlord agrees to use reasonable efforts to minimize the
         cause of any such interruption.

         In no event shall Landlord ever be liable to Tenant for any indirect,
         special or consequential damages suffered by Tenant from whatever
         cause.

14.4.    NOTICE TO MORTGAGEE - After receiving notice from any person, firm or
         other entity that it holds a mortgage which includes the Premises as
         part of the mortgaged premises, no notice from Tenant to Landlord shall
         be effective unless and until a copy of the same is given to such
         holder, and the curing of any of Landlord's defaults by such holder
         shall be treated as performance by Landlord. Tenant acknowledges by
         execution hereof that it has received notice of the mortgagees of
         record specified in Section 1.2.
<PAGE>
               GMACCM as Master Servicer for Chase Manhattan Bank
           Trustee for Salomon Brothers Mortgage Securities VII, Inc.
                          c/o GMAC Commercial Mortgage
                                  P.O. Box 1687
                                Horsham, PA 19044

14.5.    MECHANICS' LIENS - Tenant agrees immediately to discharge (either by
         payment or by the filing of the necessary bond, or otherwise) any
         mechanics', material men's or other lien against the Premises and/or
         Landlord's interest therein, which liens may arise out of any payment
         due for, or purported to be due for, any labor, services, materials,
         supplies or equipment alleged to have been furnished to or for Tenant
         in, upon or about the Premises.

14.6.    NO BROKERAGE - Tenant warrants and represents that Tenant has not dealt
         with any broker other than the broker, if any, named in Section 1.2
         hereof, in connection with the consummation of this Lease, and in the
         event any claim is made against the Landlord relative to dealings with
         brokers other than any broker named in Section 1.2. Tenant shall defend
         the claim against Landlord with counsel of Landlord's selection and
         save harmless and indemnify Landlord on account of loss, cost or damage
         which may arise by reason of any such claim.

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

14.8.    PROVISIONS BINDING, ETC - Except as herein otherwise provided, the
         terms hereof shall be binding upon and shall inure to the benefit of
         the successors and assigns, respectively, of Landlord and Tenant and,
         if Tenant shall be an individual, upon and to his heirs, executors,
         administrators, successors and assigns. If two or more persons are
         named as Tenant herein, each of such persons shall be jointly and
         severally liable for the obligations of the Tenant hereunder, and
         Landlord may proceed against anyone without first having commenced
         proceedings against any other of them. Each term and each provision of
         this Lease to be performed by Tenant shall be construed to be both a
         covenant and a condition. Unless otherwise stated herein, any consent
         or approval required herein shall be in writing and may be given or
         withheld on the sole absolute discretion of the party whose consent or
         approval is required. The reference contained to successors and assigns
         of Tenant is not intended to constitute a consent to assignment by
         Tenant, but has reference only to those instances in which Landlord may
         later give consent to a particular assignment as required by those
         provisions of ARTICLE V hereof.

14.9     RECORDING - Tenant agrees not to record the within Lease or a Notice of
         Lease without the express written consent of the Landlord.
<PAGE>
14.10    NOTICES - Whenever, by the terms of this Lease, notice shall or may be
         given either to Landlord or to Tenant, such notice shall be in writing
         and shall be delivered in hand or sent by registered or certified mail,
         postage prepaid return receipt requested:

         If intended for Landlord, addressed to Landlord at the address set
         forth in Section 1.2 of this Lease (or to such other address or
         addresses as may from time to time hereafter be designated by Landlord
         by like notice) and a copy to Casner & Edwards, One Federal Street,
         Boston, MA 02110, Attn: Peter A. Caro, Esquire.

         If intended for Tenant, addressed to Tenant at the address set forth in
         Section 1.2 of this Lease (or to such other address or addresses as may
         from time to time hereafter be designated by Tenant by like notice).

         All such notices shall be effective when delivered in hand, or when
         deposited in the United States mail within the Continental United
         States provided that the same are received within five calendar days at
         the address to which the same were sent.

14.11.   WHEN LEASE BECOMES BINDING - Employees or agents of Landlord have no
         authority to make or agree to make a lease or any other agreement or
         undertaking in connection herewith. The submission of this document for
         examination and negotiation does not constitute an offer to lease, or a
         reservation of, or option for, the Premises, and this document shall
         become effective and binding only upon the execution and delivery
         hereby by both Landlord and Tenant. All negotiations, considerations,
         representations and understandings between Landlord and Tenant are
         incorporated herein and may be modified or altered only by written
         agreement between Landlord and Tenant, and no act or omission of any
         employee or agent of Landlord shall alter, change or modify any of the
         provisions hereof.

14.12.   PARAGRAPH HEADINGS - The paragraph headings throughout this instrument
         are for convenience and reference only, and the words contained therein
         shall in no way be held to explain, modify, amplify or aid in the
         interpretation, construction or meaning of the provisions of this
         Lease.

14.13.   RIGHTS OF MORTGAGEE - This Lease shall be subordinate to any mortgage
         from time to time encumbering the Premises, whether executed and
         delivered prior to or subsequent to the date of this Lease, if the
         holder of such mortgage shall so elect. Tenant agrees to execute such
         instruments of subordination in confirmation of the foregoing agreement
         as such holder may request. The Tenant hereby appoints such holder as
         Tenant's attorney-in-fact to execute such subordination agreement upon
         default of Tenant in complying with such holder's request. The Landlord
         agrees to attempt in good faith to obtain a non-disturbance agreement
         from any such mortgagee in favor of the Tenant. Tenant agrees a) to
         attorn to any such holder upon its acquisition of title to the
         Premises, b) to execute such further evidences of attornment as such
         holder may request, c) that such attornment shall not be terminated by
         foreclosure and d) that such holder may, at its option, accept or
         reject such attornment.
<PAGE>
14.14.   STATUS REPORT - Recognizing that both parties may find it necessary to
         establish to third parties, such as accountants, banks, mortgagees or
         the like, the then current status of performance hereunder, either
         party, on the request of the other made from time to time, will
         promptly furnish to Landlord, or the holder of any mortgage encumbering
         the Premises, or to Tenant, as the case may be, a statement of the
         status of any matter pertaining to this Lease, including, without
         limitation, acknowledgments that (or the extent to which) each party is
         in compliance with its obligations under the terms of this Lease.
         Without limiting the foregoing, Tenant agrees to execute from time to
         time a Tenant Estoppel Letter.

14.15.   SECURITY DEPOSIT - Tenant agrees that the Security Deposit will be paid
         upon execution and delivery of this Lease, and that Landlord shall hold
         the same, throughout the Term of this Lease, as security for the
         performance by Tenant of all obligations on the part of Tenant to be
         kept and performed. Landlord shall have the right from time to time
         without prejudice to any other remedy Landlord may have on account
         thereof, to apply such deposit, or any part thereof, to Landlord's
         damages arising form any default on the part of the Tenant. Tenant not
         then being in default, Landlord shall return the deposit, or so much
         thereof as shall not have theretofore been applied in accordance with
         the terms of this Section 14.15, to Tenant on the expiration or earlier
         termination of the Lease Term and surrender of possession of the
         Premises by Tenant to Landlord at such time. If Landlord conveys
         Landlord's interest under this Lease, the deposit or any part thereof
         not previously applied, shall be turned over by Landlord to Landlord's
         grantee, and, if so turned over, Tenant agrees to look solely to such
         grantee for proper application of the deposit in accordance with the
         terms of this Section 14.15, and the return thereof in accordance
         herewith.

         The holder of a mortgage on property which includes the Premises shall
         never be responsible to Tenant for the return or application of any
         such deposit, whether or not it succeeds to the position of Landlord
         hereunder, unless such deposit shall have been received by such holder.

14.16.   SELF-HELP - Landlord shall have the right, but shall not be required to
         do so, to pay such sums or do any act which requires the expenditure of
         monies which may be necessary or appropriate by reason of the failure
         or neglect of Tenant to perform any of the provisions of this Lease
         after notice and the expiration of applicable cure periods, and in the
         event of the exercise of such right by Landlord, Tenant agrees to pay
         to Landlord forthwith upon demand all such sums; and if Tenant shall
         default in such payment, Landlord shall have the same rights and
         remedies as Landlord has hereunder for the failure of Tenant to pay the
         Rent. Tenant shall have thirty (30) days to correct any failure or
         neglect after notification by the Landlord before the Landlord
         exercises Self-Help. This thirty (30) day period does not apply to any
         payment as outlined in Section 13.1(a).

14.17.   HOLDING OVER - Any holding over by Tenant after the expiration of the
         Term of this Lease shall be treated as a tenancy at sufferance and the
         Tenant shall be obligated to pay the Landlord for each month or portion
         thereof, a use and occupancy charge equal to twice the monthly rent and
         expenses being charged at the conclusion of the Lease. The Tenant shall
         also pay all damages sustained by the Landlord on account thereof, and
         the
<PAGE>
         provisions of this subsection shall not operated as a waiver by
         Landlord of any right of re-entry provided in this Lease.

14.18.   NON-SUBROGATION - Insofar as, and to the extent that, the following
         provision may be effective without invalidating or making it impossible
         to secure insurance coverage obtainable from responsible insurance
         companies doing business in the locality in which the Premises are
         located (even though extra premium may result therefrom). Landlord and
         Tenant 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; and they further mutually
         agree that their respective insurance companies shall have no right of
         subrogation against the other on account thereof. In the event that
         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 extra premium. If, at the request of one party, this
         release and 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 Section 14.18 shall
         derogate from or otherwise affect releases elsewhere herein contained
         of either party for claims.

14.19.   LATE DELIVERY - It is expressly understood and agreed that if Landlord
         is unable to deliver possession of the Premises as required hereunder
         to Tenant on the Commencement Date, or on such other date as may be
         specified in this Lease, by reason of the holding over of a prior
         tenant or for any other reason, then Landlord shall have no liability
         to Tenant whatsoever on account thereof; provided, however, that Tenant
         shall not be obligated to pay rent hereunder until Landlord is able to
         deliver possession of the Premises to Tenant, and further provided that
         Tenant shall have the right to terminate this Lease in the event
         Landlord is unable to deliver possession of the Premises to Tenant
         within twenty (20) days after the date required herein by giving notice
         to Landlord of Tenant's desire to do so within fifteen (15) days after
         such twenty day period, right of termination constituting Tenant's sole
         and exclusive remedy at law or in equity for Landlord's failure so to
         deliver the Premises.

14.20.   ACCELERATED END OF TERM - INTENTIONALLY OMITTED

14.21.   RELOCATION OF PREMISES - INTENTIONALLY OMITTED

14.22.   GOVERNING LAW - This Lease shall be governed exclusively by the
         provisions hereof and by the laws of the Commonwealth of Massachusetts
         as the same may from time to time exist.

14.23.   LANDLORD'S LIABILITY - Tenant agrees from time to time to look only to
         Landlord's interest in the Building for satisfaction of any claim
         against Landlord hereunder and not to any other property or assets of
         Landlord. If Landlord from time to time transfers its interest in the
         Building (or part thereof which includes the Premises), then from and
         after each such transfer Tenant shall look solely to the interests in
         the Building of each of Landlord's transferees for the performance of
         all of the obligations of Landlord hereunder. The obligation of
         Landlord shall not be binding on any partners (or trustees or
<PAGE>
         beneficiaries) of Landlord or of any successor, individually, but only
         upon Landlord's or such successor's assets described above.

14.24.   DELIVERY OF PREMISES - Landlord and Tenant agree that the Premises are
         being leased on an "as is" basis. The renovations planned by Tenant are
         attached as Exhibit B. The Tenant agrees to be responsible for:

         1.   Complete design (only design elements required for permits) of
              all aspects of the space layout including but not limited to:

              a.  Partition layout
              b.  Reflected ceiling plans
              c.  Electrical and telephone
              d.  HVAC and sprinkler
              e.  Plumbing

         2.   Submission of all of the above to Landlord for approval.
              Landlords approval will be on form only not functionality. It
              is the Tenants responsibility to conform to all applicable
              codes. Provided all required information is submitted, then
              Landlord will provide its approval within five (5) business
              days.

         3.   No field changes to any building system without Landlord's
              prior written approval

         4.   Full compliance with insurance provisions of this Lease (See
              Section 10.2)

         5.   Obtaining all necessary permits including occupancy permit and
              providing copies of same to Landlord.

         6.   Waiver of lien certificates for all payments to all
              contractors and subcontractors

         7.   Rubbish removal entirely from the site with separate dumpster
              which location shall be approved by Landlord.

         8.   Protection and responsibility for repair, if damaged, of all
              common areas of the Building and site.

14.25    Signage - The cost of all interior and exterior directory signage will
         be the responsibility of the Tenant.

14.26    Hazardous Wastes - Tenant is responsible to maintain, at its expense,
         good air quality free of obnoxious or harmful odors emanating from any
         equipment or process. Should an air quality problem arise due to
         Tenant's use of any equipment, Tenant will immediately cease to use
         said equipment. Tenant will not reinstate use of the equipment until it
         has been determined, to the Landlord's satisfaction, that the air
         quality problem has been eliminated.

         Tenant will install, at its expense, with Landlords permission, the
         necessary equipment to
<PAGE>
         properly exhaust any fumes emitting from the Premises and provide for
         any fresh air intake required to properly balance the system.

         Tenant is also responsible for the storage and disposal of all
         chemicals used in its equipment or process. Should any odoriferous
         fumes emanate from the Tenant's premises, Tenant will immediately cease
         using the offending chemical. Reuse of the chemical will occur only
         after it has been determined by the Landlord that proper precautions
         have been taken to insure that the chemical will no longer be offensive
         or harmful to the building's air supply.

         Tenant covenants not to use any portion of the Premises, Building or
         Lot for the use, generation, treatment, storage or disposal of "oil",
         "hazardous material", "hazardous waste", or "hazardous substances"
         (collectively, the "Materials"), as such terms are defined under the
         Comprehensive Environmental Response, Compensation and Liability Act,
         42 U.S.C. S9601 et seq., as amended, the Resource Conservation and
         Recovery act of 1976, 42 U.S.C. S6901 et seq., as amended, and the
         regulations promulgated thereunder, and all applicable state and local
         laws, rules and regulations, including, without limitation,
         Massachusetts General laws, Chapters 21C and 21E (the "Superfund and
         Hazardous Waste Laws"), or remove any Materials from the Property and
         then only to the extent that the presence or removal of the Materials
         is properly licensed and approved by all appropriate governmental
         officials and in accordance with all applicable laws and regulations.
         Tenant shall promptly provide Landlord with copies of all notices
         received by Tenant, including, without limitation, any notice of
         violations, notice of responsibility or demand for action, from any
         federal state or local authority or official in connection with the
         presence of materials in or about the Property or removal of materials
         from the Property. In the event of any release of Materials by Tenant,
         as defined in the Superfund and Hazardous Laws, caused by Tenant or its
         employees, agents, contractors or invitees, Tenant shall promptly
         remedy the problem in accordance with all applicable laws and
         requirements and shall indemnify and hold the Landlord harmless from
         and against all loss, costs, liability and damage, including attorneys'
         fees and the cost of litigation, arising from the presence or release
         of any Materials by Tenant in or on the Premises or removal of
         materials from the Premises or Building. The provisions of this
         paragraph shall survive the expiration or earlier termination of this
         Lease.

14.27    Notwithstanding any provision contained herein, Tenant will be
         responsible to keep the Premises in a neat, clean and orderly condition
         free of excess refuse that could create fire or other hazards.

14.28    Notwithstanding any provisions contained herein, Tenant will use
         reasonable efforts to minimize any situation that would give other
         tenants or the public cause for concern and to keep deliveries and
         other such matters reasonably invisible.
<PAGE>
Witness the execution hereof, under seal, in any number of counterpart copies
shall be deemed an original for all purposes, as of the day and year first above
written.

Central Plaza/Wells Avenue LLC                  TolerRx, Inc.

 /s/ Raymond C. Lee                             /s/ Douglas J. Ringler
-------------------------------                 -----------------------------
Raymond C. Lee, President                       Douglas J. Ringler, President
<PAGE>
                                    EXHIBITS

  Exhibit A               Plan of Premises

  Exhibit A-1             Access Locations within Premises

  Exhibit B               Plan of Renovations

  Exhibit C               Cleaning Specifications

  Exhibit D               Rules and Regulations

  Exhibit E               Lab Function Description
<PAGE>
                                   EXHIBIT "A"
                                     1 of 2

                                    [DIAGRAM]
<PAGE>
                                   EXHIBIT "A"
                                     2 of 2

                                    [DIAGRAM]
<PAGE>
                                   EXHIBIT A-1

                                    [DIAGRAM]
<PAGE>
                                    EXHIBIT C
                                  CENTRAL PLAZA
                             CLEANING SPECIFICATIONS

CLEANING

Cleaning and janitor services as provided below:

A.       OFFICE AREAS

         Daily:  (Monday through Friday, inclusive, holidays excepted).

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

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

         3.       Vacuum all rugs and carpeted areas.

         4.       Hand dust and wipe clean with treated cloths all horizontal
                  surface; including furniture, office equipment, window sills,
                  chair rails, counter tops, door ledges, baseboards, and grill
                  work, within normal reach.

         5.       Wash clean all water fountains and adjacent floor areas.

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

         Weekly:

         1.       Brush and hand dust all carpet edges or other areas in
                  accessible to vacuum attachments.

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

         3.       Dust all ventilating, air conditioning louvers, and grills.

         Every Two Months or When Needed:

         1.       All resilient tile floors to be spray buffed.

         2.       Clean inside of all windows as needed.

         3.       Clean outside of all windows, weather permitting.

         Quarterly:

         1.       Dusting of accessible surfaces not reached by daily cleaning.
<PAGE>
         2.       Move and vacuum clean underneath all furniture that can
                  reasonably be moved.

         Daily:  (Monday through Friday, inclusive, holidays excepted).

         1.       Sweep and damp mop.

         2.       Wash and polish all mirrors, powder shelves, bright work,
                  fulshometers, piping, and toilet set hinges.

         3.       Wash both sides of all toilet seats.

         4.       Wash all basins, bowls, and urinals.

         5.       Dust all partitions, tile walls, dispensers, and receptacles.

         6.       Dust and clean all powder room fixtures.

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

         8.       Remove waste paper and refuse from the premises.

         9.       Refill tissue holders, soap dispensers, towel dispensers,
                  sanitary dispensers; materials to be furnished by landlord.

         Monthly:

         1.       Machine scrub lavatory floors.

         2.       Wash all partitions and tile walls in lavatories.

C.       MAIN LOBBIES, ELEVATORS, STAIRWELLS, AND COMMON CORRIDORS

         Daily: (Monday through Friday, inclusive, holidays excepted).

         1.       Sweep and damp mop all floors; empty and clean waste
                  receptacles; dispose of waste.

         2.       Wash all rubber mats.

         3.       Clean elevators, wash or vacuum floors.

         4.       Clean any metal work inside lobbies.

         5.       Clean any metal work surrounding building entrance doors.

         Monthly:

         1.       All resilient tile floors in public areas to be spray buffed.
<PAGE>
D.       RULES AND REGULATIONS

         1.       Smoking is prohibited within this building including without
                  limitation all common areas, stairwells, toilet rooms, tenant
                  space and any other area within the building;

         2.       The entrances, lobbies, passages, corridors, elevators,
                  halls, courts, sidewalks, vestibules, and stairways shall not
                  be encumbered or obstructed by Tenant, Tenant's agents,
                  servants, employees, licensees or visitors or be used by them
                  for any purposes other than ingress or egress to and from the
                  Premises.

         3.       The moving in or out of all sales, freight, furniture, or
                  bulky matter of any description shall take place during the
                  hours which Landlord may determine from time to time.
                  Landlord reserves the right to inspect all freight and bulky
                  matter to be brought into the Building and to exclude from
                  the Building all freight and bulky matter which violates any
                  of these Rules and Regulations or the Lease of which these
                  Rules and Regulations are a part. Landlord reserves the right
                  to have Landlord's structural engineer review Tenant's floor
                  loads on the Premises at Tenant's expense.

         4.       Tenant or the employees, agents, servants, visitors or
                  licensees of Tenant shall not at any time place, lease or
                  discard any rubbish, paper, articles, or objects of any kind
                  whatsoever outside the doors of the Premises or in the
                  corridors or passageways of the Building. No animals or birds
                  shall be brought or kept in or about the Building. Bicycles
                  shall not be permitted in the Building.

         5.       Tenant shall not place objects against glass partitions or
                  doors or windows or adjacent to any common space which would
                  be unsightly from the Building corridors or from the exterior
                  of the Building and will promptly remove the same upon notice
                  from Landlord.

         6.       Tenant shall not make noises, cause disturbances, create
                  vibrations, odors or noxious fumes or use or operate any
                  electrical devices or other devices that emit sound waves or
                  are dangerous to other tenants and occupants of the building
                  or that would interfere with the operation of any device or
                  equipment or radio or television broadcasting or reception
                  from or within the Building or elsewhere or with the operation
                  of roads or highways in the vicinity of the Building and shall
                  not place or install any projections, antennae, aerials, or
                  similar devices inside or outside of the Premises without the
                  prior written approval of Landlord.

         7.       Tenant may not (without Landlord's approval therefore, which
                  approval will be signified on Tenant's Plans submitted
                  pursuant to the Lease) and Tenant shall not permit or suffer
                  anyone to: (a) cook in the Premises; (b) place vending or
                  dispensing machines of any kind in or about the Premises; (c)
                  at any time sell, purchase or give away or permit the sale,
                  purchase, or gift of food in any form.

         8.       Tenant shall not: (a) use the Premises for lodging,
                  manufacturing or for any immoral or illegal purposes; (b) use
                  the premises to engage in the manufacture or sale of, or
                  permit the use of spirituous, fermented, intoxicating or
                  alcoholic beverages on the Premises; (c) use the Premises to
                  engage in the manufacture or sale of, or permit the use of,
                  any illegal drugs on the Premises.

         9.       No awning or other projections shall be attached to the
                  outside walls or windows. No curtains, blinds, shades, screens
                  or signs other than those furnished by Landlord shall be
                  attached to, hung in, or used in connection with any window or
                  door of the Premises without the prior written consent of
                  Landlord.

         10.      No signs, advertisement, object, notice or other lettering
                  shall be exhibited, inscribed, painted or affixed on any part
                  of the outside or inside of the Premises if visible from
                  outside of the Premises. Interior signs on doors shall be
                  painted or affixed for Tenant by Landlord or by sign painters
                  first approved by Landlord at the expense of Tenant and shall
                  be of a size, color and style acceptable to Landlord.

         11.      Tenant shall not use the name of the Building or use pictures
                  or illustrations of the Building in a advertising or other
                  publicity without the prior written consent of Landlord.
                  Landlord shall have the right to prohibit any advertising by
                  Tenant which, in Landlord's opinion, tends to impair the
                  reputation of the Building or its desirability for offices,
                  and, upon written notice from Landlord, Tenant will refrain
                  from or discontinue advertising.

         12.      Door keys for doors in the Premises will be furnished at the
                  commencement of the Lease by Landlord. No additional locks or
                  bolts of any kind shall be place upon any of the doors or
                  windows by Tenant, nor shall any changes be made in existing
                  locks or the mechanism thereof without the prior written
                  consent of Landlord. Tenant shall purchase duplicate keys only
                  from Landlord and will provide to Landlord the means of
                  opening of safes, cabinets, or vaults left on the Premises.
                  Upon the termination of its tenancy, Tenant must return to
                  Landlord all keys either furnished to or otherwise procured by
                  Tenant, and in the event of the loss of any keys so furnished
                  by Landlord, Tenant shall pay to Landlord the cost thereof.

         13.      Tenant assumes full responsibility for protecting its space
                  from theft, robbery and pilferage, which includes keeping
                  doors locked and other means of entry to the Premises closed
                  and secured.

         14.      Tenant shall not make any room-to-room canvass to solicit
                  business from other tenants in the Building and shall not
                  exhibit, sell or offer to sell, use, rent or exchange any item
                  or services in or form the Premises unless ordinarily embraced
                  within Tenant's use of the Premises as specified in its Lease.
                  Canvassing,
<PAGE>
                  soliciting and peddling in the Building are prohibited, and
                  Tenant shall cooperate to prevent the same. Peddlers,
                  solicitors and beggars shall be reported to the office of the
                  Managing Agent of the Building.

         15.      Tenant shall not mark, paint, drill into, or in any way deface
                  any part of the Building or Premises. No boring, driving of
                  nails or screws, or cutting or stringing of wires shall be
                  permitted, except with the prior written consent of Landlord,
                  and as Landlord may direct. Tenant shall not install any
                  resilient tile or similar floor covering in the Premises
                  except with prior written approval of Landlord. The use of
                  cement or other similar adhesive material is expressly
                  prohibited.

         16.      Tenant shall not waste electricity or water and agrees to
                  cooperate fully with Landlord to assure the most effective
                  operation of the Building's heating and air conditioning and
                  shall refrain from attempting to adjust controls. Tenant shall
                  keep corridor doors closed except when being used for access.

         17.      The water and wash closets and other plumbing fixtures shall
                  not be used for any purpose other than those for which they
                  were constructed, and no sweepings, rubbish, rags, or other
                  substances shall be thrown therein.

         18.      Building employees shall not be required to perform, and shall
                  not be requested by any tenant or occupant to perform, any
                  work outside of their regular duties, unless under specific
                  instructions from the office of the Managing Agent of the
                  Building.

         19.      Tenant may request heating and/or air conditioning during
                  other periods in addition to normal working hours by
                  submitting its request in writing to the office of the
                  Managing Agent of the Building no later than 2:00 p.m. the
                  preceding work day (Monday through Friday). The request shall
                  clearly state the start and stop hours of the "off-hour"
                  service. Tenant shall submit to the managing Agent a list of
                  personnel authorized to make such request. The Tenant shall be
                  charged for such operation in the form of additional rent;
                  such charges are to be determined by the Managing Agent and
                  shall be fair and reasonable and reflect the additional
                  operating costs involved.

         20.      Prior to vacating the Premises upon lease termination, Tenant
                  shall remove at Tenant's expense any and all telephone wires,
                  computer cables, and equipment related thereto, installed by
                  Tenant for Tenant's use during occupancy of the Premises.

         21.      All wiring installed in the Tenant's Premises by Tenant or
                  Tenant's agents shall be done in compliance with the rules and
                  regulations of the State Building Code Commission.

         22.      Tenant shall become familiar with the proper use and handling
                  of all fire extinguishers provided by Landlord in Tenant's
                  Premises and shall be responsible
<PAGE>
                  for the periodic inspection and maintenance of said
                  extinguishers in accordance with the manufacturer's
                  instructions.

         23.      In the event landlord is unable to deposit a check from Tenant
                  due to insufficient funds in Tenant's account, Landlord shall
                  charge Tenant as additional rent a $30 processing fee for the
                  uncollectible funds. In addition, until there are sufficient
                  funds available to allow Landlord to redeposit Tenant's check,
                  Landlord shall charge interest on the uncollectible funds in
                  accordance with the provisions of the Lease .
<PAGE>
                                    EXHIBIT E

LAB FUNCTION DESCRIPTION

The Tenant will be performing pharmaceutical research activities in its
laboratory areas. These functions include studying proteins as potential
pharmaceutical drug candidates by analyzing their behavior on other proteins,
interactions with cells and cell membranes, binding activities on cell receptors
by measuring the affinity of the protein for its receptor and the effect of this
binding on cellular functions, and manipulating DNA and cells to make proteins
that may be desirable as drugs. The assays to measure these parameters include
labeling the protein drug candidates with various enzyme or other markers (since
one can't see them with the naked eye) and studying how they interact with
various substrates by measuring enzyme activity (or other marker readouts) with
color assays or other assays for the marker. These substrates are usually
plastic plates 4-5 inches in length with multiple small wells (usually 96 wells
but this can vary) that have been treated with other proteins or cellular
products. Other assays use markers on proteins and cells such as fluorescence
tags and then passing the proteins and/or cells through specialized bench
equipment such as a fluorescence cell counter than can quantify these
fluorescence tags. The equipment in the laboratory will include computers,
specialized fluorescence and light measuring equipment, color measuring
equipment, hoods to keep specialized cells and fluids clean from the
environment, a fume hood to store and work with some laboratory reagents or
chemicals, incubators to store cells, refrigerators, and freezers.<PAGE>

                                                                   EXHIBIT 10.20

                               SUBLEASE AGREEMENT

         This Sublease Agreement ("Sublease") is made as of December 16, 2002 by
and between Centagenetix, Inc., a Delaware corporation (hereinafter referred to
as "Sublessor"), and Critical Therapeutics, Inc., a Delaware corporation
(hereinafter referred to as "Sublessee").

                              W I T N E S S E T H:

         WHEREAS, pursuant to a Lease dated as of January 16, 2002, between
Sublessor and Massachusetts Institute of Technology, a Massachusetts educational
corporation ("Landlord"), Landlord leased certain space to Sublessor (such Lease
is referred to herein as the "Lease") at the property commonly known as l2 Emily
Street, Cambridge, Massachusetts (the "Building"); and

         WHEREAS, Sublessee desires to sublet from Sublessor approximately 4,500
square feet (the "Sublet Premises") of the Premises referred to in the Lease and
described therein, of which approximately 1,500 square feet will be space shared
with Sublessor or another subtenant to be designated by Sublessor (the "Shared
Space"), located on the first floor of the Premises and outlined on the diagram
attached hereto as "Exhibit A", which shall be deemed to include any common
areas set forth in the Lease.

         NOW, THEREFORE, the parties hereto, for themselves, their successors
and assigns, mutually covenant and agree as follows:

         1. Sublet Premises. Sublessor does hereby sublease to Sublessee and
Sublessee does hereby sublease from Sublessor, for the term and upon the
conditions hereinafter provided, the Sublet Premises, being an area located on
the first floor of the Premises, and outlined on the diagram attached hereto as
"Exhibit A".

         2. Term. (a) The term ("Term") of this Sublease shall commence on the
later to occur of (i) the date upon which Sublessor delivers possession of the
Sublet Premises to Sublessee, or (ii) the date upon which Landlord's written
consent to the Sublease and to Sublessee's Work is obtained (the "Commencement
Date"); provided, however, that in the event Landlord does not give its written
consent to this Sublease on or before December 20, 2002, or the Sublessor fails
to deliver possession of the Sublet Premises to Sublessee on or before December
20, 2002, then, at the option of Sublessee, all amounts paid by Sublessee
hereunder shall be refunded forthwith and, thereupon, this Sublease shall be
void and without further recourse to the parties. The term of this Sublease
shall terminate at 11:59 p.m. on May 20, 2007, or on such earlier date upon
which said term may expire or be terminated pursuant to a termination of the
Lease or any of the conditions or limitations or other provisions of this
Sublease or pursuant to law ("Termination Date"). Notwithstanding the foregoing,
Sublessee may notify Sublessor in writing, given on or before the date which is
six (6) months prior to the Termination Date hereof, indicating Sublessee's
preference to remain in the Sublease Premises beyond the Sublease Termination
Date. Sublessor shall, within five (5) business days following receipt of
Sublessee's notice, notify Sublessee in writing whether Sublessor desires to
extend the Sublease Term for a period not to exceed the last day of Lease Term
(as such may have been extended pursuant to the terms of the Lease) and on such
other terms acceptable to Sublessor. Sublessor and Sublessee shall, within five
(5) business days (the "Negotiation Period") following

<PAGE>

the date of Sublessor's notice to Sublessee, negotiate in good faith toward
mutually acceptable terms. Following the expiration of said Negotiation Period,
Sublessee shall then notify Sublessor in writing, within five (5) business days
following the date of Sublessor's notice, whether Sublessee has elected to
extend the term of this Sublease on the terms set forth in Sublessor's notice or
as may have been mutually agreed upon by Sublessor and Sublessee during the
Negotiation Period. If the parties mutually agree to an extension of the
Sublease Term and the terms of such extension, the parties shall promptly
execute an Amendment to Sublease reflecting the terms of the parties' agreement.

         3. Annual Basic Rent and Monthly Basic Rent. Commencing on the later to
occur of (the "Rent Commencement Date") the (i) Commencement Date, and (ii) date
upon which Sublessee commences Sublessee's Work, provided, however, that in no
event shall the Rent Commencement Date occur later than January 1, 2003, annual
Basic Rent shall be One Hundred Eighty Thousand and No/100 Dollars
($180,000.00). Monthly Basic Rent ("Basic Rent") shall be the sum of Fifteen
Thousand and No/100 Dollars ($15,000.00). Basic Rent shall be payable on the
first day of each and every calendar month during the term of this Sublease. All
payments of Basic Rent shall be paid to Sublessor in advance of each month for
which such rent is due. Upon execution of this Sublease, Sublessee shall pay to
Sublessor the first installment of Basic Rent which shall be applied by
Sublessor against the first month of the Sublease term.

         If the obligation of Sublessee to pay rent hereunder begins on a day
other than on the first day of a calendar month, rent from such date until the
first day of the following calendar month shall be prorated at the rate of
one-thirtieth (1/30th) of the monthly installment for each day payable in
advance. The monthly Basic Rent, Additional Rent (as defined herein) and any
other charges herein reserved or payable shall be paid to Sublessor at the
address specified in Section 18 hereof, or at such other place as Sublessor may
designate in writing, in lawful money of the United States of America without
demand therefor and without any deduction, set-off or abatement whatever.
Sublessor covenants and agrees that it shall pay to Landlord all rent and other
amounts due under the Lease in a timely manner pursuant to all applicable
provisions of the Lease.

         4. Operating Expenses. Sublessee agrees to pay Sublessor, as
"Additional Rent" under this Sublease, (i) Operating Expenses payable pursuant
to Section 6 of the Lease applicable to the Sublet Premises, (ii) Taxes payable
pursuant to Section 6 of the Lease applicable to the Sublet Premises, (iii) any
other Additional Rent payable pursuant to Section 4.1 (b) of the Lease
applicable to the Sublet Premises, and (iii) all other charges payable pursuant
to the Lease and applicable to the Sublet Premises, which shall be payable in
advance each month (pursuant to Sublessor's written estimate of such "Additional
Rent" delivered to Sublessee) or in arrears if not billed sooner. Sublessee
shall be responsible for paying all utility charges in respect of the Sublet
Premises, including without limitation any charges for electricity, gas and
HVAC. Sublessee shall also pay to Sublessor, as Additional Rent, all charges for
any additional services requested by and provided to Sublessee. Any Additional
Rent which may be payable to Sublessor shall be apportioned during the year in
which the term of this Sublease commences and during the year in which such term
shall end, such that Sublessee shall be obligated to pay a proportionate share
of such Additional Rent which is attributable to the number of days of their

                                       2
<PAGE>

term hereof which are included in the period for which such Additional Rent is
payable by Sublessor under the Lease. Sublessee shall pay Additional Rent within
fifteen (15) days of receipt of a statement therefor from either Sublessor or
Landlord. Sublessee's obligations to pay Additional Rent during the Sublease
Term shall survive the termination of this Sublease.

         5. Security Deposit. Upon the execution of this Sublease, Sublessee
shall pay to Sublessor the sum of $60,000.00 as security (the "Security
Deposit") for the faithful performance by Sublessee of its obligations
hereunder. In the event of an Event of Default (as defined in Section 14
hereof), Sublessee hereby authorizes Sublessor, at Sublessor's election (with
notice to Sublessee) and with or without terminating this Sublease and without
prejudice to any other right or remedy Sublessor may have, to apply all or any
portion of the Security Deposit necessary to remedy such default. If said
Security Deposit or portion thereof is so applied, Sublessee, upon demand by
Sublessor, shall immediately deposit with Sublessor an amount equal to the
amount of the Security Deposit so applied. Any unapplied cash portion of the
Security Deposit shall be held by Sublessor in a non-segregated account and no
interest shall be paid thereon. Any portion of the Security Deposit remaining at
the end of the term of this Sublease shall be refunded to Sublessee within sixty
(60) days of the Sublease Termination Date.

         6. Use. Sublessee will use and occupy the Sublet Premises solely for
animal holding and tissue laboratory purposes for mice and rats only. Without
the prior written consent of Landlord and Sublessor, the Sublet Premises will
not be used for any other purposes or for any other types of animals. Sublessor
shall, at Sublessee's sole cost and expense, cooperate with Sublessee in
obtaining any necessary permits or approvals from the City of Cambridge in
connection with Sublessee's occupancy of the Sublet Premises. Sublessee will
cause all deliveries of animals to the Sublet Premises to be made as
inconspicuously as reasonably possible and will not cause any disagreeable odors
to emanate from the Building at any time. In particular, Sublessee will not
sanitize any feed for animals on the Sublet Premises or in the Building.

         7. Condition of Sublet Premises. Sublessee hereby acknowledges that the
Sublet Premises are hereby subleased in "as is" condition. To the best of
Sublessor's knowledge, as of the date hereof, the Building systems are in
operational condition.

         8. Alterations/Sublessee's Work/Sublessor's Work. (a) Subject to the
terms hereof and to the provisions of Section 11.1(f) and Exhibit F (Work
Letter) of the Lease, Sublessee shall not make any alterations, improvements or
additions to the Sublet Premises (the "Sublessee Alterations"). All such
Sublessee Alterations are subject to Sublessor's and Landlord's prior written
consent in accordance with the terms of the Lease. Sublessor's consent to any
such Alterations shall not be unreasonably withheld or delayed.

         (b) Sublessee's Plans. Sublessee intends to build-out the Sublet
Premises (excluding the Shared Space) to include laboratory space as described
on the preliminary plan attached hereto as Exhibit B ("Sublessee's Work"). In
connection with the performance of Sublessee's Work, Sublessee shall meet with
Sublessor and Sublessee's architect, Randy Lewis of Olson, Lewis & Dioli
("Architect"), to enable Architect to prepare (x) a Space Plan (as defined in
the Lease) sufficient for Landlord and Sublessor to approve Sublessee's proposed
design of the

                                       3
<PAGE>

Sublet Premises, and (z) architectural Working Drawings (as defined in the
Lease) for Sublessee's Work, all of which shall be subject to the consent of
Sublessor and Landlord as provided in the Lease ("Sublessee's Plans"). Sublessee
and Sublessor agree to use diligent efforts to cooperate in order to expedite
finalization of Sublessee's Plans as soon as possible. Landlord's and
Sublessor's approval of Sublessee's Plans is solely given for such parties own
benefit under this section and neither Sublessee nor any third party shall have
the right to rely upon Landlord's or Sublessor's approval of Sublessee's Plans
for any other purpose whatsoever. Without limiting the foregoing, Sublessee
shall be responsible for all elements of the design of Sublessee's Plans
(including, without limitation, compliance with Legal Requirements,
functionality of design, the structural integrity of the design, the
configuration of the Sublet Premises and the placement of Sublessee's furniture,
appliances and equipment), and Landlord's and Sublessor's approval of
Sublessee's Plans shall in no event relieve Sublessee of the responsibility
therefor. Prior to commencing Sublessee's Work, Sublessee shall first obtain (a)
all necessary permits and approvals with the City of Cambridge, and (b) the
prior written approval of Landlord and Sublessor to Sublessee's Work and, once
approved, to any modifications to Sublessee's Work. Sublessee shall complete and
pay for Sublessee's Work using first-grade materials and workmanship, and shall,
prior to occupying the Sublet Premises, deliver to Landlord and Sublessor (i)
final lien waivers and affidavits from its contractor and all sub-contractors,
certifying that all amounts due in connection with the completion of Sublessee's
Work have been paid in full and that Sublessee's Work is substantially complete,
subject only to the completion of minor items of decoration or adjustment, (ii)
an Architect's certificate certifying that Sublessee's Work has been completed
in accordance with Sublessee's Plans, and (iii) a final and unconditional
certificate of occupancy for the Sublet Premises issued by the City of
Cambridge. In no event shall Sublessee permit any liens to attach to the
Premises. Sublessee's Work shall become part of the Sublet Premises and shall
not be removed upon the expiration of the Sublease term, except upon the written
direction of Landlord. Subject to Sublessor's receipt of Lessor's Contribution
(as defined in the Lease), Sublessor shall be responsible for building out the
Shared Space. Notwithstanding anything to the contrary contained herein or in
the Lease, Sublessee shall be permitted, upon the expiration or earlier
termination of this Sublease, to remove from the Sublet Premises the items shown
on attached Exhibit C; provided however, that Sublessee shall repair and be
responsible for any or all damage caused by such removal.

         (c) Completion of Sublessee's Work. Sublessee shall substantially
complete Sublessee's Work and obtain a final certificate of occupancy for the
Sublet Premises by the City of Cambridge on or before March 15, 2003.

         (d) Cost of Sublessee's Work. All of Sublessee's Work shall be
performed at Sublessee's sole cost and expense (the "Cost of Sublessee's Work").

         (e) Sublessee's and Sublessor's Construction Representatives. For all
matters relating to Sublessee's Work or any other construction matters under
this Sublease, including but not limited to Sublessee approvals for all purposes
hereunder, Sublessee's construction representative is Walter Newman
("Sublessee's Construction Representative"), or such other person as designated
by Sublessee in writing to Sublessor. For all matters relating to Sublessee's
Work or any other construction matters under this Sublease, including but not
limited to

                                       4
<PAGE>

Sublessor approvals for all purposes hereunder, Sublessor's construction
representative is Carl Weissman ("Sublessor's Construction Representative"), or
such other person as designated by Sublessor in writing to Sublessee. Sublessor
agrees that Sublessor shall permit Sublessee to attend any and all meetings
attended by Sublessor involving Landlord and Sublessor shall promptly notify
Sublessee (which notice maybe oral) as soon as practicable prior to any meetings
with Landlord relating to Sublessee's Work. Each of Sublessor and Sublessee
shall cooperate with the other in obtaining approvals from the other, as such
approvals relate to Sublessee's Work.

         (f) All allowed Sublessee Alterations, including Sublessee's Work,
shall be performed in compliance with all Legal Requirements and in a good and
workmanlike manner, and free of all liens. Without limitation of the foregoing,
Sublessee agrees that its general contractor shall be licensed, insured and
bonded in the Commonwealth of Massachusetts and shall be subject to the review
and approval of Landlord and Sublessor. If any Sublessee Alterations are made
without having first obtained the required consents, Landlord or Sublessor may
remove the same, and may correct, repair and restore the Sublet Premises and any
damage arising from such removal, and Sublessee shall be liable for any and all
costs and expenses incurred by the removing party in the performance of such
work.

         9. Sublessee's Personal Property. Upon the expiration or earlier
termination of this Sublease, Sublessee shall remove all of its goods and
effects from the Sublet Premises (including, without limitation, all signs and
lettering affixed or painted by the Sublessee on the Sublet Premises), shall
repair all damage resulting from such removal or its use of the Sublet Premises,
and shall surrender the Sublet Premises, as so required, in good condition,
subject only to reasonable wear and tear and to damage, if any, by fire or other
casualty. The obligations of Sublessee as provided in this Section 9 shall
survive the termination of this Sublease.

         10. Terms of Lease. All of the terms, provisions, covenants and
conditions of the Lease, as amended, are incorporated herein by reference and
hereby made a part of and, except as herein otherwise expressly provided
(Sections 3.2, 3.3, 4.2, 4.3, 12.0, 15.0, 20.0 and the definitions of "Lessee's
Work" and "Lessor's Work" found in Section 1 of Exhibit F (the Work Letter) and
Sections 7 and 8 of Exhibit F (the Work Letter) are hereby excluded), are
superior to this Sublease and as between the parties hereto, Sublessee hereby
assumes all of the obligations (except as expressly modified herein) and shall
have all the rights of Sublessor as "Tenant" under the covenants, agreements,
terms and provisions set forth in the Lease, but only to the extent they are
applicable to the Sublet Premises. Sublessor shall have all of the rights of the
Landlord under the Lease as against Sublessee and, as between the parties
hereto, Sublessor agrees to observe and perform the terms, covenants and
conditions on its part to be observed and performed hereunder and to use
commercially reasonable efforts to cause Landlord to observe and perform those
applicable terms, covenants and conditions to be observed and performed by
Landlord under the Lease with respect to the Sublet Premises. Notwithstanding
the foregoing, Sublessor shall not be required to furnish those services or
perform those obligations under the Lease which are to be furnished or performed
by Landlord under the Lease and Sublessor shall have no liability for Landlord's
failure thereof.

                                       5
<PAGE>

         11. Sublessee's and Sublessor's Covenants. Sublessee covenants and
agrees that Sublessee will not do anything which would constitute a default
under the Lease or omit to do anything which Sublessee is obligated to do under
the terms of this Sublease and which would constitute a default under the Lease.
Sublessor covenants and agrees (a) to pay the rent and any Additional Rent
payable as required under the Lease and will not do anything which would
constitute a default under the Lease; (b) not to agree to a voluntary surrender
or early termination of the Lease, (c) to the best of Sublessor's knowledge, no
Event of Default under the Lease has been caused by either Landlord or Sublessor
and there is no condition, the existence of which would give rise to an Event of
Default following the giving of notice or expiration of grace periods, and (d)
Sublessor shall promptly deliver to Sublessee a copy of any notice of default
received from Landlord.

         12. Indemnification. (a) To the fullest extent permitted by law,
Sublessee shall and hereby does indemnify and hold Sublessor and Landlord
harmless from and against any and all actions, claims, demands, damages,
liabilities, expenses and judgments (including, without limitation, reasonable
attorneys' fees) asserted against, imposed upon or incurred by Sublessor by
reason of (a) any violation caused, suffered or permitted by Sublessee, its
agents, servants, employees or invitees, of any of the terms, covenants or
conditions of the Lease or this Sublease, and (b) any damage or injury to
persons or property occurring upon or in connection with the use or occupancy of
the Sublet Premises, except as a result of the intentional or grossly negligent
acts or omissions of Landlord or Sublessor, or their respective agents,
employees or invitees.

         (b) To the fullest extent permitted by law, Sublessor shall and hereby
does indemnify and hold Sublessee harmless from and against any and all actions,
claims, demands, damages, liabilities, expenses and judgments (including,
without limitation, reasonable attorneys' fees) asserted against, imposed upon
or incurred by Sublessee by reason of (a) any violation caused, suffered or
permitted by Sublessor, its agents, servants, employees or invitees, of any of
the terms, covenants or conditions of the Lease or this Sublease, and (b) any
damage or injury to persons or property occurring upon or in connection with
Sublessor's use or occupancy of the Premises, excepting the acts or omissions of
Landlord or Sublessee, or their respective agents, employees or invitees.

         13. Brokers. Sublessee represents and warrants to Sublessor that it has
not directly or indirectly dealt with any broker or agent with respect to the
Sublet Premises other than Steve Purpura of Richard Barry Joyce & Partners, LLC
("Broker"). Sublessor shall be responsible for the payment of any broker
commission due Broker in connection with this Sublease. Sublessee agrees to
indemnify and hold harmless Sublessor against any claim by any other broker or
agent arising out of a breach of Sublessee's representations and warranties in
this Section 13. Sublessor represents and warrants to Sublessee that it has not
directly or indirectly dealt with any broker or agent with respect to the Sublet
Premises with the exception of Broker. Sublessor agrees to indemnify and hold
harmless Sublessee against any claim by any other broker or agent arising out a
breach of Sublessor's representations and warranties in this Section 13.

                                       6
<PAGE>

         14. Defaults and Remedies.

         The following shall constitute an event of default (each, an "Event of
Default") under this Sublease:

         (i)      Sublessee shall fail to pay rent or other sums payable under
                  this Sublease within five (5) days after written notice to
                  Sublessee that the same is due and payable; provided that in
                  no event shall Sublessor be obligated to provide notice more
                  than twice in any 12 month period;

         (ii)     Sublessee shall fail to cure any other default under this
                  Sublease within twenty (20) days (or such further time as may
                  be required to diligently cure the same) from written notice
                  thereof from Sublessor to Sublessee;

         (iii)    a lien or other encumbrance shall be filed against Sublessee's
                  leasehold interest and not be discharged within ten (10) days
                  after Sublessee receives written notice thereof; or

         (iv)     any other default by Sublessee shall occur under the Lease.

         Upon the occurrence of an Event of Default, Sublessor may, in addition
to and not in derogation of any remedies for any preceding breach of covenant,
immediately or at any time thereafter and without demand or notice, enter into
and upon the Sublet Premises or any part thereof in the name of the whole, or
mail a notice of termination addressed to Sublessee, and repossess the same as
of Sublessee's former estate and expel Sublessee and those claiming through or
under Sublessee and remove its and their effects without being deemed guilty of
any manner of trespass and without prejudice to any remedies which might
otherwise be used for arrears of rent or prior breach of covenant, and upon such
entry or mailing as aforesaid this Sublease shall terminate, Sublessee hereby
waiving all statutory rights to the extent such rights may be lawfully waived.
Sublessor, without notice to Sublessee, may store Sublessee's effects and those
of any person claiming through or under Sublessee at the expense and risk of
Sublessee, and, if Sublessor 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
Sublessor from Sublessee, if any, and pay over the balance, if any to Sublessee.

         Sublessee covenants and agrees that upon the occurrence of an Event of
Default, notwithstanding any termination of this Sublease under any of the
provisions of this Section 14 or any entry or re-entry by Sublessor, whether by
summary proceedings, termination or otherwise, to pay and be liable for on the
days originally fixed herein for the payment thereof, amounts equal to the
several installments of rent and other charges reserved as they would, under the
terms of this Sublease, become due if this Sublease had not been terminated or
if Sublessor had not entered or re-entered as aforesaid and whether the Sublet
Premises be relet or remain vacant, in whole or in part, or for a period less
than the remainder of the term, or for the whole thereof, provided that in the
event the Sublet Premises be relet by Sublessor, Sublessee shall be entitled to
a credit equal to the net amount of rent received by Sublessor in reletting,
after

                                       7
<PAGE>

deduction of all expenses incurred in reletting the Sublet Premises (including
but not limited to remodeling costs, brokerage fees, and the like) and in
collecting rent in connection therewith.

         In the event that Basic Rent or other payments are not made by the date
when such payments are due, then in addition to all other remedies otherwise
available to Sublessor, said past due payments shall carry a late charge equal
to one percent (1%) of the amount of such overdue payment. Sublessee
specifically agrees to pay any such late charge to Sublessor along with the
payment of Basic Rent and other charges.

         15. Parking. Sublessee shall be entitled to use one (1) parking space
in the lot adjacent to the Building and four (4) parking spaces in the 128
Sidney Street lot. Sublessee will be responsible for the fair market rent of
such parking spaces, which fair market rent is currently $135.00 per parking
space per month. Upon at least thirty (30) days' prior written notice to
Sublessor Sublessee may request additional parking spaces (not to exceed four
(4) additional parking spaces) on Landlord's parking area at the then fair
market rent, which additional parking spaces Sublessor shall make available to
Sublessee if such additional parking spaces are not then presently being used by
Sublessor and Sublessor is entitled to use such additional parking spaces under
the Lease; provided, however, that, upon not less than thirty (30) days' prior
written notice to Sublessee, Sublessor shall have the right to recapture any
such additional parking spaces for Sublessor's use, which recapture shall be
effective as of the date set forth in Sublessor's notice to Sublessee.

         16. Entire Agreement. This Sublease, together with those provisions of
the Lease applicable hereto, contains all of the covenants, agreements, terms,
provisions, conditions, warranties and understandings relating to the leasing of
the Sublet Premises and Sublessor's obligations in connection therewith, and
neither Sublessor nor any agent or representative of Sublessor has made or is
making, and Sublessee in executing and delivering this Sublease is not relying
upon, any warranties, representations, promises or statements whatsoever, except
to the extent expressly set forth in this Sublease. The failure of Sublessee or
Sublessor to insist in any instance upon the strict keeping, observance or
performance of any covenant, agreement, term, provision or condition of this
Sublease or to exercise any election herein contained shall not be construed as
a waiver or relinquishment for the future of such covenant, agreement, term,
provision, condition or election, but the same shall continue and remain in full
force and effect. No waiver or modification of any covenant, agreement, term,
provision or condition of this Sublease shall be deemed to have been made unless
expressed in writing and signed by Landlord, Sublessee and Sublessor. No
surrender of possession of the Sublet Premises or of any part thereof or of any
remainder of the term of this Sublease shall release Sublessee from any of its
obligations hereunder unless accepted by Sublessor in writing. The receipt and
retention by Sublessor of monthly Basic Rent or Additional Rent from anyone
other than Sublessee shall not be deemed a waiver of the breach by Sublessee of
any covenant, agreement, term or provision of this Sublease, or as the
acceptance of such other person as a tenant, or as a release of Sublessee from
the further keeping, observance or performance by Sublessee of the covenants,
agreements, terms, provisions and conditions herein contained. The receipt and
retention by Sublessor of monthly Basic Rent or Additional Rent with knowledge
of the breach of any covenant,

                                       8
<PAGE>

agreement, term, provision or condition herein contained shall not be deemed a
waiver of such breach.

         17. Successors and Assigns. The obligations of this Sublease shall bind
and benefit the successors and permitted assigns of the parties with the same
effect as if mentioned in each instance where a party hereto is named or
referred to.

         18 Notices. Any and all communications delivered hereunder shall be
sent by first-class mail or overnight courier: if to Landlord, at the addresses
specified in Section 16 of the Lease; if to Sublessee, at 675 Massachusetts
Avenue, Cambridge, MA 02139, Attn: Walter Newman, with a copy to Hale & Dorr
LLP, 60 State Street, Boston, MA 02109, Attn: Michael D. MacClary, Esq., and if
to Sublessor, at 12 Emily Street, Cambridge, MA 02139, Attn: President, with a
copy to Mintz Levin Cohn Ferris Glovsky & Popeo, P.C., One Financial Center,
Boston, MA 02111, Attn: Stuart Offner, Esq., or to such other address and
attention as any of the above shall notify the others in writing. Sublessor
shall promptly deliver to Sublessee copies of any default or delinquency notice
received by Sublessor from Landlord.

         19. Insurance. Sublessee shall maintain the insurance coverages
required to be maintained by Sublessor pursuant to Section 7 of the Lease and
shall provide Sublessor, upon execution of this Sublease, with a certificate of
insurance naming Sublessor and Landlord as additional insureds. Sublessor shall
use commercially reasonable efforts to obtain from Landlord a waiver of
Landlord's and Landlord's insurer's subrogation rights benefiting Sublessee.

         20. Early Entry. [Intentionally deleted.]

         21. Incorporation of Lease Terms. All of the terms and provisions of
the Lease are hereby incorporated within the Sublease except as specifically
excluded or modified hereby. For purposes of this Sublease, Sublessee shall
perform all of the obligations of "Tenant" under the Lease, provided, however,
that Sublessor shall not be required to perform any obligations specifically
required of Landlord.

         22. Landlord's Consent. This Sublease and the obligations of the
parties hereunder are expressly conditioned upon Sublessor's obtaining prior
written consent hereto by Landlord.

         23. Counterparts. This Sublease may be executed in counterparts, and
such counterparts when taken together shall constitute one and the same
Sublease, valid and binding upon all the parties.

            [The remainder of this page is intentionally left blank]

                                       9
<PAGE>

         IN WITNESS WHEREOF, Sublessee and Sublessor have duly executed this
Sublease as of the day and year first above written.

Sublessor:

Centagenetix, Inc., a Delaware corporation

By:     /s/ Christopher Fraser
   ----------------------------------------
Name:    Christopher Fraser
Title:   Treasurer

Sublessee:

Critical Therapeutics, Inc.

By:     /s/ Paul Rubin
   ----------------------------------------
Name:    Paul Rubin
Title:   CEO

         Landlord hereby consents to the within Sublease Agreement on the terms
and conditions set forth therein. By this consent Landlord shall not be deemed:
(i) to have become a party to the Sublease or to have consented to any further
assignment or sublease of the Premises or (ii ) to have modified, waived or
affected (a) any of the provisions, covenants or conditions in the Lease, (b)
any of the obligations of the "Lessee" under the Lease or (c) any rights or
remedies of the "Lessor" under the Lease.

Landlord:

Massachusetts Institute of Technology

By:     /s/ Steven C. March
   ----------------------------------------
         Stephen C. Marsh
Its:     Managing Director, Real Estate

                                       10
<PAGE>

                                    EXHIBIT A

                         [FLOOR PLAN OF SUBLET PREMISES]

                                       11
<PAGE>

                                    EXHIBIT B

                            PLAN OF SUBLESSEE'S WORK

                                       12
<PAGE>

                                    EXHIBIT C

              ITEMS TO BE REMOVED BY SUBLESSEE FROM SUBLET PREMISES

                                   Cage Washer
                                    Autoclave
                                 Steam Generator

                                       13

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