A 32-year-old woman with myasthenia gravis (generalized, AChR antibody positive) is poorly controlled on pyridostigmine and azathioprine. CT chest is normal (no thymoma). Which immunotherapy has been approved as add-on for AChR antibody-positive generalized MG?
- A Eculizumab (anti-C5 complement) ✓
- B Rituximab (anti-CD20)
- C Natalizumab (anti-α4-integrin)
- D Tocilizumab (anti-IL-6R)
Correct answer: A. Eculizumab (anti-C5 complement)
Explanation
Eculizumab (anti-C5 monoclonal antibody) is FDA-approved for treatment-refractory generalized AChR antibody-positive myasthenia gravis based on the REGAIN trial showing significant improvement in ADL scores. Complement activation contributes to NMJ destruction in AChR-positive MG. Rituximab is used off-label primarily for MuSK-positive MG. Natalizumab is for MS; tocilizumab is for RA/inflammatory conditions. Rozanolixizumab and efgartigimod (FcRn inhibitors) are newer approvals.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.