Protagonist Reports Positive Top Line Results From Phase 2b Study of Icotrokinra Showing Potential to Transform the Treatment Paradigm for Patients With Ulcerative Colitis

Clinical response rate of 63.5% and clinical remission rate of 30.2% achieved at Week 12 with the highest dose, which continued to improve through Week 28

All three doses met the primary endpoint of clinical response at Week 12, with a favorable safety profile

These results in ulcerative colitis build on strong data recently reported for the plaque psoriasis Phase 3 program

NEWARK, CALIFORNIA / ACCESS Newswire / March 10, 2025 / Protagonist Therapeutics, Inc. ("Protagonist" or the "Company") today announced positive topline results from ANTHEM-UC, a Phase 2b study of icotrokinra (JNJ-2113), the first investigational targeted oral peptide that selectively blocks the IL-23 receptor, in adults with moderately to severely active ulcerative colitis (UC). The study conducted by Protagonist's collaboration partner, Johnson & Johnson, met its primary endpoint of clinical responsea in all icotrokinra dose groups evaluated. Additionally, the study demonstrated clinically meaningful differences versus placebo in key secondary endpoints of clinical remissionb, symptomatic remission and endoscopic improvement at Week 12.

Key findings from the ANTHEM-UC study (n=252) are summarized below:

• All three doses of once daily icotrokinra met the primary endpoint of clinical response at Week 12.

• A response rate of 63.5% for patients treated with the highest dose of icotrokinra was achieved at Week 12 versus 27.0% for placebo (p