Omeros Corporation Reports Fourth Quarter and Year-End 2013 Financial Results 4Q 2013 net loss of $1.8 million, or $0.05 per share SEATTLE, WA

Omeros Corporation Reports Fourth Quarter and Year-End 2013 Financial Results

4Q 2013 net loss of $1.8 million, or $0.05 per share

SEATTLE, WA March 13, 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 fourth quarter and year ended

December 31, 2013, which include:

a number of significant milestones in 2013, said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. In addition to submitting the NDA and MAA for Omidria, we completed successful clinical trials for OMS824 and

OMS721, advancing both into Phase 2 clinical programs. In connection with the latter two programs, OMS824 received Orphan Drug and Fast Track Designations for Huntington s disease and OMS721 received Orphan Drug Designation for

complement-mediated thrombotic microangiopathies. 2014 promises to be an exciting year we look forward to the planned commercial launch of Omidria, Phase 2 data in Huntington s disease and TMAs, and continued success across our

Fourth Quarter and Recent Highlights

Operating expenses for the three

months ended December 31, 2013 were $14.1 million, including $2.4 million of non-cash expense, compared to $9.1 million, including $2.6 million of non-cash expenses, for the same period in 2012. During the fourth quarter of

2012, operating expenses were reduced by $3.95 million due to a reimbursement Omeros received from its former insurer for expenses Omeros recognized in the third quarter of 2012 in connection with a litigation settlement. Excluding this

reimbursement, Omeros operating expenses for the three months ended December 31, 2013 increased by $1.0 million from the prior year period. The increase was primarily related to our Phase 1 clinical trials evaluating OMS824 and OMS721,

legal costs for patents, employee costs and expenses associated with preparing for our planned commercial launch of Omidria in the U.S. These increased expenses were

partially offset by lower clinical research and development expenses in the three months ended December 31, 2013 as compared to the same period in 2012 due to completion of our Omidria Phase

3 clinical trial in January 2013 and the completion of the first OMS103 Phase 3 clinical trial for meniscectomy in December 2012.

Operating expenses for

the year ended December 31, 2013 were $52.1 million, including $9.7 million of non-cash expenses, compared to $42.9 million, including $4.9 million of non-cash expenses, in 2012. The 2013 increase related primarily to our Phase 1 clinical

trials evaluating OMS824 and OMS721, non-cash rent expense associated with the lease of our new facilities, higher expenses related to the preparation and filing of the NDA and MAA and planned commercial launch for Omidria and increased legal and

employee costs, including non-cash stock-based compensation. These increased expenses were partially offset by lower clinical research and development expenses related to the completion of our Omidria Phase 3 clinical trial in January 2013 and

the first OMS103 Phase 3 clinical trial for meniscectomy in December 2012. These two clinical programs were ongoing during 2012.

year ended December 31, 2013, was $1.6 million, compared to $6.0 million in 2012. The decrease was primarily due to lower deferred revenue being recognized from our GPCR funding agreements, which were fully amortized in the first quarter of

For the quarter ended December 31, 2013, Omeros reported a net loss of $1.8 million, or $0.05 per share. The receipt of $12.5 million in

October 2013 from Omeros settlement with CCIC reduced our net loss by $0.41 per share. This compares to a net loss of $7.7 million, or $0.30 per share, for the same period in 2012, including a $3.95 million ($0.15 per share) reduction of our

loss related to a payment received upon settlement of litigation. Noncash expenses were $2.4 million ($0.08 per share) for the quarter ended December 31, 2013 and $2.6 million ($0.10 per share) for the same period in 2012.

For the year ended December 31, 2013, Omeros reported a net loss of $39.8 million, or $1.39 per share. The receipt of the $12.5 million settlement

payment from CCIC reduced our net loss by $0.44 per share. This compares to a net loss of $38.4 million, or $1.59 per share, in 2012. Noncash expenses were $9.7 million ($0.34 per share) for 2013 and $4.9 million ($0.20 per share) for 2012.

At December 31, 2013, Omeros had cash and cash equivalents and short-term investments of $14.1 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 US 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 unproven preclinical and clinical development activities, regulatory oversight, product commercialization, intellectual property claims, competitive developments and the risks, uncertainties and other factors described under the heading

Risk Factors in the company s Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 13, 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 unless required by law, 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