Omeros Announces that GPR17 Antagonists Improve Function in Model of Multiple Sclerosis

Omeros Announces that GPR17 Antagonists Improve Function in Model of Multiple

- Adds to Earlier Data Demonstrating Potential to Restore Myelin in MS
Patients -

PR Newswire

SEATTLE, April 10, 2013

SEATTLE, April 10, 2013 /PRNewswire/ -- Omeros Corporation (NASDAQ: OMER)
today announced positive data in the most commonly used model for studying the
clinical and pathological features of multiple sclerosis (MS), further
advancing its development program of GPR17-targeting compounds for the
treatment of MS. Compounds previously discovered by Omeros that inhibit GPR17,
an orphan G protein-coupled receptor (GPCR) unlocked by Omeros, significantly
improved function from experimental autoimmune encephalomyelitis (EAE) in
mice. Using its proprietary high-throughput Cellular Redistribution Assay
(CRA), Omeros believes that it alone has identified compounds that
functionally interact with GPR17 and has patents pending that are broadly
directed to any such compounds active at the receptor.

Having discovered compounds that functionally interact with GPR17, Omeros
previously showed that GPR17 antagonists promote generation of mature
oligodendrocytes, the cells that produce myelin. Myelin is a key component of
the proper functioning of the central nervous system, and myelin deficiency is
a hallmark of a large number of neurodegenerative autoimmune diseases,
including MS. In this EAE model, animals treated with GPR17-targeting
compounds, compared to untreated animals, significantly improved mean clinical
scores, which quantify disease progression by measuring motor dysfunction and
are used as a surrogate indicator of demyelination.

"Our GPCR platform – built around our proprietary CRA – continues to unlock
wholly new drug targets, and we expect that our sole knowledge of the
identities of their interacting compounds together with our patent positions
will give Omeros exclusive control of those receptors," stated Gregory A.
Demopulos, M.D., chairman and chief executive officer of Omeros. "GPR17 is one
of those receptors, and the EAE data further underscore the potential for the
compounds that we have identified with our CRA. There are no approved
remyelinating therapeutics – all approved agents for the treatment of MS are
anti-inflammatories. The GPR17 antagonists that we are developing could lead
to the first drug able to promote remyelination and restore neural function in
patients with MS."

Ongoing GPCR Program

Omeros is screening orphan and difficult-to-drug Class A and Class B GPCRs
against its small-molecule chemical libraries using its proprietary,
high-throughput cellular redistribution assay (CRA). The CRA detects receptor
antagonists, agonists, inverse agonists and allosteric modulators for a given
GPCR without requiring the receptor's ligand or any knowledge of the
receptor's signaling pathway(s). Omeros has announced that it has identified
and confirmed sets of compounds that interact selectively with 46 Class A
orphan receptors linked to metastatic melanoma (GPR19), esophageal squamous
cell carcinoma and obesity-related type-2 diabetes (GPR39), hepatocellular
carcinoma (GPR80), several types of cancer (GPR65/TDAG8), squamous cell
carcinoma (GPR87), ovarian cancer (GPR150), pancreatic cancer (GPR182), acute
lymphoblastic leukemia (P2Y8/P2RY8), ovarian and prostate cancer (OGR1),
arterial stiffness (GPR25), sleep disorders (OPN4), cognitive disorders
(GPR12), torpor or "suspended animation" and bipolar disorder (GPR50), anxiety
disorders (GPR31), schizophrenia (GPR52, GPR153), autism (GPR63), bipolar
disorder and schizophrenia (GPR78), memory and inflammatory conditions
(GPR83), psychotic and metabolic disorders (GPR27, GPR85, GPR173), cognition
(GPR151), cognitive impairments (MAS1), inflammatory responses (GPR32),
obesity and diabetes (GPR21), appetite control (GPR82, GPR101), immunological
disorders (CCRL2), rheumatoid arthritis and HIV-mediated enteropathy (GPR15),
respiratory and immune disorders (GPR141), humoral immunity (GPR183), multiple
sclerosis (GPR17), osteoarthritis (GPR22), motor control (GPR139), congenital
cataracts and birth defects of the brain and spinal cord (GPR161), regulation
of hematopoietic stem cell differentiation (GPR171), cancer stem cells and the
self-renewal and maintenance of adult stem cells (LGR4), long-term wound
repair, including the formation of new hair follicles (LGR6) and pain (MRGE).
In addition, Omeros has unlocked GPR20, GPR45, GPR135, GPR162, MRGF and OPN5,
which have not yet been definitively tied to any specific indications but are
expressed preferentially in the gastrointestinal tract (GPR20), brain (GPR45,
GPR135 and GPR162) and eye, brain, testes, spinal cord (OPN5) and dorsal root
ganglia (MRGF).

About G Protein-Coupled Receptors

GPCRs, which mediate key physiological processes in the body, are one of the
most valuable families of drug targets. According to Insight Pharma Reports,
GPCR-targeting drugs represent 30 to 40 percent of marketed pharmaceuticals.
Examples include Claritin® (allergy), Zantac® (ulcers and reflux), OxyContin®
(pain), Lopressor® (high blood pressure), Imitrex® (migraine headache),
Reglan® (nausea) and Abilify® (schizophrenia, bipolar disease and depression)
as well as all other antihistamines, opioids, alpha and beta blockers,
serotonergics and dopaminergics.

The industry focuses its GPCR drug discovery efforts mostly on non-sensory
GPCRs. Of the 363 total non-sensory GPCRs, approximately 240 have known
ligands (molecules that bind the receptors) with nearly half of those targeted
either by marketed drugs (46 GPCRs) or by drugs in development (about 80
GPCRs). There are approximately 120 GPCRs with no known ligands, which are
termed "orphan GPCRs." Without a known ligand, drug development for a given
receptor is extremely difficult.

Omeros uses its proprietary high-throughput CRA to identify small-molecule
agonists, antagonists and allosteric modulators for orphan and
difficult-to-drug GPCRs, unlocking them to drug development. Omeros believes
that it is the first to possess the capability to unlock orphan GPCRs in
high-throughput, and that currently there is no other comparable technology.
Unlocking these receptors could lead to the development of drugs that act at
these new targets. There is a broad range of indications linked to orphan
GPCRs including cardiovascular disease, asthma, diabetes, pain, obesity,
Alzheimer's disease, Parkinson's disease, multiple sclerosis, schizophrenia,
learning and cognitive disorders, autism, osteoporosis, osteoarthritis and
several forms of cancer.

About Omeros Corporation

Omeros is a clinical-stage biopharmaceutical company committed to discovering,
developing and commercializing products targeting inflammation, coagulopathies
and disorders of the central nervous system. The Company's most clinically
advanced product candidates, OMS302 for lens replacement surgery and OMS103HP
for arthroscopy, are derived from its proprietary PharmacoSurgery™ platform
designed to improve clinical outcomes of patients undergoing a wide range of
surgical and medical procedures. Omeros has five clinical development
programs. Omeros may also have the near-term capability, through its GPCR
program, to add a large number of new drug targets and their corresponding
compounds to the market. Behind its clinical candidates and GPCR platform,
Omeros is building a diverse pipeline of protein and small-molecule
preclinical programs targeting inflammation, coagulopathies and central
nervous system disorders.

Forward-Looking Statements

This press release contains forward-looking statements as defined within the
Private Securities Litigation Reform Act of 1995, which are subject to the
"safe harbor" created by those sections. These statements include, but are not
limited to, Omeros' expectations regarding its intellectual property position
around the orphan GPCRs that it unlocks; the indications that GPR17
antagonists may treat as well as their potential therapeutic benefits; and
that Omeros may have capability, through its GPCR program, to add a large
number of new drug targets and their corresponding compounds to the market.
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, 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 18, 2013. 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 publicly, even if new information becomes
available in the future.

SOURCE Omeros Corporation

Contact: Jennifer Cook Williams, Cook Williams Communications, Inc., Investor
and Media Relations, 360.668.3701,
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