Response to rozanolixizumab across treatment cycles in patients with generalised myasthenia gravis: post hoc analysis

<h3>Background</h3> In the Phase 3 MycarinG (NCT03971422) study, one cycle (six once-weekly subcutaneous infusions) of rozanolixizumab 7mg/kg or 10mg/kg significantly improved myasthenia gravis (MG)-specific outcomes versus placebo. After MycarinG, patients could enrol in open-label extensions MG0004 (NCT04124965) or MG0007 (NCT04650854). We evaluated response to rozanolixizumab over multiple treatment cycles based on Cycle 1 (C1) response. <h3>Methods</h3> Data were pooled across MycarinG, MG0004 (first 6 weeks) and MG0007 (interim data cut-off: 08 July 2022) for patients with ≥2 symptom-driven cycles. Proportion of MG-Activities of Daily Living (MG-ADL) and Quantitative MG (QMG) responders (≥2.0-point and ≥3.0-point improvement from baseline, respectively) at Day 43 in each cycle was analysed. <i>Post hoc</i> analyses of response rates were conducted based on C1 response. <h3>Results</h3> 127 patients had ≥2 symptom-driven cycles. In C1, 74.0% (94/127) and 68.5% (87/127) of patients were MG-ADL and QMG responders, respectively, at Day 43. Among MG-ADL C1 responders, MG- ADL response rates remained high over subsequent cycles (C2: 78.7% [74/94]; C3: 77.1% [54/70]; C4: 78.0% [46/59]). Of 33 (26.0%) MG-ADL non-responders at C1, 63.6% (21/33) were responders at C2. Similar patterns were observed for QMG. <h3>Conclusions</h3> Patients receiving rozanolixizumab demonstrated a high response rate over multiple cycles, irrespective of initial response.