Exhibit 99.1 Waltham, Mass, August 5, 2025 - Spyre Therapeutics, Inc. ("Spyre" or the "Company") (NASDAQ:SYRE), a clinical-stage biotechnology company utilizing best-in-class antibody engineering, dose optimization, and rational therapeutic combinations to target improved efficacy and convenience in the treatment of inflammatory bowel disease ("IBD") and other immune-mediated diseases, today announced its second quarter 2025 financial results and provided program and corporate updates. "Spyre is entering a ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 ____________________________ FORM 10-Q ____________________________ (Mark One) (Address of principal executive offices including zip code) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37722 SPYRE ...

Announced first participant dosed in Phase 1 trial of SPY003, with interim PK and safety data readout on track for the second half of 2025 Exhibit 99.1 Spyre Therapeutics Reports First Quarter 2025 Financial Results and Provides Corporate Update On track for mid-year initiations of planned Phase 2 studies in ulcerative colitis ("UC") and rheumatoid arthritis ("RA"), providing for 7+ proof-of-concept readouts in 2026 & 2027 Reported extended follow-up Phase 1 data for SPY001, supporting that the molecule is ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 ____________________________ FORM 10-Q ____________________________ (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37722 SPYRE THERAPEUTICS, INC. (Exact Name of Registrant as Specified i ...