Background: In the Phase 3 MycarinG study (MG0003/NCT03971422), one 6-week cycle of rozanolixizumab significantly improved myasthenia gravis (MG)-specific outcomes versus placebo. After MycarinG, patients could enrol in open-label extension studies (MG0004 then MG0007, or MG0007 directly). Methods: In MG0004 (NCT04124965), patients received once-weekly rozanolixizumab 7mg/kg or 10mg/kg for ≤52 weeks. In MG0007 (NCT04650854), after a cycle of rozanolixizumab 7mg/kg or 10mg/kg, subsequent cycles were based on symptom worsening at the investigator’s discretion. Pooled data are reported across MycarinG, MG0004 (first 6 weeks) and MG0007 (final data) for patients receiving ≥2 symptom-driven cycles (efficacy; ≤13 cycles) or ≥1 cycle (safety). Results: 196 patients received ≥1 rozanolixizumab dose of whom 129 received ≥2 symptom-driven cycles (7mg/kg: n=70; 10mg/kg: n=59). Treatment response was maintained from Cycles 1–13: mean change from baseline to Day 43 in MG-Activities of Daily Living score ranged from -3.2 to -4.9 (7mg/kg) and -3.2 to -6.7 (10mg/kg). Quantitative MG and MG Composite scores also improved. Treatment-emergent adverse events (TEAEs) did not increase with repeated cyclic treatment, and most were mild/moderate; the most common event was headache. Conclusions: Rozanolixizumab showed consistent improvements across MG-specific outcomes up to 13 cycles and repeated cyclic treatment was generally well tolerated. Funding: UCB.