A 28-year-old woman with known multiple sclerosis (relapsing-remitting MS, EDSS 2.5) on interferon beta-1a develops a severe relapse with optic neuritis and new T2 lesions on MRI. She is considering switching to high-efficacy therapy. Which of the following is classified as a high-efficacy disease-modifying therapy (DMT) for MS with demonstrated reduction in annual relapse rate > 60%?
- A Interferon beta-1b (Betaseron)
- B Glatiramer acetate
- C Dimethyl fumarate (Tecfidera)
- D Natalizumab (anti-VLA-4 integrin monoclonal antibody) ✓
Explanation
Natalizumab (Tysabri) is classified as a high-efficacy DMT for relapsing MS, demonstrating approximately 68% reduction in annualised relapse rate and 83% reduction in new T2 lesion accumulation in the AFFIRM trial. It blocks the alpha-4 integrin (VLA-4) on lymphocytes, preventing CNS trafficking. The major risk is progressive multifocal leukoencephalopathy (PML) due to JC virus reactivation, particularly in JC antibody positive patients. Interferon betas and glatiramer acetate are first-line moderate-efficacy drugs (30–35% ARR reduction). Dimethyl fumarate is intermediate-to-high efficacy (~50% ARR reduction in DEFINE trial). Other high-efficacy agents include ocrelizumab, ofatumumab, alemtuzumab, and cladribine.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.