Spyre Therapeutics (SYRE) 10-K 2024 FY Annual report

Exhibit 32.1

Certifications of the

Principal Executive Officer and Principal Financial Officer

Pursuant To 18 U.S.C. Section 1350,

As Adopted Pursuant To

Section 906 of The Sarbanes-Oxley Act Of 2002

In connection with the Annual Report of Spyre Therapeutics, Inc. (the “Company”) on Form 10-K for the year ended December 31, 2024, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), each of the undersigned officers of the Company hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of his knowledge:

1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: February 27, 2025	/s/ Cameron Turtle, D.Phil
	Cameron Turtle, D.Phil
	Chief Executive Officer
	(Principal Executive Officer)
	/s/ Scott Burrows
	Scott Burrows
	Chief Financial Officer
	(Principal Financial Officer and Principal Accounting Officer)