A 40-year-old woman with relapsing-remitting MS (RRMS) has had 2 relapses in the past year and a new T2 lesion on MRI. She is considering disease-modifying therapy. Which agent has the highest efficacy in reducing relapse rate but carries risk of progressive multifocal leukoencephalopathy (PML) due to JC virus?
- A Interferon beta-1a
- B Glatiramer acetate
- C Natalizumab ✓
- D Dimethyl fumarate
Correct answer: C. Natalizumab
Explanation
Natalizumab is a high-efficacy anti-α4-integrin monoclonal antibody that reduces relapses by ~68% but carries risk of PML caused by JC virus reactivation, particularly in JC antibody-seropositive patients with prior immunosuppressant use. PML risk is stratified using JC antibody index. Interferon beta and glatiramer acetate are moderate-efficacy first-line agents with no PML risk. Dimethyl fumarate has intermediate efficacy with rare PML cases reported only in lymphopenic patients.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.