Seattle, WA - December 9, 2008 - Omeros Corporation today announced favorable results from a Phase 1 vehicle-controlled study of OMS201, another of Omeros' PharmacoSurgery™ product candidates, for use during urological surgery.

The Phase 1 study of OMS201 enrolled patients undergoing endoscopic removal of urinary stones, and was designed to evaluate the systemic absorption and safety of the drug product. The pharmacokinetic data from this study show that systemic plasma levels of the active agents of OMS201 in patients were minimal and in most cases below the level of quantification. There were no serious adverse events.

"We continue to be encouraged by the progress being made in our OMS201 development program, and the completion of this study represents another successful milestone as we advance our PharmacoSurgery™ platform," stated Gregory A. Demopulos, M.D., Chairman and CEO of Omeros. "Based on these positive results, we intend to initiate a Phase 1/Phase 2 study evaluating the safety and preliminary efficacy of two higher concentrations of OMS201 in uroendoscopic surgery."

The Phase 1 study was a randomized, double-blind, vehicle-controlled and parallel-assigned study designed to evaluate the systemic absorption and safety of OMS201 in patients receiving primary treatment by endoscopic removal of urinary stones. OMS201, developed from Omeros' proprietary PharmacoSurgeryTM platform, is designed for use during urological surgery, including uroendoscopic procedures such as ureteroscopy, cystoscopy and minimally invasive prostate procedures. Added to standard irrigation solutions in urological surgery, OMS201 is delivered during the operation directly to the surgical site to inhibit surgically induced inflammation, pain and smooth muscle spasm.

About Omeros Corporation
Omeros Corporation is a clinical-stage biopharmaceutical company committed to discovering, developing and commercializing products focused on inflammation and disorders of the central nervous system. Omeros' most clinically advanced product candidates are derived from its proprietary PharmacoSurgeryTM platform designed to improve clinical outcomes of patients undergoing arthroscopic, ophthalmological, urological and other surgical and medical procedures. Omeros has four ongoing PharmacoSurgeryTM clinical development programs, and its lead product candidate, OMS103HP, is being evaluated in Phase 3 clinical trials for use during arthroscopic surgery to improve postoperative joint function and reduce postoperative pain. Omeros is also building a diverse pipeline of preclinical programs targeting inflammation and central nervous system disorders. For more information on Omeros, visit the Company's Web site at www.omeros.com

Contact:
Susan Neath
Burns McClellan
Investor & Media Relations
212-213-0006
sneath@burnsmc.com