Ra Pharmaceuticals, Inc. (NASDAQ:RARX) today announced that it has initiated dosing in the Company’s Phase 2 clinical trial evaluating RA101495 SC for the treatment of generalized myasthenia gravis (gMG). gMG is a rare, complement-mediated, autoimmune disease that causes weakness in skeletal muscles. Ra Pharma is a clinical stage biopharmaceutical company focusing on the development of next-generation therapeutics for the treatment of complement-mediated diseases and is developing RA101495 as a novel, subcutaneously-administered (SC) inhibitor of complement component 5 (C5). RA101495 SC is currently in clinical development for the treatment of paroxysmal nocturnal hemoglobinuria (PNH).

“Following promising Phase 1 data demonstrating a favorable pharmacokinetic and pharmacodynamic profile for RA101495, this Phase 2 trial is designed to evaluate the safety, tolerability, and preliminary efficacy of RA101495 in gMG,” said James F. Howard, MD, University of North Carolina School of Medicine. “RA101495 potently inhibits C5, a validated therapeutic target in myasthenia. The convenient, once-daily, SC, self-administration schedule of RA101495 may enable treatment of a broad population of gMG patients.”

The Phase 2, multicenter, randomized, double-blind, placebo-controlled trial is designed to evaluate the safety, tolerability, and preliminary efficacy of RA101495 SC in patients with gMG. The trial will enroll approximately 36 patients. At the outset of the 12-week treatment period, patients will be randomized in a 1:1:1 ratio and will receive daily, SC doses of 0.1 mg/kg of RA101495, 0.3 mg/kg of RA101495, or matching placebo. The primary efficacy endpoint is change in Quantitative Myasthenia Gravis (QMG) score from baseline to week 12. All patients will have the opportunity to receive RA101495 SC in a long-term extension study.

“gMG is a rare, autoimmune disease characterized by autoantibodies targeting proteins critical for the normal transmission of electrical signals from nerves to muscles,” said Nancy Law, CEO of the Myasthenia Gravis Foundation of America. “Patients with gMG have limited treatment options. Given the significant unmet need in this patient population, we are encouraged by the initiation of this Phase 2 trial, and we look forward to determining the potential clinical benefit of this novel, once-daily, subcutaneously-administered C5 inhibitor.”

Myasthenia gravis (MG) is a chronic, autoimmune, neuromuscular disease characterized by weakness and fatigue of voluntary muscles. Patients with MG present with muscle weakness that becomes increasingly severe with repeated use and recovers with rest. Weakness can be localized to specific muscles, such as those responsible for eye movements, but often progresses to affect a broader range, including head, limb, and respiratory muscles. This progression is often described as the generalized, or severe, form of the disease. gMG is estimated to affect over 80,000 individuals worldwide.

“Initiation of dosing in our Phase 2 trial evaluating RA101495 in gMG is a critical step in the advancement of a potential novel therapy for patients with this disabling autoimmune disorder, and we expect topline data from this trial in the first half of 2019,” said Doug Treco, PhD, President and Chief Executive Officer of Ra Pharma. “We continue to be encouraged by the positive interim data from our ongoing Phase 2 program evaluating RA101495 in patients with PNH, and we remain focused on fully maximizing the potential of RA101495’s safety, efficacy, and ease of administration to expand patient access across a range of C5-mediated disorders.”

About RA101495 SC

Ra Pharma is developing RA101495 SC for paroxysmal nocturnal hemoglobinuria (PNH), generalized myasthenia gravis (gMG), atypical hemolytic uremic syndrome (aHUS), and lupus nephritis (LN). The product is designed for convenient, once-daily, subcutaneous (SC) self-administration. RA101495 SC is a synthetic, macrocyclic peptide discovered using Ra Pharma’s powerful proprietary drug discovery technology. The peptide binds complement component 5 (C5) with sub-nanomolar affinity and allosterically inhibits its cleavage into C5a and C5b upon activation of the classical, alternative, or lectin pathways. By binding to a region of C5 corresponding to C5b, RA101495 SC also disrupts the interaction between C5b and C6 and prevents assembly of the membrane attack complex (MAC). This activity defines an additional, novel mechanism for the inhibition of C5 function. To learn more about RA101495 SC, please visit: http://rapharma.com/pipeline/ra101495/.

About Ra Pharmaceuticals

Ra Pharmaceuticals is a clinical stage biopharmaceutical company focusing on the development of next-generation therapeutics for complement-mediated 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 Statement

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 the safety, efficacy and regulatory and clinical progress of our product candidates, including RA101495. 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 RA101495, will not successfully be developed or commercialized; the risk of delay in enrollment or release of topline results from that expected; the risk that initial data from the Company’s global Phase 2 clinical program evaluating RA101495 for the treatment of PNH may not be indicative of final study results; the risk that initial data from a limited number of patients may not be indicative of results from the full patient enrollment planned for such study; 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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