Exhibit 10.1


 


Amendment
to SPONSOR LETTER AGREEMENT


 


This Amendment to the Sponsor
Letter Agreement (this “Amendment”) is entered into as of November 8, 2021 (the “Amendment Effective Date”),
by and among Capstar Sponsor Group LLC, a Delaware limited liability company (the “Sponsor”), Capstar Special Purpose
Acquisition Corp., a Delaware corporation (“Capstar”), the other holders of Capstar Class B Common Stock set forth
on Schedule I hereto (the “Other Class B Holders,” and, together with the Sponsor, collectively, the “Class
B Holders”) and Gelesis, Inc., a Delaware corporation (the “Company”).


 


Recitals


 


Whereas,
the Sponsor, Capstar, the Other Class B Holders and the Company entered into that certain Sponsor Letter Agreement, dated as of July 19,
2021 (as the same may be amended or modified from time to time in accordance with its terms, the “Sponsor Letter Agreement”),
in connection with the execution of that certain Business Combination Agreement, dated as of July 19, 2021, by and among Capstar, CPSR
Gelesis Merger Sub, Inc., a Delaware corporation (“Merger Sub”), and the Company (as the same may be amended or modified
from time to time in accordance with its terms, the “Business Combination Agreement”);


 


Whereas,
Capstar, Merger Sub and the Company have entered into that certain Amendment to the Business Combination Agreement, dated as of the date
hereof (the “BCA Amendment”); and


 


WHEREAS, in connection
with the BCA Amendment, the Sponsor, Capstar, the Other Class B Holders and the Company wish to amend certain provisions of the Sponsor
Letter Agreement in the manner set forth herein.


 


Now,
Therefore, in consideration of the representations, warranties, covenants and agreements herein made and for other good and
valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:


 


Agreement


 


1.                  
Definitions. Capitalized terms used herein without definition shall have the respective meanings assigned
to such terms in the Sponsor Letter Agreement.


 


2.                  
Amendment to Sponsor Letter Agreement. The Sponsor Letter Agreement is hereby amended as follows:


 


(a)                
Section 3 of the Sponsor Letter Agreement is hereby amended and restated in its entirety as follows:


 


“3.       Treatment
of Shares and Warrants


 


(a)       Subject
Securities. The Sponsor and the Other Class B Holders each agree that, effective upon the Closing, the number of Capstar Class A Warrants
(the “Vesting Warrants”) and the number of Capstar Class B Shares (the “Forfeiture Shares”) held
by the Sponsor and the Other Class B Holders set forth on Exhibit A hereto shall be subjected to and governed by the vesting and forfeiture
provisions set forth herein.”


 


(b)       Vesting
Warrants. The Sponsor acknowledges and agrees that the Eligible Vesting Warrants (as defined below) shall vest (and no longer be subject
to forfeiture) at such time during the period from and after the Closing through and until the date that is five (5) years after the Closing
Date (the “Sponsor Vesting Period”) as (x) the Capstar Stock Price is first equal to or exceeds $20.00 per share for
any twenty (20) Trading Days within any period of thirty (30) consecutive Trading Days or (y) there is a Capstar Sale in which the Capstar
Sale Price for the acquisition of the Capstar Shares is greater than or equal to $20.00 per share. Any Vesting Warrants that are not Eligible
Vesting Warrants as of the Closing shall be deemed fully vested (and no longer be subject to forfeiture) as of the Closing. As used herein,
 “Eligible Vesting Warrants” means the number of Vesting Warrants equal to the product of (x) the number of Vesting Warrants
set forth on Exhibit A hereto and (y) a fraction, the numerator of which is equal to the total number of Capstar Class A Shares redeemed
pursuant to the Capstar Stockholder Redemption, other than any such redemptions by the PIMCO Private Funds, as of immediately prior to
the Closing, and the denominator of which is equal to the total number of Capstar Class A Shares outstanding as of immediately prior to
such Capstar Stockholder Redemption.


 






     


     


    

 


(c)       Forfeiture
of Unvested Warrants. Vesting Warrants that remain unvested on the first Business Day after the conclusion of the Sponsor Vesting
Period shall be automatically void and of no further effect as of such date, and then surrendered by the Sponsor as promptly as practicable
thereafter, without any consideration for such forfeiture or surrender.


 


(d)       Forfeiture
Shares. The Forfeiture Shares shall, as of immediately prior to the Effective Time, be surrendered by the Sponsor and the Other Class
B Holders to Capstar for cancellation upon such surrender, without any consideration for such surrender.”


 


(b)               
Exhibit A to the Sponsor Letter Agreement is hereby amended and restated in its entirety as attached hereto as Exhibit
A to this Amendment.


 


3.                  
Effect on the Sponsor Letter Agreement. Except as specifically amended by this Amendment, the Sponsor Letter
Agreement shall remain in full force and effect, and the Sponsor Letter Agreement, as amended by this Amendment, is hereby ratified and
confirmed in all respects. From and after the Amendment Effective Date, each reference in the Sponsor Letter Agreement to “this
Agreement,” “herein,” “hereof,” “hereunder” or words of similar import, or to any provision
of the Sponsor Letter Agreement, as the case may be, shall be deemed to refer to the Sponsor Letter Agreement or such provision as amended
by this Amendment, unless the context otherwise requires.


 


4.                  
Miscellaneous. The provisions of Sections 8.2 (Entire Agreement; Assignment), 8.3 (Amendment),
8.4 (Notices), 8.5 (Governing Law), 8.7 (Construction), 8.10 (Severability), 8.11 (Counterparts; Electronic
Signatures), 8.15 (WAIVER OF JURY TRIAL), 8.16 (Submission to Jurisdiction), and 8.17 (Remedies) of the Business
Combination Agreement are incorporated by reference into this Amendment mutatis mutandis.


 


[Signature Pages Follow]


 






     


     


    

 


In
witness whereof, the undersigned have executed this Amendment as of the date first set forth above.


 


	 	SPONSOR:
	 	 
	 	CAPSTAR
    SPONSOR GROUP LLC
	 	 
	 	By:	 /s/ R. Steven Hicks
	 	 	Name: 	R. Steven Hicks
	 	 	Title: 	Manager
	 	 
	 	CAPSTAR:
	 	 
	 	Capstar
    Special Purpose Acquisition COrp.
	 	 
	 	By: 	/s/ R. Steven Hicks
	 	 	Name:	 R. Steven Hicks
	 	 	Title: 	Chief Executive Officer
	 	 
	 	COMPANY:
	 	 
	 	Gelesis,
    Inc.
	 	 
	 	By:	 /s/ Yishai Zohar
	 	 	Name: 	Yishai Zohar
	 	 	Title: 	President, Chief Executive Officer
	 	 
	 	OTHER
    CLASS B HOLDERS:
	 	 
	 	/s/
    Kathryn Cavanaugh
	 	Kathryn
    Cavanaugh
	 	 
	 	/s/John
    Ghiselli
	 	John
    Ghiselli
	 	 
	 	/s/
    James Whittenburg
	 	James
    Whittenburg




 






     


     


    

 


EXHIBIT A


 


Vesting Warrants


 


	 	 Capstar Class A Warrants
	Sponsor	2,506,416


 


Forfeiture Shares


 


	 	Capstar Class B Shares
	Sponsor	1,965,638
	Kathryn Cavanaugh	5,175
	John Ghiselli	5,175
	James Whittenburg	7,762
	TOTAL	1,983,750