Exhibit 10.29


 


***Text Omitted and Filed Separately


with the Securities and Exchange Commission.


Confidential Treatment Requested


Under 17 C.F.R. Sections 200.80(b)(4)


and 240.24b-2.


 


August 29, 2005


 


Metabasis Therapeutics, Inc.


9390 Towne
Centre Drive, Suite 300


San Diego, CA 92121


 


Re:          Exclusive
License and Research Collaboration Agreement dated as of December 23,
2003, as amended prior to the date hereof (as so amended. the “Collaboration
Agreement”) between Merck & Co., Inc. (“Merck”) and Metabasis Therapeutics,
Inc. (“Metabasis”)


 


Ladies and Gentlemen:


 


This Letter (this “Letter”)
will confirm the understanding of Merck and Metabasis regarding certain matters
relating to the Collaboration Agreement and is intended to be legally binding
on both parties. Capitalized terms used but not otherwise defined in this Letter shall have the meanings
provided in the Collaboration Agreement. Pursuant to this Letter the Parties
hereby agree to amend the Agreement as follows:


 


1.         The
definition of “Merck HCV Compound” set forth in Section 1.35 of the Agreement,
is hereby amended and restated in its entirety as follows: ““Merck HCV Compound” shall mean (a) any of the [***] on Part
A of Schedule I to the Research Plan; (b) any of the
Designated Compounds; and/or (c) any [***] and/or any [***] HepDirect
Technology or [***] Technology), [***] of the [***] listed under [***] on Part
A of Schedule I.”


 


2.         The definition of “Collaboration Compound”
set forth in Section 1.5 of the Agreement is hereby amended and restated in its
entirety: “Collaboration Compound” shall
mean a chemical entity that is synthesized solely by a Party or jointly by the
Parties prior to or in the course of the Research Program, or prior to the [***]
of the expiration or termination of the Research Program Term, that is (a) any [***]
that [***] incorporates HepDirect Technology; (b) any [***] of a [***] that [***]
incorporates HepDirect Technology; (c) any [***] that does not [***]
incorporate HepDirect Technology; and/or (d) any [***]  listed under numbers [***]  on Part A of Schedule I, whether or not they incorporate HepDirect Technology or [***]  Technology.”


 


3.         Schedule I
Part A is hereby amended to list Merck HCV Compound [***]  having the following structural formula:


 






***Confidential Treatment Requested


 


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[***]


 


[***]


 


4.         The Research Plan has been modified and is
fully set forth in its entirety in its current form in Exhibit A to this Letter;
(provided that Schedules II,
III, IV and V
to the Research Plan shall remain in the forms in effect immediately prior to
the effective date of this Letter Agreement;


 


5.         Metabasis acknowledges and agrees that Merck’s
representation and warranty under Section 6.2(c) of the Agreement extends only
to “Merck HCV Compounds” as defined in the Agreement as it existed on the
Effective Date;


 


6.         This Letter shall
become effective as of the date first written above. Except as amended by this
Letter, together with the Schedules and Exhibits attached hereto, the terms and
conditions of the Collaboration Agreement shall remain in full force and effect
in all other respects, unless further amended by written agreement in
accordance with Section 11.7 of the Collaboration Agreement. On and after the
effectiveness of this Letter, each reference in the Agreement to “this
Agreement”, “hereunder”, “hereof”, “herein” or words of like import referring
to the Collaboration Agreement shall mean and be a reference to the
Collaboration Agreement as amended by this Letter. The Parties hereby further
agree that the terms and conditions set forth in Article 11 of the
Collaboration Agreement, including without limitation the Assignment and Change
of Control provisions of Section 11.2, the Applicable Law provisions of Section
11.5 and the Dispute Resolution provisions of Section 11.6, shall apply to this
Letter as if fully set forth herein; and


 


7.         This Letter may be executed (including,
without limitation, by facsimile signature) in two counterparts, each of which
shall be deemed an original, but both of which together shall constitute one
and the same instrument.


 






***Confidential Treatment Requested


 


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If the foregoing is
acceptable to you, please sign this Letter
in the space provided below and return it to me.


 


	
   

  	
  Sincerely,

  
	
   

  	
   

  
	
   

  	
  MERCK
  & CO., INC.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Mervyn J.
  Turner

  
	
   

  	
  Name:

  	
  M.J. Turner,
  Ph.D.

  
	
   

  	
  Title:

  	
  Senior Vice
  President

  
	
   

  	
   

  	
  Worldwide
  Licensing and External

  
	
   

  	
   

  	
  Research

  



 


Agreed to
and accepted as of the date first set forth above:


 


METABASIS
THERAPEUTICS, INC.


 


 


 


	
  By:

  	
  /s/ Ed
  Baracchini

  	
   

  
	
  Name:

  	
  Ed Baracchini,
  Ph.D., MBA

  	
   

  
	
  Title:

  	
  Vice President,
  Business Development

  	
   

  



 


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EXHIBIT A


 


Amended
Research Plan


 


The Research Plan may be revised to [***]
subject to mutual agreement by the Parties and subject to availability of FTEs
within the Research Program as described in the Agreement.


 


During the [***]
of the Research Program [***]
In summary, over [***]. One of the most
interesting [***] which was found to
be [***]. When the compound was [***] at the same time the [***]. Thus the [***]. A series of [***] was observed. [***] was seen, suggesting a [***].


 


[***] 
Interestingly, the [***]
On the basis of [***] As an additional
control [***].


 


[***]


 


[***]


 


 


After [***]to the Research Program Metabasis [***] HepDirect prodrugs [***].


 


Merck assessed [***]. However, it was determined by [***].


 


[***]


 


During the last [***]the following are the high priority
objectives for the collaboration:


 


•                  Merck will analyze [***] and
determine if [***].
Metabasis will prepare [***] and the
[***]
in an attempt [***].


 


•                  In
the event that a [***] or [***].


 


•                  Merck will supply Metabasis [***].


 


•                  Metabasis
will prepare [***].


 


•                  Assuming [***] Merck will [***].


 


[***]


 






***Confidential Treatment Requested