Response to Rozanolixizumab Across Treatment Cycles in Patients With Generalized Myasthenia Gravis: A Post Hoc Analysis of Final Pooled Phase Three Data
Robert M. Pascuzzi1, Ali A. Habib2, Zabeen K. Mahuwala3, Renato Mantegazza4, Sabrina Sacconi5, John Vissing6, Tuan Vu7, Joel Baldwin8, Thaïs Tarancón8, Vera Bril9
1Neurology Department, Indiana University School of Medicine, Indiana University Health, 2University of California, Irvine, 3Department of Neuromuscular Medicine, Epilepsy and Clinical Neurophysiology, University of Kentucky, 4Department of Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS, Istituto Nazionale Neurologico Carlo Besta, 5Université Côte d'Azur, Peripheral Nervous System & Muscle Department, Pasteur 2 Hospital, Centre Hospitalier Universitaire de Nice, 6Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, 7Department of Neurology, University of South Florida Morsani College of Medicine, 8UCB, 9Ellen and Martin Prosserman Centre for Neuromuscular Diseases, Toronto General Hospital, University of Toronto
Objective:
To evaluate the response to rozanolixizumab over multiple treatment cycles in patients with generalized myasthenia gravis (gMG), based on their Cycle 1 response.
Background:
In MycarinG (Phase 3, NCT03971422), one cycle of six once-weekly subcutaneous rozanolixizumab (7 mg/kg or 10 mg/kg) infusions showed clinically meaningful improvements in MG-specific outcomes versus placebo. Patients could subsequently enroll in open-label extensions MG0004 (NCT04124965), then MG0007 (NCT04650854), or MG0007 directly.
Design/Methods:
In MG0004, patients received chronic, once-weekly rozanolixizumab 7 mg/kg or 10 mg/kg for ≤52 weeks. In MG0007, after an initial cycle of rozanolixizumab 7 mg/kg or 10 mg/kg, subsequent cycles were administered upon symptom worsening (at the investigator’s discretion). Data were pooled across MycarinG, MG0004 (first 6 weeks) and MG0007 (final data) for patients with ≥2 symptom-driven cycles. The proportion of patients achieving an MG Activities of Daily Living (MG-ADL) and Quantitative MG (QMG) response (defined as ≥2.0-point and ≥3.0-point improvement from baseline, respectively) at Day 43 in each cycle were assessed. Post hoc analyses of response rates were conducted based on Cycle 1 response.
Results:
129 patients had ≥2 symptom-driven cycles. In Cycle 1, 74.4% (n/N=96/129) and 68.2% (88/129) of patients were MG-ADL and QMG responders at Day 43, respectively. Among MG-ADL Cycle 1 responders, MG-ADL response rates remained consistently high over subsequent cycles, up to Cycle 13, ranging from 74.4% (29/39 [Cycle 10]) to 88.2% (15/17 [Cycle 13]). Among QMG Cycle 1 responders, QMG response rates were fairly consistent across cycles, ranging from 61.0% (25/41 [Cycle 9]) to 83.3% (15/18 [Cycle 12]). Of 33 (25.6%) MG-ADL non-responders at Cycle 1, 63.6% (21/33) were responders at Cycle 2. Of 41 (31.8%) QMG non-responders at Cycle 1, 50.0% (20/40) were responders at Cycle 2.
Conclusions:
Cycle 1 responders demonstrated generally consistent response rates in subsequent cycles of rozanolixizumab. Initial non-responders may benefit from additional rozanolixizumab treatment cycles.
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