Clinical Response and Durability of Response of Rusfertide (PTG-300) in Polycythemia Vera Featured Today at EHA Press Briefing; Protagonist Therapeutics Plans a Follow-on Two-Year Extension Study to Enable Further Evaluation of the Long-Term Effects of Rusfertide in PV

NEWARK, CA / ACCESSWIRE / June 9, 2023 / Protagonist Therapeutics, Inc. (NASDAQ:PTGX) ("Protagonist" or "the Company") announced today that Ronald Hoffman, MD, Icahn School of Medicine at Mount Sinai, provided a press briefing this morning on the late-breaking oral presentation abstract LB2710: Targeted Therapy of Uncontrolled Erythrocytosis in Polycythemia Vera with the Hepcidin Mimetic, Rusfertide - Blinded Randomized Withdrawal Results of the REVIVE Study at the European Hematology Association (EHA) 2023 Congress. The study results will be presented in detail by Marina Kremyanskaya, MD, PhD, Icahn School of Medicine at Mount Sinai, on Sunday, June 11, 2023 at 9:45-10:00 CEST.

"The positive outcomes of the REVIVE study showcase the efficacy and tolerability of rusfertide as a highly effective therapy for uncontrolled erythrocytosis and associated symptoms in PV, and represent a significant advancement in the treatment of this malignant myeloproliferative neoplasm," said Dr. Hoffman. "Rusfertide offers a novel hormone mimetic-based approach which acts by selectively targeting uncontrolled erythrocytosis, providing sustained and durable hematocrit control and potentially improving PV-related symptoms and quality of life in these patients."

Based on these and other previously announced data from the Phase 2 REVIVE Study of rusfertide (PTG-300) in polycythemia vera, which showed patients on rusfertide remain largely phlebotomy free with durable hematocrit control under 45%, the company is planning a follow-on two year extension study, PTG-300-21, for patients who complete the current three-year Phase 2 (REVIVE) study, thereby enabling evaluation of the effects of rusfertide in PV for up to five years.

"As previously announced, data from the randomized withdrawal portion of the Phase 2 REVIVE study showed that nearly 70% of subjects receiving rusfertide treatment met the definition of clinical responders (p=0.0003) and more than than 92% of subjects in the rusfertide arm remained phlebotomy free. These are patients who would have otherwise required frequent phlebotomy, with or without cytoreductives. Additionally, some of the study participants have remained on rusfertide treatment for more than 2.5 years, highlighting the durability of response with rusfertide. A follow-on study allows even longer-term evaluation of the durability of response with rusfertide," said Arturo Molina, MD, MS, Chief Medical Officer, Protagonist Therapeutics. "We look forward to the opportunity this follow-on study presents, to gain further insight into the long-term safety and effectiveness of this promising drug candidate."

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 2 REVIVE study is now complete, with an open-label extension underway. The global Phase 3 VERIFY study of rusfertide in polycythemia vera is ongoing. Protagonist retains all worldwide development and commercialization rights to rusfertide.

Positive topline results from the Phase 2b FRONTIER 1 study of JNJ-2113 in moderate-to-severe plaque psoriasis became available in March 2023, with further details to be shared at medical meetings starting in the second quarter of 2023. 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. A Phase 2 initiation in a second indication would further qualify the Company for a $10 million milestone. In total, Protagonist remains eligible for up to $855 million in various milestone payments and tiered royalties based on worldwide net drug sales.

More information on Protagonist, its pipeline drug candidates and clinical studies can be found on the Company's website at protagonist-inc.com.

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 the potential benefits to patients of rusfertide. 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.

Contact:

Jami Taylor
Email: j.taylor@ptgx-inc.com

SOURCE: Protagonist Therapeutics, Inc.

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