EX-10.9





 Exhibit 10.9 

Big Rock Partners Acquisition Corp. 

2645 N. Federal Highway, Suite 230 

Delray Beach, FL 33483 

May 24, 2021 
 Big Rock Partners
Sponsor, LLC 
 c/o Big Rock Partners Acquisition Corp. 
 2645
N. Federal Highway, Suite 230 
 Delray Beach, FL 33483 
 BRAC
Lending Group LLC 
 c/o David Nussbaum 
 EarlyBirdCapital, Inc.

 366 Madison Avenue, 8th Floor 
 New York, NY 10017 

Re: Sponsor Forfeiture 
 Ladies and
Gentlemen: 
 Big Rock Partners Sponsor, LLC (“Sponsor”) and BRAC Lending Group LLC (“BRAC”) hold shares of
common stock of Big Rock Partners Acquisition Corp. (“BRPA”), par value $0.001 per share (“BRPA Common Stock”). It is a condition to the consummation (“Closing”) of the transactions contemplated
under the Agreement and Plan of Merger, dated as of December 13, 2020 (as amended, the “Merger Agreement”) by and among BRPA, Big Rock Merger Corp., and NeuroRx, Inc., that Sponsor and BRAC enter into an agreement with BRPA
providing for the forfeiture and escrow of certain shares of BRPA Common Stock. Accordingly, Sponsor, BRAC, and BRPA agree as follows: 
 (a)
Sponsor and BRAC shall forfeit, and BRPA shall terminate and cancel as of the Closing, (i) an aggregate of 875,000 shares of BRPA Common Stock (the “Initial Forfeited Shares”) and (ii) one share of BRPA Common Stock for
each share of BRPA Common Stock validly redeemed in connection with the solicitation of approval of the Merger Agreement and related transactions by the holders of BRPA Common Stock originally issued in BRPA’s initial public offering pursuant
to the terms of BRPA’s Amended and Restated Certificate of Incorporation, up to a maximum of 300,000 shares of BRPA Common Stock (the “Additional Forfeited Shares,” and together with the Initial Forfeited Shares, the
“Forfeited Shares”), with the allocation of the Forfeited Shares between the Sponsor and BRAC as set forth on Exhibit A hereto; 

(b) Sponsor shall subject an aggregate of 125,000 shares of BRPA Common Stock owned by Sponsor to escrow (the “Sponsor Earnout
Shares”), which Sponsor Earnout Shares shall either be released from escrow to the Sponsor upon the achievement of the Earnout Shares Milestone (as such term is defined in the Merger Agreement) or terminated and cancelled by BRPA on
December 31, 2022 in the event that the Earnout Shares Milestone is not achieved; and 
 (c) Sponsor and BRAC shall enter into an
amendment to that certain stock escrow agreement entered into between Continental Stock Transfer & Trust Company, BRPA, BRAC, Sponsor, and the other parties thereto, on November 20, 2017 (as amended by that certain letter agreement
dated November 17, 2018) providing, among other things, for the forfeiture and cancellation of the Forfeited Shares, the escrow of the Sponsor Earnout Shares, and the shortening of the escrow period as provided therein. 












 Please indicate your agreement to the foregoing by signing in the space provided below. 

[signature page follows] 












 
			
	Very truly yours,
	
	BIG ROCK PARTNERS ACQUISITIONS CORP.


 
			
		
	By:	 	 /s/ Richard Ackerman





			
	Name: Richard Ackerman
	Title: Chief Executive Officer


  

			
	ACCEPTED AND AGREED TO:
	
	BIG ROCK PARTNERS SPONSOR, LLC
		
	By:	 	 /s/ Richard Ackerman

		 	Name: Richard Ackerman
		 	Title: Managing Member
	
	BRAC LENDING GROUP LLC
		
	By:	 	 /s/ David M. Nussbaum

		 	Name: David M. Nussbaum
		 	Title: Managing Member













 Exhibit A 
  

													
	 Name
	  	Initial Forfeited
Shares	 	  	Maximum
Additional
Forfeited Shares	 	  	Sponsor Earnout
Shares	 
	 Big Rock Partners Sponsor, LLC
	  	 	5,435	 	  	 	39,130	 	  	 	125,000	 
	 BRAC Lending Group LLC
	  	 	869,565	 	  	 	260,870	 	  	 	0	 
	 TOTAL
	  	 	875,000	 	  	 	300,000	 	  	 	125,000