Rituximab treatment in AChR-positive generalized myasthenia gravis within two years of diagnosis

Newly diagnosed acetylcholine receptor (AChR)-positive generalized myasthenia gravis (gMG) is typically managed with corticosteroids, but long-term exposure carries substantial adverse effects. We evaluated the safety and effectiveness of rituximab (RTX) as the first and the only add-on to steroid therapy in AChR-positive gMG within two years from diagnosis.

We studied 24 adults who received RTX within 24 months from gMG diagnosis (mean 9.3 ± 7.1 months). This was a retrospective, single-center observational cohort study including consecutive eligible patients. Clinical outcomes (MG-ADL, MGFA-PIS), corticosteroid doses, and AChR antibody titers were assessed at baseline and 3, 6, and 12 months.

Mean age at RTX initiation was 63 ± 15 years; 10 patients (41.7%) were ≥ 65 and 4 (17%) had thymoma. Follow-up averaged 15.5 ± 6.9 months. Patients were stratified as steroid responders (n = 16), partial responders (n = 5), and refractory (n = 3). MG-ADL scores improved from 1.9 ± 2.4-0.32 ± 0.78 at 6-months and 0.0 at 12 months. Corticosteroid dose decreased from 22.4 ± 9.0 mg/day at initiation to 11.4 ± 4.7 mg/day at 6 months and 7.7 ± 2.2 mg/day at 12 months. At 6-months, 61% achieved or maintained pharmacological remission and 30% minimal manifestations; at 12-months, 64% were in remission and 36% had minimal manifestations. AChR antibody titers declined by ~70% at both time points. No serious RTX-related adverse events requiring treatment discontinuation were observed.

Our study highlights RTX's dual role both as a steroid-sparing maintenance therapy and as an early immunosuppressive option for steroid partial responders in addition to refractory AChR-positive gMG patients.