NMO is a rare autoimmune disorder designated as an Orphan disease by the U.S. Food and Drug Administration (FDA) in which immune system cells and antibodies attack and destroy myelin cells in the optic nerves and the spinal cord leading to demyelination and loss of axons. There are currently no FDA-approved therapies for NMO. OPX-212 is specifically tailored to each patient’s immune response to a protein, aquaporin-4, which is the targeted antigen in NMO. In NMO, the immune system recognizes aquaporin-4 as foreign, thus triggering the attack. OPX-212 has a hypothesized mechanism of action to reduce the number and/or regulate aquaporin-4 reactive T-cells (ARTCs), thereby reducing the frequency of clinical relapses and subsequent progression in disability.
Patients with NMO present with acute, often severe, attacks of blindness in one or both eyes followed within days or weeks by varying degrees of paralysis in the arms and legs. Most patients have relapsing attacks (separated by months or years with partial recovery), with usually sequential index episodes of optic neuritis (ON) and myelitis. A relapsing course is more frequent in women, and nearly 90% of patients are female (typically late middle-aged). More rarely, the disease course is monophasic, with nearly simultaneous index episodes of ON and myelitis. This form may occur in younger individuals with no sex predilection. Patients with NMO frequently have other systemic autoimmune disorders, such as systemic lupus erythematosus, Sjögren's syndrome or Myasthenia Gravis. It is estimated that there are approximately 4,800 cases of NMO in the U.S. NMO has a worldwide estimated prevalence of 1-2 people per 100,000 population.