Protagonist Announces Presentations of Clinical Data with Icotrokinra in Plaque Psoriasis and Preclinical Data with PN-881 at the EADV 2025 Congress

Icotrokinra demonstrated superior skin clearance at Weeks 16 and 24 compared to deucravacitinib and similar adverse event rates to placebo in Phase 3 ICONIC-ADVANCE studies

Icotrokinra also showed sustained skin clearance and favorable safety profile in both adults and adolescents at Week 52 in Phase 3 ICONIC-LEAD study

Preclinical proof-of-concept data on PN-881, a first-in-class oral peptide targeting the IL-17 pathway, and part of Protagonist's fully owned development pipeline, including the highly potent and selective binding of IL-17A and IL-17F

NEWARK, CALIFORNIA / ACCESS Newswire / September 17, 2025 / Protagonist Therapeutics, Inc. ("Protagonist" or the "Company") today announced new data from the Phase 3 ICONIC-ADVANCE 1 and 2 studies which assessed the superiority of icotrokinra, a first-in-class investigational targeted oral peptide that selectively blocks the IL-23 receptor, compared to deucravacitinib in patients with moderate-to-severe plaque psoriasis. These data are being presented at the 2025 European Academy of Dermatology and Venereology (EADV) Congress in Paris, France. Additionally, new long-term 52-week data from the Phase 3 ICONIC-LEAD study investigating icotrokinra in adults and pediatric patients 12 years of age and older (adolescents) with moderate to severe plaque psoriasis will be presented as a late-breaking abstract at EADV.1, 2

Preclinical data on PN-881, a first-in-class oral peptide targeting the IL-17 pathway and fully owned by Protagonist, are also being presented at EADV.3 The Company expects that the first subject will be dosed in the Phase 1 single ascending and multiple ascending dose human clinical study (NCT07153146) in the coming weeks.

"The data presented at EADV demonstrate the potential for icotrokinra to set a new standard of treatment for psoriasis patients with a once-daily targeted oral therapy that selectively blocks the IL-23R. Additionally, the preclinical data on our next drug candidate in the Inflammatory and Immunomodulatory (I&I) space, PN-881, being presented at the conference highlight its potential as a first-in-class oral peptide antagonist targeting the three therapeutically relevant dimeric forms of IL-17," said Dinesh V. Patel, Ph.D., President and Chief Executive Officer at Protagonist. " Collectively, these data reinforce our ability to innovate and develop oral peptides that could potentially deliver transformative, paradigm shifting outcomes for patients. The first-in-class oral peptides Icotrokinra and PN-881 target the highly relevant biological IL-23 and IL-17 pathways respectively in the I&I space and position Protagonist Therapeutics as an emerging and prominent contributor to this therapeutic field."

ICONIC-ADVANCE 1 and 2 Study Data

The ICONIC-ADVANCE 1 and 2 studies assessed the superiority of icotrokinra compared to deucravacitinib in patients with moderate-to-severe plaque psoriasis. As previously announced, in the studies icotrokinra met both co-primary endpoints compared to placebo at Week 16 with similar adverse event rates and showed superiority to deucravacitinib at multiple timepoints in adult patients.

• Icotrokinra showed superior skin clearance vs placebo (Week 16) and deucravacitinib (Weeks 16 and 24).1

• A similar proportion of patients experienced adverse events (AEs) between icotrokinra and placebo groups, with no new safety signals identified. Icotrokinra AE rates were numerically lower vs deucravacitinib through Week 24.1

ICONIC-LEAD Study Data

In the ICONIC-LEADb drug withdrawal/re-retreatment study, icotrokinra demonstrated sustained skin clearance and a favorable safety profile through Week 52 with no new safety signals identified.

• At Week 52, adult icotrokinra PASI 90 responders re-randomized to icotrokinra at Week 24 had superior maintenance of PASI 90 response versus those re-randomized to placebo (84% vs 21%; p