Spyre Therapeutics Announces Presentations at the 21st ECCO Congress Supporting Differentiated Profile of SPY003 and Novel Animal Studies Demonstrating Superiority of Combination Approach

Spyre Therapeutics, Inc. (NASDAQ: SYRE), a clinical-stage biotechnology company pioneering long-acting antibodies and antibody combinations to redefine the standard of care for inflammatory bowel disease (“IBD”) and rheumatic diseases, today announced scientific presentations at the 21 st Congress of the European Crohn’s and Colitis Organisation (ECCO), held February 18-21, 2026 in Stockholm, Sweden.

“We are excited to share follow-up data out to 20 weeks from our Phase 1 study of SPY003, our potential best-in-class anti-IL-23 agent in development for IBD. The data showed SPY003 was well tolerated, had a differentiated PK profile supporting quarterly or twice-yearly dosing, and demonstrated targeted biological activity via a reduction in downstream cytokines. In addition, we are presenting details of our innovative SKYLINE platform trial evaluating long-acting antibodies as monotherapies and in rational combinations, as well as preclinical data demonstrating that dual targeting of TL1A and IL-23 can provide superior efficacy compared to either agent alone,” said Deanna Nguyen, M.D., SVP of Clinical Development at Spyre. “Together, these presentations highlight the strength of our antibody portfolio and our strategy to redefine the standard of care in IBD.”

The posters will be available for viewing during the ECCO Congress, and details are as follows:

Title : Interim Phase 1 Results for SPY003, a Novel Half-Life Extended Monoclonal Antibody Targeting IL-23, Suggest Potential for Q3M or Q6M Maintenance Dosing for Inflammatory Bowel Disease Authors : Y. Vugmeyster, R. McLean, P. Patel, K. Hew, C. Sheldon, E. Svejnoha, B. Wang, J. Lu, B. Connolly, M. Huyghe, J. Friedman, D. Nguyen

Title : SKYLINE-UC: the First Platform Study in Ulcerative Colitis Assessing Efficacy and Safety of Three Long-acting Antibodies Administered as Single Agents and in Combinations Authors : S. Danese, V. Jairath, J. Lu, M. Zinder, Y. Vugmeyster, J. Friedman, M. Huyghe, B. Connolly, S. Sloan, D. Nguyen

Title : Anti-TL1A and Anti-IL-23 Combination Therapy is Superior to its Constituent Monotherapies in Mouse Anti-CD40 Colitis Authors : M. Siegel, D. Giles, E. Lewis, J. Friedman, M. Rose, A. Spencer

Full session details can be accessed via the ECCO program.

About Spyre Therapeutics

Spyre Therapeutics is a clinical-stage biotechnology company pioneering long-acting antibodies and antibody combinations to redefine the standard of care for inflammatory bowel disease (“IBD”) and rheumatic diseases. Spyre's pipeline includes investigational extended half-life antibodies targeting α4β7, TL1A, and IL-23.

For more information, please visit http://spyre.com.

Forward-Looking Statements

Certain statements in this press release, other than purely historical information, may constitute "forward-looking statements" within the meaning of the federal securities laws, including for purposes of the safe harbor provisions under the United States Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, statements regarding: Spyre’s ability to achieve the expected benefits or opportunities with respect to its product candidates, including their potential commercialization; Spyre’s ongoing and future clinical development activities, including further clinical evaluation of SPY003 as monotherapy and in combinations; the potential maintenance dosing regimen for SPY003; the potential therapeutic benefits of Spyre’s product candidates as monotherapies or in combinations and their extended half-life; the potential consistency of the SPY003 Phase 1 trial final data readouts with previously disclosed data for our programs; and Spyre’s business plans, milestones, strategy and goals. The words "opportunity," "potential," "milestones," "pipeline," "strategy," "anticipate," "believe," "could," "estimate," "expect," "may," "might," "plan," "possible," "predict," "should," "will," "would," and similar expressions (including the negatives of these terms) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs and involve a number of risks and uncertainties, many of which are beyond Spyre’s control, and other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited, uncertainties and risks arising from regulatory feedback, including potential disagreement by regulatory authorities with the Company’s interpretation of data and the Company’s clinical trials for its product candidates; the potential for interim data not being delivered within expected time frames or final data not being consistent with or different than the interim data reported for our programs; the potential impact of Trump Administration policies and changes in law on our business; and those uncertainties and factors described in Spyre's most recent Annual Report on Form 10-K, as supplemented and updated by subsequent Quarterly Reports on Form 10-Q and any other filings that Spyre has made or may make with the SEC from time to time. You should not place undue reliance on forward-looking statements in this press release, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Spyre does not undertake or accept any duty to make any updates or revisions to any forward-looking statements.

For Investors: Eric McIntyre SVP of Finance and Investor Relations Spyre Therapeutics [email protected]

For Media: Josie Butler, 1AB [email protected]