Omeros Announces OMS721 Presentation at Annual Meeting of the European Society for Blood and Marrow Transplantation

-- Additional Positive “Challenge-Rechallenge” Data Reported in Patient with Stem Cell Transplant-Associated TMA --

SEATTLE--()--Omeros Corporation (NASDAQ: OMER) today announced presentation of a case report describing resolution of hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA) in a dialysis- and transfusion-dependent adolescent girl who was treated with OMS721 under a compassionate-use protocol. The presentation “Resolution of acute kidney injury secondary to TA-TMA by the anti-MASP-2 monoclonal antibody OMS721 in a pediatric HSCT recipient” occurred at the 43rd Annual Meeting of the European Society for Blood and Marrow Transplantation in Marseille, France on Monday, March 27, 2017. Marco Zecca, M.D., Director of Pediatric Oncology at the Fondazione IRCCS Policlinico San Matteo, presented the data. OMS721 is Omeros’ lead human monoclonal antibody targeting mannan-binding lectin-associated serine protease-2 (MASP-2), the effector enzyme of the lectin pathway of the complement system.

The presentation describes a girl who developed HSCT-TMA following stem cell transplantation at 14 years of age. She was initially treated with eculizumab but did not tolerate treatment, developing pulmonary edema that recurred on retreatment with eculizumab. The HSCT-TMA became life-threatening and she required hemodialysis and daily platelet transfusions. Dr. Zecca, the patient’s physician, requested OMS721 for compassionate-use treatment and Omeros complied. Following OMS721 treatment, the patient was able to discontinue hemodialysis and to decrease substantially her platelet transfusion requirements. Recently, the patient’s dose of OMS721 was tapered, but she developed a viral infection that reactivated her HSCT-TMA. Her TMA was again successfully treated with restoration of the original OMS721 dose. To date, she has remained free of both dialysis and transfusions.

“This patient had severe TMA that I believe would have caused her death,” stated Dr. Zecca. “Her positive response to OMS721 treatment, both initially and following her virus-induced relapse during tapering, was impressive – the results of OMS721 treatment in this challenge-rechallenge scenario underscore the important effects of the drug. Since the poster was produced, her TMA has remained in remission and we have been able to discontinue her platelet transfusions. Her rapid response has been heartening, and we all are grateful for this remarkable outcome.”

Thrombotic microangiopathy is a potentially life-threatening complication of HSCT. Approximately 20,000 HSCT procedures are performed in the U.S. annually, and TMA is reported to occur in up to 30 percent of HSCT patients. Although the kidney is the most commonly affected organ, HSCT-TMA is a multi-system disorder and can also manifest clinically in the lungs, gastrointestinal tract and central nervous system. Reported mortality in patients with multi-organ involvement is greater than 90%. Even in patients who survive acute episodes, HSCT-TMA increases the risk for chronic kidney disease and end-stage renal disease.

About Omeros’ MASP Programs

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. OMS721 is Omeros’ lead human MASP-2 antibody. Following discussions with both the FDA and the European Medicines Agency, a Phase 3 program for OMS721 in atypical hemolytic uremic syndrome (aHUS) 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; the other has reported positive data both in patients with hematopoietic stem cell transplant-associated thrombotic microangiopathy (TMA) and in those with aHUS. 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. The FDA has granted OMS721 both orphan drug status for the prevention (inhibition) of complement-mediated TMAs and fast track designation for the treatment of patients with aHUS.

Omeros also has identified MASP-3 as the critical activator of the human complement system’s alternative pathway, 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 Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 16, 2017. 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.

Contacts

Cook Williams Communications, Inc.
Jennifer Cook Williams
Investor and Media Relations
360.668.3701
jennifer@cwcomm.org

Contacts

Cook Williams Communications, Inc.
Jennifer Cook Williams
Investor and Media Relations
360.668.3701
jennifer@cwcomm.org