Rozanolixizumab improves outcomes in severe myasthenia gravis

Key takeaways:

• Rozanolixizumab improved outcomes in patients with muscle-specific kinase antibody-positive generalized myasthenia gravis.
• Efficacy was consistent with overall cohort of patients with myasthenia gravis.

Rozanolixizumab improved myasthenia gravis symptoms in people with muscle-specific kinase antibody-positive disease, according to a poster presented at the 2023 MDA Clinical & Scientific Conference in Dallas.

“Muscle-specific kinase antibody-positive (MuSK Ab+) generalized myasthenia gravis is often more severe and harder to treat than acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis,” Ali Habib, MD, an associate clinical professor of neurology at the University of California, Irvine, and colleagues wrote. “This study was conducted to analyze the efficacy of rozanolixizumab, a neonatal Fc receptor inhibitor, in a subgroup of patients with MuSK Ab+ generalized myasthenia gravis.”

Habib and colleagues enrolled 200 adults with class II to IVa myasthenia gravis, MuSK Ab+ or AChR Ab+, in a phase 3 trial of rozanolixizumab. Participants were randomly assigned to receive six weekly doses of rozanolixizumab 7 mg/kg, rozanolixizumab 10 mg/kg or placebo. Changes in disease symptoms were assessed using scores on Myasthenia Gravis Activities of Daily Living (MG-ADL), Myasthenia Gravis Composite (MGC) and Quantitative Myasthenia Gravis (QMG).

According to results, MG-ADL scores decreased significantly in participants taking either dosage of rozanolixizumab compared with placebo by the end of 6 weeks (both P < .001). The least squares mean change from baseline was –3.37 for rozanolixizumab 7 mg/kg, 3.4 for rozanolixizumab 10 mg/kg and 0.78 for placebo. MGC and QMG scores also improved significantly from baseline in both rozanolixizumab groups compared with the placebo group (both P < .001).

In total, 21 participants had MuSK Ab+ myasthenia gravis, five of whom received rozanolixizumab 7 mg/kg. The remaining 16 patients were split evenly between rozanolixizumab 10 mg/kg and placebo.

Similar to the overall findings, people with MuSK Ab+ myasthenia gravis had greater improvement from baseline on the MG-ADL when taking rozanolixizumab 7 mg/kg (7.28) or 10 mg/kg (4.16) compared with placebo (2.28).

Further, participants with MuSK Ab+ disease in the rozanolixizumab 7 mg/kg (14.14) and 10 mg/kg (8.56) groups had greater improvement from baseline on the MGC compared with the placebo group (1.4).

Scores for the QMG followed the same trend, with participants with MuSK Ab+ disease having a greater improvement in scores from baseline when taking rozanolixizumab 7 mg/kg (10.79) or 10 mg/kg (7.01) compared with placebo (3.87).