Exhibit 10.51  TENTH AMENDMENT TO LEASE  THIS
TENTH AMENDMENT TO LEASE (this Tenth Amendment) is made as of the 8th day of
May, 2009 (the Tenth Amendment Date), by and between THE REALTY ASSOCIATES
FUND VI, L.P., a Delaware limited partnership (Landlord) and CUBIST
PHARMACEUTICALS, INC., a Delaware corporation (Tenant).  RECITALS:  WHEREAS,
by a lease (the Original Lease) dated as of January, 2004, California State
Teachers Retirement System (Calsters) leased to Tenant approximately 15,475
rentable square feet of space, consisting of a portion of the second (Suite 2201-55)
and fourth (Suite 4201-55) floors in the building known as 45-55 Hayden
Avenue, Lexington, Massachusetts (the Building); and  WHEREAS,
Landlord has succeeded to the interests of Calsters as landlord under the
Lease; and  WHEREAS,
the Original Lease has been amended by: a First Amendment to Lease between
Landlord and Tenant, dated as of September 29, 2005 (the First Amendment);
and by a Second Amendment to Lease between Landlord and Tenant dated as of November 18,
2005 (the Second Amendment); and by a Third Amendment to Lease between
Landlord and Tenant dated as of June 20, 2007 (the Third Amendment); and
by a Fourth Amendment to Lease dated as of October 25, 2007 (the Fourth
Amendment); and by a Fifth Amendment to Lease (the Fifth Amendment) dated as
of December 18, 2007; and by a Sixth Amendment to Lease (the Sixth
Amendment) dated as of July 31, 2008; and by a Seventh Amendment to Lease
(the Seventh Amendment) dated as of November 18, 2008; and by an Eighth
Amendment to Lease (the Eighth Amendment), dated as of November 18,
2008, and by a Ninth Amendment to Lease (the Ninth Amendment) dated as of December 19,
2008 (the Original Lease, as so amended, being referred to as the Lease),
pursuant to which the size of the premises demised under the Original Lease was
increased to 151,129 rentable square feet (the Existing Premises). The
Existing Premises consist of Suites 2201-55, 2200-55, 3000-55, 4201-55, 4200-55,
4600-45, 1000-55, 3200-55, 3201-55, 2600-45, 2800-45, 2100-45 and 2100-55; and  WHEREAS,
by letter dated as of April 27, 2006, and pursuant to the Second
Amendment, Tenant elected to include Suite 2200-55 (also known as the
Comet Space) in the Existing Premises for the remainder of the Lease Term; and  WHEREAS,
Landlord and Tenant now desire to further amend the Lease to, among other
things, expand the size of the Existing Premises by adding thereto
approximately 5,528 rentable square feet of space, known as Suite 2700-45,
on the second floor of the Building (the AON Space), and to adjust the rent
and certain provisions, all on the terms and conditions set forth below.


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, and intending to be legally bound hereby, Landlord and
Tenant hereby agree as follows:  1.             Defined Terms.
All of the foregoing recitals are true and correct. Unless otherwise defined
herein, all capitalized terms used in this Tenth Amendment shall have the
meanings ascribed to them in the Lease, the Lease shall be amended to
incorporate any additional definitions provided for in this Tenth Amendment, and
all references in the Lease to the Lease or this Lease or herein or hereunder
or similar terms or to any section thereof shall mean the Lease, or such
section thereof, as amended by this Tenth Amendment.  2.             Additional Terms
and Definitions. (a) From and after the Tenth Amendment Effective
Date, the following terms set forth in Article 1 Reference Data of the
Lease are hereby amended or added, as applicable, to have the following
meanings:  PREMISES:
  The
  following areas in the 45 and 55 Hayden Avenue portions of the Building:
  (i) Suite 2201-55 on the second floor and Suite 4201-55 on the
  fourth floor, (ii) Suite 4200-55 on the fourth floor of the
  Building, (iii) Suite 2200-55 on the second floor of the Building,
  and (iv) Suite 3000-55 on the third floor of the Building; and
  (v) Suite 4600-45 on the fourth floor of the 45 Hayden Avenue
  portion of the Building; (vi) Suite 1000-55 on the first floor of the 55
  Hayden Avenue portion of the Building; (vii) Suite 3200-55 on the
  third floor of the 55 Hayden Avenue portion of the Building;
  (viii) Suite 3201-55 on the third floor of the 55 Hayden Avenue
  portion of the Building; (ix) Suite 2600-45 on the second floor of
  the 45 Hayden Avenue portion of the Building; (x) Suite 2800-45 on
  the second floor of the 45 Hayden Avenue portion of the Building; (xi)
  Suite 2100-45 on the second floor of the 45 Hayden Avenue portion of the
  Building; (xii) Suite 2100-55 on the second floor of the 55 Hayden
  Avenue portion of the Building, and (xiii) Suite 2700-45 on the second
  floor of the 45 Hayden Avenue portion of the Building. All such spaces are
  shown on Exhibit A-10, attached hereto and incorporated herein.   2


RENTABLE FLOOR AREA OF THE PREMISES:
  Approximately
  156,657 square feet of the 45 and 55 Hayden Avenue portions of the Building
  as follows (i) 6,755 rentable square feet on the second floor contained
  in Suite 2201-55, (ii) 8,720 rentable square feet on the fourth
  floor contained in Suite 4201-55 and 31,453 rentable square feet on the
  fourth floor of the Building contained in Suite 4200-55, (iii) 6,150
  rentable square feet on the second floor of the Building contained in Suite 2200-55,
  (iv) 30,019 rentable square feet on the third floor of the Building
  contained in Suite 3000-55; (v) 25,405 rentable square feet on the
  fourth floor of the 45 Hayden Avenue portion of the Building contained in Suite 4600-45,
  (vi) 12,146 rentable square feet on the first floor of the Building
  contained in Suite 1000-55; (vii) 6,215 rentable square feet on the
  third floor of the Building contained in Suite 3200-55; and (viii) 4,280
  rentable square feet on the third floor of the Building contained in Suite 3201-55;
  (ix) 3,089 rentable square feet on the third floor of the Building
  contained in Suite 2600-45; (x) 2,805 rentable square feet on the
  second floor of the Building contained in Suite 2800-45; (xi) 1,184
  rentable square feet on the second floor of the Building contained in Suite 2100-45;
  (xii) 12,908 rentable square feet on the second floor of the Building
  contained in Suite 2100-55; and (xiii) approximately 5,528 rentable
  square feet on the second floor of the Building contained in Suite 2700-45.  (b)           From
after the Tenth Amendment Effective Date, the term Annual Rent for the Premises
shall be as set on Schedule I to this Tenth Amendment.  3.             [Intentionally
Omitted]  4.             Operating
Expenses and Real Estate Taxes. Tenants obligations under Section 4.2
of the Lease to pay Operating Expenses with respect to the AON Space shall be
computed using the calendar year ending December 31, 2009 as a base year;
and Tenants obligations under Section 4.2 of the Lease to pay increases
in Real Estate Taxes with respect to the AON Space shall be computed using the
fiscal year ending June 30, 2009 as the base year.  3


5.             Effective Date;
Delivery and Condition. (a) The Tenth Amendment Effective Date shall
be the later to occur of (i) July 1, 2009 and (ii) the date on
which Rath & Strong, Inc. (the Existing Tenant) vacates and
surrenders the AON Space and Landlord delivers possession of the AON Space to
Tenant.  (b)           Tenant acknowledges that, except as explicitly provided in
this Tenth Amendment and the Lease, it is leasing the AON Space in its current
AS IS condition, without any representation or warranty whatsoever on the part
of Landlord. Tenant currently occupies the Existing Premises and is fully
familiar with their condition and that of the common areas of the Building, and
Tenant acknowledges that, to the best of Tenants knowledge (upon reasonable
investigation and inquiry), the Existing Premises and the AON Space are in good
condition and suitable for Tenants uses. Without limiting the foregoing,
Tenant agrees that Landlord has no obligation to perform any work in or to
either the Existing Premises or the AON Space to prepare the same for Tenants
continued use and occupancy.  (c)           Landlord acknowledges that Tenant desires to make
certain alterations or improvements in the AON Space to make the same more suitable for Tenants
occupancy. Such alterations or improvements may include tenant improvements to
the AON Space, installation of fixtures
in the AON Space, and architectural and
engineering expenses in connection therewith (collectively, the AON
Space Improvements). All AON Space Improvements shall be undertaken by Tenant in strict
accordance with the applicable requirements of the Lease (including without
limitation Sections 3.3 and 3.4). The AON Space Improvements shall be deemed substantially complete on that date on which
the AON Space Improvements have been
completed except for items of work (and, if applicable, adjustment of
equipment and fixtures) which can be completed after Tenant has taken occupancy
of the AON Space, or any part thereof, without causing undue interference with
Tenants use of the AON Space or such part thereof. To the extent that (i) such work is substantially completed in
accordance with such Lease requirements, and (ii) receipted invoices (and
other material required under the Lease such as, but not limited to, lien
waivers from any contractor or subcontractor performing the AON Space Improvements) showing the actual cost thereof are
presented to Landlord during the Term of the Lease, and (iii) at the time
of any advance of funds, there then exists (A) no Event of Default on the
part of Tenant, nor (B) any Actionable Event of Default (as defined in the
Third Amendment), Landlord shall reimburse Tenant, within thirty (30) days
after receipt of each such invoice (together with lien waivers for all costs
theretofore billed), for costs actually incurred by Tenant (excluding the costs
of furniture), as evidenced by such invoices, in connection with the design and
construction of the AON Space
Improvements, but in no event shall Landlord be obligated to reimburse Tenant
more than the lesser of (x) such actual cost, or (y) One
Hundred Thirty-eight Thousand Two Hundred Dollars ($138,200.00), or $25.00 per
square foot of Rentable Area in the AON Space (the AON Space Improvements
Allowance). No portion of the AON Space Improvements Allowance may be applied to costs of
purchasing or installing furniture or wiring/cabling for the AON Space. If the Existing Tenant vacates and surrenders
possession of the AON Space prior to June 30, 2009,  4


Landlord shall grant Tenant reasonable access to the
AON Space from and after such surrender (and the Existing Tenant vacating the
AON Space) for the purpose of commencing theAON Space Improvements in the AON Space. To the extent that
Tenant has not requested disbursement of any portion of the AON Space Improvements Allowance prior to the expiration or
earlier termination of the Lease, Landlord shall have no further obligation to
reimburse Tenant for any such costs incurred by Tenant.  6.Contingency.Tenant acknowledges that the Tenth Amendment
Effective Date occurring prior to the original expiration date of the lease
with the Existing Tenant is contingent on Landlords ability to enter into a termination
agreement with the Existing Tenant, on terms and conditions acceptable to
Landlord in its sole discretion, pursuant to which the Existing Tenant would
vacate and surrender possession of the AON Space on or before June 30,
2009. If Landlord is unable to enter into a termination agreement with the
Existing Tenant, on terms and conditions acceptable to Landlord in its sole
discretion, on or before May 15, 2009, then Landlord shall so advise
Tenant and Landlord shall have the right to terminate this Tenth Amendment by
giving notice to Tenant (unless, prior to the giving of such notice, Landlord
and the Existing Tenant reach such an agreement). Upon any such termination,
this Tenth Amendment shall be void and without further force or effect, and
Landlord shall have no liability hereunder.  7.             Parking.  From and after the Tenth Amendment Effective
Date, Section 10.19 of the Lease shall be amended by, in the first
sentence thereto:  (a)           Replacing five
hundred three with five hundred twenty-one (521); and  (b)Replacing 151,129 with 156,657.  8.             Brokers.  Tenant covenants, represents and warrants to
Landlord that Tenant has had no dealings or communications with any broker or
agent (other than Grubb & Ellis Company and Richards Barry Joyce &
Partners) in connection with this Tenth Amendment, and Tenant covenants and
agrees to pay, hold harmless and indemnify the Landlord from and against any
and all cost, expense (including reasonable attorneys fees) or liability for
any compensation, commission or charges to any broker or agent (other than the
foregoing named brokers) claiming through the Tenant with respect hereto.  9.             Exhibits.  Exhibit A-10 attached hereto is
hereby substituted for Exhibit A-8 to the Lease. All references in
the Lease to Exhibit A-1, A-2, A-3, A-4, A-5, A-6
or A-8 shall be replaced by references to Exhibit A-10.  10.           Successors.  This Tenth Amendment shall be binding upon
and inure to the benefit of the parties hereto and their respective successors
and assigns, subject to the provisions of the Lease regarding assignment or
other transfers of each partys rights under the Lease.  5


11.           Authority.  Each party represents and warrants to the
other that each person executing this Tenth Amendment on behalf of such party
has the authority to do so and that such execution has fully obligated and
bound such party to all terms and provisions of this Tenth Amendment.  12.           No Further
Amendment.  It is understood and
agreed that all other conditions and terms contained in the Lease not herein
specifically amended shall remain unmodified and in full force and effect, and
the Lease, as modified by this Tenth Amendment, is hereby ratified and
confirmed.  13.           Tenant
Representations. As a material inducement to Landlord entering into this
Tenth Amendment, Tenant represents and certifies to Landlord that as of the
date hereof: (i) the Lease, as modified hereby, and together with that
certain letter dated September 24, 2007 from Ron Friedman to Jack Kerrigan,
with the subject line Response to Specific Security Questions  Hayden Woods
Corporate Center, contains the entire agreement between the parties hereto
relating to the Premises and that, except for that certain Amended and Restated
Declaration of Covenants and Easements between the Landlords predecessor in
title with respect to the Building and Tenant, as amended to date (the Declaration)
there are no other agreements between the parties relating to the Premises, the
Building or the Lease which are not contained or referred to herein or in the
Lease, (ii) to the best of Tenants knowledge, Landlord is not in default
(continuing beyond the expiration of any applicable notice or grace periods) in
any respect in any of the terms, covenants and conditions of the Lease; (iii) Tenant
has no existing setoffs, counterclaims or defenses against Landlord under the
Lease; (iv) Tenant has not assigned or pledged its leasehold interest
under the Lease, or sublet or licensed or granted any other occupancy rights with
respect to any or all of the Premises; (v) no consent or approval of any
third party or parties is required in order for Tenant to enter into and be
bound by this Tenth Amendment; and (vi) Tenant is not, and the performance
by Tenant of its obligations hereunder shall not render Tenant, insolvent
within the meaning of the United States Bankruptcy Code, the Internal Revenue
Code or any other applicable law, code or regulation.  14.           Landlord
Representations.  As a material
inducement to Tenant entering into this Tenth Amendment, Landlord represents
and certifies to Tenant that as of the date hereof: (i) the Lease, as
modified hereby, and together with that certain letter dated September 24,
2007 from Ron Friedman to Jack Kerrigan, with the subject line Response to
Specific Security Questions  Hayden Woods Corporate Center, contains the
entire agreement between the parties hereto relating to the Premises and that,
except for the Declaration, there are no other agreements between the parties
relating to the Premises, the Building or the Lease which are not contained or
referred to herein or in the Lease, (ii) to the best of Landlords
knowledge, there exists no Event of Default or Actionable Event of Default on
the part of Tenant in any respect in any of the terms, covenants and conditions
of the Lease; (iii) no consent or approval of any third party or parties
is required in order for Landlord to enter into and be bound by this Tenth
Amendment; and  6


(iv) Landlord has the right to lease the Tenth Amendment Expansion
Space, as provided herein, to Tenant.  15.           Governing Law.
The Lease, this Tenth Amendment and the rights and obligations of both parties
thereunder and hereunder shall be governed by the laws of The Commonwealth of
Massachusetts.  16.           HVAC.  Landlord and Tenant acknowledge that letter
from Tenants counsel to Landlords counsel dated August 13, 2007, with a
subject line 45-55 Hayden Avenue, Lexington, MA, and the response from
Landlords counsel dated October 18, 2007.  17.           Counterparts. This Tenth
Amendment may be executed in counterparts, each of which shall be an original
and all of which counterparts taken together shall constitute one and the same
instrument.  [Text Ends Here]  7


IN WITNESS WHEREOF, the undersigned have hereunto se their hands and
seals as of the date first above written.  LANDLORD:The
  Realty Associates Fund VI, L.P., a Delaware limited partnershipBy:
  Realty Associates Fund VI LLC, a Massachusetts limited liability company,
  general partnerBy:
  Realty Associates Advisors LLC, a Delaware limited liability company, ManagerBy:
  Realty Associates Advisors Trust, a Massachusetts business trust, ManagerBy:
  /s/
  Christopher J. GoodName:
  Christopher J. GoodTitle:
  Regional DirectorBy:
  Realty Associates Fund VI Texas Corporation, a Texas corporation, general
  partnerBy:
  /s/
  Christopher J. GoodName:
  Christopher J. GoodTitle:
  Regional DirectorTENANT:CUBIST
  PHARMACEUTICALS, INC.By:
  /s/
  David W.J. McGirrName:David W.J. McGirrTitle:
  Senior Vice President and Chief Financial Officer  8


Exhibit A-10  Plans of Premises    SECOND
  FLOOR
  CUBIST SUITE 220045-55
  HAYDEN AVENUE
  6,150 RSFLEXINGTON,
  MA  9


SECOND
  FLOOR
  CUBIST SUITE 220145-55
  HAYDEN AVENUE
  6,755 RSFLEXINGTON,
  MA  10


THIRD
  FLOOR
  MOTOROLA SUITE 300045-55
  HAYDEN AVENUE
  30,019 RSFLEXINGTON,
  MA  11


FOURTH
  FLOOR
  CUBIST SUITE 420045-55
  HAYDEN AVENUE
  31,453 RSFLEXINGTON,
  MA  12


FOURTH
  FLOOR
  CUBIST SUITE 420145-55
  HAYDEN AVENUE
  8,720 RSFLEXINGTON,
  MA  13


CUBIST
  SUITE 4600-45
  25,405
  RSF  14


CUBIST SUITE 1000-55
  12,146
  RSF  15


Cubist Suites 3200-55 and 3201-55
  10,495
  RSF  16


Cubist Suite 2800-45
  2,805
  RSF  17


Cubist Suites 2600-45
  3,089
  RSF  18


Cubist Suite 2100-45
  1,184
  RSF  19


Cubist Suite 2100-55
  12,908
  RSF  20


Cubist Suite 2700-45
  5,528
  RSF  21


SCHEDULE I TO TENTH AMENDMENT  Annual Rent  Annual Rent for the Premises shall be the sum of the rents shown below
for each portion of the Premises, determined as of the date in question. This
Schedule does not include payments due under the Seventh Amendment in respect
of the Lobby Space, which shall be in addition to the amounts shown below.  As to Suites 2201-55, 4201-55 and 4200-55:  (a)For the period
from [Effective Date of First Amendment],
2006 through July 31, 2009:  (i) As
to Suite 2201-55 and Suite 4201-55:  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SF5/1/06  1/31/07
  
  $
  371,400.00
  
  $
  30,950.00
  
  $
  24.002/1/07  1/31/08
  
  $
  386,875.00
  
  $
  32,238.58
  
  $
  25.002/1/08  7/31/09
  
  $
  402,350.00
  
  $
  33,529.17
  
  $
  26.00  plus
(ii) as to Suite 4200-55:  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SF7/1/06  4/30/07
  
  $
  723,419.00
  
  $
  60,284.92
  
  $
  23.005/1/07  4/30/08
  
  $
  739,145.50
  
  $
  61,595.46
  
  $
  23.505/1/08  4/30/09
  
  $
  754,872.00
  
  $
  62,906.00
  
  $
  24.005/1/09  7/31/09
  
  $
  794,188.25
  
  $
  66,182.35
  
  $
  25.25  (b)           For the period after July 31,
2009, as to all of Suites 2201-55, 4201-55 and 4200-55:  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SF8/1/09  4/30/10
  
  $
  1,184,932.00
  
  $
  98,744.33
  
  $
  25.255/1/10  4/30/11
  
  $
  1,208,396.00
  
  $
  100,699.67
  
  $
  25.755/1/11  4/30/12
  
  $
  1,231,860.00
  
  $
  102,655.00
  
  $
  26.255/1/12  4/30/13
  
  $
  1,267,056.00
  
  $
  105,588.00
  
  $
  27.005/1/13  4/30/14
  
  $
  1,325,716.00
  
  $
  110,476.33
  
  $
  28.255/1/14  4/30/15
  
  $
  1,384,376.00
  
  $
  115,364.67
  
  $
  29.505/1/15  4/30/16
  
  $
  1,419,572.00
  
  $
  118,297.67
  
  $
  30.25  22


As to Suite 2200-55:  RENTAL PERIOD
  
  TOTAL ANNUAL RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SF6/1/06  4/30/07
  
  $
  140,415.00
  
  $
  11,787.50
  
  $
  23.005/1/07  4/30/08
  
  $
  144,525.00
  
  $
  12,043.75
  
  $
  23.505/1/08  4/30/09
  
  $
  147,600.00
  
  $
  12,300.00
  
  $
  24.005/1/09  4/30/10
  
  $
  155,287.50
  
  $
  12,940.63
  
  $
  25.255/1/10  4/30/11
  
  $
  158,362.50
  
  $
  13,196.88
  
  $
  25.755/1/11  4/30/12
  
  $
  161,437.50
  
  $
  13,453.13
  
  $
  26.255/1/12  4/30/13
  
  $
  166,050.00
  
  $
  13,837.50
  
  $
  27.005/1/13  4/30/14
  
  $
  173,737.50
  
  $
  14,478.13
  
  $
  28.255/1/14  4/30/15
  
  $
  181,425.00
  
  $
  15,118.75
  
  $
  29.505/1/15  4/30/16
  
  $
  186,037.50
  
  $
  15,503.13
  
  $
  30.25  As to Suite 3000-55:  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/08
  
  $
  780,494.00
  
  $
  65,041.17
  
  $
  26.005/1/08  4/30/09
  
  $
  810,513.00
  
  $
  67,542.75
  
  $
  27.005/1/09  4/30/10
  
  $
  825,522.50
  
  $
  68,793.54
  
  $
  27.505/1/10  4/30/11
  
  $
  840,532.00
  
  $
  70,044.33
  
  $
  28.005/1/11 - 4/30/12
  
  $
  900,570.00
  
  $
  75,047.50
  
  $
  30.005/1/12 4/30/13
  
  $
  945,598.50
  
  $
  78,799.88
  
  $
  31.505/1/13 4/30/14
  
  $
  975,617.50
  
  $
  81,301.46
  
  $
  32.505/1/14 4/30/15
  
  $
  1,035,655.50
  
  $
  83,304.63
  
  $
  34.505/1/15 4/30/16
  
  $
  1,065,674.50
  
  $
  88,806.21
  
  $
  35.50  As to Suite 4600-45  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/09
  
  $
  819,311.25
  
  $
  68,275.94
  
  $
  32.255/1/09  4/30/10
  
  $
  844,716.25
  
  $
  70,393.02
  
  $
  33.255/1/10  4/30/11
  
  $
  870,121.25
  
  $
  72,510.10
  
  $
  34.255/1/11  4/30/12
  
  $
  895,526.25
  
  $
  74,627.19
  
  $
  35.255/1/12 - 4/30/13
  
  $
  920,931.25
  
  $
  76,744.27
  
  $
  36.255/1/13 4/30/14
  
  $
  946,336.25
  
  $
  78,861.35
  
  $
  37.255/1/14 4/30/15
  
  $
  971,741.25
  
  $
  80,978.44
  
  $
  38.255/1/15 4/30/16
  
  $
  997,146.25
  
  $
  83,095.52
  
  $
  39.25  23


As to Suite 1000-55  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/08
  
  $
  266,024.16
  
  $
  22,168.68
  
  N/A5/1/08  4/30/09
  
  $
  346,161.00
  
  $
  28,846.75
  
  $
  28.505/1/09  4/30/10
  
  $
  352,234.00
  
  $
  29,352.83
  
  $
  29.005/1/10  4/30/11
  
  $
  358,307.00
  
  $
  29,858.92
  
  $
  29.505/1/11  4/30/12
  
  $
  364,380.00
  
  $
  30,365.00
  
  $
  30.005/1/12 - 4/30/13
  
  $
  370,453.00
  
  $
  30,871.08
  
  $
  30.505/1/13 4/30/14
  
  $
  376,526.00
  
  $
  31,377.17
  
  $
  31.005/1/14 4/30/15
  
  $
  382,599.00
  
  $
  31,883.25
  
  $
  31.505/1/15 4/30/16
  
  $
  388,672.00
  
  $
  32,389.33
  
  $
  32.00  As to
Suites 3200-55 and 3201-55  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/09
  
  $
  338,463.75
  
  $
  28,205.31
  
  $
  32.255/1/09  4/30/10
  
  $
  348,958.75
  
  $
  29,079.90
  
  $
  33.255/1/10  4/30/11
  
  $
  364,701.25
  
  $
  30,391.77
  
  $
  34.255/1/11  4/30/12
  
  $
  369,948.75
  
  $
  30,829.06
  
  $
  35.255/1/12  4/30/13
  
  $
  380,443.75
  
  $
  31,703.65
  
  $
  36.255/1/13  4/30/14
  
  $
  390,938.75
  
  $
  32,578.23
  
  $
  37.255/1/14  4/30/15
  
  $
  401,433.75
  
  $
  33,452.81
  
  $
  38.255/1/15  4/30/16
  
  $
  411,928.75
  
  $
  34,327.40
  
  $
  39.25  As to
Suites 2600-45 and 2800-45  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/09
  
  $
  190,081.50
  
  $
  15,840.13
  
  $
  32.255/1/09  4/30/10
  
  $
  195,975.50
  
  $
  16,331.25
  
  $
  33.255/1/10  4/30/11
  
  $
  201,869.50
  
  $
  16,822.46
  
  $
  34.255/1/11  4/30/12
  
  $
  207,763.50
  
  $
  17,313.63
  
  $
  35.255/1/12  4/30/13
  
  $
  213,657.50
  
  $
  17,804.79
  
  $
  36.255/1/13  4/30/14
  
  $
  219,551.50
  
  $
  18,295.96
  
  $
  37.255/1/14  4/30/15
  
  $
  225,445.50
  
  $
  18,787.13
  
  $
  38.255/1/15  4/30/16
  
  $
  231,339.50
  
  $
  19,278.29
  
  $
  39.25  24


As to
Suites 2100-45 and 2100-55  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SFThrough 4/30/09
  
  $
  454,467.00
  
  $
  37,872.25
  
  $
  32.255/1/09  4/30/10
  
  $
  468,559.00
  
  $
  39,046.58
  
  $
  33.255/1/10  4/30/11
  
  $
  482,651.00
  
  $
  40,220.91
  
  $
  34.255/1/11  4/30/12
  
  $
  496,743.00
  
  $
  41,395.25
  
  $
  35.255/1/12  4/30/13
  
  $
  510,835.00
  
  $
  42,569.58
  
  $
  36.255/1/13  4/30/14
  
  $
  524,927.00
  
  $
  43,743.91
  
  $
  37.255/1/14  4/30/15
  
  $
  539,019.00
  
  $
  44,918.25
  
  $
  38.255/1/15  4/30/16
  
  $
  553,111.00
  
  $
  46,092.33
  
  $
  39.25  As to Suite 2700-45  RENTAL PERIOD
  
  TOTAL ANNUAL
  RENT
  
  MONTHLY PAYMENT
  
  RENTAL RATE/SF7/1/09  4/30/10
  
  $
  183,806.00
  
  $
  15,317.17
  
  $
  33.255/1/10  4/30/11
  
  $
  189,334.00
  
  $
  15,777.83
  
  $
  34.255/1/11  4/30/12
  
  $
  194,862.00
  
  $
  16,238.50
  
  $
  35.255/1/12  4/30/13
  
  $
  200,390.00
  
  $
  16,699.17
  
  $
  36.255/1/13  4/30/14
  
  $
  205,918.00
  
  $
  17,159.83
  
  $
  37.255/1/14  4/30/15
  
  $
  211,446.00
  
  $
  17,620.50
  
  $
  38.255/1/15  4/30/16
  
  $
  216,974.00
  
  $
  18,081.17
  
  $
  39.25  25