In late June 2023, global biopharmaceutical company UCB announced that the U.S. Food and Drug Administration (FDA) approved RYSTIGGO (rozanolixizumab-noli) for adults living with AchR or MuSK antibody positive generalized myasthenia gravis. The approval was granted under Priority Review, which offers a six-month review timeline rather than the standard ten. 

The complement-cascade, immune cells, and pathogenic IgG autoantibodies—all elements of neuromuscular junction dysregulation—play a role in driving generalized myasthenia gravis. This dysregulation makes it more difficult for nerves and muscles to communicate. Ultimately, this leads to the “grave muscle weakness” that characterizes myasthenia gravis. 

RYSTIGGO, administered subcutaneously, is a humanized IgG4 monoclonal antibody. It works by reducing how much IgG is circulating in your blood. This protects and preserves muscle function. Following this approval, RYSTIGGO should be available for patient use by the end of this year. 

Studying RYSTIGGO

The drug’s approval hinged on data from the Phase 3 MycarinG clinical trial. During the trial, researchers aimed to understand how RYSTIGGO improved patients’ abilities to stand from sitting, breathe, talk, swallow, and perform other similar daily actions. The trial showed that RYSTIGGO improved patient outcomes, reduced negative side effects, and strengthened muscle function. 

Some side effects did occur, including diarrhea, fever, hypersensitivity reactions, nausea, headache, and an increased risk of infections. In a smaller subset of patients, aseptic meningitis occurred. 

What is Generalized Myasthenia Gravis (gMG)? 

Myasthenia gravis (MG) is an antibody-mediated autoimmune neuromuscular disorder; the name translates to “grave muscle weakness.” While MG is treatable, some individuals fail to respond well. These individuals are considered to have generalized myasthenia gravis. They often experience severe side effects from their treatments, do not achieve disease stability, and may relapse upon any medication tapering. Muscle weakness from gMG may be debilitating. Other symptoms may include:

• Dysphagia (difficulty swallowing)
• Slurred speech
• Extreme fatigue
• Drooping eyelids
• Difficulty climbing stairs or walking long distances
• Double or blurred vision
• Muscle weakness in the face, arms, legs, and throat
• Difficulty chewing food
• Shortness of breath
• Respiratory failure
• Myasthenic crisis (severe weakness requiring respiratory support)