Final Results from the Protagonist PROPEL Study Support Further Clinical Development of PTG-100 for the Treatment of Ulcerative Colitis

NEWARK, Calif., Aug. 6, 2018 /PRNewswire/ -- Protagonist Therapeutics, Inc. (Nasdaq:PTGX) today announced results from an independent blinded re-analysis of the Phase 2 PROPEL study of oral alpha-4-beta-7 integrin antagonist PTG-100 for the treatment of patients with ulcerative colitis (UC). No safety concerns were noted with PTG-100. The data from blinded endoscopy re-reads and a comprehensive data review provide signals of clinical efficacy and support further development of PTG-100.

In March 2018, Protagonist announced discontinuation of the study following a planned interim analysis conducted by an independent Data Monitoring Committee (DMC). The interim data revealed an unusually high placebo rate of clinical remission (24 percent, approximately four times higher than historical norms for similar UC studies) that led to a futility decision and discontinuation of the trial. A re-read of the endoscopies by the CRO's subcontractor and a subsequent fully blinded re-read of the endoscopies by an independent third party, Robarts Clinical Trials, confirmed that a subset of the initial endoscopy reads provided by the CRO were in error. If the re-read of endoscopy results had been utilized for the interim futility analysis, the trial would have continued. Results of the complete data set as read by Robarts are summarized below. In addition, improvements observed in independent, blinded histological scores favor PTG-100 over placebo and correlate with the clinical remission and endoscopic response outcomes from the re-analysis.

"The discontinuation of the PROPEL study was an unfortunate consequence of a human error in the endoscopy readouts provided by the CRO," commented Dinesh V. Patel, Ph.D., Protagonist President and Chief Executive Officer. "Based upon an established, safe, and specific mechanism for IBD, PTG-100 offers compelling, patient-focused differentiation by virtue of being an oral drug. We look forward to meeting with the FDA during the second half of 2018 to discuss next steps and plan to present the PROPEL data at a future medical conference. Overall, we also view this data as supportive of the concept of GI-restricted, oral targeted therapy approach for the treatment of IBD. In addition, the most recent financing of $22 million enables us to continue further development of PTG-100."

"It is highly encouraging to see the results that support further study of PTG-100 as there is a clear importance for an oral alpha-4-beta-7 integrin antagonist in expanding the current treatment paradigm," commented William J. Sandborn, M.D., Chief, Division of Gastroenterology, Professor of Medicine at the University of California San Diego School of Medicine. "An oral therapy approach is particularly notable when viewed in the context of advancement in the field, as integrin-targeted therapies begin to replace TNF-targeted therapies in a first line treatment setting for ulcerative colitis. We look forward to the results from upcoming clinical studies of PTG-100 that may allow us to further assess the degree of clinical efficacy and utility for this oral approach on a proven mechanism."

About the Phase 2b PROPEL Trial

The Phase 2b PROPEL trial was a global, randomized, double-blind, placebo-controlled, two-stage adaptive clinical trial to assess the safety, efficacy, and dose-optimization of three doses (150 mg, 300 mg, or 900 mg) of PTG-100 compared to placebo for 12 weeks in patients with moderate to severe ulcerative colitis. The primary efficacy endpoint of the study was the proportion of patients who achieved clinical remission as defined by rectal bleeding, stool frequency, and endoscopic subscores of the Mayo score.  The study was halted in March 2018 following a planned interim analysis that met pre-specified criteria for futility.

Conference Call and Webcast Information

Protagonist executives will host a conference call at 5:00 a.m. PT/8:00 a.m. ET today. To access the live call, dial 1-844-515-9178 (U.S./Canada) or 1-614-999-9313 (international) and refer to conference ID number 6996945. The call will also be webcast and will be accessible from "Events & Presentations" in the Investors section of the company's website at www.protagonist-inc.com. A replay will be available on the company's website approximately two hours after the call and will remain available for 60 days.

About Protagonist Therapeutics, Inc.

Protagonist Therapeutics is a clinical stage biopharmaceutical company that utilizes a proprietary technology platform to discover and develop novel peptide-based drugs to transform existing treatment paradigms for patients with significant unmet medical needs. PTG-100 is an oral alpha-4-beta-7 integrin antagonist peptide that is under evaluation for potential treatment of inflammatory bowel diseases. The Company's interleukin-23 receptor antagonist peptide, PTG-200, is currently in a Phase 1 clinical trial in healthy volunteers to support a Phase 2 study in Crohn's disease. The IL-12/23 pathway blockade is an approach that has been validated through an FDA-approved injectable antibody drug. The company has entered into a worldwide license and collaboration agreement with Janssen Biotech for the clinical development of PTG-200. Protagonist has also applied its innovative peptide platform outside of gastrointestinal disease areas and is developing an injectable hepcidin mimetic, PTG-300, for the potential treatment of anemia and iron overload related to rare blood diseases with an initial focus on beta-thalassemia. The Company has completed a Phase 1 clinical trial with PTG-300, which established pharmacodynamic-based clinical proof-of-concept in normal healthy volunteers. The U.S. Food and Drug Administration has granted Orphan Drug Designation to PTG-300 for beta-thalassemia.

Protagonist is headquartered in Newark, California, with pre-clinical and clinical staff in California and discovery operations in both California and Brisbane, Queensland, Australia. For further information, please visit http://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, the potential for our programs including PTG-100 and the potential re-commencement of clinical studies of PTG-100 in ulcerative colitis, our collaborations and milestone payments we may receive under them, the initiation and availability of results of our clinical trials, our research and development plans, the utility of our intellectual property, and the adequacy of our capital resources. 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, 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.  We discuss many of these risks in greater detail under the heading "Risk Factors" contained in our quarterly report on Form 10-Q for the three months ended March 31, 2018 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:
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SOURCE Protagonist Therapeutics, Inc.