Ravulizumab for Myasthenia Gravis

The Pharmaceutical Benefits Scheme (PBS) listing for ravulizumab has been expanded to include generalised myasthenia gravis (gMG). Myasthenia gravis is a chronic autoimmune disorder that affects postsynaptic acetylcholine receptors (AChR). Neuromuscular transmission is disrupted, causing weakness in voluntary muscles. To be eligible for PBS-subsidised therapy, patients must have a positive serology for AChR binding autoantibodies. It is thought that at least 80% of people with gMG have antibodies to AChR.

Ravulizumab is a terminal complement inhibitor. It binds with high affinity to complement protein C5 and prevents its cleavage to C5a and C5b. By inhibiting downstream complement activation, ravulizumab prevents formation of the membrane attack complex (MAC), a key driver of damage at the neuromuscular junction.

Ravulizumab is administered by intravenous infusion, with maintenance dosing every eight weeks. Its safety and efficacy in gMG were demonstrated in the double-blind, randomised CHAMPION MG study. Compared with placebo, ravulizumab produced rapid and clinically meaningful improvements in patient‐ and physician‐reported outcomes. During the open-label extension period (up to four years), these benefits were maintained in patients who continued ravulizumab. Patients who switched from placebo to ravulizumab experienced rapid improvements in activities of daily living, muscle strength, fatigue, and quality of life.

Although early steps of complement activation are preserved, ravulizumab increases the risk of infection, particularly with Neisseria species and other encapsulated bacteria. Life-threatening meningococcal infections have occurred during ravulizumab therapy. Patients should receive meningococcal vaccination at least two weeks before starting ravulizumab.