Third PharmacoSurgery™ Platform Product Candidate in Clinical Trials

Seattle, Washington - September 9, 2008 - Omeros Corporation today announced that it is enrolling patients in a Phase1/Phase 2 study of OMS302, the Company's third PharmacoSurgery™ product candidate, for use during ophthalmologic surgery. At least 60 patients undergoing age-related cataract extraction with lens replacement are planned for enrollment in the study.

"With the initiation of this study, all three of Omeros' current PharmacoSurgery product candidates are now in the clinic," said Gregory A. Demopulos, M.D., Chairman and CEO of Omeros. "Each of the two agents in OMS302 is currently used individually and perioperatively during eye surgery. OMS302 combines these two agents and their pharmacologic activities into a single proprietary product candidate. With approximately three million cataract procedures performed annually in the U.S. alone, OMS302 is designed to address a large and growing market."

The Phase 1/Phase 2 trial is a randomized, double-blind, vehicle-controlled and parallel-assigned study evaluating the effects of OMS302 on dilation of the pupil during cataract surgery and on pain, discomfort and inflammation following the procedure. OMS302 is added to standard irrigation solutions used in ophthalmologic surgery and is delivered directly to the eye during the operation. PharmacoSurgery™ product candidates are proprietary combinations of therapeutic agents designed to act simultaneously at multiple discrete targets to preemptively block the molecular-signaling and biochemical cascade caused by surgical trauma and to provide clinical benefits both during and after surgery. The lead product candidate in the PharmacoSurgery™ platform is OMS103HP, which is currently in two Phase 3 clinical programs evaluating its safety and ability to improve postoperative joint function and reduce pain following arthroscopic surgery. The urological PharmacoSurgery™ product candidate OMS201, currently in a fully enrolled Phase 1 clinical study, is designed to inhibit surgically induced inflammation, pain and smooth muscle spasm, thereby facilitating uroendoscopy and reducing postoperative frequency, urgency and discomfort.

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