SEATTLE, Dec. 18, 2013 /PRNewswire/ -- Omeros Corporation (NASDAQ: OMER) today announced that OMS721, the company's lead human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2), the key regulator of the lectin pathway of the immune system, has received orphan drug designation from the U.S. Food and Drug Administration (FDA) for prevention of complement-mediated thrombotic microangiopathies (TMAs). TMAs, including atypical hemolytic uremic syndrome and thrombotic thrombocytopenic purpura, are a family of rare, debilitating and life-threatening disorders characterized by multiple thrombi (clots) in the microcirculation of the body's organs, most commonly the kidney and brain. The lectin pathway, one of the principal complement activation pathways in the immune system, is thought to play a central role in the development of TMAs. By targeting MASP-2, OMS721 specifically blocks the lectin pathway. Omeros controls the worldwide rights to MASP-2 and all therapeutics targeting MASP-2. Omeros is completing a Phase 1 study to assess the safety and pharmacokinetics of OMS721. As previously announced, at the highest subcutaneous dose administered to date in this study, OMS721 achieved serum concentrations that resulted in a high degree of inhibition of lectin pathway activation. The serum concentrations seen in the Phase 1 subjects are similar to those associated with efficacy in animal models of diseases, including TMA, linked to the lectin pathway. Omeros expects to report additional Phase 1 clinical data in early 2014. The Phase 2 clinical program evaluating OMS721 for the prevention of complement-mediated TMAs is expected to begin in the first quarter of 2014. "We are pleased that the FDA has granted orphan drug designation for OMS721. The designation should accelerate the development of OMS721 and, given the limitations of current treatments for TMAs, we look forward to initiating our Phase 2 clinical program next quarter," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "The remainder of this year and the first part of 2014 promise to be exciting times across other Omeros programs as well. This month we will initiate our OMS824 Phase 2 clinical program in Huntington's disease – earlier granted orphan drug designation by the FDA – and could also report Phase 2a data for OMS824 in schizophrenia. We then look to the potential marketing approval of Omidria™, its launch completing our transition to a commercial company." Orphan designation by the FDA is granted to promote the development of drugs that target conditions affecting 200,000 or fewer U.S. patients annually and that are expected to provide significant therapeutic advantage over existing treatments. Orphan designation qualifies a company for benefits that apply across all stages of drug development, including accelerated approval process, seven years of market exclusivity following marketing approval, tax credits on U.S. clinical trials, eligibility for orphan drug grants, and waiver of certain administrative fees.