SECOND AMENDMENT

     THIS SECOND AMENDMENT (the “Second Amendment”) is made and entered into as
of July 6, 2009 by and between MA-RIVERVIEW/245 FIRST STREET, L.L.C., a Delaware
limited liability company (“Landlord”) and COMBINATORX, INCORPORATED, a Delaware
corporation (“Tenant”).

RECITALS

A.      Landlord and Tenant are parties to that certain lease dated October 18,
2005, which lease has been previously amended by instruments dated March 9, 2006
(the “First Amendment”) and June 5, 2006 (the “Commencement Letter”)
(collectively, the “Lease”). Pursuant to the Lease, Landlord has leased to
Tenant space currently containing approximately 63,329 rentable square feet (the
“Original Premises”) comprised of (i) 18,035 rentable square feet of office
space known as Suite No. 1600 on the 16th floor (the “Office Space”) of the
office tower building located at 245 First Street, Cambridge, Massachusetts,
commonly known as 245 First Street (the “Office Building”), (ii) 22,095 rentable
square feet of lab space known as Suite No. 400 on the 4th floor (the “4th Floor
Lab Space”) of the mid-rise building located at 245 First Street, Cambridge,
Massachusetts, commonly known as Cambridge Science Center (the “Science
Building”), and (iii) 23,199 rentable square feet of lab space known as Suite
No. 300 on the 3rd floor (the “3rd Floor Lab Space”) of the Science Building,
all as more particularly described in the Lease. The Property contains the
Office Building and the Science Building, which are sometimes jointly or
severally referred to herein as the “Building”.   B.      Tenant desires to
surrender a portion of the Original Premises to Landlord containing
approximately 40,130 comprised of (i) 18,035 rentable square feet of office
space known as Suite No.1600 on the 16th floor of the Office Building as shown
on Exhibit A to the Lease (“Reduction Space 1”) and (ii) 22,095 rentable square
feet of lab space known as Suite No. 400 on the 4th floor of Science Building as
shown on Exhibit A to the Lease (“Reduction Space 2”) and that the Lease be
appropriately amended, and Landlord is willing to accept such surrender on the
following terms and conditions.  

     NOW, THEREFORE, in consideration of the above recitals which by this
reference are incorporated herein, the mutual covenants and conditions contained
herein and other valuable consideration, the receipt and sufficiency of which
are hereby acknowledged, Landlord and Tenant agree as follows:

1.      Reduction Space 1.     1.01.      Reduction Space 1 Effective Date.     
A.      Landlord and Tenant acknowledge that Tenant has vacated Reduction Space
1 in accordance with the terms of the Lease on or prior to June 15, 2009, which
is the date immediately preceding the Reduction Space 1 Effective Date (defined
in Section 1.01.B. below) and Tenant shall fully comply with all obligations
under the Lease respecting Reduction Space 1 up to the Reduction Space 1
Effective Date, including those provisions relating to the condition of
Reduction Space 1 and removal of Tenant’s  

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  Property therefrom (other than the Suite 1600 Personal Property, as herein
defined) and except as otherwise expressly provided in this Second Amendment.
Notwithstanding the foregoing, Landlord agrees that Tenant shall have no
obligation to remove any of the Initial Office Alterations, Required Removables,
Cable or any other alterations, additions, improvements, wires or cabling in
Reduction Space 1. As consideration for Landlord’s agreement to reduce the size
of the Original Premises, Tenant shall execute and deliver to Landlord a Bill of
Sale in the form attached hereto as Exhibit A (“Suite 1600 Bill of Sale”) to
transfer, sell and convey to Landlord the personal property owned by Tenant and
described in the Suite 1600 Bill of Sale (the “Suite 1600 Personal Property”),
and, following delivery of the Suite 1600 Bill of Sale to Landlord and
satisfaction and/or waiver of the contingency set forth in Section 1.01D below,
Tenant agrees that Landlord may retain or dispose of the Suite 1600 Personal
Property in whatever manner Landlord deems appropriate. Tenant hereby represents
and warrants to Landlord that Tenant is the absolute owner of the Suite 1600
Personal Property, the Suite 1600 Personal Property is free and clear of all
liens, charges and encumbrances, and Tenant has full right, power and authority
to sell and otherwise transfer the Suite 1600 Personal Property described in the
Suite 1600 Bill of Sale. Tenant hereby agrees to indemnify and hold Landlord and
Landlord Related Parties harmless from and against any costs, claims, damages or
liability (including, without limitation, reasonable attorneys fees) arising as
a result of a breach of the foregoing representations in this Section 1.01.A.
Notwithstanding the foregoing, Landlord acknowledges and agrees that Tenant has
satisfied the conditions of the Lease regarding the surrender and vacation of
Reduction Space 1.     B.      Effective as of June 16, 2009 (the “Reduction
Space 1 Effective Date”), the Premises is decreased by 18,035 rentable square
feet on the 16th floor of the Office Building by the elimination of Reduction
Space 1. As of the Reduction Space 1 Effective Date, Reduction Space 1 shall be
deemed surrendered by Tenant to Landlord, the Lease shall be deemed terminated
with respect to Reduction Space 1, and the “Premises”, as defined in the Lease,
shall be deemed to mean the Original Premises, less Reduction Space 1; provided,
if Tenant shall violate any provision hereof or if Tenant’s representations
herein shall be false or materially misleading, Landlord shall have the right to
declare this Second Amendment null and void and to reinstate the Lease with
respect to Reduction Space 1 in addition to, and not in lieu of, any other
rights or remedies available to Landlord.     C.      If Tenant shall holdover
in Reduction Space 1 beyond the day immediately preceding the Reduction Space 1
Effective Date, the terms of Section 22 of the Lease shall apply to Reduction
Space 1.   1.02.      Base Rent/Office Base Rent. Effective as of the Reduction
Space 1 Effective Date, the schedule of Base Rent payable with respect to the
Office Space is as provided below:  

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Period    Annual Rate Per    Monthly Base Rent for      Square Foot    Office
Space 

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Reduction Space 1    $30.00    $45,087.50  Effective Date – 9/30/09         

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  and Tenant shall continue to pay Base Rent for 3rd Floor Lab Space and the 4th
Floor Lab Space as provided in the Original Lease subject to Section 2 below.  
  1.03.      Additional Consideration. As additional consideration for the
reduction of the Premises by Reduction Space 1, Tenant agrees to pay Landlord
$500,000.00 (the “Reduction Space 1 Reduction Fee”) on or before October 1,
2009.      Failure to pay the Reduction Space 1 Reduction Fee as herein provided
shall be deemed a default under the Lease.     1.04.      Tenant’s Pro Rata
Share. Commencing on October 1, 2009, Tenant’s Pro Rata Share for the Office
Building is decreased from 12.1405% to 0% and Tenant’s Pro Rata Share for the
Buildings is decreased by 6.4627% from 22.6934% to 16.2307%. Notwithstanding
anything in this Second Amendment to the contrary, Tenant shall remain liable
for all year-end adjustments with respect to Tenant’s Pro Rata Share of Office
Expenses and Office Taxes applicable to Reduction Space 1 for that portion of
the calendar year or fiscal year, as applicable, preceding October 1, 2009. Such
adjustments shall be paid at the time, in the manner and otherwise in accordance
with the terms of the Lease, unless otherwise specified in this Second
Amendment.     1.05.      Parking. Effective as of Reduction Space 1 Effective
Date, Section 2 (Parking) of Exhibit E of the Lease shall be amended to reflect
that 22 unreserved parking spaces leased to Tenant will be deemed returned to
Landlord effective as of Reduction Space 1 Effective Date, and shall no longer
be available to Tenant.      The use of the remaining Spaces shall be subject to
the terms of Section 2 of Exhibit E of the Lease.     1.06.      Demise.
Notwithstanding any contrary provision in this Second Amendment, prior to the
Reduction Space 1 Effective Date, Tenant shall make such alterations and
improvements as are necessary to separately demise the systems (and related
meters, if any) currently serving the Reduction Space 1 in common with other
portions of the Premises, from the remaining portions of the Premises, such that
they will serve only the Premises as it is then constituted under the Lease
after the termination of Reduction Space 1 in compliance with the Lease.   2.   
  Reduction Space 2.     2.01.      Reduction Space 2 Effective Date.      A.   
  Tenant shall vacate Reduction Space 2 in accordance with the terms of the
Lease on or prior to the date that is the later of (i) the date that is 60 days
after the date that the contingency under Section 2.02.D has been satisfied
and/or waived and (ii) August 31, 2009, which date shall be the date immediately
preceding the “Reduction Space 2 Effective Date” and  

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  Tenant shall fully comply with all obligations under the Lease respecting
Reduction Space 2 up to the Reduction Space 2 Effective Date, including those
provisions relating to the condition of Reduction Space 2 and removal of
Tenant’s Property therefrom (other than the Suite 400 Personal Property, as
herein defined) and except as otherwise provided in this Second Amendment.
Notwithstanding the foregoing but except as required by Section 2.06 below,
Landlord agrees that Tenant shall have no obligation to remove any of the
Initial Lab Alterations, Required Removables, Cable or any other alterations,
additions, improvements, wires or cabling in Reduction Space 2. As consideration
for Landlord’s agreement to reduce the size of the Original Premises, Tenant
shall execute and deliver to Landlord a Bill of Sale in the form attached hereto
as Exhibit B (“Suite 400 Bill of Sale”) to transfer, sell and convey to Landlord
the personal property owned by Tenant and described in the Suite 400 Bill of
Sale (the “Suite 400 Personal Property”), and, following delivery of the Suite
400 Bill of Sale to Landlord and satisfaction and/or waiver of the contingency
set forth in Section 2.01(D) below, Tenant agrees that Landlord may retain or
dispose of the Suite 400 Personal Property in whatever manner Landlord deems
appropriate. Tenant hereby represents and warrants to Landlord that Tenant is
the absolute owner of the Suite 400 Personal Property, the Suite 400 Personal
Property is free and clear of all liens, charges and encumbrances, and Tenant
has full right, power and authority to sell and otherwise transfer the Suite 400
Personal Property described in the Suite 400 Bill of Sale. Tenant hereby agrees
to indemnify and hold Landlord and Landlord Related Parties harmless from and
against any costs, claims, damages or liability (including, without limitation,
reasonable attorneys fees) arising as a result of a breach of the foregoing
representations in this Section 2.01.A. Tenant shall, prior to the Reduction
Space 2 Effective Date, cause to be performed by a qualified environmental
consultant approved by Landlord an inspection of Reduction Space 2 (including
visual inspection, geiger counter evaluation, airborne and surface monitoring)
to confirm that Reduction Space 2 is free of biological, chemical and
radioactive hazards. Tenant shall deliver a copy of the inspection report
(“Inspection Report”) to Landlord. If the Inspection Report is not reasonably
satisfactory to Landlord, Landlord shall so notify Tenant, indicating the nature
of Landlord’s dissatisfaction. Tenant shall be responsible for abating or, at
Landlord’s election, paying the cost of abating any conditions(s) indicated by
Landlord.   B.      Effective as of Reduction Space 2 Effective Date, the
Premises is decreased from 22,095 rentable square feet on the 4th floor of the
Science Building by the elimination of Reduction Space 2. As of the Reduction
Space 2 Effective Date, Reduction Space 2 shall be deemed surrendered by Tenant
to Landlord, the Lease shall be deemed terminated with respect to Reduction
Space 2, and the “Premises”, as defined in the Lease, shall be deemed to mean
the Premises as it is then constituted under the Lease, less Reduction Space 2;
provided, if Tenant shall violate any provision hereof or if Tenant’s
representations herein shall be false or materially misleading, Landlord shall
have the right to declare this Second Amendment null and void and to reinstate
the Lease with respect to  

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  Reduction Space 2 in addition to, and not in lieu of, any other rights or
remedies available to Landlord.     C.      If Tenant shall holdover in
Reduction Space 2 beyond the day immediately preceding the Reduction Space 2
Effective Date, the terms of Section 22 of the Lease shall apply to Reduction
Space 2.     D.      Notwithstanding anything in this Section 2.01 to the
contrary, Section 2 of this Second Amendment is specifically contingent upon
Landlord, on or before 30 days after the date of this Second Amendment (the
“Reduction Space 2 Contingency Date”) entering into a new lease, lease amendment
or other written agreement (“New Agreement”) with another tenant or third party
(“New Tenant”) to lease Reduction Space 2.      Landlord is currently
negotiating the terms of the New Agreement with the New Tenant. Landlord shall
notify Tenant within 3 business days after the full execution of the New
Agreement by New Tenant. If the New Agreement has not been fully executed on or
before the Reduction Space 2 Contingency Date, then Landlord may terminate this
Section 2 by notifying Tenant (“Reduction Space 2 Termination Notice”) on or
before the earlier of (i) 5 business days after the Reduction Space 2
Contingency Date and (ii) execution of the New Agreement by New Tenant.
Landlord’s failure to provide a Reduction Space 2 Termination Notice within the
time periods provided above shall render Landlord’s termination right as
provided in this Section 2.01D null and void, and the contingency described in
this Section 2.01(D) shall be deemed waived. Time is of the essence with respect
to the time periods provided herein. In the event that the contingency is not
satisfied or waived by Landlord, if Tenant has paid the Reduction Space 2
Reduction Fee to Landlord (as described in Section 2.03 of this Second
Amendment), Landlord shall return the Reduction Space 2 Reduction Fee to Tenant
within 14 days after the Reduction Space 2 Contingency Date and this Section 2
shall be null and void and of no force or effect, and the Lease and this Second
Amendment otherwise shall continue in full force and effect.   2.02.      Base
Rent/Lab Base Rent. Effective as of September 1, 2009, the schedule of Lab Base
Rent payable with respect to the Premises for the balance of the Term and
Extended Term is the following:  

Period    Annual Rate    Monthly LAB      Per Square    Base Rent      Foot     

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9/1/09 – 11/30/11    $48.00    $92,796.00 

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12/01/11 – 11/30/16    $53.00    $102,462.25 

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12/01/16 – 01/31/17    $53.00    $102,462.25 

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2.03.      Additional Consideration. As additional consideration for the
reduction of the Premises by Reduction Space 2, Tenant agrees to pay Landlord
$1,000,000.00 (the “Reduction Space 2 Reduction Fee”). Tenant agrees to pay
Landlord $500,000.00 of the Reduction Space 2 Reduction Fee on or before January
1, 2010, and the remaining $500,000.00 of the Reduction Space 2 Reduction Fee  

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  on or before July 1, 2010. Failure to pay the Reduction Space 2 Reduction Fee
as herein provided shall be deemed a default under the Lease.     2.04.     
Tenant’s Pro Rata Share. Commencing on Reduction Space 2 Effective Date,
Tenant’s Pro Rata Share for the Science Building is decreased from 34.7049% to
17.7754% and Tenant’s Pro Rata Share for the Buildings is decreased by 7.9175%
from 16.2308% to 8.3133%. Notwithstanding anything in this Second Amendment to
the contrary, Tenant shall remain liable for all year-end adjustments with
respect to Tenant’s Pro Rata Share of Lab Expenses and Lab Taxes applicable to
Reduction Space 2 for that portion of the calendar year or fiscal year, as
applicable, preceding the Reduction Space 2 Effective Date. Such adjustments
shall be paid at the time, in the manner and otherwise in accordance with the
terms of the Lease, unless otherwise specified in this Second Amendment.    
2.05.      Parking. Effective as of Reduction Space 2 Effective Date, Section 2
(Parking) of Exhibit E of the Lease shall be amended to reflect that 26
unreserved parking spaces leased to Tenant will be deemed returned to Landlord
effective as of Reduction Space 2 Effective Date, and shall no longer be
available to Tenant.      The use of the remaining Spaces shall be subject to
the terms of Section 2 of Exhibit E of the Lease.     2.06.      Demise.
Notwithstanding any contrary provision in the Lease or this Second Amendment,
prior to the Reduction Space 2 Effective Date, Tenant shall (i) make such
alterations and improvements as are necessary to separately demise the systems
(and related meters, if any) currently serving the Reduction Space 2 in common
with other portions of the Premises, from the remaining portions of the
Premises, such that they will serve only the Premises as it is then constituted
under the Lease after the termination of the Reduction Space 2; (ii) remove the
internal stairway connecting the 4th Floor Lab Space and the 3rd Floor Lab Space
and cap the ceiling of the 3rd Floor Space in compliance with the Lease and
applicable law; and (iii) Tenant shall be obligated to do all things necessary
to decommission Reduction Space 2 as lab space and shall provide Tenant with the
Inspection Report with respect to Reduction Space 2.   3.      Other Pertinent
Provisions. Landlord and Tenant agree that, effective as of the date of this
Second Amendment (unless different effective date(s) is/are specifically
referenced in this Section), the Lease shall be amended in the following
additional respects:     3.01.      Landlord Notice Addresses. Effective as of
date of this Second Amendment, Section 1.12 (Notice Addresses) of the Lease is
hereby amended to reflect that notices to Landlord shall be addressed as
follows:  

Landlord:    With copies to:    MA-Riverview/245 First Street, L.L.C.    Equity
Office  c/o Equity Office    Two North Riverside Plaza  125 Summer Street, 17th
Floor    Suite 2100  Boston, Massachusetts 02110    Chicago, Illinois 60606 
Attention: Property Manager    Attn: General Counsel 

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and

Neal, Gerber & Eisenberg LLP
Two North LaSalle Street
Suite 1700
Chicago, Illinois 60602
Attn: Audrey E. Selin, Esq.

Rent shall be made payable to an entity, and sent to the address or addresses,
Landlord designates in writing to Tenant and shall be made by good and
sufficient check payable in United States of America currency, by federal wire
transfer of immediately available funds to an account designated by Landlord or
by other means acceptable to Tenant and Landlord.

3.02.      Unrelated Business Income. The following is added as Section 26.10 of
the Lease:     “Unrelated Business Income. If Landlord is advised by its counsel
at any time that any part of the payments by Tenant to Landlord under this Lease
may be characterized as unrelated business income under the United States
Internal Revenue Code and its regulations, then Tenant shall enter into any
reasonable amendment proposed by Landlord to avoid such income, so long as the
amendment does not increase the amount that would otherwise be payable by Tenant
under this Lease or require Tenant to accept fewer services from Landlord than
this Lease provides. Landlord shall reimburse Tenant for reasonable legal fees
incurred by Tenant to review such amendment, which reimbursement not to exceed
$1,500.00.”   3.03.      Parking. Effective as of date of this Second Amendment,
Section 2.02 of Exhibit E of the Lease, as amended by Section 11.01.B. of the
First Amendment, is further amended by deleting (i) the amount “210.00” and
replacing it with the amount “$260.00, and (ii) the amount “260.00” and
replacing the amount with “$290.00”.   3.04.      Deleted Provisions. Section
11.02 (Right of First Offer) of First Amendment and Section 5 (Right of First
Offer) of Exhibit E of the Lease are hereby deleted in their entirety and are of
no further force and effect.   3.05.      Roof Signs. Effective as of the date
of this Second Amendment, Section 11.03 (Signage) of First Amendment is hereby
amended by deleting any references to the Roof Signs. If Tenant has installed
such Roof Signs then effective as of the date of this Second Amendment Tenant
shall remove such Roof Signs in accordance with the terms of the Lease.   3.06. 
    Storage and Facility Space. Effective as of the date of this Second
Amendment, the definition of “Premises” shall be amended to clarify that
“Tenant’s proportionate share of the Ph Treatment Room on the first floor of the
Science Building and Tenant’s proportionate share of the 3A Annex Space in the
Science Building” means and includes Rooms 3300, 3103 and 3104 located in the
annex of the third floor of the Building and the space currently made available
 

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  to Tenant in the water treatment facility located on the first floor of the
Building (the “Current Storage and Facility Space”). The Current Storage and
Facility Space shall remain the same throughout the Term and shall be unaffected
by the termination of Reduction Space 1 and/or the Reduction Space 2.   4.     
Letter of Credit. The parties agree that Landlord is currently holding a Letter
of Credit in the amount of $4,000,000.00. The parties agree that the Lease shall
be amended with respect to the Letter of Credit as follows:     4.01.     
Effective as of the date of this Second Amendment, Section 6 (Letter of Credit)
of the First Amendment shall be deleted in its entirety.     4.02.     
Effective as of the date of this Second Amendment, Section 1.01 (General
Provisions) of Exhibit E (Additional Provisions) to the Lease is hereby amended
as follows: (i) the words “in the face amount of $2,500,000.00 (the “Letter of
Credit Amount”)” shall be deleted in their entirety and replaced with the
following words “in the face amount of $4,000,000.00 (the “Letter of Credit
Amount”)” and (ii) the number “120” in the 13th line is hereby deleted and
replaced with “60”.     4.03.      Effective as of the date of this Second
Amendment, Section 1.06 (Reduction of Letter of Credit Amount) of Exhibit E
(Additional Provisions) to the Lease is hereby amended as follows: the words
“then Tenant may reduce the Letter of Credit Amount as follows: (i)
$2,000,000.00 effective as of the third anniversary of the Lab Space
Commencement Date; (ii) $1,625,000.00 effective as of the fourth anniversary of
the Lab Space Commencement Date; (iii) $1,250,000.00 effective as of the fifth
anniversary of the Lab Space Commencement Date;      (iv)      $875,000.00
effective as of the sixth anniversary of the Lab Space      Commencement Date;
and (v) $500,000.00 effective as of the seventh anniversary of the Lab Space
Commencement Date.” shall be deleted in their entirety and replaced with the
following words:      “then Tenant may reduce the Letter of Credit Amount to the
following amounts:      (i)      $2,500,000.00 effective as of December 1, 2009;
(ii) $1,800,000.00 effective as of December 1, 2010; (iii) $1,200,000.00
effective as of December 1, 2011; and (iv) $800,000.00 effective as of December
1, 2012.”     4.04.      Tenant shall maintain and keep in effect during the
remainder of the Extended Term the Letter of Credit that Tenant provided in
connection with the execution of the Lease. If at any time during the Term (as
the same may be extended) Landlord reasonably determines that the financial
condition of the issuing bank is such that Landlord’s ability to draw upon the
Letter of Credit is, or in the future may be, impaired, restricted, refused or
otherwise affected, then Tenant shall, within 10 business days of Landlord’s
written request to Tenant, obtain a renewal or replacement Letter of Credit in
form acceptable to Landlord in substitution of the then current Letter of Credit
from an issuing bank acceptable to Landlord in Landlord’s reasonable discretion.
S   5.      Contingency. If Section 2 is deemed null and void pursuant to
Section 2.01.D. with respect to Reduction Space 2, then all Sections of the
Second Amendment other than Section 1, Sections 3.01, 3.02, 3.03 and 3.06,
Section 4.04, Section 5, and the first   8       

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  sentence of Section 7 shall be null and void and of no force or effect, and
the Lease shall continue in full force and effect as if the voided sections of
this Second Amendment had not been a part of this Second Amendment.   6.     
Representations. Each party represents to the other that it has full power and
authority to execute this Second Amendment and that no consent or approval of
any third party is required to enter into this Second Amendment. Tenant
represents that it has not made any assignment, sublease, transfer, conveyance
of the Lease or any interest therein or in Reduction Space 1 and Reduction Space
2 other than those explicitly recited herein and further represents that it has
no knowledge of any claim, demand, obligation, liability, action or cause of
action by any other party respecting, relating to or arising out of Reduction
Space 1 and Reduction Space 2, and Tenant agrees to indemnify and hold harmless
Landlord and the Landlord Related Parties from all liabilities, expenses,
losses, claims, demands, judgments, damages or costs, including without
limitation, reasonable attorneys’ fees, arising from (i) any breach of any of
the foregoing representations or (ii) to the extent Tenant would be obligated to
so indemnify and hold Landlord and/or any of the Landlord Related Parties
harmless under the terms of the Lease, any claim, demand, obligation, liability,
action or cause of action by any other party hereafter made respecting, relating
to or arising out of Reduction Space 1 and/or Reduction Space 2.     Tenant
acknowledges that Landlord will be relying on this Second Amendment in entering
into leases for Reduction Space 1 and Reduction Space 2 with other parties.  
7.      Miscellaneous.     7.01.      The Lease as amended by this Second
Amendment and the attached exhibits, which are hereby incorporated into and made
a part of this Second Amendment, set forth the entire agreement between the
parties with respect to the matters set forth herein. This Second Amendment
shall be binding upon and shall inure to the benefit of Landlord and Tenant and
their respective legal representatives, successors and assigns. There have been
no additional oral or written representations or agreements. Under no
circumstances shall Tenant be entitled to any Rent abatement, improvement
allowance, leasehold improvements, or other work to the Premises, or any similar
economic incentives that may have been provided to Tenant in connection with
entering into the Lease, unless specifically set forth in this Second Amendment.
Except as required by Law or the Securities Exchange Commission rules and
regulations, Tenant agrees that neither Tenant nor its agents or any other
parties acting on behalf of Tenant shall disclose any matters set forth in this
Second Amendment or disseminate or distribute any information concerning the
terms, details or conditions hereof to any person, firm or entity (other than to
Tenant’s agents and other parties acting on behalf of Tenant without obtaining
the express written consent of Landlord.     7.02.      Except as herein
modified or amended, the provisions, conditions and terms of the Lease shall
remain unchanged and in full force and effect.     7.03.      In the case of any
inconsistency between the provisions of the Lease and this Second Amendment, the
provisions of this Second Amendment shall govern and control.     7.04.     
Submission of this Second Amendment either party is not an offer to enter into
this Second Amendment but rather is a solicitation for such an offer. Neither  

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  Landlord nor Tenant shall not be bound by this Second Amendment until both
Landlord and Tenant have executed and delivered the same to the other. Tenant
agrees that its execution of this Second Amendment constitutes a firm offer to
enter the same, which may not be withdrawn for a period of 5 business days after
delivery to Landlord (or such other period as may be expressly provided in any
other agreement signed by the parties).   7.05.      The capitalized terms used
in this Second Amendment shall have the same definitions as set forth in the
Lease to the extent that such capitalized terms are defined therein and not
redefined in this Second Amendment.   7.06.      Tenant hereby represents to
Landlord that Tenant has dealt with no broker, agent or finder in connection
with this Second Amendment, other than the Tenant’s broker, Richards, Barry,
Joyce and Partners (“Tenant’s Broker”).     Tenant agrees to indemnify and hold
Landlord, its members, managers, principals, beneficiaries, partners, officers,
directors, employees, mortgagee(s) and agents, and the respective principals and
members of any such agents (collectively, the “Landlord Related Parties”)
harmless from all claims of any brokers claiming to have represented Tenant in
connection with this Second Amendment including Tenant’s Broker. Landlord hereby
represents to Tenant that Landlord has dealt with no broker, agent or finder in
connection with this Second Amendment other than Tenant’s Broker. Landlord
agrees to indemnify and hold Tenant, its members, managers, principals,
beneficiaries, partners, officers, directors, employees, and agents, and the
respective principals and members of any such agents harmless from all claims of
any brokers claiming to have represented Landlord in connection with this Second
Amendment.   7.07.      Intentionally omitted.   7.08.      This Second
Amendment may be executed in counterparts and shall constitute an agreement
binding on all parties notwithstanding that all parties are not signatories to
the original or the same counterpart provided that all parties are furnished a
copy or copies thereof reflecting the signature of all parties. Transmission of
a facsimile or by email of a pdf copy of the signed counterpart of this Second
Amendment shall be deemed the equivalent of the delivery of the original, and
any party so delivering a facsimile or pdf copy of the signed counterpart of
this Second Amendment by email transmission shall in all events deliver to the
other party an original signature promptly upon request.   7.09.     
NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN THIS SECOND AMENDMENT OR
THE LEASE, THE LIABILITY OF LANDLORD     (AND OF ANY SUCCESSOR LANDLORD) SHALL
BE LIMITED TO THE LESSER OF (A) THE INTEREST OF LANDLORD IN THE PROPERTY, OR (B)
THE EQUITY INTEREST LANDLORD WOULD HAVE IN THE PROPERTY IF THE PROPERTY WERE
ENCUMBERED BY THIRD PARTY DEBT IN AN AMOUNT EQUAL TO 70% OF THE VALUE OF THE
PROPERTY. TENANT SHALL LOOK SOLELY TO LANDLORD’S INTEREST IN THE PROPERTY FOR
THE RECOVERY OF ANY JUDGMENT OR AWARD AGAINST LANDLORD OR ANY LANDLORD RELATED
PARTY. NEITHER LANDLORD NOR ANY LANDLORD RELATED PARTY SHALL BE PERSONALLY
LIABLE FOR ANY JUDGMENT OR DEFICIENCY, AND IN NO EVENT SHALL LANDLORD OR  

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ANY LANDLORD RELATED PARTY BE LIABLE TO TENANT FOR ANY LOST PROFIT, DAMAGE TO OR
LOSS OF BUSINESS OR ANY FORM OF SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGE.
BEFORE FILING SUIT FOR AN ALLEGED DEFAULT BY LANDLORD, TENANT SHALL GIVE
LANDLORD AND THE MORTGAGEE(S) WHOM TENANT HAS BEEN NOTIFIED HOLD MORTGAGES,
NOTICE AND REASONABLE TIME TO CURE THE ALLEGED DEFAULT. WITHOUT LIMITING THE
FOREGOING, IN NO EVENT SHALL LANDLORD OR ANY MORTGAGEES OR LANDLORD RELATED
PARTIES EVER BE LIABLE FOR ANY CONSEQUENTIAL OR INCIDENTAL DAMAGES OR ANY LOST
PROFITS OF TENANT.

[SIGNATURE ARE ON FOLLOWING PAGE]

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     IN WITNESS WHEREOF, Landlord and Tenant have duly executed this Second
Amendment under seal in two or more counterparts as of the day and year first
above written.

LANDLORD:          MA-RIVERVIEW/245 FIRST STREET,    L.L.C.,    A  Delaware
limited liability company          By: Illegible          Name:          Title: 
        Date: August 3, 2009         

TENANT:          COMBINATORX, INCORPORATED,    a    Delaware  corporation       
  By:    /s/ Robert Forrester          Name:    Robert Forrester         
Title:    Interim President and CEO          Date: July 6, 2009         

12

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EXHIBIT A

FORM OF SUITE 1600 BILL OF SALE

This Exhibit is attached to and made a part of the Second Amendment by and
between

MA-RIVERVIEW/245 FIRST STREET, L.L.C., a Delaware limited liability company

(“Landlord”) and COMBINATORX, INCORPORATED, a Delaware corporation (“Tenant”)
for space in the Building located at 245 First Street, Cambridge, Massachusetts
02142.

SUITE 1600 BILL OF SALE

     Seller, COMBINATORX, INCORPORATED, a Delaware corporation, having its
principal place of business at 245 First Street, Suite 300, Cambridge,
Massachusetts 02142, in consideration of $1.00 and other valuable consideration,
receipt and sufficiency whereof is hereby acknowledged, does hereby sell,
assign, transfer and set over to Buyer, MA-RIVERVIEW/245 FIRST STREET, L.L.C., a
Delaware limited liability company, the personal property described on Schedule
1 attached hereto (collectively, the “Suite 1600 Personal Property”) located in,
or otherwise servicing, Suite No. 1600 located on the 16th floor of the building
commonly known as 245 First Street located at 245 First Street, Cambridge,
Massachusetts 02142.

     Seller hereby represents and warrants to Buyer that Seller is the absolute
owner of said Suite 1600 Personal Property, that said Suite 1600 Personal
Property is free and clear of all liens, charges and encumbrances, and that
Seller has full right, power and authority to sell said Suite 1600 Personal
Property and to make this bill of sale. ALL WARRANTIES OF QUALITY, CONDITION,
FITNESS OF USE, AND MERCHANTABILITY ARE HEREBY EXCLUDED AND BUYER ACCEPTS THE
SUITE 1600 PERSONAL PROPERTY IN ITS “AS IS” / “WHERE IS” CONDITION.

     If this bill of sale is signed by more than one person, all persons so
signing shall be jointly and severally bound hereby.

IN WITNESS WHEREOF, Seller has caused this bill of sale to be signed and sealed
in

its name by its officers thereunto duly authorized this    day of    , 2009. 
SELLER:              COMBINATORX,    INCORPORATED, a Delaware         
corporation              By:              Name:              Title:             

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Commonwealth of Massachusetts          Middlesex, ss.              On this   
day of         , 2009,    before me, the undersigned notary  public, personally
appeared    , the                                                               
       of 

CombinatoRx, Incorporated, proved to me through satisfactory evidence of
identification, which

was    , to be the person whose name is signed on the preceding or attached 
document, and acknowledged to me that he signed it, as    of  CombinatoRx,
Incorporated, voluntarily for its stated purpose.     

Notary Public
___________________________

My commission expires
___________________

14

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SCHEDULE 1

LIST OF SUITE 1600 PERSONAL PROPERTY

                                 ITEM DESCRIPTION    QUANTITY 

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

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  3 drawer all wood filing cabinet    8 

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3 drawer wood top metal filing cabinet    9 

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5 drawer metal filing cabinet    8 

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2 drawer metal filing cabinet    12 

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

2 drawer wood top metal filing cabinet    3 

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

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

2 drawer wood front/top filing cabinet    7 

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wooden front PED    36 

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guest chairs (wooden and plastic arms)    113 

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conference room tables    5 

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small metal bookcase    19 

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large metal bookcase    13 

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cafeteria tables    10 

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cafeteria chairs    80 

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bar stools    11 

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round wooden office tables    4 

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dishwasher    1 

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small dairy refrigerator    2 

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toaster oven    1 

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cubicles    30 

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window cubicles    7 

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offices    27 

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shared offices    4 

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

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hoteling space (3+ seats)    1 

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video conferencing equipment    1 

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IT rack    1 

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projectors and screens    5 

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

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EXHIBIT B

FORM OF SUITE 400 BILL OF SALE

This Exhibit is attached to and made a part of the Second Amendment by and
between

MA-RIVERVIEW/245 FIRST STREET, L.L.C., a Delaware limited liability company

(“Landlord”) and COMBINATORX, INCORPORATED, a Delaware corporation (“Tenant”)
for space in the Building located at 245 First Street, Cambridge, Massachusetts
02142.

SUITE 400 BILL OF SALE

     Seller, COMBINATORX, INCORPORATED, a Delaware corporation, having its
principal place of business at 245 First Street, Suite 300, Cambridge,
Massachusetts 02142, in consideration of $1.00 and other valuable consideration,
receipt and sufficiency whereof is hereby acknowledged, does hereby sell,
assign, transfer and set over to Buyer, MA-RIVERVIEW/245 FIRST STREET, L.L.C., a
Delaware limited liability company, the personal property described on Schedule
1 attached hereto (collectively, the “Suite 400 Personal Property”) located in,
or otherwise servicing, Suite No. 400 located on the 4th floor of the building
commonly known as 245 First Street located at 245 First Street, Cambridge,
Massachusetts 02142.

     Seller hereby represents and warrants to Buyer that Seller is the absolute
owner of said Suite 400 Personal Property, that said Suite 400 Personal Property
is free and clear of all liens, charges and encumbrances, and that Seller has
full right, power and authority to sell said Suite 400 Personal Property and to
make this bill of sale. ALL WARRANTIES OF QUALITY, CONDITION, FITNESS OF USE,
AND MERCHANTABILITY ARE HEREBY EXCLUDED AND BUYER ACCEPTS THE SUITE 400 PERSONAL
PROPERTY IN ITS “AS IS” / “WHERE IS” CONDITION.

     If this bill of sale is signed by more than one person, all persons so
signing shall be jointly and severally bound hereby.

     IN WITNESS WHEREOF, Seller has caused this bill of sale to be signed and
sealed in its name by its officers thereunto duly authorized this day of , 2009.

SELLER:

COMBINATORX, INCORPORATED, a Delaware corporation

By:
_____________________________________
Name:
__________________________________
Title:
____________________________________

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Commonwealth of Massachusetts          Middlesex, ss.              On this   
day of         , 2009,    before me, the undersigned notary  public, personally
appeared    , the                                                               
       of 

CombinatoRx, Incorporated, proved to me through satisfactory evidence of
identification, which

was    , to be the person whose name is signed on the preceding or attached 
document, and acknowledged to me that he signed it, as    of  CombinatoRx,
Incorporated, voluntarily for its stated purpose.     

Notary Public
___________________________

My commission expires
___________________

17

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SCHEDULE 1

LIST OF SUITE 400 PERSONAL PROPERTY

                                 ITEM DESCRIPTION    QUANTITY 

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

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

  3 drawer wood top metal filing cabinet    4 

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

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

5 drawer metal filing cabinet    1 

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

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

2 drawer metal filing cabinet    1 

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

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

2 drawer wood top metal filing cabinet    5 

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

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

guest chairs (wooden and plastic arms)    36 

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

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

conference room tables    1 

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

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

large metal bookcase    2 

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

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

round wooden office tables    1 

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

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small dairy refrigerator    3 

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

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cubicles    12 

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

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offices    4 

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

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shared offices    6 

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carrels    18 

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

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projectors and screens    1 

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

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Metal pedestal small mobile files cabinets    18 

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Animal storage racks    9 

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cold room    1 

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cage washer    1 

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autoclave    2 

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

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necropsy table    1 

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duplex work bench (stay clean) ventilated    1 

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

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fume hood    4 

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cable trays in server room    all 

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glass wash machine    1 

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18

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