Omeros Reports Additional Positive Phase 1 Clinical Data for OMS824 for the Treatment of Cognitive Disorders

SEATTLE, Feb. 11, 2014 /PRNewswire/ -- Omeros Corporation (NASDAQ: OMER) today announced additional positive data from its Phase 1 program for OMS824, the lead compound in Omeros' phosphodiesterase 10 (PDE10) program. This clinical trial evaluated the extent to which OMS824 binds to PDE10, an enzyme expressed in the region of the brain that has been linked to a wide range of diseases that affect cognition. In the latest cohort enrolled in this trial, OMS824 achieved a high of approximately 70‑percent engagement at PDE10 without evidence of extrapyramidal symptoms (EPS). These data further support the potential of OMS824 to have a high therapeutic index in the treatment of patients with schizophrenia, Huntington's disease and other cognitive disorders. Omeros is completing a Phase 2a trial evaluating the drug in patients with schizophrenia and will start enrollment in a Phase 2 trial for Huntington's disease this quarter.

The results reported today were in healthy male subjects receiving OMS824 once daily for 10 days. Positron emission tomography (PET) scans were used to measure the binding activity of OMS824 to PDE10 in the brain on the last day of dosing. An average of 66‑percent occupancy at PDE10 was seen in the striatum, the region of the brain that plays a critical role in cognition. The drug was well tolerated in all subjects with mild somnolence as the main side effect. Since the maximally tolerated dose has not been reached, Omeros is now planning to evaluate a higher dose of OMS824 in the trial to determine whether an even higher level of PDE10 occupancy can be achieved.

Effective inhibition of PDE10 is considered a novel and promising mechanism to treat central nervous system disorders. Intolerable side effects, particularly EPS, are an important limitation to PDE10 inhibitors currently in development, narrowing the therapeutic index (the ratio of the toxic dose to the effective dose) and likely prohibiting the evaluation of these compounds at higher levels of target engagement. The results in the current cohort along with previously reported data from this clinical trial indicate that OMS824 may not be similarly constrained by such side effects.

"OMS824 continues to allow increased dosing that is well tolerated and delivers a significantly higher level of interaction at the target enzyme than has been reported for any other PDE10 inhibitor," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "Given the absence to date of limiting side effects in any of the healthy subjects or schizophrenia patients administered OMS824, we plan to evaluate a higher dose in both the Phase 2a schizophrenia and the Phase 1 PET trials. In parallel, we will soon initiate enrollment in our OMS824 Phase 2 clinical trial in Huntington's disease."

Omeros was recently awarded Orphan Drug and Fast Track Designations for the OMS824 program in Huntington's disease by the US Food and Drug Administration.

About Omeros' PDE10 Program
PDE10 is an enzyme that is expressed in areas of the brain linked to diseases that affect cognition and psychomotor functions, including Huntington's disease and schizophrenia. Huntington's disease is a hereditary neurodegenerative disorder that leads to movement, cognition, and behavioral abnormalities and premature death. Schizophrenia is a group of severe brain disorders characterized by an abnormal interpretation of reality, which can manifest as delusions, hallucinations, and/or disordered thinking and behavior. Cognitive dysfunction is responsible for substantial disability in both of these diseases and is not meaningfully improved by current medications. Omeros' proprietary compound OMS824, currently in Phase 2 clinical programs, inhibits PDE10 and is being developed for the treatment of cognitive disorders. In addition to potential benefits on cognition, OMS824 could also improve the motor and psychiatric abnormalities in Huntington's disease as well as the positive (e.g., hallucinations) and negative (e.g., flat affect) symptoms of schizophrenia. Omeros has been awarded both Orphan Drug and Fast Track Designations by the US FDA to evaluate OMS824 in Huntington's disease, and a Fast Track application to the FDA for the evaluation of OMS824 in schizophrenia is currently under review.

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, 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 commercial launch planned for 2014. Omeros' five 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