What is the recommended treatment for a patient with multiple sclerosis (MS) who has new lesions on the right side, including a 0.3cm subcortical and approximately 0.6cm periventricular lesion, in addition to previous lesions on the left side?

Treatment Recommendation for MS Patient with New Active Lesions

This patient requires immediate escalation or initiation of disease-modifying therapy (DMT), as the presence of new lesions on MRI—particularly two new lesions on the right side plus two previously missed lesions on the left—demonstrates ongoing inflammatory disease activity that necessitates treatment intensification. 1

Evidence of Active Disease Requiring Treatment

• The presence of new T2 lesions between serial MRI scans is a critical indicator of subclinical disease activity and represents ongoing inflammatory demyelination that warrants therapeutic intervention 1

• Your patient has demonstrated clear radiographic disease progression with 4 total active lesions (2 new right-sided lesions plus 2 left-sided lesions missed on prior imaging), involving both periventricular and subcortical white matter in a pattern highly characteristic of MS 2

• Serial MRI detecting new or enlarging lesions provides sufficient information about subclinical disease activity and disease progression, even without clinical relapses 1

Treatment Algorithm Based on Current Disease Status

If Currently Untreated (Treatment-Naïve):

Initiate high-efficacy DMT immediately given the demonstrated active inflammatory disease with multiple new lesions 3, 4

• First-line high-efficacy options include:

  • Natalizumab (Tysabri): Reduces annualized relapse rates by up to 68% compared to placebo, though requires monitoring for PML risk with anti-JCV antibody testing 5, 3
  • Ocrelizumab or other anti-CD20 monoclonal antibodies: Highly effective for reducing relapses and MRI lesion activity 3
  • Sphingosine 1-phosphate receptor modulators (fingolimod, siponimod, ozanimod): Oral agents with 54-60% reduction in relapse rates 3

• Moderate-efficacy alternatives (if high-efficacy agents contraindicated):

  • Interferon beta-1a (Avonex, Rebif) or interferon beta-1b (Betaseron): Reduce relapses by 29-34% 6, 3
  • Glatiramer acetate (Copaxone): Similar efficacy profile to interferons 7, 3

If Currently on DMT (Treatment Failure):

This represents breakthrough disease activity requiring immediate treatment escalation 1, 8

• Switch to a higher-efficacy DMT from a different mechanism of action class 1, 3

• Enhanced MRI surveillance is required during the transition period: Brain MRI every 3-4 months for up to 12 months when switching between certain DMTs, particularly when transitioning from natalizumab to other therapeutics 1

• Consider the washout period carefully to balance risk of disease reactivation versus risk of additive immunosuppression 1

MRI Monitoring Protocol Going Forward

Follow-up brain MRI should be performed every 3-12 months depending on treatment choice and disease activity level 1

• Minimum annual MRI is recommended for all patients with MS on DMT 1

• More frequent monitoring (every 3-4 months) is indicated for:

  • Patients at high risk of serious treatment-related adverse events (e.g., PML with natalizumab) 1, 5
  • Patients switching DMTs during the transition period 1
  • Patients with recent evidence of high disease activity 1

• MRI protocol should include:

  • T2-weighted or T2 FLAIR sequences to detect new or enlarging lesions 1
  • Gadolinium-enhanced T1-weighted sequences to detect acute inflammatory activity (contrast-enhancing lesions) 1
  • Same MRI system and imaging protocol as baseline for accurate comparison 1

Critical Safety Considerations

For natalizumab specifically (if chosen as high-efficacy option):

• Mandatory anti-JCV antibody testing before initiation to stratify PML risk 5
• Baseline brain MRI is essential to differentiate future MS lesions from potential PML 5
• Enrollment in TOUCH® Prescribing Program is required due to PML risk 5
• Seroconversion rate is 3-8% annually, requiring periodic retesting of anti-JCV antibody status 5

For all DMTs:

• Monitor for infections, infusion/injection site reactions, and secondary autoimmune effects 3
• Specific monitoring requirements vary by agent (e.g., cardiac monitoring for sphingosine 1-phosphate receptor modulators, liver function tests for multiple agents) 3, 4

Common Pitfalls to Avoid

• Do not delay treatment while waiting for clinical relapse—radiographic activity alone warrants intervention 1

• Do not continue ineffective therapy—new lesions on current DMT represent treatment failure requiring escalation 1, 8

• Do not use spinal cord MRI for routine monitoring—brain MRI is more sensitive for detecting disease activity and easier to standardize 1

• Ensure accurate scan positioning between serial MRIs for reliable assessment of lesion changes over time 1