The US Food and Drug Administration (FDA) has just approved a new drug Satralizumab for adults with anti-aquaporin-4 (AQP4) antibody-positive Neuromyelitis Optica Spectrum Disorder.
Neuromyelitis optica spectrum disorder (NMSOD) is an autoimmune inflammatory disease that damages the optic nerve and spinal cord, causing blindness, muscle weakness, and paralysis.
NMOSD affects up to 15,000 people in the United States and about 200,000 people worldwide.
In one single drug study, 76.5% of satralizumab-treated patients were relapse-free at 96 weeks, compared with 41.1% with placebo.
Symptoms of NMOSD include either optic neuritis or myelitis. Optic neuritis is an inflammation of the optic nerve leading to pain in the eye which is followed by vision loss. Only one eye is usually affected although sometimes both eyes may be involved. Another symptom of NMSOD is inflammation of the spinal cord. Affected individuals have pain in the spine or limbs, and paralysis of the lower limbs with possible loss of bowel and bladder control.
It may be difficult to tell NMOSD from multiple sclerosis because both cause optic neuritis and myelitis as symptoms. Optic neuritis and myelitis tend to be more severe in NMOSD. In many cases of NMOSD, initial symptoms of vision loss improve with the standard treatment of high dose corticosteroids, with a partial recovery of vision, motor, sensory, and bladder function. If NMOSD recurs frequently it causes significant permanent vision loss and/or spinal cord function causing blindness and impaired mobility.
Autoimmune disorders happen when the body’s natural defenses against invading pathogens begin to attack healthy tissue. These immune defenses, for reasons not known, attack some proteins in the central nervous system, especially aquaporin-4.
NMOSD is diagnosed from a detailed patient history, clinical evaluation, physical findings, and specialized testing. Tests include blood tests, cerebrospinal fluid examination and magnetic resonance imaging. A blood test for AQP4-IgG, is highly specific and moderately sensitive for NMOD.