The US Food and Drug Administration (FDA) has approved rozanolixizumab-noli (Rystiggo) for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor (AchR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.
gMG is a heterogeneous group of rare autoimmune diseases characterized by postsynaptic defect of neuromuscular transmission, often due to the presence of antibodies against AchR (AChR-Ab+). Some gMG patients test negative for AChR-Ab+ – these individuals are sometimes referred to as seronegative patients. Approximately 40% of seronegative gMG patients have anti-muscle-specific receptor tyrosine kinase (MuSK) antibodies.
Rozanolixizumab is a humanized IgG4 monoclonal antibody that binds to the neonatal Fc receptor (FcRN), resulting in the reduction of circulating IgG. It is the only FDA-approved treatment in adults for both anti-AChR and anti-MuSK antibody-positive gMG, the two most common subtypes of gMG.
The FDA approval was largely based on data from the Phase 3 MycarinG study. Recently published in Lancet Neurology. A total of 200 patients were enrolled and were randomized to receive once weekly injections of rozanolixizumab 7 mg/kg (n= 66), rozanolixizumab 10 mg/kg (n=67), or placebo (n=66). The primary outcome measure was change in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score and the study observed highly significant improvements in both rozanolixizumab treated groups compared to placebo. MG-ADL assesses the impact of gMG on daily functions of eight signs or symptoms that are typically affected in gMG. These include activities such as breathing, talking, swallowing, and being able to rise from a chair.
The most common adverse reactions with rozanolixizumab were headache, infections, diarrhea, pyrexia, hypersensitivity reactions, and nausea.
Rozanolixizumab is expected to be commercially available during the 3rd quarter of 2023.
To learn more about gMG, visit our learning center at checkrare.com/myasthenia-gravis/
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Reference
Bril V et al. Efficacy and safety of rozanolixizumab in patients with generalised myasthenia gravis: a randomised, double-blind, placebo-controlled, adaptive Phase 3 study MyCarinG study. Lancet Neurol.2023;22(5):383-94.
