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 (Clincialtrials.gov: 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.