Omeros Corporation Reports First Quarter 2014 Financial Results Secures Additional $50.4 Million in Cash in 1Q 2014 Seattle, WA

Omeros Corporation Reports First Quarter 2014 Financial Results

Secures Additional $50.4 Million in Cash in 1Q 2014

Seattle, WA May 12, 2014 Omeros Corporation (NASDAQ: OMER), a clinical-stage biopharmaceutical company committed to discovering,

developing and commercializing small-molecule and protein therapeutics targeting inflammation, coagulopathies and disorders of the central nervous system, today announced recent highlights and financial results for the first quarter of 2014, which

We continue to expect approval of Omidria this quarter, said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros.

Completing an additional $50 million of equity and debt financings in March strengthened our financial position, and we are preparing for the planned U.S. market launch of Omidria in the second half of this year. The remainder of our pipeline

also continues advancing, with Phase 2 small-molecule and antibody clinical programs recently initiated in schizophrenia, Huntington s and TMAs with preliminary data from the latter two expected this year, and two more programs OMS527

for addiction and OMS616 for bleeding slated to enter the clinic in 2015. From the 54 orphan GPCRs that we control, we have begun compound optimization targeting a handful of these receptors linked to cancer and remyelination. Our expected

transition to a commercial company together with likely clinical data from our pipeline s industry-leading compounds promise to make the remainder of 2014 exciting.

First Quarter and Recent Highlights

For the quarter ended March 31, 2014, Omeros reported a net loss of $16.6 million, or $0.54 per share. This

compares to a net loss of $10.5 million, or $0.40 per share, for the same period in 2013. Noncash expenses were $2.6 million ($0.09 per share) for the quarter ended March 31, 2014 and $2.2 million ($0.08 per share) for the same period in 2013.

Operating expenses for the three months ended March 31, 2014 were $15.8 million, including $2.6 million of non-cash expenses, compared to $11.1 million,

including $2.2 million of non-cash expenses, for the same period in 2013. The increase was primarily related to preparing for the expected U.S. commercial launch of Omidria, to expenses associated with the Phase 2 clinical trials evaluating OMS721

in TMAs and OMS824 in schizophrenia and Huntington s disease as well as to the manufacturing costs of clinical material of both compounds.

for the quarter ended March 31, 2014 was $100,000 compared to $1.1 million for the same period in 2013. This decrease was primarily due to lower revenue recognized from our GPCR funding agreement with Vulcan Inc., which was fully amortized in the

first quarter of 2013.

At March 31, 2014, Omeros had cash and cash equivalents and short-term investments of $52.2 million.

About Omeros Corporation

Omeros is a clinical-stage

biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics targeting inflammation, coagulopathies and disorders of the central nervous system. Derived from its proprietary

PharmacoSurgery platform, the Company s lead drug product, Omidria (OMS302) for lens replacement surgery, is currently under review for marketing approval by both the U.S. Food and

Drug Administration and the European Medicines Agency with U.S. commercial launch planned for the second half of 2014. Omeros six other clinical programs are focused on schizophrenia, Huntington s disease and cognitive impairment;

addictive and compulsive disorders; complement-related diseases; and 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 Omeros ability to

obtain regulatory approval for its New Drug Application in the U.S. and 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 May 12, 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.

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