Omeros Corporation Reports First Quarter 2019 Financial Results - Conference Call Today at 4:30 p.m. ET - SEATTLE, WA

Omeros Corporation Reports First Quarter 2019 Financial Results

- Conference Call Today at 4:30 p.m. ET -

SEATTLE, WA - May 9, 2019 - Omeros Corporation (NASDAQ: OMER), 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, disorders of the central nervous system and immune-related diseases, including cancers, today announced recent highlights and developments as well as financial results for the first quarter ended March 31, 2019, which include:

"We are pleased with the company's performance to date in 2019, having made substantial strides on all fronts," said Gregory A. Demopulos, M.D., Omeros' chairman and chief executive officer. Once again we

saw OMIDRIA posting record quarterly sell-through numbers, up 14 percent over the record set in 4Q 2018, and the product's growth trajectory has continued this quarter. Narsoplimab is advancing across three Phase 3 programs and, based on recent interactions with FDA, we expect very soon to wrap up the remaining criteria for the primary endpoint in stem cell TMA, are confident that our data will support a BLA approval and are moving forward with preparations for a commercial launch. Our PDE7 inhibitor, OMS527, is also faring well in its Phase 1 clinical trial, which is slated to finish later this quarter or next. Further expanding our complement franchise, both OMS906, our antibody against MASP-3, and our small-molecule MASP-2 inhibitor are planned to enter the clinic next year. We are also continuing to drive the development of our small-molecule compounds targeting GPR174, a receptor that increasingly appears to control a major cancer pathway. Across all of these efforts, our primary focus remains the patient. In over 600,000 procedures, cataract surgery patients have experienced the benefits of OMIDRIA, and we look forward to making narsoplimab commercially available worldwide in the near future."

First Quarter and Recent Developments

For the quarter ended March 31, 2018, revenues were $21.8 million, all relating to sales of OMIDRIA. This compares to OMIDRIA revenues of $1.6 million and of $22.0 million in the first and fourth quarters of 2018, respectively. 1Q 2019 revenues reflect the seasonally lower volume of cataract surgery performed in the first quarter and the timing of normal wholesaler purchases shifting from the end of March to the first two days of April, when net sales to wholesalers were approximately $2.4 million. Inventory units on hand at wholesalers at December 31, 2018 and March 31, 2019 were effectively the same. Gross-to-net deductions decreased from 28.3 percent in 4Q 2018 to 27.0 percent in 1Q 2019.

Sell-through for 1Q 2019 was a record high, increasing 14 percent from the previous high-water mark set in the 4Q 2018. Sell-through in the current quarter has continued to grow at a double-digit rate over the same period in the first quarter.

Total costs and expenses for the three months ended March 31, 2019 were $41.0 million compared to $29.3 million for the same period in 2018. The increase in the current year quarter was due primarily to higher third-party manufacturing scale-up costs for our narsoplimab program as we continue to increase our production capacity to meet anticipated clinical and commercial requirements, as well as increased expenses associated with pre-commercialization activities for narsoplimab and sales and marketing costs related to the re-introduction of OMIDRIA.

For the three months ended March 31, 2019, Omeros reported a net loss of $24.3 million, or $0.50 per share, which included non-cash expenses of $6.0 million, or $0.12 per share. This compares to the prior year's first quarter for which Omeros reported a net loss of $30.1 million, or $0.62 per share, which included non-cash expenses of $4.3 million, or $0.09 per share.

Overall decrease in cash, cash equivalents and short-term investments for 1Q 2019 was $13.3 million. As of March 31, 2018, the company had $47.2 million of cash, cash equivalents and short-term investments available for operations.

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 today at 1:30 p.m. Pacific Time; 4:30 p.m. Eastern Time. 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 4095776. 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 4095776.

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, disorders of the central nervous system and immune-related diseases, including cancers. 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, 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," "objective," "plan," "potential," "predict," "project," "should," "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, intellectual property claims, competitive developments, litigation, 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 1, 2019, as supplemented from time to time by the company's Quarterly Reports on Form 10-Q. 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

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UNAUDITED CONSOLIDATED BALANCE SHEET DATA