Omeros announces positive data from OMS824 Phase 1 clinical trial

Omeros Corporation (NASDAQ: OMER) today announced positive data from the Company's Phase 1 clinical trial evaluating the pharmacokinetics of OMS824, the lead compound in Omeros' phosphodiesterase 10 (PDE10) program, further supporting that OMS824 can achieve superior target engagement with lesser side effects compared to other PDE10 inhibitors in development. With these data and the previously announced encouraging results from the OMS824 positron emission tomography (PET) clinical trial, Omeros is advancing OMS824 into Phase 2 clinical programs. OMS824 selectively inhibits PDE10, an enzyme expressed in areas of the brain linked to a wide range of diseases that affect cognition, including Huntington's disease and schizophrenia.

The OMS824 Phase 1 clinical trial included single- and multiple-dose escalation studies that enrolled 100 healthy male subjects: 60 subjects received a single dose of OMS824, 24 subjects received multiple doses for seven to 10 days, and 16 subjects received placebo. The data announced today are at the highest multiple-dose level administered and, at this dose, OMS824 was well tolerated and the only apparent drug-related adverse events were mild. Almost all adverse events were self-limiting, resolving during the 10-day dosing period. In May of this year, Omeros reported that a lower dose evaluated in an ongoing PET clinical trial demonstrated target engagement greater than had previously been reported for any PDE10 inhibitor (an average of approximately 50-percent and a maximum of approximately 70-percent engagement) without the dose-limiting side effects seen with other PDE10 inhibitors. Pharmacokinetic data at the high dose announced today showed an approximately two-fold increase in plasma concentration over that of the dose used in the earlier-reported PET trial. This same high dose level is scheduled to be evaluated in the ongoing PET trial and is expected to demonstrate substantially higher target engagement. The Phase 1 clinical trial results predict that OMS824, at well-tolerated doses, will effectively inhibit PDE10 and support continuing development for the treatment of Huntington's disease, schizophrenia and other central nervous system disorders.

"These findings are unprecedented based on our knowledge of the work to date in the area of PDE10 inhibition and could result in a significant competitive advantage across a range of CNS indications," stated Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. "With this further confirmation of the unique pharmacology of our PDE10 inhibitor, Omeros is well positioned to initiate Phase 2 programs in schizophrenia and Huntington's disease before year-end."