A 32-year-old woman with relapsing-remitting MS develops a new optic neuritis episode despite being on interferon-beta-1a for 2 years. MRI shows 3 new T2 lesions in 12 months. What is the most appropriate next step?
- A Escalate to a high-efficacy disease-modifying therapy such as natalizumab or ocrelizumab ✓
- B Switch to a different interferon preparation
- C Add oral methylprednisolone as long-term therapy
- D Switch to glatiramer acetate
Correct answer: A. Escalate to a high-efficacy disease-modifying therapy such as natalizumab or ocrelizumab
Explanation
Highly active RRMS with new relapses and MRI lesions while on platform therapy (interferons, glatiramer acetate) is an indication for escalation to high-efficacy DMTs. Natalizumab (anti-VLA-4, AFFIRM trial) and ocrelizumab (anti-CD20, OPERA trials) significantly reduce annualised relapse rates by 60–75%. Switching between platform therapies (interferons to glatiramer) is unlikely to address breakthrough disease. Oral steroids are for acute relapses, not disease modification.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.