EX-10.4



 Exhibit 10.4 

CYTOMX THERAPEUTICS, INC. 

STOCK OPTION AGREEMENT 

(2010 Stock Incentive Plan) 

THIS STOCK OPTION AGREEMENT (the “Agreement”) confirms that CYTOMX THERAPEUTICS, INC., a Delaware corporation
(the “Company”), has granted to the employee identified below (“Holder”) a stock option (the “Option”) to purchase the number of shares of the Common Stock of the Company set forth below. The Option
is granted on the terms and conditions set forth below and in the 2010 Stock Incentive Plan sponsored by the Company, as amended from time to time (as so amended, the “Plan”), the terms of which are incorporated herein. 

1. NAME OF
HOLDER:                                      
                                         
                                         
                         

2. DATE OF
GRANT:                                       
                                         
                         (the “Date of Grant”). 

3. NUMBER OF SHARES:                 
(            ) shares of Company Common Stock (the “Option Shares”). 

4. EXERCISE PRICE.                     
Dollars ($            ) per share. 
 5. TYPE OF OPTION.
For income tax purposes, the Option shall be treated as the following type of option: 
 [    ] Incentive
Option 
 [    ] Nonqualified Stock Option 

6. TERM OF OPTION. The term of the Option will begin as of the Date of Grant set forth above and, unless sooner terminated in accordance with the terms
of the Plan, will expire ten (10) years from Date of Grant. 
 7. EXPIRATION. The Option is subject to termination prior to the
expiration of the term of the Option set forth above in the event of the termination of Holder’s employment with the Company or any of its subsidiaries or the occurrence of certain other events specified in the Plan. 

8. EXERCISE. The Option may be exercised only to the extent that the Holder has become vested in the Option pursuant to Section 9, below.

 9. VESTING. 
 9.1
VESTING COMMENCEMENT
DATE:                                       
                                         
                     
 9.2
VESTING SCHEDULE. Subject to Holder’s continuous employment with the Company or its subsidiaries, Holder shall become vested in this Option (and this Option shall become exercisable by Holder) as follows: Holder shall vest in
(a) twenty-five percent (25.0%) of the Option Shares after twelve (12) months of continuous employment with the Company or one of its subsidiaries from and after the Vesting Commencement Date, and (b) an additional one
forty-eighth (1/48th) of the Option Shares after each subsequent month of continuous employment. 







 10. RESTRICTION ON TRANSFER OF OPTION. Except as otherwise expressly permitted in the Plan, Holder may not
transfer all or any portion of Holder’s interest in the Option other than by will or the laws of descent and distribution. 
 11. ADDITIONAL
AGREEMENTS UPON ISSUANCE OF OPTION SHARES. 
 11.1 RIGHT OF FIRST REFUSAL AGREEMENT. Upon exercise of the Options and
issuance of the Option Shares, such Option Shares shall be subject to, and Holder shall execute and be bound by, a right of first refusal agreement in such form as the Board of the Company shall prescribe granting the Company an option to purchase
any Option Shares thereafter proposed to be transferred by the Holder. 
 11.2 LOCK-UP/MARKET STAND-OFF AGREEMENT. Upon
exercise of the Options and issuance of the Option Shares, such Option Shares shall be subject to, and Holder shall execute and be bound by, a lock-up/market standoff agreement in such form as the Board of the Company shall prescribe pursuant to
which Holder shall covenant and agree that, during such period as is determined by the Company’s underwriters, Holder shall not, to the extent requested by the Company, sell or otherwise transfer or dispose of any Option Shares. The
lock-up/market stand-off agreement shall provide the Company with the right to enforce such covenants, including but not limited to the imposition of stop transfer instructions. 

12. ACKNOWLEDGEMENT BY HOLDER. Holder acknowledges that Holder has received and reviewed a copy of the Plan, and the Option is subject to the terms and
conditions of the Plan. 
 13. TERMS OF AGREEMENT. Wherever the form of this Agreement provides for the insertion of additional information
(such as the designation of the type of Option in Section 5 above, or the vesting schedule for the Option in Section 9 above), (a) such additional information may be inserted in hand-written form, (b) such information shall be
deemed to be part of this Agreement for all purposes, and (c) Holder, by reason of executing this Agreement, shall be deemed to have accepted such additional information. 

[signature page follows] 

  
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 IN WITNESS WHEREOF, the undersigned have executed this Agreement, effective as of the Date
of Grant specified above. 
  

							
	“COMPANY:”	 		 	“HOLDER:”
			
	CYTOMX THERAPEUTICS, INC., a Delaware corporation	 		 	
				
	By	 	  
	 		 	  

		 	Name & title:	 		 	Signature of Holder
			
	Address and Facsimile No. of Company:	 		 	  

Printed Name of Holder

			
	 CytomX Therapeutics, Inc.
 460 Ward
Drive, Suite E-1
	 		 	Address and Facsimile No. of Company:
	Santa Barbara, California 93111	 		 	
	Facsimile No.: (    )                 	 		 	  

		 		 	  

		 		 	  


  

  
 3 








 CYTOMX THERAPEUTICS, INC. 

NOTICE OF EXERCISE OF STOCK OPTION 

(2010 Stock Incentive Plan) 
  

	TO:	CytomX Therapeutics, Inc. 

 Attention: Chief Financial Officer 

343 Oyster Point Boulevard, Suite 100 

South San Francisco, California 94080-1913 
  

	RE:	Exercise of Stock Option 

 I hereby elect to exercise the following-described stock option (the
“Option”) granted to me under the CYTOMX THERAPEUTICS, INC., 2010 Stock Incentive Plan (Please complete the following) for the number of shares of Common Stock indicated below: 

 

							
	 Date of Grant of Option
 Being
Exercised:*                                    
	 		 		 	 No. Shares of Common Stock
 for which Option
Being Exercised:
                                    

				
	Type of Option*	 		 		 	Full Name in which Shares are to be Issued:
	[    ] Incentive Option	 		 		 	
	[    ] Nonqualified Stock Option	 		 		 	  

				
	Exercise Price Per Share:*
$                                    	 		 		 	

 * Check the terms of your Option 

1. Exercise Price. I am forwarding with this Notice a check in the amount of $
             payable to “CYTOMX THERAPEUTICS, INC.” representing the aggregate exercise price for the number of shares of Common Stock that I have elected to
exercise my Option. 
 2. Withholding Taxes. If my Option is a “Nonqualified Stock Option” and if the Company has advised
me that I must deposit with the Company funds to cover withholding taxes due upon exercise of my Option, then I also have attached the additional sum of $             [enter
“N/A” if your Option is an Incentive Stock Option or if you are not an employee of the Company] to cover the cost of those withholding taxes. 

Please use the following as my address on the stock books and records of the Company: 

 

									
		 	  
	 	
		 	Street Address	 		 		 	
		 	  
	 	
		 	City, State and Zip Code	 		 	Area Code and Telephone Number	 	

  

							
	  
	 		 	  

	Printed Name of Holder	 		 	Signature of Holder	 	Date                


 

									
	ACKNOWLEDGEMENT BY COMPANY
				
		 		 		 	CYTOMX THERAPEUTICS, INC., a Delaware corporation
					
	  
	 		 		 	By	 	  

	Date	 		 		 		 	Name & title: