Efgartigimod in Very-Late-Onset Generalized Myasthenia Gravis: A Real-World Study on Effectiveness and Safety

This study evaluated the safety and effectiveness of efgartigimod in patients with Very-Late-Onset Generalized Myasthenia Gravis (VLOGMG), a population that often presents with more severe symptoms and limited treatment responses.

Forty-two patients aged ≥ 65 years were retrospectively included. Clinical assessments, including MG activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis (QMG) scores, prednisone dosage, laboratory data, and adverse events, were recorded at each follow-up.

At week 4, 97.6% (41/42; 95% CI, 87.4-99.9) of patients were MG-ADL responders (≥ 2-point improvement). Notably, 83.3% (95% CI, 69.4-92.8) maintained response through week 12 (p < 0.001). Clinically meaningful improvement (CMI, ≥3-point QMG decrease) occurred in 97.6% of patients (41/42; 95% CI, 87.4-99.9), with a mean response time of 6.37 ± 5.46 days (95% CI, 4.63-8.11). Minimal symptom expression (MSE, MG-ADL score of 0 or 1) was achieved in 45% (95% CI, 30-61%), 60% (95% CI, 44-74%), and 45% (95% CI, 30-61%) of patients at weeks 4, 8, and 12, respectively. Prednisone dosage was tapered from a median of 20 (20, 30) mg/day to 10 (5, 15) mg/day by week 12. Most patients (88.1%) had ≥ 1 comorbidity, and 61.9% had multimorbidity. Efgartigimod was well tolerated, without evidence of worsening of pre-existing conditions.

Efgartigimod provided rapid symptom relief in older adults with VLOGMG and demonstrated steroid-sparing benefits across patients with various comorbidities. The high response rates and sustained improvement suggest that early use of fast-acting therapies may serve as a bridge to conventional long-term treatments. Larger prospective studies are warranted to confirm these findings.

Efgartigimod is associated with clinical benefit in patients with VLOGMG, allowing corticosteroid reduction without compromising comorbidity stability. Early initiation may enable faster disease control and more durable responses.