Multi-center Phase 2 clinical trial on track to initiate in the second half of 2019

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Jun. 4, 2019-- Ra Pharmaceuticals, Inc. (Nasdaq:RARX) today announced the U.S. Food and Drug Administration’s (FDA) clearance of the Company’s Investigational New Drug (IND) application for zilucoplan for the treatment of immune-mediated necrotizing myopathy (IMNM). The Company is on track to initiate a Phase 2 clinical trial in the second half of 2019.

“Patients with IMNM face a severe, chronic, debilitating autoimmune disease with limited treatment options and no approved therapies,” said Andrew Mammen, M.D., Ph.D., Muscle Disease Unit Leader, Laboratory of Muscle Stem Cells and Gene Regulation, and Principal Investigator for the Phase 2 study at the National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD. “Given the availability of diagnostic autoantibodies and the central role of terminal complement activation in the pathophysiology of the disease, zilucoplan has the potential to become a targeted therapy for patients with IMNM. The results observed in the recent Phase 2 clinical trial of zilucoplan in generalized myasthenia gravis (gMG), a neuromuscular disease similarly characterized by autoantibody-mediated complement activation and tissue injury, provide strong rationale for the clinical evaluation of zilucoplan in this disease.”

IMNM is an autoimmune myopathy characterized by skeletal muscle necrosis, severe proximal limb weakness, and elevated creatine kinase (CK) levels. IMNM is categorized into two subtypes defined by the presence of distinct autoantibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) or signal recognition particle (SRP). In IMNM, these autoantibodies drive complement-mediated necrosis of muscle fibers, resulting in severe, progressive, and debilitating proximal muscle weakness. IMNM affects more than 15,000 patients in the United States, European Union, and Japan. There are currently no approved therapies for the treatment of IMNM.

The randomized, double-blind, placebo-controlled, multi-center, Phase 2 trial will evaluate the safety, tolerability, and efficacy of zilucoplan in patients with IMNM who are positive for anti-HMGCR or anti-SRP autoantibodies. Patients will be randomized in a 1:1 ratio to receive daily subcutaneous (SC) doses of 0.3 mg/kg zilucoplan or placebo. Randomization will be stratified based on antibody status (anti-HMGCR+ versus anti-SRP+). The trial is expected to enroll approximately 24 patients with an eight-week treatment period. The primary endpoint will be change in CK from baseline to week eight. Following completion of the trial, patients will have the option to enter into an open-label long-term extension study with zilucoplan.

“The IMNM program represents a meaningful expansion of our neuromuscular pipeline for zilucoplan, as we aim to leverage the unique properties of a small peptide in tissue-based complement-mediated disorders and build on the success of our Phase 2 trial for zilucoplan in gMG,” said Doug Treco, Ph.D., President and Chief Executive Officer of Ra Pharma. “We look forward to the initiation of this Phase 2 clinical trial in the second half of this year, an important step forward in our efforts to bring innovative and accessible therapies to patients and build a leading complement-focused neurology and neuromuscular portfolio.”

Analyst and Investor Event

Ra Pharma will host an analyst and investor event on Tuesday, June 18, 2019, at 8:30 a.m. E.T. The event will feature a presentation by Andrew Mammen, M.D., Ph.D., Muscle Disease Unit Leader, Laboratory of Muscle Stem Cells and Gene Regulation, and Principal Investigator for the Phase 2 study at the National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD. The event will be webcast live and can be accessed by visiting the investor relations section of the Company’s website, www.rapharma.com. A replay will be available and archived on the site for three weeks.

About Zilucoplan

Ra Pharma is developing zilucoplan and zilucoplan extended release (XR) for generalized myasthenia gravis (gMG), immune-mediated necrotizing myopathy (IMNM), and other tissue-based, complement-mediated disorders with high unmet medical need. The product candidate is designed for convenient subcutaneous (SC) self-administration. Zilucoplan is an investigational, synthetic, macrocyclic peptide discovered using Ra Pharma's powerful proprietary drug discovery technology. The peptide is designed to bind complement component 5 (C5) with sub-nanomolar affinity and allosterically inhibit its cleavage into C5a and C5b upon activation of the classical, alternative, or lectin pathways.

About Ra Pharmaceuticals

Ra Pharmaceuticals is a clinical-stage biopharmaceutical company focused on leading the field of complement biology to bring innovative and accessible therapies to patients with rare diseases. The Company discovers and develops peptides and small molecules to target key components of the complement cascade. For more information, please visit: www.rapharma.com.

Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding Ra Pharma's ability to expand patient access to important therapies, the potential, safety, efficacy, and regulatory and clinical progress of Ra Pharma's product candidates, including without limitation zilucoplan and our zilucoplan XR program, beliefs regarding clinical trial data, statements regarding trial design, timeline, and enrollment of Ra Pharma's ongoing and planned clinical programs, including without limitation the Phase 2 trial of zilucoplan for the treatment of IMNM and long-term extension study, and plans to host an analyst and investor event. All such forward-looking statements are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include the risks that Ra Pharma's product candidates, including zilucoplan, will not successfully be developed or commercialized, in the timeframe we expect or at all; as well as the other factors discussed in the “Risk Factors” section in Ra Pharma’s most recently filed Annual Report on Form 10-K, as well as other risks detailed in Ra Pharma’s subsequent filings with the Securities and Exchange Commission. There can be no assurance that the actual results or developments anticipated by Ra Pharma will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, Ra Pharma. All information in this press release is as of the date of the release, and Ra Pharma undertakes no duty to update this information unless required by law.

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Source: Ra Pharmaceuticals, Inc.

Investors:
Ra Pharmaceuticals, Inc.
Natalie Wildenradt, 617-674-9874
nwildenradt@rapharma.com

Media:
Argot Partners
David Rosen, 212-600-1902
david.rosen@argotpartners.com