Exhibit 10.11

 

SUBLEASE

This Sublease (the “Sublease”) is made as of September 8, 2006 by and between
Archemix Corp., a Delaware corporation, having an address of 300 Third Street,
Cambridge,  Massachusetts 02142 (“Sublandlord”) and Momenta Pharmaceuticals,
Inc., a Delaware corporation, having an address of 675 West Kendall Street,
Cambridge, MA 02142 (“Subtenant”).

W I T N E S S E T H:

A.            Three Hundred Third Street L.L.C., predecessor-in-interest to
ARE-MA Region No. 28, LLC, a Delaware limited liability company (“Landlord”), as
landlord, and Sublandlord, as tenant, entered into a Lease dated April 11, 2005,
as amended by (i) that First Amendment to Lease dated July 9, 2006, between
Sublandlord and Landlord (collectively, the “Overlease”), pursuant to which
Sublandlord leases approximately 67,451 rentable square feet of space (the
“Premises”) located on the first, second and P-1 and P-2 levels of the building
known as 300 Third Street, Cambridge, Massachusetts (the “Building”).  A
partially redacted copy of the Overlease is attached hereto and incorporated
herein as “Exhibit A”;

B.            Subtenant desires to sublease from Sublandlord and Sublandlord
desires to sublease to Subtenant, a portion of the Premises as identified on
“Exhibit B” attached hereto and incorporated herein (hereinafter referred to as
the “Subleased Premises”), which Subleased Premises shall consist of
approximately 22,364 rentable square feet located on a portion of the second
floor of the Building as set forth on attached “Exhibit B”.

NOW, THEREFORE, in consideration of the mutual covenants herein contained and
for other good and valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, the parties hereto hereby agree as follows:

1.  DEMISE OF SUBLEASED PREMISES.  Sublandlord hereby demises and subleases to
Subtenant, and Subtenant hereby hires and takes from Sublandlord, the Subleased
Premises for the term and upon the conditions hereinafter set forth, in “AS IS,
WHERE IS” condition, subject to the completion of Sublandlord’s Work (as
hereinafter defined), together with the right to use, on a non-exclusive basis,
the lavatories, hallways, lobbies and other common elements of the Building
and/or the Premises appurtenant to the Subleased Premises.   If Subtenant
desires additional premises for purposes of solvent storage or waste
neutralization (“Storage Space”), Subtenant shall notify Sublandlord in writing
thereof and Sublandlord shall cooperate with Subtenant and use commercially
reasonable efforts to lease from Landlord such Storage Space desired by
Subtenant and to thereupon sublease same to Subtenant.  Subtenant shall be
responsible for all Fixed Rent and Additional Rent charged by Landlord
applicable to any

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Storage Space.  Notwithstanding the foregoing, the securing of such Storage
Space by Sublandlord shall not be a condition to the effectiveness of this
Sublease.   If Subtenant does not elect to lease any Storage Space, then
Sublandlord shall cooperate with Subtenant to share a portion of Sublandlord’s
waste neutralization and solvent storage areas located within Sublandlord’s
Premises to accommodate Subtenant’s reasonable requirements, subject to
Sublandlord’s reasonable requirements for Sublandlord’s operations.  Subtenant
agrees to pay its proportionate share of the costs thereof.

2.  TERM.              (a)  Initial Term.  The initial term of this Sublease
(the “Term”) shall commence on the later to occur of (i) the date of this
Sublease, (ii) the date on which Landlord’s written consent to this Sublease is
obtained and delivered to Subtenant, and (iii) the date on which Sublandlord
delivers possession of the Subleased Premises to Subtenant (the “Commencement
Date”).  Notwithstanding the foregoing, in the event such Landlord’s consent to
this Sublease is not obtained in accordance with Section 15 herein and
possession of the Subleased Premises delivered to Subtenant on or before the
date which is sixty (60) days following the date of Sublandlord’s execution of
this Sublease, then either party shall have the right to cancel this Sublease on
fifteen (15) days written notice to the other (the “Cancellation Notice”) and
with the giving of such notice, this Sublease shall be deemed canceled and no
further force or effect and neither party shall have any liability or obligation
to the other in respect thereof. Notwithstanding the foregoing, if within
fifteen (15) days after the giving of the Cancellation Notice, Landlord’s
consent is received and possession of the Subleased Premises delivered to
Subtenant, then the Cancellation Notice shall be deemed null and void and this
Sublease shall continue in full force and effect.  The Term shall of this
Sublease shall end on April 30, 2011 (the “Expiration Date”), as it may be
extended hereunder, or shall end on such earlier date upon which such term may
expire or be terminated pursuant to the provisions hereof or pursuant to law. 
The Term and any extension thereof in accordance with the provisions of this
Sublease is referred to as the “Term”.

(b)           Extended Term.  Provided that, at the time Subtenant elects to
exercise the option herein granted, (i) this Sublease is in full force and
effect, (ii) Subtenant is not in default beyond any applicable notice and grace
periods hereunder, and (iii) Subtenant or an Affiliated Transferee (as defined
in Section 16.B of the Overlease) is occupying all of the Subleased Premises,
Subtenant shall have the option, upon written notice to Sublandlord
(“Subtenant’s Extension Notice”) given not less than six (6) months prior to the
expiration of the Expiration Date, to extend the Term of this Sublease for an
additional four (4) year period (the “Extended Term”) expiring on April 30,
2015, subject to Sublandlord’s Termination Option and Subtenant’s Termination
Option (as such terms are hereinafter defined).  The Extended Term shall
commence immediately following the end of the initial Term hereof.  All terms
and conditions applicable during the initial Term shall apply during the
Extended Term including without limitation the obligation of Subtenant to pay
Fixed Rent and its Pro Rata Share of Operating Expenses and Taxes except that
(x) Subtenant shall have no further right to extend this Sublease beyond the
Extended Term hereinabove provided, (y) there shall be no tenant improvement
allowance, and (z) such Extended Term shall be subject to the parties’
Termination Options.

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(c)           Sublandlord’s Termination Option.  From and after the earlier to
occur of (i) the date of Subtenant’s Extension Notice, if any, and (ii) October
1, 2010 and continuing through the Term as such Term may be extended,
Sublandlord shall have the right to terminate this Sublease (“Sublandlord’s
Termination Option”) as follows:

(i) where Subtenant has delivered to Sublandlord Subtenant’s Extension Notice as
hereinabove provided, upon delivery of written notice to Subtenant within thirty
(30) days following the date of Sublandlord’s receipt of Subtenant’s Extension
Notice, which termination shall be effective upon the Expiration Date hereof; or

(ii) where Subtenant has delivered to Sublandlord Subtenant’s Extension Notice
as hereinabove provided, and Sublandlord has failed to deliver written notice to
Subtenant within such thirty (30) day period as provided in subsection (i)
above, upon delivery of written notice to Subtenant, which termination shall be
effective on a date specified in Sublandlord’s notice which shall be not less
than nine (9) months following the date of such notice (“Sublandlord’s Early
Termination Date”).

If Sublandlord exercises Sublandlord’s Termination Option under subsection (i)
above, then (i) all rent payable under this Sublease shall be paid and
apportioned as of the Expiration Date; (ii) neither party shall have any rights,
estates, liabilities, or obligations under this Sublease for the period accruing
after Expiration Date, except those which are incurred, have accrued or relate
to the period prior to Expiration Date, and (iii) Subtenant shall surrender and
vacate the entire Subleased Premises and deliver possession thereof to
Sublandlord on or before the Expiration Date in the condition required under
both this Sublease and the Overlease.

If Sublandlord exercises Sublandlord’s Termination Option under subsection (ii)
above, then (i) all rent payable under this Sublease shall be paid and
apportioned as of the Sublandlord’s Early Termination Date;  (ii) neither party
shall have any rights, estates, liabilities, or obligations under this Sublease
for the period accruing after Sublandlord’s Early Termination Date, except those
which are incurred, have accrued or relate to the period prior to Sublandlord’s
Early Termination Date, and (iii) Subtenant shall surrender and vacate the
entire Subleased Premises and deliver possession thereof to Sublandlord on or
before Sublandlord’s Early Termination Date in the condition required under both
this Sublease and the Overlease.

(d)           Subtenant’s Termination Option.  Provided that Subtenant is not in
default under this Sublease beyond any applicable notice and grace periods on
either the date Subtenant exercises Subtenant’s Termination Option (as
hereinafter defined) or, or unless waived in writing by Sublandlord, on
Subtenant’s Early Termination Date (as hereinafter defined), after the earlier
to occur of (i) the date of Subtenant’s Extension Notice, if any, and (ii)
October 1, 2010, and continuing through the Term as such Term may be extended,
Subtenant shall have the right to terminate this Sublease upon the giving of
nine (9) months’ prior written notice to Sublandlord (“Subtenant’s Termination
Option”), which termination shall be effective on the date that is nine

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(9) months following the date of such written notice to Sublandlord
(“Subtenant’s Early Termination Date”). If Subtenant exercises Subtenant’s
Termination Option, then (i) all rent payable under this Sublease shall be paid
and apportioned as of the Subtenant’s Early Termination Date; (ii) neither party
shall have any rights, estates, liabilities, or obligations under this Lease for
the period accruing after Subtenant’s Early Termination Date, except those which
are incurred, have accrued or relate to the period prior to Subtenant’s Early
Termination Date, and (iii) Subtenant shall surrender and vacate the entire
Subleased Premises and deliver possession thereof to Sublandlord on or before
Subtenant’s Early Termination Date in the condition required under both this
Sublease and the Overlease.

(e)           Notwithstanding anything to the contrary contained herein, in no
event shall the exercise of Subtenant’s Termination Option or Sublandlord’s
Termination Option cause the Sublease Term to terminate prior to April 30, 2011.

3.  SUBORDINATION TO AND INCORPORATION OF THE OVERLEASE.

(a)  This Sublease is in all respects subject and subordinate to the terms and
conditions of the Overlease and to the matters to which the Overlease, including
any amendments thereto, is or shall be subordinate.  Subtenant agrees that
Subtenant has reviewed and is familiar with the Overlease and the Sublease, and
will not do or suffer or permit anything to be done which would result in a
default or breach (whether or not subject to notice or grace periods) on the
part of Sublandlord under the Overlease or cause the Overlease to be
terminated.  Sublandlord agrees that it will not (i) do or suffer or permit
anything to be done which would result in a default or breach under the
Overlease or cause the Overlease to be terminated, or (ii) modify or amend the
Overlease, or take any other action which results in the modification, surrender
or cancellation of Overlease to the extent such modification, surrender or
cancellation decreases any of Subtenant’s rights under this Sublease or
increases any of Subtenant’s obligations under this Sublease, without the prior
written consent of Subtenant.  If, however, the Overlease is terminated prior to
its scheduled expiration for any reason whatever, this Sublease shall likewise
terminate, without further notice.

(b)  Except as otherwise expressly provided in this Sublease, the terms,
covenants, conditions, rights, obligations, remedies and agreements of the
Overlease are incorporated into this Sublease by reference and made a part
hereof as if fully set forth herein and shall constitute the terms of this
Sublease, mutatis, mutandis, Sublandlord being substituted for “Landlord”
thereunder, Subtenant being substituted for “Tenant” thereunder and “Subleased
Premises” being substituted for “Premises” thereunder, except to the extent that
such terms do not relate to the Subleased Premises or are inapplicable to, or
specifically inconsistent with the terms of this Sublease, it being understood
and agreed that Sublandlord will not be acting as, or assuming any of the
responsibilities of, Landlord, and all references in the Overlease to
Landlord-provided services or Landlord insurance requirements, and any other
references which by their nature relate to the owner or operator of the
Building, rather than to a tenant of the Building subleasing space to a
subtenant, shall continue to be references to Landlord and not to Sublandlord. 
All

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capitalized terms used and not otherwise defined herein shall have the same
meaning as set forth in the Overlease.

(c)  The following provisions of the Overlease shall not be incorporated herein
by reference and are expressly excluded from the terms of this Sublease:  any
redacted portions of the Overlease, Article 1 (clauses A - N, P, Q & S), Article
2 [Premises, Term and Commencement Date], Article 3 [Rent], Article 5(A) and (B)
[Tenant’s Work/Alterations and Additions], Article 12(E) [Signs], the second and
third sentences of Article 12(G) [Condition of Premises], Article 16(C)
[Recapture], Articles 23(e) and (h) [Security Deposit], 24 [Brokerage
Commission], 28(A), (B), (C), (E), (G) and (H) [Additional Rights Reserved By
Landlord], 30(C) [Notices], 30(J) [Limitation of Liability], 30(K) [Memorandum
of Lease], 30(Z) [Dispute Resolution], 31 [Right of First Refusal], 32 [Right of
First Option], 33 [Termination Option], 34 [Generator], Attachment No. 1 to
Exhibit B, Exhibit C and attachments thereto [Workletter], Exhibit F [Generator
Space], Exhibit E [Rent Commencement Date Confirmation], Exhibit G [Tenant’s
List of Hazardous Materials], and Exhibit K [Flammables License Application].

(D)           FOR THE PURPOSES OF INCORPORATION HEREIN, THE TERMS OF THE
OVERLEASE ARE SUBJECT TO THE FOLLOWING ADDITIONAL MODIFICATIONS:

(I)            IN ALL PROVISIONS OF THE OVERLEASE (UNDER THE TERMS THEREOF AND
WITHOUT REGARD TO MODIFICATIONS THEREOF FOR PURPOSES OF INCORPORATION INTO THIS
SUBLEASE) REQUIRING THE APPROVAL OR CONSENT OF LANDLORD, SUBTENANT SHALL BE
REQUIRED TO OBTAIN THE APPROVAL OR CONSENT OF BOTH SUBLANDLORD (WHICH APPROVAL
OR CONSENT OF SUBLANDLORD SHALL NOT BE UNREASONABLY WITHHELD, CONDITIONED OR
DELAYED) AND LANDLORD.

(II)           IN ALL PROVISIONS OF THE OVERLEASE REQUIRING THE TENANT TO
SUBMIT, EXHIBIT TO, SUPPLY OR PROVIDE LANDLORD WITH EVIDENCE, CERTIFICATES, OR
ANY OTHER MATTER OR THING, SUBTENANT SHALL BE REQUIRED TO SUBMIT, EXHIBIT TO,
SUPPLY OR PROVIDE, AS THE CASE MAY BE, THE SAME SIMULTANEOUSLY TO BOTH LANDLORD
AND SUBLANDLORD.  IN ANY SUCH INSTANCE, SUBLANDLORD SHALL REASONABLY DETERMINE
IF SUCH EVIDENCE, CERTIFICATE OR OTHER MATTER OR THING SHALL BE SATISFACTORY.

(III)          NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN ARTICLE 10
OR ARTICLE 11 OF THE OVERLEASE, SUBLANDLORD SHALL HAVE NO OBLIGATION TO RESTORE
OR REBUILD ANY PORTION OF THE SUBLEASED PREMISES AFTER ANY DESTRUCTION OR TAKING
BY EMINENT DOMAIN.

(IV)          SUBLANDLORD SHALL NOT BE DEEMED TO HAVE MADE ANY OF LANDLORD’S
REPRESENTATIONS, WARRANTIES AND INDEMNITIES UNDER THE OVERLEASE (PROVIDED,
HOWEVER, THAT TO THE EXTENT PERMITTED UNDER THE OVERLEASE, OR AS OTHERWISE
CONSENTED TO BY LANDLORD, SUBLANDLORD HEREBY ASSIGNS TO SUBTENANT THE THIRD
PARTY BENEFITS OF SUCH REPRESENTATION, WARRANTIES AND INDEMNITIES OF LANDLORD
AND THE RIGHT TO ENFORCE SAME, PROVIDED, HOWEVER, THAT SUBLANDLORD SHALL ALSO
RETAIN THE RIGHTS TO ENFORCE SUCH REPRESENTATIONS, WARRANTIES AND INDEMNITIES).

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(V)           SUBLANDLORD SHALL NOT BE DEEMED OR CONSTRUED IN ANY WAY TO
INDEMNIFY SUBTENANT FOR ANY BREACH OF LANDLORD UNDER THE OVERLEASE OR ANY OTHER
ACTIONS OR OMISSIONS OF LANDLORD.

 

(vi)          Section 30(T) of the Overlease shall be amended by including the
following language at the end of the paragraph: “, or to the Securities Exchange
Commission or such other entity as required by law.”

4.  RENT.

(a) Beginning on the earlier to occur of (i) March 10, 2007 and (ii) Subtenant’s
beneficial use of the Subleased Premises for the conduct of its business, and
continuing through the Sublease Term, including any Extended Term (if
applicable), Subtenant shall pay to Sublandlord annual fixed rent (the “Fixed
Rent”) per annum in the amount of One Million Seventy-Three Thousand Four
Hundred Seventy-Two and No/100 Dollars ($1,073,472.00) in advance in equal
monthly installments of Eight-Nine Thousand Four Hundred Fifty-Six and No/100
Dollars ($89,456.00), pro-rated on a per diem basis in the case of any partial
months during the Term addressed to Sublandlord at the address set forth in this
Sublease, Attn:  Chief Financial Officer,  or such other address set forth in a
written notice to Subtenant.  Subtenant’s Fixed Rent shall be proportionately
adjusted in the event Subtenant leases any Storage Space from Sublandlord.

(b)           Except as otherwise set forth herein, each monthly installment
shall be payable on or before the first day of the calendar month for which such
payment is made, without notice or demand and without abatement, set-off or
deduction.

(c)           In addition to the Fixed Rent and any other sums which Subtenant
may be obligated to pay pursuant to any other provision of this Sublease,
Subtenant agrees to pay to Sublandlord as “Additional Rent” hereunder as and
when such sums are due and payable by Sublandlord under the Overlease, or as
otherwise hereinafter provided:

(i)            “Expense Adjustment Amount” in an amount equal to 33.15%,
(“Subtenant’s Pro Rata Share”) of the amounts payable by Sublandlord on account
of Operating Expenses and Real Estate Taxes pursuant to Article 4(A) of the
Overlease, which Subtenant’s Pro Rata Share shall be proportionately adjusted in
the event Subtenant leases any Storage Space from Sublandlord;

(ii)           the cost of all utilities consumed by Subtenant in the Subleased
Premises, including but not limited to electricity, natural gas and water,
sewer, steam, fire protection, telephone and other communication and alarm
services (the “Utility Charges”).  Subtenant agrees that Subtenant’s usage of
electricity and gas shall be measured by separate sub-meter to be installed by
Subtenant, and Subtenant shall pay Subtenant’s Pro Rata Share of all other
utilities supplied to the Subleased Premises and

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not directly billed to Subtenant by the utility provider;

(iii)          the Parking Fee (as hereinafter defined in Section 22 hereof);

(iv)          all Subtenant Surcharges (as hereinafter defined); and

(v)           if pursuant to Section 1 above, Subtenant leases any Storage
Space, Subtenant shall pay all Fixed Rent and Additional Rent charged by
Landlord in respect of the Storage Space (“Storage Space Charges”).

(d)  As used herein, the term “Subtenant Surcharges” shall mean any and all
amounts other than the Expense Adjustment Amount, Utility Charges, Parking Fee
and the Storage Space Charges which become due and payable by Sublandlord to
Landlord under the Overlease whether as additional rent or for any extra
services or otherwise, which would not have become due and payable but for the
acts and omissions of Subtenant under this Sublease or which are otherwise
attributable to the Subleased Premises, including, but not limited to:  (i) any
increases in the Landlord’s fire, rent or other insurance premiums resulting
from any act or omission of Subtenant, (ii) any additional rent under the
Overlease payable by Sublandlord on account of Subtenant’s use of other extra
services above those provided in Article VII of the Overlease, and (iii) any
additional rent under the Overlease payable by Sublandlord on account of any
other additional service as may be provided to the Subleased Premises. 
Notwithstanding the foregoing, Subtenant Surcharges shall not include (i)
amounts which relate to the acts or omissions of Sublandlord under the Overlease
and not the acts or omissions of Subtenant under this Sublease, (ii) maintenance
and repairs with respect to any non-common areas of the Premises (other than the
Subleased Premises); or (iii) Fixed Rent pursuant to the Overlease, and, except
as expressly provided in this Sublease, items of Additional Rent pursuant to the
Overlease.  Subtenant shall pay the Additional Rent set forth in subsections (c)
and (d) of this Section 4 within thirty (30) days after the presentation of
statements therefor by the Landlord or Sublandlord to Subtenant.

(e)           To the extent any utilities to the Subleased Premises are not
separately sub-metered, if Subtenant or any other occupant of the Premises makes
use of any utilities during hours other than during Building business hours, or
if Subtenant or any other occupant of the Premises adds any machinery,
appliances or equipment which materially increases or decreases the aggregate
electrical load in the Subleased Premises or other portions of the Premises, as
the case may be, the applicable Utility Charges shall be adjusted
proportionately to reflect any change in such use.

(f)            Sublandlord shall provide copies of all bills (or relevant
portions thereof) received from Landlord affecting or relating to Subtenant’s
use of the Subleased Premises to Subtenant promptly upon receipt. 
Notwithstanding the foregoing, (i) if the Overlease provides that a payment of
additional rent is payable by the Sublandlord to Landlord within a shorter
period of time, Subtenant shall pay the additional rent provided for in this
Section 4 relating to such payment of additional rent not later than the
business day preceding the date that Sublandlord

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shall be so required to pay, and (ii) if the Overlease provides that a payment
of additional rent thereunder is payable by Sublandlord to Landlord, on demand,
then Subtenant shall pay any additional rent provided for in this Section 4
relating to such payment of additional rent under the

Overlease, upon the demand of Sublandlord.  Any failure or delay by Sublandlord
in billing any sum set forth in this Section 4 shall not constitute a waiver of
Subtenant’s obligation to pay the same in accordance with the terms of this
Sublease.

(g)  Upon its receipt thereof, Sublandlord shall furnish to Subtenant a copy of
each notice or statement from Landlord affecting the Subleased Premises with
respect to Subtenant’s obligations hereunder, together with Sublandlord’s
calculation (if applicable) of the amount owed by Subtenant hereunder and the
basis for such calculation.  If Sublandlord disputes the correctness of any such
notice or statement and if such dispute is resolved in Sublandlord’s favor, or
if Sublandlord shall receive any refund of rent without a dispute, Sublandlord
shall promptly pay to Subtenant Subtenant’s Pro Rata Share of any refund (after
deducting from the amount of any such refund an equitable portion of all
expenses, including court costs and reasonable attorneys’ fees, incurred by
Sublandlord in resolving such dispute) received by Sublandlord in respect (but
only to the extent) of any related payments of rent made by Subtenant less any
amounts theretofore received by Subtenant directly from Landlord, and relating
to such refund; provided, however, that, if Sublandlord is required under the
terms of the Overlease to pay such amounts pending the determination of any such
dispute (by agreement or otherwise), Subtenant shall pay the full amount of the
Fixed Rent, Expense Adjustment Amounts, Utility Charges, the Parking Fee, the
Storage Space Charges and Subtenant Surcharges in accordance with this Sublease
and the Landlord’s statement or notice.

(h)   Subtenant’s obligation to pay the Fixed Rent, the Expense Adjustment
Amount, Utility Charges, the Parking Fee, the Storage Space Charges, Subtenant
Surcharges and all other sums payable under this Section 4 or otherwise under
this Sublease and Sublandlord’s obligation to pay any amounts due to Subtenant
under this Sublease shall survive the termination or earlier expiration of this
Sublease until such amounts have been paid in full.

(i)  The Fixed Rent, Expense Adjustment Amount, Utility Charges, the Parking
Fee, the Storage Space Charges, Subtenant Surcharges and any other amounts
payable pursuant to this Sublease (“Rent”) shall be paid by Subtenant to
Sublandlord at the address first set forth above, or at such other place as
Sublandlord may hereafter designate from time to time in writing, in lawful
money of the United States of America, by, at Sublandlord’s option, a good
unendorsed check, subject to collection, as and when the same become due and
payable, without demand therefor and without any deduction, set-off or abatement
whatsoever.  Any other amounts of additional rents and other charges herein
reserved and payable shall be paid by Subtenant in the manner and to the persons
set forth in the statement from Sublandlord describing the amounts due.  In the
event of nonpayment of any component of Rent reserved hereunder, Sublandlord
shall have all the rights and remedies with respect thereto as are herein
provided for in case of nonpayment of the Fixed Rent reserved hereunder.

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(J)  ALL PAST DUE INSTALLMENTS OF RENT SHALL BEAR INTEREST AT THE DEFAULT RATE
RESERVED UNDER THE OVERLEASE FROM THE DATE DUE UNTIL PAID.  ADDITIONALLY,
SUBTENANT SHALL BE RESPONSIBLE FOR ALL LATE CHARGES PAYABLE BY SUBLANDLORD UNDER
ARTICLE 3 OF THE OVERLEASE AS A RESULT OF ANY LATE PAYMENT BY SUBTENANT
HEREUNDER.

5.             SECURITY DEPOSIT.

(a)           To secure the full and faithful performance by Subtenant of all
the terms, provisions, conditions, covenants and obligations (including, without
limitation, the payment of rent) on Subtenant’s part to be performed hereunder,
on or before the Commencement Date hereof, Subtenant shall deliver to
Sublandlord a security deposit (“Security Deposit”) in the amount of Two Million
Nine Hundred Seven Thousand Three Hundred Twenty Dollars ($2,907,320.00)
in either (i) cash or (ii) an unconditional, clean, irrevocable “evergreen”
letter of credit, payable on sight, in form and substance satisfactory to
Sublandlord and otherwise in accordance with the requirements of Article 23 of
the Overlease.   Said Security Deposit shall be proportionately increased in the
event Subtenant leases any Storage Space.  Sublandlord hereby approves Silicon
Valley Bank, N.A. as the issuer of the letter of credit.   The failure to timely
deliver any subsequent or extension letter of credit shall constitute a material
default hereunder for which no notice need be given, and for which no grace or
cure period need be allowed (notwithstanding anything herein set forth to the
contrary) and the letter of credit, then in effect, may be presented for payment
and negotiated notwithstanding that no other default may then exist under this
Sublease and upon such presentment and negotiation, the default for Subtenant’s
failure to so deliver shall be deemed to have been cured.  In the event
Subtenant defaults beyond any applicable notice and cure periods herein set
forth in respect of any of the terms, provisions, conditions, covenants and
obligations of this Sublease, including, but not limited to, the payment of
Fixed Rent and Additional Rent, Sublandlord may, without first applying any
other security, use, apply or retain the whole or any part of the proceeds of
the letter of credit or cash security deposit delivered as security hereunder to
the extent required for the payment of any Fixed Rent or Additional Rent or any
other sum as to which Subtenant is in default or for any sum which Sublandlord
may incur or may be required to incur by reason of Subtenant’s default in
respect of any of the terms, provisions, conditions, covenants and obligations
on Subtenant’s part to be performed hereunder, including but not limited to, any
actual out-of-pocket damages or deficiencies which accrued before or after the
commencement of summary proceedings or other re-entry by Sublandlord.    If
Subtenant shall fully and faithfully comply with all of the terms, provisions,
covenants and conditions of this Sublease, the letter of credit or cash security
deposit shall be returned to Subtenant after the Expiration Date and after
delivery of possession of the Sublease Premises to Sublandlord.  Every cash
security deposit or letter of credit deposited with Sublandlord hereunder shall
be transferable by its terms to an assignee of Sublandlord’s interests under the
Overlease without charge to Sublandlord and without any further responsibility
and liability with respect to such security and Subtenant agrees to look solely
to such assignee of Sublandlord (who may be an assignee/successor-in-interest,
by way of example and not by limitation, as a result of a merger with
Sublandlord, as a result of a purchase of substantially all of

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Sublandlord’s assets, etc.) for the return of the cash security deposit or
letter of credit or the proceeds thereof.  The provisions of the preceding
sentence are self-operative without the need for further documentation. 
Subtenant shall not assign or encumber or attempt to assign or encumber
any cash security deposit or letter of credit or any of the proceeds thereof.

(h)           If Subtenant shall faithfully perform all of the covenants and
agreements contained in this Sublease on the part of Subtenant to be performed
and provided that there is not an Event of Default under the terms and
conditions of this Sublease, the Security Deposit shall be reduced as follows:

(i)                                     to an amount equal to Two Million Four
Hundred Ninety-Three Thousand Five Hundred Eighty-Six and No/100 Dollars
($2,493,586.00) upon Subtenant having fully satisfied its obligations set forth
in Section III (D) of Exhibit C attached hereto;

(ii)                                  to an amount equal to One Million Eight
Hundred Seventy Thousand Three Hundred One Dollars ($1,870,301.00) upon the end
of the third Sublease Year (for purposes hereof, the term “Sublease Year” shall
refer to the first 12 month period following the Commencement Date hereof and
each succeeding 12 month period following such Commencement Date); and

(iii)                               in the event this Sublease is extended as
hereinabove provided, to an amount equal to One Million Two Hundred Forty-Six
Thousand Seven Hundred Ninety-Three and No/100 Dollars ($1,246,793.00) upon the
end of the fifth Sublease Year.

If the Security Deposit is a letter of credit, Subtenant shall, upon thirty (30)
days’ prior written notice to Landlord, effectuate a substitution of the then
current letter of credit, with a new letter of credit reflecting the applicable
reduced amount set forth above, and otherwise subject to all of the terms and
conditions set forth in this Section.  If the Security Deposit is in the form of
cash, Sublandlord shall, upon thirty (30) days’ prior written request of
Subtenant, and provided that there is not an Event of Default under the terms
and conditions of this Sublease either at the time of such request or at the
time that such reduction is to take effect, refund to Subtenant the applicable
difference between the then current amount of the Security Deposit and the
reduced amount.

6.  USE OF SUBLEASED PREMISES.  Subtenant shall use the Subleased Premises only
for those purposes allowed under the Overlease, and for no other purposes
whatsoever.  Sublandlord agrees that Subtenant shall be permitted, subject to
Subtenant obtaining all applicable permits and approvals and to Sublandlord’s
rights under the Overlease.

7.  CONDITION OF SUBLEASED PREMISES.

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(a)           Subtenant represents and warrants that it has made a thorough
examination of the Subleased Premises and it is familiar with the condition
thereof.  Subtenant acknowledges that it enters into this Sublease without any
representation or warranties by Sublandlord or anyone acting or purporting to
act on behalf of Sublandlord, as to present or future condition of the Subleased
Premises or the appurtenances thereto or any improvements therein or of the
Building, except as otherwise expressly set forth herein.  Sublandlord hereby
represents that the Subleased Premises shall be in broom clean condition and
free of all occupants and from all personalty when delivered to Subtenant.  It
is further agreed that, other than the Sublandlord’s Work, Sublandlord has no
obligation to perform any work therein or contribute to the cost of any work.

(b)           On or before the date that is three (3) months following the
Commencement Date, subject to Sublandlord’s receipt of all necessary approvals,
Sublandlord shall substantially complete a demising wall within the Subleased
Premises, demising the Subleased Premises from the remainder of the Premises
(“Sublandlord’s Work”), provided that Sublandlord shall use commercially
reasonable efforts not to materially interfere with the performance by Subtenant
of Subtenant’s Work (as hereinafter defined) within the Subleased Premises.

(c)           Subtenant, at its sole cost and expense, in accordance with the
attached “Exhibit C”, subject to Subtenant’s receipt of the Subtenant Allowance
(as hereinafter defined) and Subtenant’s receipt of all necessary approvals,
shall design, perform and complete all other improvements to the Subleased
Premises as more particularly set forth in the work letter attached hereto as
“Exhibit C” (herein called “Subtenant’s Work”).  Subtenant shall complete all of
Subtenant’s Work in good and workmanlike manner, fully paid for and free from
liens, in accordance with the plans and specifications approved by Landlord and
Sublandlord as provided in “Exhibit C”.  Notwithstanding the fact that the
foregoing activities may occur prior to the Rent Commencement Date, Subtenant
agrees that all of Subtenant’s obligations provided for in this Sublease shall
apply during the period from the Commencement Date to the Rent Commencement
Date, with the exception of any obligation to pay Fixed Rent, Expense Adjustment
Amounts and the Storage Space Charges.  Notwithstanding the foregoing, Subtenant
shall pay to Sublandlord all Utility Charges and Subtenant Surcharges applicable
to such period.   Sublandlord shall provide Subtenant with a Subtenant Work
Allowance to reimburse Subtenant for all or part of the cost of Subtenant’s Work
as more particularly set forth in the attached “Exhibit C”.  Subtenant shall use
all commercially reasonable efforts during the performance of Subtenant’s Work
to minimize interference with the business operations of other tenants in the
Building.

(d)           Subtenant shall, at its sole cost and expense, provide janitorial
and cleaning services to the Subleased Premises.

8.  ALTERATIONS.  Other than as expressly set forth herein, Subtenant shall make
no alterations, installations, additions or improvements in or to the Subleased
Premises

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(“Alterations”), without first obtaining Sublandlord’s prior written consent,
which consent shall not be unreasonably withheld, conditioned or delayed.   
Notwithstanding the foregoing, all Subtenant Alterations, including Subtenant’s
Work, shall be subject to the terms of the Overlease and to the consent of
Landlord.

9.  FAILURE OF SUBLANDLORD TO PERFORM OBLIGATIONS.  Subtenant acknowledges and
agrees that Sublandlord shall have no obligation to provide any services to the
Subleased Premises or to perform the terms, covenants, conditions or obligations
contained in the Overlease on the part of Landlord to be performed.  Subtenant
agrees to look solely to Landlord for the furnishing of such services and the
performance of such terms, covenants, conditions or obligations.  In the event
that Landlord shall fail to furnish such services or to perform any of the
terms, covenants, conditions or obligations contained in the Overlease on its
part to be performed, Sublandlord shall be under no obligation or liability
whatsoever to Subtenant for such failure.  In any event, Subtenant shall not be
allowed any abatement or diminution of rent under this Sublease because of
Landlord’s failure to perform any of its obligations under the Overlease unless
Sublandlord is entitled to an abatement under the terms of the Sublease, in
which event, Subtenant shall be entitled to a proportionate and equitable
abatement.  Sublandlord agrees, however, that in the event that if Landlord
shall fail to provide the services or perform the obligations to be provided or
performed by it pursuant to the terms of the Overlease, Sublandlord shall, upon
written notice from Subtenant, use commercially reasonable efforts to enforce
the terms of the Overlease, at Subtenant’s sole cost and expense.  If Landlord
shall default in the performance of any of its obligations under the Overlease,
Sublandlord shall, upon request and at the expense of Subtenant, timely
institute and diligently prosecute any action or proceeding reasonably requested
by Subtenant in order to have Landlord comply with any obligation of Landlord
under the Overlease or as required by law.   Subtenant shall indemnify and hold
harmless Sublandlord from and against any and all costs or claims arising out of
or in connection with any such action or proceeding undertaken by Sublandlord on
behalf of Subtenant.  Subtenant shall not make any claim against Sublandlord for
any damage which may arise, nor shall Subtenant’s obligations hereunder be
diminished, by reason of (i) the failure of Landlord to keep, observe or perform
any of its obligations pursuant to the Overlease, unless such failure is due to
Sublandlord’s default under this Sublease, or (ii) the acts or omissions of
Landlord, its agents, contractors, servants, employees, invitees or licensees. 
In the event that Sublandlord elects to enforce its rights under the Overlease
with respect to the Subleased Premises, Sublandlord shall charge Subtenant for
its pro rata share of such costs.  The provisions of this Section 9 shall
survive the expiration or earlier termination of the Term hereof.

10.  ACCESS.  Sublandlord and Landlord and their respective agents may, at
reasonable times and upon reasonable notice, enter to view the Subleased
Premises, and make repairs and alterations as Sublandlord and/or Landlord should
elect to do and may show the Subleased Premises to others, before the expiration
of the Term; provided, however, that Sublandlord may show the Subleased Premises
to prospective tenants only during the last twelve (12) months of the Term;
provided, further, at Subtenant’s election, except in cases of emergency, access
to the

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Subleased Premises shall be in the presence of a representative of Subtenant. 
Upon entry by Sublandlord to the Subleased Premises, Sublandlord shall use
commercially reasonable efforts to minimize interference with Subtenant’s use
and occupancy of the Subleased Premises.

11.  INDEMNIFICATION/INSURANCE.

(a)           Subtenant shall defend, indemnify and hold harmless Sublandlord
and its agents, successors and assigns, from and against any and all injury,
loss, costs, expenses, liabilities, claims or damage (including attorneys’ fees
and disbursements) to any person or property (i) arising from, related to, or in
connection with any use or occupancy of the Subleased Premises by Subtenant,
(ii) arising from, related to, or in connection with any act or omission
(including, without limitation, construction and repair of the Subleased
Premises in connection with Subtenant’s Work or subsequent work) of Subtenant,
its agents, contractors, employees, customers and invitees, or (iii) which
occurs in any part of the Property other than the Subleased Premises and is
caused by the negligence or willful misconduct of Subtenant, which indemnity
extends to any and all claims arising from any breach or default in the
performance of any obligation on Subtenant’s part to be performed under the
terms of this Sublease.  This indemnification shall survive the expiration or
termination of the Sublease Term.

(b)  Sublandlord shall defend, indemnify and hold Subtenant harmless from and
against all claims, causes of action, liabilities, losses, costs and expenses
arising from or in connection with any injury or other damage or damages to any
person or property resulting from the negligence or willful misconduct of
Sublandlord, its agents, contractors, employees, customers and invitees. This
indemnification shall survive the expiration or termination of the Sublease
Term.

(c)           In no event shall Sublandlord be liable for any consequential
damages hereunder nor shall Subtenant be liable for any consequential damages
hereunder, except as may result from Subtenant’s failure to timely surrender the
Subleased Premises at the expiration or earlier termination of the Term.

(d)           Subtenant shall carry insurance for all personal property and
trade fixtures on the Subleased Premises and for all Alterations, including but
not limited to Subtenant’s Work,  performed by Subtenant or on its account. 
Subtenant shall also carry all insurance as required in the Overlease, naming
Sublandlord and Landlord as additional insureds on all policies required
thereunder.

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(e)           The parties agree that all property insurance carried by either
party with respect to the Subleased Premises, whether or not required by this
Sublease, shall include a waiver of the subrogation of rights of recovery to the
extent such rights have been waived by the insured party prior to the occurrence
of loss or injury.  Each party shall be entitled to have duplicates or
certificates of any policies containing such provisions.  Each party hereby
waives any rights of recovery against the other for loss or injury against which
the waiving party is protected by insurance containing provisions denying to the
insurer acquisition by subrogation of rights of recovery, reserving, however,
any rights with respect to any excess of loss or injury over the amount
recovered by such insurance.

12.  ASSIGNMENT AND SUBLETTING.  Subtenant shall not assign, sell, transfer
(whether by operation of law or otherwise), pledge, mortgage or otherwise
encumber this Sublease or any portion of its interest in the Subleased Premises,
nor sublet all or any portion of the Subleased Premises or permit any other
person or entity to use or occupy all or any portion of the Subleased Premises,
without the prior written consent of Sublandlord (which consent of Sublandlord
shall not be unreasonably withheld, conditioned or delayed) and Landlord, and in
accordance with the terms of Article 16 of the Overlease.  Notwithstanding the
foregoing, the provisions of Section 16.B of the Overlease shall apply to an
assignment or sublease by Subtenant to an “Affiliated Transferee” as if such
transfer were an assignment or sublease, as applicable, by Sublandlord, as
Tenant, under the Overlease.   Notwithstanding anything in the Overlease to the
contrary, if Subtenant desires to assign this Sublease or sublet more than
sixty-seven percent  (67%) of the Subleased Premises (other than to an
Affiliated Transferee), Subtenant shall have the right to notify Sublandlord in
writing in advance.   Sublandlord shall have thirty (30) days from the date of
receipt of Subtenant’s notice, to elect to recapture the Subleased Premises
effective upon the proposed effective date of the sublease or assignment (but
not earlier than sixty (60) days following the date of Subtenant’s notice),
which election shall be in writing and delivered within said thirty (30) day
period.  If Sublandlord does not elect to recapture or fails to notify Subtenant
of its election within such thirty day period, upon Subtenant’s receipt of a
bona fide offer for an assignment of this Sublease or sublease of more than
sixty-seven percent (67%) of the Subleased Premises and the giving of written
notice to Sublandlord of such offer and the receipt by Sublandlord of any
information related to the proposed sublease or assignment reasonably requested
by Sublandlord, Sublandlord shall have five (5) business days in which to either
consent to or deny the proposed sublease or assignment.  To the extent not
inconsistent with the terms of this Section 12, the terms and provisions of
Article 16 of the Overlease shall apply to this Sublease between Subtenant and
Sublandlord.

13.  CASUALTY AND CONDEMNATION.  Notwithstanding anything to the contrary
contained in this Sublease or in the Overlease, Subtenant shall not have the
right to terminate this Sublease as to all or any part of the Subleased
Premises, or be entitled to an abatement of Fixed Rent, the Expense Adjustment
Amounts, Utility Charges, the Parking Fee, the Storage Space Charges , Subtenant
Surcharges, or any other component of Rent or additional rent, by reason of a
casualty or condemnation affecting the Subleased Premises unless Sublandlord is
entitled to terminate the Overlease or is entitled to a corresponding abatement
under the Overlease.  If Sublandlord is entitled to terminate the Overlease for
all or any portion of the Subleased Premises by reason of casualty or

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condemnation, Sublandlord shall notify Subtenant thereof prior to giving any
notice to Landlord and Subtenant may terminate this Sublease as to any
corresponding part of the Subleased Premises by written notice to Sublandlord
given at least five (5) business days prior to the date(s) Sublandlord is
required to give notice to Landlord of such termination under the terms of the
Overlease.

14.  CONSENTS.  In no event shall Sublandlord be liable for failure to give its
consent or approval in any situation where consent or approval has been withheld
or refused by Landlord, whether or not such withholding or refusal was proper,
provided, however that Sublandlord shall use commercially reasonable efforts to
obtain such consents.

15.  CONSENT OF LANDLORD.  (a)  Sublandlord and Subtenant hereby acknowledge and
agree that this Sublease is subject to and conditioned upon Sublandlord
obtaining the written consent (the “Consent”) of Landlord as provided in the
Overlease.  Sublandlord agrees to use commercially reasonable efforts to obtain
the Consent.  Promptly following the execution and delivery of this Sublease by
Sublandlord and Subtenant, Sublandlord shall submit this Sublease to Landlord. 
It is expressly understood and agreed that notwithstanding anything to the
contrary contained herein, the Term shall not commence, Subtenant shall not take
possession of the Subleased Premises or any part thereof, nor shall Subtenant’s
other obligations hereunder begin to accrue, until the Consent has been
obtained.  Subtenant hereby agrees that it shall cooperate in good faith with
Sublandlord and shall comply with any reasonable requests made of Subtenant by
Sublandlord or Landlord in the procurement of the Consent.

(b)           In addition to the Consent, Sublandlord agrees to request from
Landlord, and to use commercially reasonable efforts to obtain, at no expense to
Sublandlord, a recognition agreement, whereby Landlord agrees to recognize
Subtenant upon the terms of this Sublease upon a termination of the Overlease.  
Any such recognition agreement, however, shall not be a condition to the
commencement of this Sublease and the failure to obtain such recognition
agreement shall not give Subtenant the right to terminate this Sublease pursuant
to Section 2(a) hereof.

16.  DEFAULTS.  Subtenant covenants and agrees that in the event that it shall
default in the performance of any of the terms, covenants and conditions of this
Sublease beyond any applicable notice, grace or cure periods or of the Overlease
as incorporated herein (collectively, an “Event of Default”), Sublandlord shall
have the right to (i) any and all remedies reserved by Landlord under the
Overlease, which are incorporated herein and made a part hereof, with the same
force and effect as if herein specifically set forth in full, and (ii) any and
all other rights and remedies available to Sublandlord at law and in equity.

17.  NOTICE.  Whenever, by the terms of this Sublease, any notice, demand,
request, approval, consent or other communication (each of which shall be
referred to as a “notice”) shall or may be given either to Sublandlord or to
Subtenant, such notice shall be in writing and shall be sent by nationally
recognized overnight courier providing for receipted delivery, or by registered
or certified mail, return receipt requested, postage prepaid, addressed as
follows (or to such other

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address or addresses as may from time to time hereafter be designated by
Sublandlord or Subtenant, as the case may be, by like notice):

(a)                                  If intended for Sublandlord, to:

Archemix Corp.
300 Third Street
Cambridge, Massachusetts 02142

Attn:  Chief Financial Officer

and to:

Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
One Financial Center
Boston, MA  02111
Attention:  Stuart A. Offner, Esq.

(b)                                 If intended for Subtenant, to:

Momenta Pharmaceuticals, Inc.
675 West Kendall Street
Cambridge, MA 02142
Attention:  Richard P. Shea, CFO

and to:

Foley Hoag LLP
155 Seaport Boulevard
Boston, MA 02210
Attn:  Real Estate Department

All such notices shall be deemed to have been served on the date of actual
receipt (in the case of hand delivery), or one (1) business day after such
notice shall have been deposited with a nationally recognized overnight courier,
or three (3) business days after such notice shall have been deposited in the
United States mails within the continental United States (in the case of mailing
by registered or certified mail as aforesaid).

18.  SURRENDER OF SUBLEASED PREMISES.  Subtenant shall at the expiration or
other termination of this Sublease remove all Subtenant’s goods and effects from
the Subleased Premises.   Subtenant shall deliver to Sublandlord the Subleased
Premises and all keys, locks

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thereto, and other fixtures connected therewith and all alterations and
additions made to or upon the Subleased Premises, except those alterations and
additions that may be required by Landlord or Sublandlord to be removed, in good
order and condition, normal wear and tear and damage by fire or other casualty
not caused by Subtenant excepted; provided, however, Sublandlord agrees that
Subtenant shall have no obligation to remove any alterations or additions if,
with respect to any given alteration or addition, Subtenant previously requested
in writing a written waiver of such obligation by Sublandlord and Landlord and
Sublandlord and Landlord have delivered such written waiver to Subtenant.  In
addition, if Subtenant fails to surrender the Subleased Premises in the
condition required hereunder, Sublandlord shall have the right to cause the
Subleased Premises to be restored to such condition and charge the cost thereof
to Subtenant.  In the event of Subtenant’s failure to remove any of Subtenant’s
property from the Subleased Premises, Sublandlord and Landlord are hereby
authorized, without liability to Subtenant for loss or damage thereto, and at
the sole risk of Subtenant, to remove and store any of the property at
Subtenant’s expense, or to retain same under Sublandlord’s or Landlord’s control
or to sell at public or private sale, without notice any or all of the property
not so removed and to apply the net proceeds of such sale to the payment of any
sum due hereunder, or to destroy such property.

19.  BROKER.  Subtenant represents and warrants to Sublandlord that Subtenant
has not dealt, either directly or indirectly, with any broker in connection with
this Sublease, or the sub-subletting of the Subleased Premises to Subtenant,
other than CB Richard Ellis and GVA Thompson Doyle Hennessy & Stevens (the
“Brokers”) and Sublandlord shall be solely responsible for all fees of the
Brokers.  Subtenant shall indemnify Sublandlord from and against any and all
loss, costs and expenses, including reasonable attorney’s fees, incurred by
Sublandlord, resulting from a breach of such representation and warranty. 
Sublandlord represents and warrants to Subtenant that Sublandlord has not dealt,
either directly or indirectly, with any broker in connection with this Sublease,
or the sub-subletting of the Subleased Premises to Subtenant, other than the
Brokers.  Sublandlord shall indemnify Subtenant from and against any and all
loss, cost and expenses, including reasonable attorneys’ fees, incurred by
Subtenant, resulting from a breach of such representation and warranty.

20.  COUNTERPARTS.   This Sublease may be executed in one or more counterparts,
and by different parties hereto on separate counterparts, each of which shall be
deemed an original, but all of which together shall constitute one and the same
instrument.

21.  PARKING.  Subject to the terms of Article 26 of the Overlease, Sublandlord
shall provide Subtenant with, and Subtenant shall lease from Sublandlord,
twenty-four (24) of the parking spaces allocated to Sublandlord under the
Overlease, which parking spaces shall be on an unassigned, unreserved basis, at
the fair market parking rates as established by Landlord from time to time (the
“Parking Fee”), which Parking Fee shall be paid by Subtenant at the same time
and in the same manner as Subtenant’s monthly payments of Fixed Rent.

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22.  ROOF RIGHTS.   If Subtenant desires to locate telecommunications equipment,
an emergency generator and/or HVAC equipment on the roof of the Building
(collectively “Roof Rights”), Subtenant shall notify Sublandlord in writing
thereof and Sublandlord shall cooperate with Subtenant and use commercially
reasonable efforts to obtain same from Landlord on Subtenant’s behalf, at
Subtenant’s expense.  Subtenant shall be responsible for any and all Additional
Rent charged by Landlord applicable to any Roof Rights.  Any Roof Rights shall
be subject to Subtenant securing of all necessary permits and approvals and the
terms of the Overlease.   Notwithstanding the foregoing, the securing of such
Roof Rights by Sublandlord shall not be a condition to the effectiveness of this
Sublease.

23. LOADING DOCK.  SUBTENANT SHALL HAVE THE NON-EXCLUSIVE RIGHT TO UTILIZE THE
LOADING DOCK AND FREIGHT ELEVATOR AS SUBLANDLORD ON THE SAME TERMS AND
CONDITIONS AS SET FORTH IN ARTICLE 7(B) OF THE OVERLEASE.

24. SIGNAGE.  Subtenant shall have the right, at Subtenant’s expense, to install
(i) Subtenant’s identification signage, including its name and logo, in the
second floor elevator lobby, and (ii) building standard signage in the first
floor lobby, provided that such signage is coordinated with Landlord, consistent
with other signage in the Building and in compliance with all applicable laws.

25.  LIMITATION OF ESTATE.  Subtenant’s estate shall in all respects be limited
to, and be construed in a fashion consistent with, the estate granted to
Sublandlord by Landlord.  From and after the Commencement Date, Subtenant shall
stand in the place of Sublandlord and shall defend, indemnify and hold
Sublandlord harmless with respect to all covenants, warranties, and obligations
of Subtenant hereunder.  In the event Sublandlord is prevented from performing
any of its obligations under this Sublease by a breach by Landlord of a term of
the Overlease, then, except as otherwise expressly agreed to herein,
Sublandlord’s sole obligation in regard to its obligation under this Sublease
shall be to use reasonable efforts in diligently pursuing the correction or cure
by Landlord of Landlord’s breach under the Overlease.

26.    ENTIRE AGREEMENT.  IT IS UNDERSTOOD AND ACKNOWLEDGED THAT THERE ARE NO
ORAL AGREEMENTS BETWEEN THE PARTIES HERETO AFFECTING THIS SUBLEASE, AND THIS
SUBLEASE SUPERSEDES AND CANCELS ANY AND ALL PREVIOUS NEGOTIATIONS, ARRANGEMENTS,
BROCHURES, AGREEMENTS AND UNDERSTANDINGS, IF ANY, BETWEEN THE PARTIES HERETO OR
DISPLAYED BY SUBLANDLORD TO SUBTENANT WITH RESPECT TO THE SUBJECT MATTER
THEREOF, AND NONE THEREOF SHALL BE USED TO INTERPRET OR CONSTRUE THIS SUBLEASE. 
THIS SUBLEASE AND ANY EXHIBITS AND SCHEDULES ATTACHED HERETO CONTAIN ALL OF THE
TERMS, COVENANTS, CONDITIONS, WARRANTIES AND AGREEMENTS OF THE PARTIES RELATING
IN ANY MANNER TO THE RENTAL, USE AND OCCUPANCY OF THE SUBLEASED PREMISES AND
SHALL BE CONSIDERED TO BE THE ONLY AGREEMENTS BETWEEN THE PARTIES HERETO AND
THEIR REPRESENTATIVES AND AGENTS.  NONE OF THE TERMS, COVENANTS, CONDITIONS OR
PROVISIONS OF THIS SUBLEASE CAN BE MODIFIED, DELETED OR ADDED TO EXCEPT IN A
WRITING SIGNED BY THE PARTIES HERETO WHICH IS CONSENTED TO BY LANDLORD.  ALL
NEGOTIATIONS AND ORAL AGREEMENTS ACCEPTABLE TO BOTH PARTIES HAVE BEEN MERGED
INTO AND ARE INCLUDED HEREIN.  THERE ARE NO REPRESENTATIONS OR WARRANTIES
BETWEEN THE PARTIES, EXCEPT ANY EXPRESS REPRESENTATIONS AND

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agreements contained in this Sublease.

27.           NOTICE OF SUBLEASE.  At the request of either party, Sublandlord
and Subtenant will execute and record a notice of sublease pursuant to M.G.L.
c.183, § 4.

IN WITNESS WHEREOF, Sublandlord and Subtenant herein have duly executed this
instrument on the day and year first above written.

SUBLANDLORD:

ARCHEMIX CORP.

 

 

 

 

 

 

 

By:

/s/ Gregg Beloff

 

 

Title:

CFO, VP, Secretary

 

 

 

Duly authorized

 

 

 

 

 

 

SUBTENANT:

MOMENTA PHARMACEUTICALS, INC.

 

 

 

 

 

 

 

By:

/s/ Richard P. Shea

 

Richard P. Shea, its Chief Financial Officer and
Treasurer, duly authorized

 

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EXHIBIT A

OVERLEASE

Note: Momenta Pharmaceuticals, Inc. is not a party to this Exhibit A. Pursuant
to Item 601 of Regulation S-K, such exhibit is not being filed herewith.

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EXHIBIT B

SUBLEASED PREMISES

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EXHIBIT C

300 Third Street – Subtenant’s Work

WORK LETTER FOR SUBTENANT WORK

I.              PLANS, WORKING DRAWINGS AND SPECIFICATIONS

A.            Sublandlord hereby approves the selection of Subtenant’s
registered professional architect, Olson Lewis Dioli & Doktor (“Subtenant’s
Architect”) to prepare the documents described herein, at Subtenant’s expense. 
Subtenant shall require Subtenant’s Architect to conditionally grant full rights
for Sublandlord’s use of such documents in the event of a Subtenant default
under the Sublease.   In connection therewith, all mechanical, electrical,
plumbing and fire protection engineering and all structural engineering (if any)
shall be performed at Subtenant’s sole expense, by a competent and qualified
engineer reasonably acceptable to Sublandlord and Landlord. (“Subtenant’s
Engineering Consultants”).  Subtenant’s Architect shall coordinate all work by
Subtenant’s Engineering Consultants such that the Plans and the Working Drawings
(both defined below) are a seamless set of design and construction documents
issued by Subtenant’s Architect.  Subtenant shall have the right to substitute
another competent and qualified professional architect for the above-reference
architect, which such substitute architect shall be reasonably acceptable to
Sublandlord and Landlord, and following such substitution, the substitute
architect shall be “Subtenant’s Architect”.

B.            No later than October 31, 2006, Subtenant shall endeavor to submit
to Sublandlord and Landlord its plans (the “Plans”), substantially complete in
all respects for the Subleased Premises consisting of one (1) set of
reproducibles and two (2) sets of prints illustrating the work proposed to be
done by Subtenant (as approved by Sublandlord, the “Subtenant’s Work”).   The
Plans shall include, but not be limited to:

1       Partition layout and door locations,

2.      Power and telephone outlet plans,

3.      Preliminary furniture and equipment layouts,

4.      Finishes schedule,

5.      Reflected ceiling plan including the location of the ceiling grid, light
fixtures, HVAC supply diffusers and return air grilles, sprinkler heads, smoke
and fire detectors, exit signs, speakers and all other items as needed for
proper engineering of the Subleased Premises,

6.      Wall elevations, sections and details including direct entrances from
public areas into the Subleased Premises,

7.      Subtenant’s complete electrical, HVAC, mechanical and plumbing design
criteria including single-line drawings as appropriate, locations of special
HVAC and electrical apparatus, a preliminary electrical load summary,  special
heating, ventilating and air conditioning equipment as needed, concentrated file
and / or library structural loads and any other equipment or systems which may
require modification of the structural, mechanical, fire protection, plumbing,
electrical or life safety components of the building,

8.      Specific identification of work items and equipment which require
long-lead delivery times in order to achieve completion of Subtenant’s Work
without delay.

The Plans shall be fully coordinated with Exhibit B to the Overlease, and shall
comply with all applicable governmental laws, ordinances, building codes,
orders, regulations and restrictions and property insurance requirements.

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C.         Sublandlord and Landlord shall review same for compatibility with
Base Building systems or as otherwise provided in Exhibit B to the Overlease,
and provide to Subtenant a letter of comments.    If either Sublandlord or
Landlord observes discrepancies with such, Sublandlord shall so notify Subtenant
who shall promptly correct the Plans to bring same into compliance and resubmit
to Sublandlord and Landlord for review.  Upon receiving approval from the
Sublandlord and Landlord the Subtenant will be allowed to use the Plans to apply
for the building permit (but Sublandlord makes no representation that said
building permit may be issued on this basis).

D.         Based upon and not later than 30 days following Sublandlord’s and
Landlord’s initial response to Subtenant’s Plans submission, Subtenant shall
endeavor to prepare and submit to Sublandlord the architectural, HVAC,
mechanical, electrical, plumbing and all other construction drawings and
specifications (the “Working Drawings”) necessary to perform all of Subtenant’s
Work.

E.         Sublandlord and Landlord shall review same for substantial
consistency with the approved Plans and shall, in writing, approve portions of
the Working Drawings which reasonably conform to the Plans and disapprove those
portions which do not so conform, specifying the reasons for such disapproval.  
Subtenant shall, at its sole expense, promptly correct the Working Drawings to
conform to the approved Plans and resubmit to Sublandlord and Landlord for
review and approval.  Following Subtenant’s resubmission of the Working Drawings
to Sublandlord and Landlord, Sublandlord shall notify Subtenant in writing that
either, (a) Landlord and Sublandlord approves the Working Drawings, as revised,
or (b) Sublandlord and/or Landlord disapproves the Working Drawings, with
reasons for such disapproval.  Such process shall continue until Sublandlord and
Landlord approve Subtenant’s Working Drawings.

F.       On or before the date which is twenty (20) days prior to Subtenant’s
commencement of Subtenant’s Work, Subtenant shall prepare and submit to
Sublandlord and Landlord, for each of Sublandlord’s and Landlord’s review and
approval:

1.          An itemized statement of Subtenant’s estimate of the Total Cost of
Subtenant’s Work, as defined in Section III (A) of this Exhibit C, to prepare
the Subleased Premises in accordance with the approved Working Drawings along
with any costs needed to modify the Base Building to accommodate Subtenant’s
Work (the “Cost Proposal”).  Subtenant’s Cost Proposal shall specifically
break-out and itemize the costs attributable to Subtenant’s Work under Section
II(B) hereof,

2.         A copy of a building permit issued by the City of Cambridge for
Subtenant’s Work proposed to be performed,

3.        The names, and addresses for all contractors which Subtenant proposes
to utilize to perform Subtenant’s Work; Subtenant has, with the approval of
Sublandlord, designated the Richmond Group, Inc., as its general contractor,
provided, that, Subtenant shall have the right to substitute another competent
and qualified general contractor reasonably acceptable to Sublandlord and
Landlord for the above-reference general contractor.  Sublandlord shall not
assess any construction management or review fee in connection with Subtenant’s
Work, provided, however, that any construction management or review fee charged
by Landlord in connection with Subtenant’s Work shall be deducted from the
Subtenant Allowance.

4.        Certificates, issued by insurance companies licensed to do business in
Massachusetts, evidencing that worker’s compensation, public liability and
builder’s risk property insurance policies are in force and will be maintained
by all contractors proposed by Subtenant to perform Subtenant’s Work, with
Sublandlord and Landlord named as an additional insureds,

5.        If any penetrations of the roof, or of the exterior skin of the
building, is required to complete the Work, evidence of contractors’
qualifications to perform such work with, in each instance, written
certification by Subtenant’s contractor or architect, acceptable to Sublandlord
and Landlord, that the watertight integrity of the Building will not be
compromised upon completion,

6.        A proposed preliminary schedule for the proposed Subtenant’s Work,

 

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7.        Copies of Subtenant’s construction agreements with its contractors for
Subtenant’s Work, and

8.        Five (5) sets of the Working Drawings.

G.       In the event that any specific item or any other submittal made
pursuant to paragraph I(F) above other than the Cost Proposal under I(F)(1)
above, is unsatisfactory to Sublandlord or Landlord because it is not in
compliance with this Exhibit C or the requirements of this Sublease or the
Overlease, Sublandlord shall provide Subtenant with written notification of
same.   Subtenant shall negotiate in good faith with parties responsible for
such unsatisfactory portions of the submittal and, failing resolution of the
matters in question, shall submit revised submissions for Sublandlord’s and
Landlord’s review.   Both Subtenant and Sublandlord shall use diligent efforts
to complete this review procedure within twenty (20) business days following
Subtenant’s submissions to Sublandlord and Landlord.

H.      Approval by Sublandlord and Landlord of the Plans, the Working Drawings
or the Cost Proposal shall not be deemed to mean approval of structural
capacity, size of ducts and piping, adequacy of electrical wiring, system
equipment capacities or any other technical matter relating to Subtenant’s
Work.   Such approvals shall not relieve Subtenant of responsibility for proper
design and construction of Subtenant’s Work in compliance with all applicable
governmental laws, ordinances, building codes, orders, regulations and
restrictions and insurance underwriter requirements.

I.         Subtenant shall, at its sole expense, but subject to reimbursement
from the Subtenant Allowance (defined below), retain the services of Subtenant’s
Architect and Subtenant’s Engineering Consultants to monitor Subtenant’s Work
pursuant to Attachment I hereto.

II.         SUBTENANT’S WORK AND CHANGES IN SUBTENANT’S WORK

A.      Subtenant’s Work.  Subtenant shall be fully responsible for all matters
that must be accomplished to substantially complete Subtenant’s Work in
accordance with this Exhibit C including, without limitation, filing plans and
other pertinent documentation with the proper governmental authorities;
obtaining all necessary building permits and occupancy certificates; promptly
removing,  any mechanics, materialmen and like liens; supervising all details of
Subtenant’s Work; expending funds for overtime labor as needed; paying
contractors and subcontractors; maintaining harmonious labor relations between
Subtenant contractor’s work trades and those employed by Sublandlord’s
contractors and any separate contractors; promptly removing, repairing and /or
restoring damaged, lost or destroyed work; removing Subtenant’s contractors’
debris from the building; payment of Subtenant’s Architect and Subtenant’s
Engineering Consultants fees, insurance costs, legal and brokerage fees, if any,
costs of utilities consumed during the Work, filing and permit fees and the
like.

B.            Changes to Subtenant’s Work.    Subtenant may, at Subtenant’s sole
responsibility for all costs associated therewith, by written notification to
Sublandlord and Landlord, request changes to the approved Plans or to the
approved Working Drawings or to Subtenant’s Work already installed (the “Change
Proposal”).   Such notification shall be accompanied by a summary of the
additional costs, or savings, involved with the proposed change, an estimate of
the period of time by which the date of substantial completion of Subtenant’s
Work will be affected by the change with a new Cost Proposal.  Sublandlord’s and
Landlord’s review and approval of each such Change Proposal shall be conducted
pursuant to paragraphs I (G) and I (H).

III.           TOTAL COST AND PAYMENTS

 

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A.    The term “Total Cost”, as used in this Exhibit C, shall mean the sum of
all costs included in Subtenant’s Cost Proposal reviewed by Sublandlord and
Landlord pursuant to Section I, plus any additional costs due to Change
Proposals approved by Sublandlord and Landlord pursuant to paragraph II (B) plus
any additional out-of-pocket costs actually incurred by Subtenant to design and
construct Subtenant’s Work including, without limitation:

1.               all hard and soft costs of Subtenant’s construction, including
the cost of labor and materials and all design, architectural and engineering
costs, including Subtenant’s Engineering Consultants, the cost of all necessary
governmental approvals;

2.               permits and fees as required by governmental authorities having
jurisdiction over Subtenant’s Work,

3.               insurance premiums for liability, worker compensation and
property damage coverages, architects and engineers fees as required to prepare
the Plans and the Working Drawings and monitor the Subtenant’s Work, including
tasks listed in paragraph I,

4.               expenses of on-site, and off-site, material inspections and
tests.

B.          Sublandlord shall provide Subtenant with an allowance of up to one
hundred thirty dollars ($130.00) per square foot (up to Two Million Nine Hundred
Seven Thousand Three Hundred Twenty Dollars ($2,907,320.00)) of rentable area of
the Subleased Premises (“Subtenant Allowance”) toward the Total Cost of
Subtenant’s Work.

C.         Periodically, but not more often than monthly, Subtenant shall
prepare and submit to Sublandlord and Landlord, certified by Subtenant’s
Architect, a cost summary of all costs incurred by Subtenant during the
preceding month to prepare the Subleased Premises for occupancy pursuant to the
approved Working Drawings, along with a current reconciliation of Subtenant’s
Total Cost as outlined in paragraph III (A) and the Subtenant Allowance, as
outlined in paragraph III (B), a summary of monies spent to-date and previous
payments made, copies of all contractor payment applications, invoices and the
like received by Subtenant, retainage amounts withheld, lien waivers from all
contractors providing labor, materials or services for Subtenant’s Work and any
further cost backup information as Sublandlord or Landlord may request.  Within
sixty (60) days following Subtenant’s full compliance with its obligations set
forth in this paragraph III (C), Sublandlord shall pay to Subtenant, or, at
Sublandlord’s election, to the relevant contractor(s) if Subtenant shall not
have already paid the same:  (i) the amount requested by Subtenant in such
summary of costs, provided that the aggregate amount requested is not less than
$50,000.00 (except with regard to the final advance), and provided that the
final advance shall be subject to Subtenant’s compliance with all of the
provisions of paragraph III (D) below.  Upon completion of Subtenant’s Work, if
Subtenant’s Total Costs are less than the Subtenant Allowance, any unused
Subtenant Allowance shall not be available for use by Tenant as a rent credit,
and shall be automatically forfeited as to any amount of such allowance not
properly requested by Tenant in accordance with the terms and conditions set
forth herein.   Subtenant shall be solely responsible for any amount of
Subtenant’s Total Costs which exceeds the Subtenant Allowance.

D.            Upon completion of Subtenant’s Work, Subtenant shall provide to
each of Sublandlord and Landlord the following:

1.                                       a certificate of Subtenant’s Architect
that Subtenant’s Work has been substantially completed in accordance with the
Working Drawings approved by Sublandlord and Landlord;

2.                                       evidence reasonably satisfactory to
Sublandlord, including without limitation, final lien waivers, that all labor
and materials included in Subtenant’s Work have been paid in full;

3.             a certificate of occupancy issued by the City of Cambridge with
respect to the Subleased Premises or such other approval permitting Subtenant to
occupy the Subleased Premises;

4.             such other documentation, if any, as may be reasonably required
by Sublandlord or as may be required by Landlord; and

5.             a Notice of Substantial Completion, prepared by Subtenant
pursuant to Massachusetts General Laws, chapter 254, and recorded by Subtenant’s
Contractor at Middlesex South Registry.

IV.                SUBTENANT’S AND SUBLANDLORD’S REPRESENTATIVES

 

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A.                                   Subtenant and Sublandlord each hereby
designate a sole construction representative with respect to matters set forth
in this Exhibit C Work Letter for Subtenant’s Work and such person shall have
full authority and responsibility to act on behalf of Subtenant and / or
Sublandlord as required herein.

Subtenant’s Construction Representative:     Richard P. Shea or any replacement
designated in writing by Subtenant.

Sublandlord’s Construction Representative:   Pat Marolda or any replacement
designated in writing by Sublandlord

V.            Sublandlord agrees that with respect to any approval or consent of
Sublandlord under this Exhibit C, Sublandlord will not unreasonably withhold,
condition or delay such approval or consent.

Attachment 1:       Monitoring of Subtenant’s Work

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Attachment 1 to Exhibit C Work Letter for Subtenant Fit Up

Monitoring of Subtenant’s Work

1.             Subtenant’s Architect and Subtenant’s Engineering Consultants
responsible for preparing the Working Drawings shall monitor, by regular visits
to the building, the progress of the Subtenant’s Work to ensure conformance to
the Working Drawings.   A report of each such visit including a listing of all
items of unacceptable work observed during such visits, along with copies of all
correspondence between Subtenant and Subtenant’s Architect and Subtenant’s
Engineering Consultants, shall be submitted to Subtenant’s contractors and to
Subtenant, and to Sublandlord’s Representatives and to Landlord.

2.             The appropriate Subtenant’s Architect and/or Subtenant’s
Engineering Consultant shall review all contractor shop drawings and submittals
pertaining to Subtenant’s Work and require Subtenant’s contractors resubmit same
until an approved set is obtained.

3.             The appropriate Subtenant’s Architect and/or Subtenant’s
Engineering Consultant shall prepare any clarifying drawings and supplementary
information as may be needed to explain the intent of the Working Drawings to
Subtenant contractors.

4.             The appropriate Subtenant’s Architect and/or Subtenant’s
Engineering Consultant shall review and certify the Subtenant’s contractors’
monthly applications for payment.

5.             Subtenant’s Architect shall certify as to the Date of Substantial
Completion of Subtenant’s Work. Within ten (10) business days thereafter, the
appropriate Subtenant’s Architect and/or Subtenant’s Engineering Consultant
shall prepare, and issue, a comprehensive listing of incomplete and unacceptable
items of work (the so-called “punch list”) for approval by Subtenant,
Sublandlord and Landlord.  After approval by Subtenant, Sublandlord and
Landlord, the appropriate Architect or Engineer shall monitor punch list items
until completion which will occur no later than thirty (30) days following
Substantial Completion of Subtenant’s Work, or within a reasonable time
thereafter if such punchlist items cannot reasonably be completed within such
thirty (30) day period.

6.             Following completion of all items contained with the so-called
punch list, Subtenant’s Architect shall certify as to the Date of Final
Completion of the Subtenant’s Work and issue its Final Certificate For Payment
to Subtenant’s contractors.

7.             Subtenant’s Architect shall monitor Contractor’s completion of
as-built drawings for the Subtenant’s Work and deliver a reproducible set of
same to Subtenant and to Sublandlord with Architect’s Final Certificate for
Payment.

 

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