Omeros Gets Orphan Designation for TMA Treatment

Omeros Corp. has received Orphan Drug designation from the FDA for OMS721 for prevention of complement-mediated thrombotic microangiopathies (TMAs). OMS721, the company’s lead human monoclonal antibody, targets mannan-binding lectin-associated serine protease-2 (MASP-2), the key regulator of the lectin pathway of the immune system.

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 is completing a Phase I study to assess the safety and pharmacokinetics of OMS721. 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 I 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 I data in early 2014. The Phase II program evaluating OMS721 for the prevention of complement-mediated TMAs is expected to begin in 1Q14.

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.