About Neuromyelitis Optica Spectrum Disorder (NMOSD)

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease of the central nervous system in which a person’s immune system invades the optic nerves and spinal cord leading to vision loss and paralysis. NMOSD was long considered a version of multiple sclerosis (MS), but in 2004, doctors discovered an antibody (a protein in the blood) that helped create a discrete diagnosis. Unlike in MS, the disease does not progress between attacks, but the attacks themselves are generally more severe than in those patients with MS. Generally characterized by an unpredictable and relapsing course, NMO causes increasing disability with each attack. Though most patients partially recover function between attacks, some patients will suffer permanent vision loss and/or diverse neurological symptoms; a few, even death.

The name of the disorder that includes both optic nerve and spinal symptoms has undergone many changes over the centuries.  During the late 18^th and throughout much of the 19^th century, it was known primarily as spinal amaurosis. In 1894, Dr. Eugene Devic called the disorder with combined eye and spinal symptoms “neuromyelitis optica”.  But for years, NMO was called Devic’s Disease. Over time, that moniker has fallen into disuse, as Neuromyelitis optica (NMO) and Neuromyelitis optica spectrum disorder (NMOSD) have become the more common monikers. The words “spectrum disorder” were added to the formal name of the disease in 2015 when physicians defined a broad continuum of clinical presentations as NMOSD that include spinal cord and/or optic nerve involvement as well as other indications, because they are all due to the same immunological mechanisms.

NMOSD strikes more females than males. The prevalence of the disease ranges from 0.5 – 10 per 100,000. Africans, East Asians and Latin Americans tend to have a higher prevalence of NMOSD than Caucasian populations in Europe and the United States.

When NMOSD attacks, patients may experience optic neuritis – inflammation of the optic nerves that causes eye pain and reduced vision in one or both eyes and/or transverse myelitis – inflammation of a segment of the spinal cord, causing sensory changes, potential loss of bladder and bowel control, numbness, tingling and possible paralysis. Attacks of the brainstem can lead to hiccupping, nausea and/or vomiting. Corticosteroids and plasmapheresis (removing and replacing components of a patient’s blood) are effective in stopping NMO relapses. Many experience unusual fatigue that can persist long after the treatment and healing period.

After treatment for acute attacks, the disease exists in a sort of remission state. At these times, there is no active disease progression, but patients continue to suffer from symptoms due to previous damage in the nervous system. In order to prevent additional injury from future attacks, it is imperative that people with NMOSD take medication regularly. NMOSD never goes away on its own, so preventive treatment is required lifelong. There are a number of medications that successfully suppress the immune system in NMOSD patients.

The majority of people with NMO have an antibody that mistakenly attacks a particular protein in the central nervous system (CNS), the Aquaporin 4 (AQP4) water channel, the most abundant water channel protein in the CNS. Others suffering with radiological and clinical criteria consistent with NMO may have either no currently-identified antibody, or may test positive for a recently-discovered antibody, MOG (myelin oligodendrocyte glycoprotein).

Though there is no cure for NMOSD at this time, we are encouraged that the last fifteen years have brought an abundance of interest and a number of positive therapies, including three drugs approved for NMOSD by the FDA in 2019 and 2020. There are additional drugs already on the horizon, and we are proud to participate in a number of studies and trials to improve treatments and one day, we hope, to find a cure.

Approved Medications for NMO

Patients may know that in late June of 2019, the first drug for NMOSD was approved by the FDA. This drug, eculizumab, produced by Alexion, has the brand name Soliris. It was approved for adults suffering from NMOSD who are anti-aquaporin 4 (AQP4) antibody positive. Soliris is a monoclonal antibody that blocks the c5 protein in complement, which is part of the body’s immune system. It is an intravenous medication that must be administered every two weeks for patients with NMO. The eculizumab trial in children could potentially expand the patient population to include AQP4-positive children. The second trial is for a variation of the medication that would allow for less frequent infusions – every 8 weeks instead of every 2 weeks.

One year later, in June of 2020, the second drug for aquaporin-4-positive patients got FDA approval. This drug, inebilizumab, known as Uplizna, is administered by infusion twice a year. Uplizna is a monoclonal antibody that works by depleting CD-19 in B cells. Uplizna is produced by the pharmaceutical company Viela Bio.

In August, 2020, a third medication for AQP4+ patients with NMO was approved by the FDA. Enspryng, by Genentech, targets the interleukin 6 (IL-6) receptor which is believed to play a role in inflammation in NMO. This monoclonal antibody can be self-administered by patients at home with subcutaneous injections every four weeks after an initial loading dose.

For patients experiencing attacks, we recommend rapid intervention with:

• Intravenous corticosteroids (Solumedrol) and/or
• Plasma exchange (PLEX)

Many patients who were diagnosed before 2019 were prescribed off-label medications for their disease. When these drugs are successful in preventing attacks, physicians may not change the therapy regimens. These drugs include:

• Rituxan (Rituximab)
• CellCept (Mycophenolate Mofetil)
• Imuran (Azathioprine)
• Prednisone
• Methotrexate

Therapy Comparison Chart

Dr. Michael Levy and representatives from The Sumaira Foundation for NMO have built this chart and video series comparing the three FDA-approved medications for patients with Aquaporin-4-positive NMO. We hope this summary can help you make informed choices about therapies you might want to discuss with your physician.