What is the recommended treatment for a patient with optic neuritis and positive MOG (Myelin Oligodendrocyte Glycoprotein) antibody after initial treatment with intravenous (IV) Methylprednisolone (methylprednisolone) for 5 days?

Management After IV Methylprednisolone for MOG-Antibody Positive Optic Neuritis

This patient should be started on an oral prednisone taper following the 5-day course of IV methylprednisolone, and strong consideration should be given to initiating long-term immunosuppressive maintenance therapy given the high relapse risk in MOG-antibody disease.

Immediate Post-IV Steroid Management

Oral prednisone taper is the standard approach following IV methylprednisolone for optic neuritis. 1 The typical regimen involves oral prednisone 1 mg/kg/day for 11 days following the IV course, then tapering over 2-4 weeks. 2, 1 This approach has been validated in the landmark Optic Neuritis Treatment Trial, which demonstrated that IV methylprednisolone followed by oral prednisone speeds visual recovery. 1

• Start oral prednisone at 1 mg/kg/day (typically 60-80 mg daily) immediately after completing the 5-day IV course 1
• Continue this dose for 11 days, then taper gradually over 2-4 weeks 2, 1
• Critical pitfall: Never use oral prednisone alone as initial treatment for optic neuritis, as this actually increases the risk of recurrent episodes (relative risk 1.79) 1

Long-Term Maintenance Therapy Considerations

The decision to initiate maintenance immunosuppression in MOG-antibody disease is critical, as 56-83% of patients experience relapses. 3 This is substantially higher than previously reported rates and represents a major management consideration.

Evidence Supporting Maintenance Therapy:

• Relapse rates in MOG-antibody disease are high: 56.3% of patients in recent cohorts experienced relapsing disease, with most relapses occurring within the first year after diagnosis 3
• 83.3% of MOG-antibody patients were ultimately treated with chronic immunosuppression in real-world practice 3
• Delaying immunosuppressive treatment may cause irreversible optic nerve damage 4

Recommended Maintenance Options:

Rituximab is the most commonly used maintenance therapy for MOG-antibody disease, though evidence for superiority over other agents is limited. 3

Alternative maintenance therapies include:

• Mycophenolate mofetil (MMF): Frequently used and well-tolerated 3, 4
• IVIG: Alternative option for maintenance 3
• Ocrelizumab or ofatumumab: Other anti-CD20 agents 3

For this specific patient with bilateral optic perineuritis and positive MOG antibody, I would strongly recommend initiating maintenance therapy immediately given:

• Bilateral involvement on MRI (higher risk feature)
• Positive MOG antibody (56-83% relapse risk) 3
• All known relapses in MOG disease occur within one year of diagnosis 3

Practical Treatment Algorithm:

1. Week 1-2: Complete oral prednisone taper as described above 2, 1

2. Week 2-3: Initiate maintenance immunosuppression with either:

   • First choice: Mycophenolate mofetil 1-2 g/day divided twice daily 3, 4
   • Alternative: Rituximab 1000 mg IV on days 0 and 14, then maintenance dosing 3

3. Ongoing monitoring:

   • Visual acuity and visual field testing monthly for first 3 months, then every 3 months 4
   • OCT to monitor RNFL thickness for subclinical progression 4
   • Watch specifically for new symptoms within the first year (highest relapse risk period) 3

Critical Caveats:

• Do not use plasmapheresis in this case—it is reserved for refractory cases or specific conditions like anti-GBM disease, not as routine treatment for MOG-antibody optic neuritis 5
• Do not administer IVIG before potential plasmapheresis, as plasmapheresis would remove the immunoglobulin 5, 6
• The patient's good response to IV methylprednisolone does not eliminate relapse risk—maintenance therapy decisions should be based on MOG-antibody positivity and bilateral involvement, not acute treatment response 3
• Early treatment is crucial: Patients treated early after symptom onset have more pronounced responses to steroids 7