-- 15 Year-Old with Stem Cell Transplant-Associated TMA Had Previously Developed Additional Life-Threatening Condition while on Soliris^® --

SEATTLE--(BUSINESS WIRE)--Dec. 6, 2016-- Omeros Corporation (NASDAQ: OMER) today announced that, following physician request, it will provide continued supply of OMS721 for a pediatric patient with hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA) who is currently receiving the drug under the company’s compassionate use program. The patient’s treating physician requested extended access to OMS721 for his 15 year-old patient given her positive results with OMS721 treatment, including discontinuation of dialysis. HSCT-TMA most commonly affects the kidneys but can also damage the lungs, gastrointestinal tract and central nervous system, and severe cases often require dialysis and carry a mortality rate in excess of 90 percent. OMS721 is Omeros’ lead human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2). In addition to its Phase 2 clinical program in TMA, OMS721 is currently in a Phase 3 program for patients suffering from atypical hemolytic uremic syndrome and in a Phase 2 program for renal diseases, including immunoglobulin A (IgA) nephropathy and membranous nephropathy.

Approximately 20,000 HSCT procedures are performed in the U.S. annually, and TMA is reported to occur in approximately 10 to 25 percent of HSCT patients. HSCT-TMA patients frequently have a complex history of disease. This pediatric patient had received a stem cell transplant to treat a rare life-threatening anemia. Following her transplant, she developed TMA. She began treatment with Soliris and improved but developed pulmonary edema so Soliris treatment was stopped. Following relapse of her HSCT-TMA, she received a low dose of Soliris and again developed pulmonary edema, again requiring discontinuation of Soliris treatment. Her TMA progressed and she developed renal failure requiring dialysis. When she began OMS721 treatment, she had been on dialysis for several months and required daily platelet transfusions.

After three weeks of OMS721 treatment the patient was able to discontinue dialysis. The frequency of platelet transfusions has been decreased by more than 50 percent despite bone marrow suppression caused by other concurrent conditions. Two measures of red blood cell destruction have also substantially improved on OMS721 treatment: her haptoglobin has normalized on OMS721 treatment and her lactate dehydrogenase (LDH) has decreased by more than 50% percent but still remains slightly elevated. All OMS721 administrations have been well tolerated by the patient, and no side effects have been observed with this treatment. The patient is also now able to spend weekends at home with her family. Because of the patient’s improvement on OMS721, her treating physician requested, and Omeros granted, an extension of the OMS721 compassionate use treatment protocol under which this pediatric patient is being treated.

“The patient, her family and her team of physicians are obviously thrilled with her improvement on OMS721,” stated Marco Zecca, M.D., Director of Pediatric Hematology/Oncology at Fondazione IRCCS Policlinico San Matteo in Pavia, Italy. “Stem cell transplant-related TMA is a devastating and often fatal condition, and this is a patient who had failed other treatment. Her response to OMS721 is impressive, underscored by her ability to stop dialysis. We appreciate receiving ongoing access to OMS721 for her treatment, and we look forward to her continued improvement and a return to a more healthy and normal life.”

“All of us at Omeros feel privileged to participate in the care of this young girl,” stated Gregory A. Demopulos M.D., Chairman and Chief Executive Officer of Omeros. “We remain committed to supporting both her and her physicians in her care and to her continued recovery. While treatment results are routinely described in numbers and statistics, this patient demonstrates the human side of our work, and it is heartening.”

Omeros’ OMS721 compassionate use program is active internationally.

About Omeros’ MASP-2 Program

Omeros controls the worldwide rights to MASP-2 and all therapeutics targeting MASP-2, a novel pro-inflammatory protein target involved in activation of the complement system, which is an important component of the immune system. The complement system plays a role in the inflammatory response and becomes activated as a result of tissue damage or microbial infection. MASP-2 is the effector enzyme of the lectin pathway, one of the principal complement activation pathways. Importantly, inhibition of MASP-2 does not appear to interfere with the antibody-dependent classical complement activation pathway, which is a critical component of the acquired immune response to infection, and its abnormal function is associated with a wide range of autoimmune disorders. MASP-2 is generated by the liver and is then released into circulation. Adult humans who are genetically deficient in one of the proteins that activate MASP-2 do not appear to be detrimentally affected by the deficiency. Omeros has received both Orphan Drug status and Fast Track designation from the U.S. FDA for its lead human MASP-2 antibody OMS721. Following discussions with both the FDA and the European Medicines Agency, a Phase 3 program for OMS721 in atypical hemolytic uremic syndrome is in progress. Also, two Phase 2 trials are ongoing. One is evaluating OMS721 in glomerulonephropathies, which has generated positive data in patients with immunoglobulin A (IgA) nephropathy and with membranous nephropathy and the other is being conducted in patients with thrombotic microangiopathies (TMAs), with positive data reported in patients with hematopoietic stem cell transplant-associated TMA. In addition to potential intravenous administration, Omeros plans to commercialize OMS721 for one or more therapeutic indications as a subcutaneous injection and is also developing small-molecule inhibitors of MASP-2. Based on requests from treating physicians, Omeros has established a compassionate-use program for OMS721, which is active in both the U.S. and Europe.

Omeros also has identified MASP-3 as the protein that is critical to the activation of the complement system’s alternative pathway in humans, which is linked to a wide range of immune-related disorders. In addition to its lectin pathway inhibitors, the company is advancing its development of antibodies and small-molecule inhibitors against MASP-3 to block activation of the alternative pathway.

About Omeros Corporation

Omeros is a biopharmaceutical company committed to discovering, developing and commercializing both small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, coagulopathies and disorders of the central nervous system. Part of its proprietary PharmacoSurgery^® platform, the company’s first drug product, OMIDRIA^® (phenylephrine and ketorolac injection) 1% / 0.3%, was broadly launched in the U.S. in April 2015. OMIDRIA is the first and only FDA-approved drug (1) 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 and (2) that contains an NSAID for intraocular use. In the European Union, the European Commission has approved OMIDRIA for use in cataract surgery and lens replacement procedures to maintain mydriasis (pupil dilation), prevent miosis (pupil constriction), and to reduce postoperative eye pain. Omeros has clinical-stage development programs focused on: complement-associated thrombotic microangiopathies; complement-mediated glomerulonephropathies; Huntington’s disease and cognitive impairment; and addictive and compulsive disorders. In addition, Omeros has a proprietary G protein-coupled receptor (GPCR) platform, which is making available an unprecedented number of new GPCR drug targets and corresponding compounds to the pharmaceutical industry for drug development, and a platform used to generate antibodies.

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 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 Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 9, 2016. 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.

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Source: Omeros Corporation

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Jennifer Cook Williams
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