Omeros Corporation Reports Third Quarter 2018 Financial Results Conference Call Friday November 9th at 8:30 a.m.

Omeros Corporation Reports Third Quarter 2018 Financial Results

Conference Call Friday November 9th at 8:30 a.m. ET

SEATTLE, WA November 8, 2018 Omeros Corporation (NASDAQ: OMER) today announced recent highlights and developments as

well as financial results for the third quarter ended September 30, 2018, which include:

We are pleased with the strong demand that we are seeing for OMIDRIA so soon following reinstatement of its pass-through payment

status, said Gregory A. Demopulos, M.D., chairman and chief executive officer of Omeros. We expect that ramp to continue, generating a growing revenue stream to support our advancing pipeline. Omeros lead product in that pipeline,

our MASP-2 inhibitor OMS721, is driving toward U.S. and European commercialization in stem-cell TMA, we believe that the recent positive data in IgA nephropathy meaningfully de-risks the program s Phase 3 pivotal trial, and the aHUS program is

enrolling. Our Phase 1 trial for our PDE7 inhibitor OMS527 is progressing nicely and, to date, the drug is demonstrating a good safety profile and predictable pharmacokinetics. OMS906, our MASP-3 inhibitor, is targeted for clinical development in

late 2019 followed by our orally administered MASP-2 inhibitors, which are slated to enter the clinic in 2020. Our team has done a great job managing the advancement of these assets while focusing on delivering our products to the market to meet the

urgent needs of patients, and I expect that we will see equal or greater achievements in 2019.

Third Quarter and Recent Developments

ended September 30, 2018, revenues were $4.6 million, all relating to sales of OMIDRIA. This compares to OMIDRIA revenues of $1.7 million in 2Q 2018 and $21.7 million for the third quarter of 2017. The increase over the last

quarter is primarily due to revenues from the company s wholesalers in anticipation of renewed buying from ASCs and hospitals as a result of the reinstatement of pass-through reimbursement on October 1, 2018. The decrease from 3Q 2017 is

due to the significant reduction in OMIDRIA use by ASCs and hospitals in 3Q 2018 as a result of the absence of transitional pass-through reimbursement, which expired for OMIDRIA beginning January 1, 2018.

During the last week of September and for October 2018, the company saw OMIDRIA sales from the company s wholesalers to its customers (sell-through)

increase significantly compared to the first three quarters of 2018. In addition, in October 2018, the company s ASC and hospital customers purchased approximately 17,500 units of OMIDRIA from its wholesalers. October 2017 was the single

highest sell-through month for OMIDRIA and in October 2018, the first month of pass-through reinstatement for OMIDRIA, the drug achieved 81% of this record high.

Total costs and expenses for the three months ended September 30, 2018 were $40.1 million compared to $26.8 million for the same period in

2017. The increase from the prior quarter was primarily due to higher manufacturing scale-up costs including the acquisition of manufacturing materials for the OMS721 programs and to incremental costs

associated with initiating the OMS721 IgA nephropathy Phase 3 clinical trial and the July 2018 initiation of the company s Phase 1 clinical trial in OMS527. These increases were partially offset by decreased OMIDRIA patent litigation costs.

For the three months ended September 30, 2018, Omeros reported a net loss of $39.5 million, or $0.81 per share, which included non-cash expenses of $5.0 million ($0.10 per share). In comparison, for the prior year s third quarter Omeros reported a net loss of $7.5 million, or $0.16 per share including non-cash expenses of $4.2 million ($0.09 per share).

As of September 30, 2018, the company had

$55.2 million of cash, cash equivalents and short-term investments available for operations and another $5.8 million in restricted investments.

Conference Call Details

Omeros management will host a conference call to discuss the financial results and to provide an update on business activities. The call will be held at

5:30 a.m. Pacific Time; 8:30 a.m. Eastern Time tomorrow, Friday November 9, 2018. To access the live conference call via phone, please dial (844) 831-4029 from the United States and Canada or (920) 663-6278 internationally. The participant passcode is 7771247. Please dial in approximately 10 minutes prior to the start of the call. A telephone replay will be available for one week following the call and may be

accessed by dialing (855) 859-2056 from the United States and Canada or (404) 537-3406 internationally. The replay passcode is 7771247.

To access the live or subsequently archived webcast of the conference call on the internet, go to the company s website at www.omeros.com and

select Events under the Investors section of the website. To access the live webcast, please connect to the website at least 15 minutes prior to the call to allow for any software download that may be necessary.

About Omeros Corporation

Omeros is a commercial-stage

biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, complement-mediated diseases and disorders of the

central nervous system. The company s drug product OMIDRIA (phenylephrine and ketorolac intraocular solution) 1% / 0.3% is marketed for use during cataract surgery or intraocular lens

(IOL) replacement to maintain pupil size by preventing intraoperative miosis (pupil constriction) and to reduce postoperative ocular pain. In the European Union, the European Commission has approved OMIDRIA for use in cataract surgery and other IOL

replacement procedures to maintain mydriasis (pupil dilation), prevent miosis (pupil constriction), and to reduce postoperative eye pain. Omeros has multiple Phase 3 and Phase 2 clinical-stage development programs focused on: complement-associated

thrombotic microangiopathies; complement-mediated glomerulonephropathies; cognitive impairment; and addictive and compulsive disorders. In addition, Omeros has a diverse group of preclinical programs and a proprietary G protein-coupled receptor

(GPCR) platform through which it controls 54 new GPCR drug targets and corresponding compounds, a number of which are in preclinical development. The company also exclusively possesses a novel antibody-generating platform.

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, likely , look forward to, may, plan, potential, predict, project, prospects, should, slated,

will, would and similar expressions and variations thereof. 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 product commercialization and commercial operations,

unproven preclinical and clinical development activities, regulatory oversight, the ability for OMIDRIA to obtain separate reimbursement as part of CMS OPPS, 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 November 8,

2018. 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

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except share and per share data)

UNAUDITED CONSOLIDATED BALANCE SHEET DATA