Omeros Announces Positive OMS721 Data in Serum from Patients with aHUS

SEATTLE, March 10, 2014 /PRNewswire/ -- Omeros Corporation (NASDAQ: OMER) today announced positive data using OMS721, the lead human monoclonal antibody in Omeros' mannan-binding lectin-associated serine protease-2 (MASP-2) program, in ex vivo studies of endothelial activation relevant to the pathophysiology of human atypical hemolytic uremic syndrome (aHUS), a form of thrombotic microangiopathy (TMA).  TMAs 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. In February, Omeros reported positive results from its OMS721 Phase 1 clinical trial and, earlier this month, announced submission of an investigational new drug application to the U.S. Food and Drug Administration (FDA) to initiate a Phase 2 clinical trial in patients with TMA, including patients with aHUS.

The data announced today resulted from studies conducted in support of the clinical evaluation of OMS721 by Prof. Giuseppe Remuzzi and colleagues Marina Noris and Miriam Galbusera at the Mario Negri Institute for Pharmacological Research in Bergamo, Italy, and the Clinical Research Center for Rare Diseases "Aldo e Cele Daccò" of the same Institute, a European center for collecting and studying TMA samples. The experimental model is based on the finding that serum samples from aHUS patients cause complement deposition and thrombus formation when incubated with human microvascular endothelial cells. The data reported today showed that OMS721 significantly inhibited complement deposition in the model using serum samples from aHUS patients obtained during the acute phase of disease (p<0.01) and during remission (p<0.001) compared to untreated controls. Experiments evaluating the effects of OMS721 on thrombus formation are planned. Prof. Remuzzi's laboratories have previously shown in this same model system that treatment with agents that block the complement factor C5 has a similar inhibitory effect on complement deposition. Eculizumab (Soliris^®) is an anti-C5 monoclonal antibody that is approved by the FDA and the European Medicines Agency to treat patients with aHUS.

"The OMS721 data in serum samples from aHUS patients are of great interest even in relation to disease pathophysiology," stated Prof. Remuzzi, MD, FRCP, Research Coordinator at the Institute and international expert in the study of kidney disease who has contributed major advances to the understanding of the pathophysiology of hemolytic uremic syndrome.

"We are excited by the performance of OMS721 in serum samples from aHUS patients," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "These data indicate that the lectin pathway, and MASP-2 specifically, are involved in the pathophysiology of aHUS, one of the devastating TMAs. We look forward to initiating enrollment next quarter in our OMS721 Phase 2 trial in patients with aHUS and other TMAs, and we hope to be able to share the results later this year."

About Omeros' MASP-2 Program

Omeros controls the worldwide rights to MASP-2 and all therapeutics targeting MASP-2, a novel pro-inflammatory protein target involved in activation of the complement system, which is an important component of the immune system. The complement system plays a role in the inflammatory response and becomes activated as a result of tissue damage or microbial infection. MASP-2 appears to be unique to, and required for the function of, one of the principal complement activation pathways, known as the lectin pathway. Importantly, inhibition of MASP-2 does not appear to interfere with the antibody-dependent classical complement activation pathway, which is a critical component of the acquired immune response to infection, and its abnormal function is associated with a wide range of autoimmune disorders. MASP-2 is generated by the liver and is then released into the circulation. Adult humans who are genetically deficient in one of the proteins that activate MASP-2 do not appear to be detrimentally affected by the deficiency. Therefore, Omeros believes that it may be possible to deliver MASP-2 antibodies systemically and OMS721, its lead MASP-2 antibody, is designed to be self-administered by subcutaneous injection.

Omeros also believes that it has identified the proteins that activate the complement system's alternative pathway in humans, which is linked to a wide range of immune-related disorders. In addition to its lectin pathway inhibitors, the Company is advancing the development of antibodies that would block activation of the alternative pathway alone or in combination with the lectin pathway.

About Omeros Corporation

Omeros is a clinical-stage biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics targeting inflammation, coagulopathies and disorders of the central nervous system. Derived from its proprietary PharmacoSurgery^® platform, the Company's lead drug product, Omidria™ (OMS302) for lens replacement surgery, is currently under review for marketing approval by both the US Food and Drug Administration and the European Medicines Agency with US commercial launch planned for the second half of 2014. Omeros' six other clinical programs are focused on schizophrenia, Huntington's disease and cognitive impairment; addictive and compulsive disorders; complement-related diseases; and preventing problems associated with surgical procedures. Omeros also has a proprietary GPCR platform, which is making available an unprecedented number of new GPCR drug targets and corresponding compounds to the pharmaceutical industry for drug development.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, which are subject to the "safe harbor" created by those sections for such statements. All statements other than statements of historical fact are forward-looking statements, which are often indicated by terms such as "anticipate," "believe," "could," "estimate," "expect," "goal," "intend," "look forward to", "may," "plan," "potential," "predict," "project," "should," "will," "would" and similar expressions. Forward-looking statements are based on management's beliefs and assumptions and on information available to management only as of the date of this press release. Omeros' actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including, without limitation, risks associated with Omeros' unproven preclinical and clinical development activities, regulatory oversight, product commercialization, intellectual property claims, and the risks, uncertainties and other factors described under the heading "Risk Factors" in the Company's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 7, 2013. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements, and the Company assumes no obligation to update these forward-looking statements, even if new information becomes available in the future.

SOURCE Omeros Corporation