Batoclimab as Induction and Maintenance Therapy in Patients With Generalized Myasthenia Gravis: Rationale and Study Design of a Phase 3 Clinical Trial


Clinical Trials

Poster Number: M268


Michael Benatar, MD, PhD, University of Miami Miller School of Medicine, Heinz Wiendl, MD, FAAN, Department of Neurology, University of Münster, Münster, Germany, Richard Nowak, MD, MS, Yale University School of Medicine, Yan Zheng, PhD, Immunovant, Inc., Richard Valanzola, MS, Immunovant, Inc., Tess Karlson, BS, Immunovant, Inc., Sheetal Patel, MD, MS, Immunovant, Inc., William Macias, MD, PhD, Immunovant, Inc.

BACKGROUND: Despite recent advances in the field of myasthenia gravis (MG), there remain unmet treatment needs.

OBJECTIVE: Describe an innovative phase 3 clinical trial of batoclimab, a fully human monoclonal antibody that inhibits the neonatal fragment crystallizable receptor, in generalized MG (gMG).

METHODS: Adults with gMG will be randomized 1:1:1 to induction treatment with batoclimab 680 mg, 340 mg, or placebo, administered once weekly (QW) for 12 weeks as a subcutaneous injection at home or in the clinic. The primary endpoint is the change from baseline to Week 12 on the Myasthenia Gravis Activities of Daily Living (MG-ADL) score. Batoclimab-treated patients achieving a ≥2-point improvement from baseline on MG-ADL at Week 10 or Week 12 (responders) will be re-randomized to maintenance treatment with batoclimab (340 mg QW or every other week [Q2W]) or placebo for 12 weeks; batoclimab non-responders will be switched to placebo for 12 weeks, then discontinued. Placebo-treated patients from the induction period will be re-randomized to batoclimab 340 mg QW or Q2W during maintenance. Patients completing the maintenance period who are responders in the induction and/or maintenance periods will continue their maintenance batoclimab dose (or switch to 340 mg QW if on placebo) for a 52-week long-term extension. Patients experiencing a flare during the extension may receive open-label rescue treatment with batoclimab 680 mg QW for 4 weeks, followed by 340 mg QW.

RESULTS: The FLEX trial ( NCT05403541) is recruiting participants.

SUMMARY/CONCLUSION: FLEX will explore different induction and maintenance doses of batoclimab in gMG, with a goal of informing clinical practice.