Protagonist Therapeutics Announces Positive Topline Results for Phase 2b FRONTIER 1 Clinical Trial of Oral IL-23 Receptor Antagonist JNJ-2113 (PN-235) in Psoriasis

JNJ-2113 (formerly PN-235) met the study's primary endpoint, with a statistically significantly higher proportion of adult patients with moderate-to-severe plaque psoriasis achieving PASI-75 in all treatment groups at Week 16 compared to placebo

Treatment was well tolerated, with no meaningful difference in frequency of adverse events across treatment groups

NEWARK, Calif., March 7, 2023 /PRNewswire/ -- Protagonist Therapeutics, Inc. (Nasdaq: PTGX) ("Protagonist" or "the Company"), today announced positive topline results from its collaboration with Janssen Biotech, Inc., one of the Janssen Pharmaceutical Companies of Johnson & Johnson (Janssen), in the FRONTIER 1 Phase 2b clinical trial evaluating the oral Interleukin-23 receptor (IL-23R) antagonist peptide JNJ-2113 in patients with moderate-to-severe plaque psoriasis.

Data from the 255-patient study showed that JNJ-2113 achieved the study's primary efficacy endpoint, with a statistically significant greater proportion of patients who received JNJ-2113 achieving PASI-75 (a 75% improvement in skin lesions as measured by the Psoriasis Area and Severity Index) responses compared to placebo at Week 16 in all five treatment groups. A clear dose response was observed across an eight-fold dose range. Treatment was well tolerated, with no meaningful difference in frequency of adverse events across treatment groups versus placebo. Data will be presented from various pre-clinical and clinical studies on JNJ-2113 at medical conferences beginning in the second quarter of 2023.

"We are thrilled to be at this transformative junction, with JNJ-2113 being the first- and only-in-class oral IL-23 receptor antagonist as a potential oral targeted therapy for plaque psoriasis, further underscoring the strength of our innovative peptide technology platform. A full measure of JNJ-2113 should be evident when the FRONTIER 1 Phase 2b data are shared at an upcoming medical conference. It is our expectation that JNJ-2113 will progress into a Phase 3 registrational study in plaque psoriasis on the strength of these data. We are excited about JNJ-2113's potential prospects across the spectrum of additional IL-23 mediated diseases," said Dinesh V. Patel, Ph.D., President and Chief Executive Officer at Protagonist.

Dr. Patel continued, "We see this as a watershed moment for Protagonist, the industry, and patients by successfully targeting a systemic immunomodulatory IL-23 monoclonal antibody pathway through an oral peptide antagonist. We are humbled to be part of this significant scientific breakthrough."

JNJ-2113 Clinical Trials

The FRONTIER 1 Phase 2b trial (NCT05223868) was designed to assess the efficacy and safety of JNJ-2113 in patients with moderate-to-severe plaque psoriasis. It is a randomized, multicenter, double-blind, placebo-controlled study that evaluated three once-daily dosages and two twice-daily dosages of JNJ-2113 taken orally. The primary endpoint of the study is the proportion of patients achieving PASI-75 at 16 weeks.

Beyond the recently completed Phase 2b FRONTIER 1 study and a Phase 1 trial (NCT05062200) in healthy Japanese and Chinese participants, JNJ-2113 is currently being studied in multiple trials, also led by Janssen. FRONTIER 2 (NCT05364554) is a long-term extension study of JNJ-2113 in adults with moderate to severe plaque psoriasis; the SUMMIT Phase 2a trial (NCT05357755) is testing a delayed release JNJ-2113 tablet versus placebo in adults with moderate to severe plaque psoriasis; and a Phase 1 trial (NCT05703841) of an immediate release formulation of JNJ-2113 in healthy Chinese adult participants is currently recruiting.

Janssen License and Collaboration Agreement

JNJ-2113 (formerly known as PN-235) was discovered and is being developed pursuant to the license and collaboration agreement between Protagonist and Janssen Biotech, Inc., one of the Janssen Pharmaceutical Companies of Johnson & Johnson. Protagonist completed a Phase 1 study of JNJ-2113 in healthy volunteers in October of 2021 and Janssen retains exclusive, worldwide rights to develop in Phase 2 and beyond, and to commercialize compounds derived from the research conducted pursuant to the agreement against a broad range of indications.

About Protagonist

Protagonist Therapeutics is a biopharmaceutical company with peptide-based new chemical entities rusfertide and JNJ-2113 (formerly PN-235) in advanced stages of clinical development, both derived from the Company's proprietary technology platform. Rusfertide, a mimetic of the natural hormone hepcidin, is the Company's lead drug candidate, currently in a global Phase 3 stage of development. The Phase 3 VERIFY and Phase 2 REVIVE studies of rusfertide in polycythemia vera are ongoing. Protagonist retains all worldwide development and commercialization rights to rusfertide.

Advancement of JNJ-2113 into a Phase 3 study and meeting the primary endpoint in that study would qualify Protagonist for milestone payments of $50 million and $115 million, respectively. In total, Protagonist remains eligible for up to $855 million in various milestone payments and tiered royalties based on worldwide net drug sales.

Cautionary Note on Forward-Looking Statements

This press release contains forward-looking statements for purposes of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include statements regarding our intentions or current expectations concerning, among other things, our expectations regarding Janssen's development of JNJ-2113 (formerly PN-235), our receipt of milestones and other payments under our license and collaboration agreement with Janssen, and the commercial potential of JNJ-2113. In some cases, you can identify these statements by forward-looking words such as "anticipate," "believe," "may," "will," "expect," or the negative or plural of these words or similar expressions. Forward-looking statements are not guarantees of future performance and are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated, including, but not limited to, our ability to develop and commercialize our product candidates, our ability to earn milestone payments under our collaboration agreement with Janssen Biotech, the impact of the current COVID-19 pandemic on our discovery and development efforts, our ability to use and expand our programs to build a pipeline of product candidates, our ability to obtain and maintain regulatory approval of our product candidates, our ability to operate in a competitive industry and compete successfully against competitors that have greater resources than we do, and our ability to obtain and adequately protect intellectual property rights for our product candidates. Additional information concerning these and other risk factors affecting our business can be found in our periodic filings with the Securities and Exchange Commission, including under the heading "Risk Factors" contained in our most recently filed periodic reports on Form 10-K and Form 10-Q filed with the Securities and Exchange Commission. Forward-looking statements are not guarantees of future performance, and our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate, may differ materially from the forward-looking statements contained in this press release. Any forward-looking statements that we make in this press release speak only as of the date of this press release. We assume no obligation to update our forward-looking statements, whether as a result of new information, future events or otherwise, after the date of this press release.

SOURCE Protagonist Therapeutics, Inc.