Neuromyelitis Optica
Spectrum Disorders (NMOSD)

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What causes relapsing NMOSD?

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Neuromyelitis Optica Spectrum Disorders (NMOSD) is a rare disorder caused by the immune system attacking the body’s healthy cells, with attacks directed mostly against the eyes and spinal cord. This causes inflammation of the spinal cord and optic nerve, which can cause loss of vision, mobility, and sensation. Although there is no cure for NMOSD, investigators are seeking a treatment to prevent additional attacks or relapses.

• 90% of NMOSD patients have relapsing NMOSD and many patients continue to relapse (have attacks) despite current management.

• Disability may get worse with every relapse.

infographic showing statistics regarding the percentage of affected people with nmo


ID: NCT01892345

New clinical studies may further help investigators understand the causes of relapse in NMOSD. By investigating a potential treatment for NMOSD, we may better understand how to prevent debilitating relapses in the future.

Alexion is studying the safety and efficacy of an investigational medicine as a potential treatment for relapsing NMO and NMOSD.

If you are an NMOSD patient (or a friend or family member of a patient) who is interested in participating in this study, contact Alexion at

For more information about the locations of the study centers, visit:

    -  Click here to see a map of site locations.


Who is eligible to participate?

If you have been diagnosed with relapsing NMO or NMOSD, you may be eligible to participate in the PREVENT Study

Participants must be 18 years or older and:

Have a positive blood test for the NMO-antibody

Experienced at least 2 attacks or relapses in the past 12 months

•  Can include the first attack that led to initial diagnosis

- OR -

Experienced 3 attacks or relapses in the past 24 months with at least 1 attack or relapse in the last 12 months

•  Can include the first attack that led to initial diagnosis

    Download and print this checklist to review with your doctor

What does participation involve?

You may be able to continue to take your present NMO or NMOSD medications  and receive the study medication (this is called an “add-on” study).

• If you choose to participate in the study and meet all entry criteria, you will be randomized to one of two treatment groups. One group will receive the investigational medication and the other group will receive placebo. Placebo looks like the investigational medication but does not contain the investigational ingredient. In this study, 2 out of 3 participants will receive the same investigational medication and 1 out of 3 will receive placebo.

• This is a “double blind study” which means that neither you nor the study doctor and his/her staff know whether you are receiving the investigational medication or placebo. In fact, no one who is involved in the study will know what you received until the study is complete.

The investigational medication and placebo are given intravenously (IV) at the study doctor’s office or infusion center.

• There are potential side effects. Your study doctor will discuss these with you and they will be explained in the informed consent you will need to sign to be part of the study.

• While participating in the study, it is possible that your NMO or NMOSD symptoms may improve, remain the same or worsen.

• Your condition will be carefully monitored throughout the study, with ongoing communication between the study doctor and your personal doctor. You may withdraw from the study at any point.

• You may be eligible to enroll in a second study, called an “extension study", where all participants receive the investigational medication.

infographic showing how many participants receive active medication for nmo

Resources for NMOSD

    -  NIH: National Institute of Neurological Disorders and Strokes

    -  Guthy Jackson Foundation

    -  Transverse Myelitis Assocation

    -  Mayo Clinic: Neuromyelitis Optica

    -  Read more about Alexion and NMOSD


1. http//
2. Jarius S. Wildemann B, Paul F. Neuromyelitis optica: clinical features, immunopathogenesis and treatment. Clinical and Experimental Immunology, 2014;176:149–164.
3. Collongues N, Marignier R, Zephir H, et al. Neuromyelitis optica in France: A multicenter study of 125 patients. Neurology, 2010;74:736-742.

Neuromyelitis Optica (NMO) Infographic