EX-10.19(f)



 Exhibit 10.19(f) 

Unity Biotechnology 
 3280 Bayshore Blvd., Suite 100 

Brisbane, CA 94005 
 September 15, 2016

 Mayo Foundation for Medical Education and Research 

200 First Street SW 
 Rochester,
MN 55905 
 Attn: Daniel D. Estes 

re:    Addendum to Amendment 4 to Exclusive License Agreement 

Dear Daniel: 
 As you know, Mayo
Foundation for Medical Education and Research (“Mayo”) and Unity Biotechnology, Inc. (“Unity”) are parties to an Exclusive License Agreement (“Agreement”), effective as of June 28, 2013. Pursuant to
Section 2.2 of the Agreement, Mayo granted to Unity an option to include within the licenses granted under the Agreement any “Additional Developments” (as defined in the Agreement) developed during the IP Capture Period (as defined in
the Agreement). In connection with the grant of such option, Mayo further agreed to promptly notify Unity in writing of all Additional Inventions developed by Mayo personnel during the IP Capture Period and to provide Unity with a suitable
description of such Additional Invention together with such other information as Unity may reasonably request for purposes of enabling Unity to assess its interest in such Additional Developments. 

As requested by Mayo, Unity is providing this letter to confirm that it has received timely notice of the Additional Inventions listed in
Appendix A hereto (each such additional Invention identified by Mayo’s designated case number) and to provide a summary of which Additional Inventions it has elected to license, which it has declined to license and which Additional Inventions
are still under consideration. Appendix A indicates with respect to each Additional Invention whether 1) Unity will be declining a license 2) Unity is exercising its option to a license, or 3) Unity would like to learn more about the Additional
Invention from the Mayo innovators before deciding whether to exercise its option. Additionally, as requested by Mayo, Appendix A, also lists those patent applications that have been filed as of the current date for those Additional Inventions
exercised under the option. 
 If Mayo is in agreement with the summary provided in Appendix A, we ask that you please so indicate by
signing below and kindly returning a copy of this letter to me. A duplicate original is enclosed for your records. If you have any questions or comments, please do not hesitate to contact me at [***] or by
e-mail at [***]. Thank you. 
 Sincerely, 

  
 [***] Certain information in this
document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 









	
	 /s/ Nathaniel E. David

	Nathaniel E. David, Ph.D.
	CEO
	Unity Biotechnology, Inc.

 Agreed and accepted: 
 Mayo
Foundation for Medical Education and Research 
  

			
	 /s/ Daniel D. Estes

	Name:	 	Daniel D. Estes
	Title:	 	Assistant Treasurer
	Date:	 	9-23-2016


  
 [***] Certain information in this
document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions. 








 APPENDIX A 

[***] 

  
 [***] Certain information in this
document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.