EX-10.20



 Exhibit 10.20 

*** INDICATES MATERIAL THAT WAS OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT WAS REQUESTED. ALL SUCH OMITTED MATERIAL WAS FILED SEPARATELY WITH THE
SECURITIES AND EXCHANGE COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. 
 THIRD AMENDMENT
TO THE 
 LICENSE, DEVELOPMENT AND COMMERCIALIZATION AGREEMENT 

THIS THIRD AMENDMENT (this “Amendment”) to the License, Development and Commercialization Agreement (as hereinafter defined), is
effective as of the 9th day of October 2013 (the “Third Amendment Effective Date”), by and between Bayer Pharma AG (formerly known as Bayer Schering Pharma AG), a German corporation,
with a place of business at Muellerstrasse 178, Berlin 13342, Germany (“Bayer”), and Syndax Pharmaceuticals, Inc., a Delaware corporation, with a place of business at 400 Totten Pond Road, Suite 140, Waltham, Massachusetts 02451, USA
(“Licensee”). 
 WHEREAS, Bayer and Licensee entered into that certain License, Development and Commercialization Agreement dated
as of March 26, 2007, as amended (the “License Agreement”); and 
 WHEREAS, Bayer and Licensee desire to amend the License
Agreement as described below. 
 NOW, THEREFORE, in consideration of the mutual covenants and agreements set forth herein, Bayer and
Licensee mutually agree as follows: 
 1. Definitions. Capitalized terms used in this Amendment and not otherwise defined in this
Amendment shall have the meanings set forth in the License Agreement. 
 2. Effective Date. This Amendment shall become effective as
of the Third Amendment Effective Date. 
 3. Sales Milestones. Section 6.3.3.1 of the License Agreement is hereby deleted in its
entirety and replaced with the following: 
 6.3.3.1 Licensee shall make the following milestone payments to Bayer upon the occurrence of the
corresponding event below: 
  

					
	 Milestone
	  	Payment	 
		
	 Aggregate annual Net Sales of Product in the Territory first reaches $***
	  	$	***	  
	 Aggregate annual Net Sales of Product in the Territory first reaches $***
	  	$	***	  
	 Aggregate annual Net Sales of Product in the Territory first reaches $***
	  	$	***	  








 4. Royalties. Section 6.4 (including subsections 6.4.1 and 6.4.2) of the License
Agreement is hereby deleted in its entirety and replaced with the following: 
 6.4. Royalty Payments. In partial consideration of the
license and rights granted to it by Bayer under this Agreement, Licensee shall pay to Bayer, on a country-by-country basis, during the Royalty Term in each such country, a royalty on Net Sales of the Product, in the following amounts: 

 

					
	 Net Sales
	  	Royalty (% of Net Sales)	 
		
	 On that portion of annual Net Sales of the Product from $*** to $***
	  	 	***	% 
	 On that portion of annual Net Sales of the Product from $*** to $***
	  	 	***	% 
	 On that portion of annual Net Sales of the Product from $*** to $***
	  	 	***	% 
	 On that portion of annual Net Sales of the Product above $***
	  	 	***	% 

 5. Know-How Royalty. Section 6.5.2 of the License Agreement is hereby deleted in its entirety.

 6. Effect of Amendment. Except as expressly amended in this Amendment, all terms and conditions of the License Agreement shall
remain in full force and effect. 
 7. Counterparts. This Amendment may be executed in two or more counterparts, each of which shall
be deemed to be an original, but all of which together shall constitute one and the same instrument. 
 [Signature Page Follows] 

 
 *** INDICATES MATERIAL THAT WAS OMITTED AND FOR WHICH CONFIDENTIAL TREATMENT WAS
REQUESTED. ALL SUCH OMITTED MATERIAL WAS FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. 

  
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 IN WITNESS WHEREOF, the Parties hereto have executed this Amendment as indicated by the
signatures below. 
  

									
	BAYER PHARMA AG	 		 	SYNDAX PHARMACEUTICALS, INC.
					
	By:	 	 /s/ Andreas Fibig
	 		 	By:	 	 /s/ Arelene M. Morris

					
	Name:	 	Andreas Fibig	 		 	Name:	 	Arlene M. Morris
					
	Title:	 	Chairman of the Board of Management of Bayer Pharma AG	 		 	Title:	 	Chief Executive Officer
					
	By:	 	 /s/ Karl Ziegelbauer
	 		 		 	
					
	Name:	 	Karl Ziegelbauer	 		 		 	
					
	Title:	 	Head TRG Oncology/Gynecological Therapy	 		 		 	

  
 *** INDICATES MATERIAL THAT WAS OMITTED AND FOR WHICH
CONFIDENTIAL TREATMENT WAS REQUESTED. ALL SUCH OMITTED MATERIAL WAS FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO RULE 406 PROMULGATED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. 

  
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