Press Release Protagonist Therapeutics Announces the Selection of Oral Peptide PN-235 into Phase 2 Clinical Development Program for Multiple Indications

Protagonist Therapeutics (Nasdaq: PTGX) ("Protagonist" or "the Company") today announced the selection of PN-235 (JNJ-77242113) as the final candidate for all clinical studies in multiple indications based on intervention of the Interleukin-23 (IL-23) pathway, under the Company's collaboration with Janssen Biotech, Inc. (Janssen). In addition to the previously announced Phase 2 clinical study of PN-235 in psoriasis, new Phase 2 clinical studies of PN-235 in inflammatory bowel diseases (IBD) are expected to commence in late 2022. Further development of PN-232 (JNJ-7510586) will be discontinued in favor of PN-235 based on its superior potency, and overall pharmacokinetic and pharmacodynamic profile.

"We are delighted to see PN-235 emerge as the clear focal point going forward, after over four-plus years of a highly productive and ongoing collaboration with Janssen," said Dinesh V. Patel, PhD, President and CEO of Protagonist. "We look forward to exploring the full potential of a highly differentiated, oral targeted therapy like PN-235, thereby potentially addressing persistent unmet needs of patients with immune-mediated diseases like psoriasis and IBD."

Protagonist will earn a $25 million milestone in connection with the initiation of the first Phase 2 study of PN-235 in psoriasis in early 2022. Protagonist is also eligible for a $10 million milestone in connection with the start of the second indication-based Phase 2 study. Protagonist is eligible for up to approximately $900 million in development-related milestone payments, in addition to the $87.5M in milestones already earned. Under the terms of the collaboration, Janssen will conduct all future clinical studies, including these anticipated Phase 2 studies, and will be solely financially responsible for any such studies.

About Protagonist

Protagonist Therapeutics is a biopharmaceutical company with multiple peptide-based investigational new chemical entities in different stages of development, all derived from the Company's proprietary technology platform.

Protagonist's pipeline includes rusfertide (PTG-300), an investigational, injectable hepcidin mimetic currently in a Phase 2 proof-of-concept clinical trial for polycythemia vera (PV), a Phase 2 study in PV subjects with high hematocrit levels, and a recently completed Phase 2a study for hereditary hemochromatosis. The Company plans to initiate a single, global Phase 3 randomized, placebo-controlled trial evaluating the efficacy and safety of a once weekly, subcutaneously self-administered dose of rusfertide.

The Company is also evaluating an orally delivered, gut-restricted alpha-4-beta-7 integrin specific antagonist peptide (PN-943) currently in a Phase 2 study in adults with moderate to severe active ulcerative colitis (UC). The Company is targeting ulcerative colitis as the initial indication.

The Company has a worldwide license and collaboration agreement with Janssen Biotech, Inc., for the development of oral peptide IL-23 receptor antagonists. Compounds in development include PN-235, a second-generation oral interleukin-23 receptor antagonist candidate. Under the collaboration with Janssen, PN-235 is expected to advance into Phase 2 studies in psoriasis and new Phase 2 clinical studies in inflammatory bowel diseases.

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, the Company's collaboration with Janssen, the timing of Janssen's PN-235 trials and the potential benefits of PN-235. 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 agreements, 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.