Omeros Provides Update on PDE10 Inhibitor Program

SEATTLE, Oct. 21, 2014 -- Omeros Corporation (OMER) today provided an update on OMS824, the company's phosphodiesterase 10 (PDE10) inhibitor in development for the treatment of schizophrenia and Huntington's disease. OMS824 selectively inhibits PDE10, an enzyme expressed in areas of the brain linked to a wide range of diseases that affect cognition. Omeros has suspended its Huntington's clinical trial as it further evaluates an observation from a nonclinical study in rats. The observation occurred in several of the rats receiving the study's maximum dose of OMS824, a dose that resulted in OMS824 free-plasma concentrations multiply higher than those that have been measured in patients. Non-human primates exposed to plasma concentrations equal to those in the rat demonstrated no findings similar to the observation reported from the rat study. OMS824 has been well tolerated in all human clinical trials.  

Earlier this year, Omeros initiated a Phase 2 trial of OMS824 in patients with Huntington's disease. That trial is a sequential-cohort dose-escalation study that evaluates the safety and tolerability of OMS824 dosed for four weeks in patients with Huntington's disease. Concurrent with the clinical OMS824 program, Omeros is conducting nonclinical studies to allow clinical trials of longer duration. Following preliminary data collection from a 13‑week nonclinical study in rats, Omeros submitted a report on an observation in several of the rats receiving the maximum dose administered in the study to FDA's Division of Neurology Products and its Division of Psychiatry Products where Omeros has its Investigational New Drug applications for Huntington's disease and schizophrenia, respectively. The drug exposure at that maximum dose in the rat study is multiply above the drug exposure in humans at the doses used in the Huntington's disease trial, and the potential relevance of the nonclinical findings to humans, if any, is unknown. Based on follow-up communications with FDA, Omeros has suspended the ongoing Huntington's disease trial, the only OMS824 trial actively enrolling. FDA has requested that Omeros further evaluate the nonclinical data from the 13-week rat study as well as nonclinical studies that did not yield the observation in order to characterize it more fully prior to reinitiating the clinical trial.

In addition to the 13-week rat study, Omeros has conducted several nonclinical studies with OMS824 in rats and in primates, including a 13‑week nonclinical study in primates, at equally high drug exposures to those resulting from the maximal dose in the rat study, with no findings similar to the observation reported from the most recent study in rats. To date, over 120 people have received OMS824 for up to four weeks and the drug is well tolerated. Omeros plans to release available data from the Phase 2 Huntington's program later this year. In addition, other Omeros programs are on track for their near-term milestones.

"Omeros is further evaluating the data from the nonclinical animal studies of OMS824," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "Based on currently available data, we do not believe that the observation in the rats is caused by OMS824. We will work with the FDA and look forward to continuing the Phase 2 Huntington's trial."

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 Orphan Drug designation by the US FDA to evaluate OMS824 in Huntington's disease, and received Fast Track designation from the FDA for the development of OMS824 to treat cognitive impairment in Huntington's disease.

About Omeros Corporation

Omeros is a biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, coagulopathies and disorders of the central nervous system. Derived from its proprietary PharmacoSurgery® platform, the Company's first drug product, Omidria™ (phenylephrine and ketorolac injection) 1%/0.3%, has been approved by the FDA for use during cataract surgery or intraocular lens replacement (ILR) to maintain pupil size by preventing intraoperative miosis (pupil constriction) and to reduce postoperative ocular pain. Omeros is completing preparations for a planned U.S. product launch in the fourth quarter of 2014. Omidria is currently under review for marketing approval by the European Medicines Agency. Omeros also has six clinical-stage development programs focused on complement-related thrombotic microangiopathies, Huntington's disease, schizophrenia, and cognitive impairment; on addictive and compulsive disorders; and on 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 effectiveness of Omidria™ sales and marketing efforts, Omidria market acceptance, product pricing and reimbursement, Omeros' ability to obtain regulatory approval for its Marketing Authorization Application in the EU for the commercialization of Omidria, Omeros' unproven preclinical and clinical development activities, regulatory oversight, product commercialization, intellectual property claims, competitive developments, litigation, 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 August 11, 2014. 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.