What is the role of Rituximab (rituximab) in treating transverse myelitis?

Rituximab for Transverse Myelitis

Rituximab should be considered as a second-line treatment option for transverse myelitis that fails to respond adequately to first-line corticosteroids and IVIG, particularly in cases with positive autoimmune antibodies or when associated with neuromyelitis optica spectrum disorder. 1

Treatment Algorithm for Transverse Myelitis

First-Line Therapy (Always Start Here)

• Administer high-dose intravenous methylprednisolone 1g daily for 3-5 days as the initial treatment 1
• For moderate to severe cases with significant weakness or sensory changes, combine corticosteroids with IVIG 2g/kg over 5 days 1
• Immediately discontinue any potential causative agents if identified 1

When to Consider Rituximab (Second-Line)

• Use rituximab for patients who do not respond adequately to corticosteroids and IVIG 1
• Strongly consider rituximab in cases with positive autoimmune encephalopathy antibodies 1
• Rituximab is particularly beneficial in neuromyelitis optica spectrum disorder (NMOSD)-associated transverse myelitis with positive aquaporin-4 IgG 1

Rituximab Dosing and Monitoring Strategy

• The standard dose is 375 mg/m² administered weekly for 4 consecutive weeks 2
• Critical monitoring requirement: Follow monthly CD19 counts to identify early B-cell repopulation, as low doses have high rates of early repopulation 3
• The mean time until CD19 population exceeds 2% is 184 days after a 1000 mg dose (range 52-288 days) versus only 99 days after a 100 mg dose 3
• Monitor for infusion reactions, which occur in approximately 20% of patients 2

Evidence Quality and Clinical Context

The evidence for rituximab in transverse myelitis comes from multiple sources with varying strength. The most recent guideline evidence 1 recommends rituximab as second-line therapy, though this is based on extrapolation from its effectiveness in related autoimmune neurological disorders 4.

Important caveat: Research evidence shows variable outcomes with rituximab in neuromyelitis optica and related conditions. One study found that 6 of 9 patients continued to have relapses after rituximab treatment, with particularly poor outcomes when used as first-line immunosuppression 5. However, a more recent case report demonstrated successful treatment of EBV-associated transverse myelitis with intravenous rituximab 6, and another case showed success in SLE-associated myelitis 7.

Special Clinical Scenarios

NMOSD-Associated Transverse Myelitis

• More aggressive immunosuppression may be required in aquaporin-4 IgG positive cases 1
• These patients benefit from rituximab as it targets the B-cell mediated pathophysiology 4

Autoimmune-Associated Cases

• Continued immunosuppression after acute treatment is necessary to prevent recurrence 1
• Maintenance therapy with agents like azathioprine is often needed, as relapses occur in 50-60% of cases during corticosteroid dose reduction 1

Safety Considerations and Monitoring

• Monitor serum immunoglobulin levels before and periodically after rituximab, particularly with multiple courses, due to risk of hypogammaglobulinemia 2
• Screen for hepatitis B before initiating therapy, as reactivation is a rare but potentially fatal complication 2
• Be aware of rare severe mucocutaneous reactions and multifocal leukoencephalopathy 2
• Standard monitoring includes complete blood count, hepatic and renal function tests 8, 9

Prognostic Factors Affecting Treatment Success

• Delay beyond 2 weeks in initiating therapy is associated with poor prognosis 1
• Extensive spinal cord MRI lesions, especially longitudinally extensive transverse myelitis affecting ≥3 vertebral segments, predict worse outcomes 1
• Reduced muscle strength or sphincter dysfunction at presentation indicates poorer prognosis 1

Alternative if Rituximab Fails

• Plasma exchange therapy should be considered for patients who do not respond to corticosteroids, IVIG, or rituximab 1