Protagonist Announces New Icotrokinra Data in Ulcerative Colitis Showing Potential for a Standout Combination of Therapeutic Benefit and a Favorable Safety Profile in Once-daily Pill

Icotrokinra met the primary endpoint of clinical response at all three doses, with 36.5% of patients treated achieving endoscopic improvement and 30.2% achieving clinical remission at the highest dose at Week 12 in the Phase 2b ANTHEM-UC study

These data support the promise of a first-in-class targeted oral peptide that selectively blocks the IL-23 receptor as a potential new option for people with moderately to severely active ulcerative colitis

Registrational Phase 3 study in ulcerative colitis and Phase 2b/3 study in Crohn's disease anticipated to begin patient enrollment in Q4 2025

NEWARK, CALIFORNIA / ACCESS Newswire / October 7, 2025 / Protagonist Therapeutics, Inc. ("Protagonist" or the "Company") today announced additional Week 12 results from the Phase 2b ANTHEM-UC study of icotrokinra, a first-in-class investigational targeted oral peptide that selectively blocks the IL-23 receptor, in adults with moderately to severely active ulcerative colitis (UC). The study met its primary endpoint, with all once-daily icotrokinra dose groups achieving clinical responsea at Week 12 and showing clinically meaningful improvements versus placebo across key secondary endpoints.1 These results underscore the potential of icotrokinra to deliver a valuable combination of significant therapeutic benefit and a favorable safety profile with once-daily oral dosing and are featured at United European Gastroenterology (UEG) Week 2025.

At Week 12, patients treated with 400 mg of icotrokinra once daily achieved a clinical response rate of 63.5% versus 27% for placebo (p