Exhibit
10.2


FIRST
AMENDMENT TO LEASE


THIS FIRST AMENDMENT TO LEASE (this “First Amendment”)
is dated as of May 16, 2006, between CARRAMERICA REALTY, L.P., a Delaware
limited partnership (“Landlord”) and METABASIS
THERAPEUTICS, INC., a Delaware corporation (“Tenant”).


A.                                   Landlord
and Tenant are parties to that certain Lease dated as of December 21, 2004 (the
“Lease”), with respect to certain premises (the “Premises”) located at 11119
North Torrey Pines Road, San Diego, California (the “Building”), pursuant to
which Landlord leased to Tenant 81,816 rentable square feet in the Building, as
more particularly identified in the Lease. 
Initially capitalized terms not specifically defined herein shall have
the meanings set forth in the Lease.


B.                                     Landlord
and Tenant desire to amend the Lease in order to confirm the terms of the Lease
relating to the Additional Allowance, as defined in Section 3 of Appendix C to
the Lease.


NOW THEREFORE, in consideration of the foregoing
recitals, the mutual covenants and agreements contained herein, and for other
good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, Landlord and Tenant agree, and amend the Lease as follows:


1.                                       Effective
Date.  This First Amendment shall be
deemed effective as of the date first written above (the “Effective Date”).


2.                                       Additional
Allowance.  Reference is made to
Section 3 of Appendix C of the Lease, in which the following provision appears
(such provision repeated here for convenience of reference):


“Landlord further agrees to make available up to $245,448 ($3 per
rentable square foot) (“Additional Allowance”) to Tenant to pay for any Change
Orders approved by Tenant in accordance with Section 2, provided that (a) the
actual amount of the Additional Allowance utilized by Tenant shall be amortized
over the Term with interest at 8%, and added to the Monthly Base Rent paid by
Tenant under the Lease; and (b) prior to the Rent Commencement Date, Landlord
and Tenant shall execute an amendment to this Lease to reflect any such
adjustment in the Monthly Base Rent.”


Landlord and Tenant hereby acknowledge that the actual
amount of the Additional Allowance utilized by Tenant was $300,000, and the
parties agree that the Lease is amended accordingly.  Further, the parties agree that the monthly
amortized amount of the Additional Allowance is $3,639, and such amount shall
be payable in the same manner and at the same time as Base Rent.  Landlord further acknowledges Tenant has paid
such amount each month from November 1, 2005 through the Effective Date.


3.                                       Rent
Commencement Date.  Item 10 of the
Schedule to the Lease is hereby amended so that the “Second Rent Commencement
Date” shall mean the first day of the 25th









 



month following the Rent Commencement Date, and the “Third
Rent Commencement Date” shall mean the first day of the 43rd month following the Rent Commencement Date.


4.                                       Counterparts.  This First Amendment may be executed in any
number of counterparts, each of which when so executed and delivered shall be
deemed to be an original and all of which counterparts taken together shall
constitute but one and the same instrument. 
Signature pages may be detached from the counterparts and attached to a
single copy of this First Amendment to physically form one document.


5.                                       Brokers.  Each party (each, the “Indemnifying Party”)
represents to the other party that it has dealt with no brokers in connection
with this First Amendment.  The
Indemnifying Party hereby agrees to indemnify, defend and hold harmless the
other party from claims through the Indemnifying Party by any broker for a
commission or other fee arising out of this First Amendment.


6.                                       Reaffirmation
of Obligations.  Landlord and Tenant
hereby acknowledge and reaffirm all of the terms of the Lease, as such Lease
has been amended by this First Amendment, and agrees that any reference made in
any other document to the Lease shall mean the Lease as amended pursuant to
this First Amendment.  Except as
expressly provided herein, the Lease remains unmodified and in full force and
effect.


7.                                       Miscellaneous.   The agreements, conditions and provisions
herein contained shall apply to and bind the heirs, executors, administrators,
successors and assigns of the parties hereto.  
If any provisions of this First Amendment or the Lease shall be
determined to be illegal or unenforceable, such determination shall not affect
any other provision of the Lease or this First Amendment and all such other
provisions shall remain in full force and effect.  If there is any inconsistency between the
provisions of this First Amendment and the other provisions of the Lease, the
provisions of this First Amendment shall control with respect to the subject
matter of this First Amendment.  This
First Amendment shall be construed in accordance with the laws of the state of
California.  This First Amendment
constitutes a part of the Lease and is incorporated by this reference.


SIGNATURES APPEAR ON FOLLOWING PAGE



 2














 


IN WITNESS WHEREOF, Landlord and Tenant have caused
this First Amendment to be duly executed and delivered as of the date first
above written.


“Landlord”


CARRAMERICA
REALTY, L.P.,

a Delaware limited partnership


	
  By:

  	
  CarrAmerica Realty GP Holdings, LLC,

  	
   

  
	
   

  	
  a Delaware limited liability company,

  	
   

  
	
   

  	
  its general partner

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
  CarrAmerica Realty Operating Partnership, L.P.,

  	
   

  
	
   

  	
  a Delaware limited partnership,

  	
   

  
	
   

  	
  its sole member

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
  CarrAmerica Realty Corporation,

  	
   

  
	
   

  	
  a Maryland corporation,

  	
   

  
	
   

  	
  its general partner

  	
   

  



 


	
  By:

  	
  /s/ W.M. O’Donnell, JR

  	
   

  
	
  Print Name:

  	
  W.M. O’Donnell, JR

  	
   

  
	
  Print Title:

  	
  Managing Director

  	
   

  
					



 


“Tenant”


METABASIS
THERAPEUTICS, INC.,

a California corporation


	
  By:

  	
  /s/ John W. Beck

  	
   

  
	
  Print Name:

  	
  John W. Beck

  	
   

  
	
  Print Title:

  	
  Senior VP Finance and CFO