CUSIP No. 39536G105

EXHIBIT 99.1

JOINT FILING AGREEMENT

The undersigned, being duly authorized thereunder, hereby execute this agreement as an exhibit to this Schedule 13D to evidence the agreement of the below-named parties, in accordance with the rules promulgated pursuant to the Securities Exchange Act of 1934, to file this Schedule 13D (including amendments thereto) jointly on behalf of each such party.

MORNINGSIDE VENTURE INVESTMENTS LIMITED
By:	/s/ Frances Anne Elizabeth Richard
	Frances Anne Elizabeth Richard, Director
MVIL, LLC
By:	/s/ Cheng Yee Wing Betty
	Cheng Yee Wing Betty, Manager
/s/ Frances Anne Elizabeth Richard
Frances Anne Elizabeth Richard
/s/ Jill Marie Franklin
Jill Marie Franklin
/s/ Peter Stuart Allenby Edwards
Peter Stuart Allenby Edwards
/s/ Cheung Ka Ho
Cheung Ka Ho
/s/ Cheng Yee Wing Betty
Cheng Yee Wing Betty
/s/ Wong See Wai
Wong See Wai