Omeros Corporation Reports Second Quarter 2012 Financial Results Seattle, WA

Omeros Corporation Reports Second Quarter 2012 Financial Results

Seattle, WA August 7, 2012 Omeros Corporation (NASDAQ: OMER), a clinical-stage biopharmaceutical company committed to

discovering, developing and commercializing products targeting inflammation, coagulopathies and disorders of the central nervous system, today announced its financial results for the second quarter of 2012.

expenses for the quarter ended June 30, 2012 were $9.8 million compared to $6.1 million for the same period in 2011. The increase in operating expenses primarily relates to increased Phase 3 clinical trial expenses for OMS302 and OMS103HP and

an increase in expenses in connection with preclinical work for Omeros PDE10 and MASP-2 programs in preparation for their advancement into the clinic. For the quarter ended June 30, 2012, Omeros reported a net loss of $8.5 million, or

$0.38 per share, compared to a net loss of $5.3 million, or $0.24 per share, for the same period in 2011.

At June 30, 2012, Omeros had

cash, cash equivalents and short-term investments of $7.3 million. On July 2, 2012, Omeros completed a public offering pursuant to which it sold 3,365,854 shares of its common stock at a price of $10.25 per share for estimated net proceeds of

Our two ongoing Phase 3 clinical trials continued to advance during the quarter OMS302 for lens replacement

procedures and OMS103HP for arthroscopic meniscectomy surgery and we expect to report data for both in the second half of this year, said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. We have also

begun to prepare the NDA for OMS302 which, assuming positive data from the ongoing clinical trial, we expect to submit to the FDA during the first part of 2013. Our other programs also progressed, and we plan to file an IND for our PDE10 inhibitor

this quarter with an IND for our MASP-2 antibody scheduled to follow in early 2013. The capital received from our recent financing is expected to help Omeros achieve these and other significant milestones throughout the coming year.

Second Quarter and Recent Highlights

About Omeros Corporation

Omeros is a clinical-stage biopharmaceutical company committed to discovering, developing and commercializing products targeting inflammation,

coagulopathies and disorders of the central nervous system. The Company s most clinically advanced product candidates are derived from its proprietary PharmacoSurgery platform designed to improve clinical outcomes of patients undergoing a

wide range of surgical and medical procedures. Omeros has four ongoing clinical development programs. Omeros may also have the near-term capability, through its GPCR program, to add a large number of new drug targets and their corresponding

compounds to the market. Behind its clinical candidates and GPCR platform, Omeros is building a diverse pipeline of protein and small-molecule preclinical programs targeting inflammation, coagulopathies and central nervous system disorders.

Forward-Looking Statements

This press release contains forward-looking statements as defined within the Private Securities Litigation Reform Act of 1995, which are subject to the

safe harbor created by those sections. These statements include, but are not limited to, Omeros expectations that it will report data from its two ongoing Phase 3 clinical trials this year; that it will be able to file an NDA for

OMS302 during the first part of 2013; that it will file an IND for its PDE10 program this quarter; that it will file an IND for its MASP-2 program in early 2013; that the capital it received from the recent public offering will help it meet these

and other significant milestones throughout the coming year; and that Omeros may have capability, through its GPCR program, to add a large number of new drug targets and their corresponding compounds to the market. 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, 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 7, 2012. 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 publicly, even if new

information becomes available in the future.

Jennifer Cook Williams

Cook Williams Communications, Inc.

Investor and Media Relations

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except share and per share data)

CONSOLIDATED BALANCE SHEET DATA