Protagonist Therapeutics Announces Updated Phase 2 Data Supporting Long-Term Efficacy of Rusfertide in Polycythemia Vera

NEWARK, Calif., June 11, 2021 /PRNewswire/ -- Protagonist Therapeutics (Nasdaq:PTGX) ("Protagonist" or "the Company") today announced updated results from the ongoing Phase 2 study of rusfertide, an investigational new drug being evaluated for the treatment of polycythemia vera (PV). These data were presented in an oral presentation today at the European Hematology Association (EHA) 2021 Virtual Congress.

"This data set cumulatively builds on previously presented scientific evidence demonstrating rusfertide's potential as the first-in-class, non-cytoreductive treatment option for polycythemia vera, a disease that currently has limited therapeutic options and a demonstrated significant unmet medical need," said Dinesh Patel, Ph.D., President and Chief Executive Officer of Protagonist. "The possibility of advancing PV treatment beyond the current standard of care is compelling to patients and the medical community. The durability of effect and symptom improvements being observed in our fully enrolled Phase 2 study, along with the recent Breakthrough Therapy Designation from the FDA, provides further support for the advancement of rusfertide into Phase 3 clinical development in early 2022."

Summary of Results:

• Therapeutic phlebotomies were essentially eliminated and a target hematocrit of less than 45 percent was maintained for the vast majority of patients treated with rusfertide
• Rusfertide demonstrated long-term control of hematocrit, as well as durability of effect based on patients treated up to 18 months
• Rusfertide treatment also led to reversal of iron deficiency as evidenced by increasing serum ferritin, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values
• Rusfertide demonstrated similar efficacy in all patients, independent of risk group or prior and concurrent therapy
• Benefits were observed in patient reported outcomes, as shown by improvement in PGI-C and reduction in MPN-SAF Symptom Scores, attributed largely to the sub-scores of fatigue and concentration, consistent with improvement in iron deficiency
• The current data indicate that rusfertide is well tolerated. The most common adverse events observed were transient injection site reactions

"These results provide additional evidence that rusfertide may have a clinical benefit for patients with polycythemia vera," said Ronald Hoffman, MD, the Albert A. and Vera G. List Professor of Medicine and Director of the Myeloproliferative Disorders Research Program at Mount Sinai in New York. "The need for a new non-cytoreductive therapeutic option in PV is urgent. I look forward to the next steps in rusfertide's development for this disease, as it may alleviate the burden of phlebotomy for patients who cannot control their hematocrit levels through currently existing treatment options and need an alternative therapeutic approach."

The ongoing Phase 2 rusfertide study in PV is designed to monitor the safety profile and obtain evidence of efficacy in patients requiring frequent phlebotomies (at least three phlebotomies in the prior six months). The study design consists of three stages: a 16-week open-label stage with weekly subcutaneous doses from 10 to 80 mg and dose escalation or reduction, as necessary every four weeks; a 12-week maintenance period at doses that effect desired hematocrit levels; and then a randomized and blinded withdrawal stage (1:1 treatment vs. placebo) for up to 12 weeks. The study also has an open-label extension for up to three years to monitor long-term safety and other effects. The primary endpoint is the control of hematocrit below 45 percent during the blinded randomized withdrawal period. Other endpoints of this clinical proof-of-concept study include measurement of blood parameters (hematocrit and hemoglobin levels), reductions or delay in phlebotomy requirements, and symptoms related to quality of life.

Additional information is available at https://clinicaltrials.gov/ct2/show/NCT04057040 and http://ptg300pvstudy.com/.

Conference Call and Webcast Information

Protagonist management will host a conference call and webcast today at 8:00 a.m. ET to provide a research update and brief corporate update. The call will feature Ronald Hoffman, M.D., Albert A. and Vera G. List Professor of Medicine, Hematology and Medical Oncology, and Director of the Myeloproliferative Disorders Research Program at Mount Sinai Hospital, and a lead investigator of the Phase 2 study. To access the live call, dial [phone] (U.S./Canada) or [phone] (international) five minutes prior to the call and ask to be joined to the Protagonist Therapeutics call. A live and archived webcast will also be accessible in the Investors section of the Company's website at www.protagonist-inc.com.

About Protagonist Therapeutics

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 Phase 2 study for hereditary hemochromatosis. Based on the feedback provided by the FDA and EU regulatory authorities, 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). 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 included in this agreement are PTG-200, PN-235 and PN-232. PTG-200 is an orally delivered, gut-restricted, interleukin-23 receptor specific antagonist peptide in a Phase 2 clinical trial for Crohn's disease. PN-235 and PN-232, both second-generation oral interleukin-23 receptor antagonist candidates, are currently in Phase 1 studies.

Protagonist is headquartered in Newark, California. For further information, please visit www.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 our intentions or current expectations concerning, among other things, potential benefits of rusfertide for the treatment of PV and our plans conduct a Phase 3 trial evaluating rusfertide for PV. 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.

 

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