New Treatment for Rare Autoimmune Disease

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RESEARCH UPDATE

Neuromyelitis optica spectrum disorder (NMOSD) is a rare but severe chronic medical disorder that attacks the central nervous system (CNS) dominated by inflammation and immune attack of the optic nerve (optic neuritis) and inflammation of the spinal cord (myelitis). Symptoms include eye pain, vision loss or numbness, weakness, or paralysis of the arms and legs, and loss of bladder and bowel control. Women and African-Americans are at a greater risk of the disease. NMOSD, also known as Devic disease or neuromyelitis optica, is estimated to affect approximately 4000 to 8000 people in the United States.

During acute attacks, the standard treatment is high-dose intravenous corticosteroids or plasma exchange in treatment-resistant cases. Relapse prevention is the primary goal of treatment.

SOLIRIS^® (eculizumab) by Alexion is the first and only FDA-approved treatment for NMOSD in adults who have tested positive for anti-aquaporin-4 (AQP4) auto-antibodies.^1,2 In these patients, eculizumab has been shown to reduce relapse, decrease re-hospitalizations, and hindered the need to treat acute attacks with corticosteroids and plasma exchange.

Activation of complement cascade result in severe rare and ultra-rare disorders like paroxysmal nocturnal hemoglobinuria (PNH); atypical hemolytic uremic syndrome (aHUS); anti-acetylcholine receptor (AchR) antibody-positive generalized myasthenia gravis (gMG); and anti-aquaporin-4 (AQP4) antibody-positive NMOSD. Eculizumab is a humanized monoclonal IgG antibody that is a first-in-class complement inhibitor which binds to complement protein C5, preventing cleavage into C5a and C5b. Blocking the formation of C5b inhibits the subsequent formation of terminal complex C5b-9 or MAC.

The drug is administered by intravenous infusion over 35 minutes in adults at a dose of 900 mg weekly for the first four doses starting on day 1. This is followed by 1200 mg every two weeks starting at week 4.

Eculizumab is only available through a program called the SOLIRIS REMS (Risk Evaluation and Mitigation Strategy). Treatment is contraindicated in patients with unresolved serious Neisseria meningitidis infection and in those who are not currently vaccinated against Neisseria.

Since eculizumab affects the immune system, it can lower the ability to fight infections and increase the chance of contracting serious and life-threatening meningococcal and other infections. Patients should have all the recommended vaccinations before starting SOLIRIS, receive 2 weeks of antibiotics if one urgently starts SOLIRIS, and stay up to date with recommended vaccinations during treatment. Effects of eculizumab on pregnancy/breastfeeding and children are unknown.

The most common adverse effects of eculizumab are the common cold (upper respiratory infection); pain or inflammation of the nose or throat (nasopharyngitis); back pain; diarrhea; dizziness; flu like symptoms; joint pain (arthralgia); and bruising. No cases of meningococcal infection were observed in the study.

Dr Burman is Co-Medical Director of the Pediatric Sleep Medicine Program at UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA.

Disclosures:

1. Federal Drug Administration. FDA approves first treatment for neuromyelitis optica spectrum disorder, a rare autoimmune disease of the central nervous system [press release]. June 27, 2019. https://www.fda.gov/news-events/press-announcements/fda-approves-first-treatment-neuromyelitis-optica-spectrum-disorder-rare-autoimmune-disease-central. Accessed July 12, 2019.

2. Lennon VA, Wingerchuk DM, Kryzer TJ, et al. A serum autoantibody marker of neuromyelitis optica: distinction from multiple sclerosis. Lancet. 2004;11-17;364:2106-2112.