Exhibit 10.9


Momenta
Pharmaceuticals, Inc.


Nonstatutory Stock Option Agreement

Granted Under 2004 Stock Incentive Plan, as amended


1.             Grant of Option.


This agreement evidences
the grant by Momenta Pharmaceuticals, Inc., a Delaware corporation (the “Company”),
on August 22, 2006 (the “Grant
Date”) to Craig Wheeler, the Company’s President
as of such date and Chief Executive Officer as of September 12, 2006 (the “Participant”),
of an option to purchase, in whole or in part, on the terms provided herein and
in the Company’s 2004 Stock Incentive Plan, as amended (the “Plan”), a total of
355,223 shares (the “Shares”) of common stock, $0.0001 par
value per share, of the Company (“Common Stock”) at $16.18 per Share.  Unless earlier terminated, this option shall
expire at 5:00 p.m., Eastern time, on August 21, 2016 (the
“Final Exercise Date”).


It is intended that the
option evidenced by this agreement shall not be an incentive stock option as
defined in Section 422 of the Internal Revenue Code of 1986, as amended, and
any regulations promulgated thereunder (the “Code”).  Except as otherwise indicated by the context,
the term “Participant”, as used in this option, shall be deemed to include any
person who acquires the right to exercise this option validly under its terms.


2.             Vesting Schedule.


Subject to the
acceleration provisions set forth in that certain Employment Agreement, dated
August 22, 2006, between the Company and the Participant (the “Employment
Agreement”), this option will become exercisable (“vest”) as to (i) 25% of the
original number of Shares on August 22, 2007 and (ii) as to an additional 6.25%
of the original number of Shares at the end of each successive three-month period
following August 22, 2007 until the fourth anniversary of the Grant Date.


The right of exercise
shall be cumulative so that to the extent the option is not exercised in any
period to the maximum extent permissible it shall continue to be exercisable,
in whole or in part, with respect to all Shares for which it is vested until
the earlier of the Final Exercise Date or the termination of this option under
Section 3 hereof or the Plan.


3.             Exercise of Option.


(a)           Form
of Exercise.  Each election to
exercise this option shall be by written notice in the form attached hereto as Exhibit
A, signed by the Participant, and received by the Company at its principal
office, accompanied by this agreement, and payment in full in the manner
provided in the Plan.  The Participant
may purchase less than the number of shares covered hereby, provided that no
partial exercise of this option may be for any fractional share.


(b)           Continuous Relationship with the
Company Required.  Except as
otherwise provided in this Section 3, this option may not be exercised
unless the Participant, at the time he exercises this option, is, and has been
at all times since the Grant Date, an employee, officer or









 



director of, or
consultant or advisor to, the Company or any other entity the employees,
officers, directors, consultants, or advisors of which are eligible to receive
option grants under the Plan (an “Eligible Participant”).


(c)           Termination
of Relationship with the Company. 
Subject to the provisions set forth in the Employment Agreement, if the
Participant ceases to be an Eligible Participant as a result of:


(1)           voluntary
resignation of his employment from the Company other than for “Good Reason” (as
defined in the Employment Agreement), then, except as provided in
paragraphs (d) and (e) below, the right to exercise this option shall
terminate three months after such cessation
(but in no event after the Final Exercise Date), provided  that
this option shall be exercisable only to the extent that the Participant was
entitled to exercise this option on the date of such cessation; or


(2)           termination
by Participant of his employment with the Company for “Good Reason” (as defined
in the Employment Agreement) or termination of Participant’s employment by the
Company without “cause” (as defined in the Employment Agreement), then, except
as provided in paragraphs (d) and (e) below, the right to exercise this
option shall terminate one year after such cessation (but in no event after the
Final Exercise Date), provided  that this option shall be
exercisable only to the extent that the Participant was entitled to exercise
this option on the date of such cessation.


Notwithstanding
the foregoing, if the Participant, prior to the Final Exercise Date, violates
the non-competition or confidentiality provisions of any employment contract,
confidentiality and nondisclosure agreement or other agreement between the
Participant and the Company, the right to exercise this option shall terminate
immediately upon written notice to the Participant from the Company describing
such violation.


(d)           Exercise
Period Upon Death or Disability. 
Subject to the provisions set forth in the Employment Agreement, if the
Participant dies or becomes disabled (within the meaning of
Section 22(e)(3) of the Code) prior to the Final Exercise Date while he is
an Eligible Participant and the Company has not terminated such relationship
for “cause” as specified in paragraph (e) below, this option shall be
exercisable, within the period of one year following the date of death or
disability of the Participant, by the Participant (or in the case of death by
an authorized transferee), provided  that this option shall be
exercisable only to the extent that this option was exercisable by the
Participant on the date of his or her death or disability, and further provided
that this option shall not be exercisable after the Final Exercise Date.


(e)           Discharge
for Cause.  If the Participant, prior
to the Final Exercise Date, is discharged by the Company for “cause” (as
defined in the Employment Agreement ), the right to exercise this option shall
terminate immediately upon the effective date of such discharge.


4.             Withholding.


No Shares will be issued pursuant to the exercise of this option unless
and until the Participant pays to the Company, or makes provision satisfactory
to the Company for payment



 2
 






 



of, any federal,
state or local withholding taxes required by law to be withheld in respect of
this option.


5.             Nontransferability of Option.


This option may not be
sold, assigned, transferred, pledged or otherwise encumbered by the
Participant, either voluntarily or by operation of law, except by will or the
laws of descent and distribution, and, during the lifetime of the Participant,
this option shall be exercisable only by the Participant.


6.             Provisions of the Plan.


This option is subject to
the provisions of the Plan, a copy of which is furnished to the Participant
with this option.


IN WITNESS WHEREOF, the
Company has caused this option to be executed under its corporate seal by its
duly authorized officer.  This option
shall take effect as a sealed instrument.


	
  

  	
  MOMENTA PHARMACEUTICALS, INC.

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Dated: August
  22, 2006

  	
  By:

  	
    /s/ Richard P. Shea

  	
   

  	
   

  
	
   

  	
   

  	
  Richard P. Shea

  	
   

  	
   

  
	
   

  	
   

  	
  Vice President, Chief Financial Officer

  



 



 3
 






 



 


PARTICIPANT’S ACCEPTANCE


The undersigned hereby accepts the foregoing option
and agrees to the terms and conditions thereof. 
The undersigned hereby acknowledges receipt of a copy of the Company’s
2004 Stock Incentive Plan, as amended.


	
  

  	
  PARTICIPANT:

  
	
   

  	
   

  
	
   

  	
   

  
	
   

  	
   

  	
  /s/ Craig A. Wheeler

  
	
   

  	
   

  	
   

  
	
   

  	
  Address:

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  
					



 



 4














 


EXHIBIT A


NOTICE OF STOCK OPTION EXERCISE


Date:                           


Participant name and address:


                                             


                                             


                                             


 


Attention:  Treasurer


Dear Sir or Madam:


I am the holder of an
Nonstatutory Stock Option granted to me under the Momenta Pharmaceuticals, Inc.
(the “Company”) 2004 Stock Incentive Plan, as amended, on                     
for the purchase of                    
shares of Common Stock of the Company at a purchase price of $                 
per share.


I hereby exercise my
option to purchase                 
shares of Common Stock (the “Shares”), for which I have enclosed                      
in the amount of $                 .  Please register my stock certificate as
follows:


	
  

  	
   

  	
   

  	
  (check applicable box)

  
	
   

  	
   

  	
   

  	
   

  
	
  Name(s):

  	
   

  	
   

  	
  o

  	
  TEN COM

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
  o

  	
  TEN ENT

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Address:

  	
   

  	
   

  	
  o

  	
  JT TEN

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  Tax I.D. #:

  	
   

  	
   

  	
  o

  	
  UNIF GIFT MIN ACT

  



 


I represent, warrant and covenant as follows:


1.             I
am purchasing the Shares for my own account for investment only, and not with a
view to, or for sale in connection with, any distribution of the Shares in
violation of the Securities Act of 1933 (the “Securities Act”), or any rule or
regulation under the Securities Act.









 



 


2.             I have had such opportunity as I have deemed adequate to
obtain from representatives of the Company such information as is necessary to
permit me to evaluate the merits and risks of my investment in the Company.


3.             I have sufficient experience in business, financial and
investment matters to be able to evaluate the risks involved in the purchase of
the Shares and to make an informed investment decision with respect to such
purchase.


4.             I can afford a complete loss of the value of the Shares
and am able to bear the economic risk of holding such Shares for an indefinite
period.


	
  Very truly yours,

  
	
   

  
	
   

  
	
   

  	
   

  
	
  (Signature)

  



 



 6