Omeros Corporation announced that its proprietary Cellular Redistribution Assay (CRA) technology, which to date has successfully 'unlocked' 46 of the 80 total Class A orphan G Protein-Coupled Receptors (GPCRs) for drug development, has identified small molecules that interact with a Class B GPCR. Like the Class A GPCRs, Class B receptors are important players in a broad range of disorders, having been linked to various types of cancer (breast, brain, prostate, kidney, liver, pancreatic and gastrointestinal); multiple sclerosis, attention deficit-hyperactivity, learning and memory impairments, depression and other neuropsychiatric disorders; multiple metabolic disorders including diabetes and obesity; immunologic disorders; osteoporosis and infertility. Of the 49 Class B GPCRs, 34 are orphans.

An orphan receptor is one for which there is no known ligand, or functionally active molecule. In developing drugs against a given receptor, ligands are used as templates for medicinal chemistry and, without them, drug development is extremely difficult. In addition to continuing its screening of Class A orphan GPCRs, Omeros has begun screening orphan and non-orphan Class B receptors.

Of the non-orphan Class B receptors, the Company will prioritize those for which there are already commercially successful drugs -- peptide or protein drugs that require intravascular or intramuscular injection. Class B GPCRs have large extracellular domains and their natural ligands are generally large peptides, making the development of orally active, small-molecule drugs against these receptors, such as glucagon and parathyroid hormone (PTH), a persistent challenge. Despite the fact that oral agents are not available, the markets for the Class B GPCR-targeting peptide drugs are large, with sales of PTH drugs alone, for example, exceeding $1 billion annually.

Omeros' CRA technology finds functionally active small molecules for GPCRs, and could lead to the development of oral medications for many of the Class B GPCRs.