What is the dosage regimen for MABTHERA (Rituximab) in the treatment of Multiple Sclerosis (MS)?

Rituximab Dosing Protocol for Multiple Sclerosis

For multiple sclerosis treatment, rituximab should be administered at a dose of 1000 mg intravenously on day 1 and day 15 for induction, followed by maintenance dosing of 1000 mg every 6 months. 1

Dosing Regimens for MS

• Two standard dosing options are available for MS treatment:

  • Fixed dose: 1000 mg IV administered on days 1 and 15 for induction, then 1000 mg every 6 months for maintenance 1
  • BSA-based dose: 375 mg/m² IV once weekly for 4 weeks for induction, then repeated as needed based on clinical response 1, 2

• For maintenance therapy in MS, rituximab is typically administered every 6 months, though some protocols use every 4 months in cases with breakthrough disease activity 3, 1

• Low-dose maintenance regimens (<1000 mg yearly) have shown efficacy in maintaining suppression of inflammatory disease activity in patients with stable MS 4

Efficacy in Multiple Sclerosis

• Rituximab has demonstrated significant efficacy in reducing relapse frequency in relapsing-remitting MS, with studies showing a reduction in annualized relapse rates from 0.84 to 0.37 5, 6

• Treatment with rituximab results in dramatic reduction of gadolinium-enhancing lesions on brain MRI scans in RRMS patients 5, 6

• Observational studies show approximately 75.6% of MS patients remain free from evidence of disease activity during rituximab treatment 7

• The effect of rituximab on disease progression in primary progressive MS appears to be marginal, with more benefit observed in relapsing forms of MS 6

Pre-Treatment Assessment

• Before initiating rituximab therapy, obtain:
  • Baseline immunoglobulin levels (IgG, IgM, IgA) 1, 2
  • Hepatitis B and C antibody screening 1, 2
  • Latent tuberculosis screening 1, 2
  • Complete blood count with differential 1

Monitoring During Treatment

• Monitor complete blood count with differential at baseline and at 2-4 month intervals during treatment 1, 2

• Assess clinical response through disease-specific parameters including relapse frequency, MRI activity, and disability progression 1

• Watch for IgM flare, which can occur particularly at treatment initiation 1

Safety Considerations

• Infusion-related reactions are common (up to 77% during first infusion) but are typically mild to moderate 5, 2

• Common infections include nasopharyngitis, upper respiratory tract infections, urinary tract infections, and sinusitis 5

• Serious adverse events to monitor include:

  • Progressive multifocal leukoencephalopathy (rare but serious) 1
  • Hepatitis B reactivation 1
  • Serious infections (rituximab likely increases risk compared to interferon beta or glatiramer acetate) 8

• Long-term rituximab treatment appears safe for up to 2 years of therapy according to available evidence 6

Treatment Duration and Discontinuation

• Long-term effects of rituximab on inflammatory disease activity have been observed, with rare disease reactivation in patients who discontinued treatment 4

• Disease reactivation is uncommon after discontinuation, suggesting durable effects beyond the treatment period 4

• For patients with stable disease, consider dose reduction to <1000 mg yearly which may be sufficient to maintain suppression of inflammatory disease activity 4