What is the treatment for Neuromyelitis optica?

Treatment of Neuromyelitis Optica Spectrum Disorder (NMOSD)

Rituximab is the most effective treatment for neuromyelitis optica spectrum disorder, demonstrating superior reduction in relapse rates compared to azathioprine and other immunosuppressants. 1

Acute Attack Management

First-Line Treatment

• High-dose intravenous methylprednisolone (IVMP) at 1000 mg/day for 3-5 days is the initial recommended treatment for acute NMOSD attacks 2, 3
• Treatment should be initiated promptly, as delay beyond 2 weeks is associated with poorer outcomes and increased risk of severe neurological deficit 1

Second-Line/Add-on Treatment

• Plasma exchange (PLEX) should be initiated early in severe attacks or when response to steroids is inadequate 1, 4
• PLEX has shown clinical improvement in 79.2% of patients with NMOSD and should be considered as part of initial treatment in severe cases 1, 5
• Early initiation of PLEX alongside IVMP may provide better outcomes than sequential therapy (IVMP followed by PLEX) 5

Long-Term Disease-Modifying Therapy

First-Line Options

• Rituximab (RTX) is superior to azathioprine in reducing relapse rates in NMOSD patients 1
• Mycophenolate mofetil (MMF) has demonstrated significant decrease in mean Expanded Disability Status Scale (EDSS) scores 1
• Azathioprine (AZA) can be effective but has higher rates of side effects and discontinuation compared to other immunosuppressants 1

Newer FDA-Approved Biologics

• Eculizumab, inebilizumab, satralizumab, and ravulizumab have been approved for AQP4-IgG-positive NMOSD and may replace traditional immunosuppressants 6
• These targeted therapies are based on the antibody and complement-dependent pathophysiology of NMOSD 3

Treatment Algorithm

1. Diagnosis confirmation: Confirm NMOSD diagnosis with AQP4-IgG testing and MRI imaging
2. Acute attack treatment:
   • Start IVMP 1000 mg/day for 3-5 days 2
   • Consider early PLEX (5-7 exchanges) for severe attacks or poor response to IVMP 1, 4
3. Long-term therapy initiation:
   • First choice: Rituximab (typically 375 mg/m² weekly for 4 weeks or 1000 mg × 2 weeks apart) 1
   • Alternative options: Mycophenolate mofetil (1-3 g/day) or azathioprine (2-3 mg/kg/day) 1
   • For AQP4-IgG positive patients: Consider newer biologics (eculizumab, inebilizumab, satralizumab) 6

Special Considerations

Monitoring

• Regular ophthalmological evaluations including visual acuity, visual fields, and funduscopy are necessary to monitor treatment response 2
• Visual-evoked potentials may detect bilateral optic nerve damage before it becomes clinically apparent 2

Adverse Events

• IVMP: Common adverse events include hyperglycemia (43.5%) and infection (29%) 7
• PLEX: Common adverse events include hypocalcemia (63.6%), hypofibrinogenemia (42.4%), and hypotension (30.3%) 7
• Immunosuppressants: Monitor for infections, hepatotoxicity, and bone marrow suppression 1

Risk Factors for Poor Outcomes

• Extensive spinal cord MRI lesions 1
• Reduced muscle strength or sphincter dysfunction at presentation 1
• Presence of antiphospholipid antibodies 1
• Delay in therapy initiation (>2 weeks) 1

Treatment Pitfalls to Avoid

• Misdiagnosis as multiple sclerosis - NMOSD requires different treatment approaches 3
• Inadequate duration of acute treatment - relapses are common (50-60%) during corticosteroid dose reduction 1
• Failure to initiate PLEX early in severe cases 5
• Discontinuing maintenance therapy prematurely - long-term immunosuppression is typically required 1, 6