gMG is a rare autoimmune disorder characterised by severe muscle weakness. In gMG, inflammation causes damage at the connection point between nerve cells and the muscles they control (known as the neuromuscular junction or NMJ). This damage leads to a breakdown of communication between the brain and muscles, causing loss of muscle function and severe weakness.

About 85% of people with gMG produce specific antibodies that bind to the surface of the cells at the NMJ. This binding activates the complement cascade and causes the immune system to attack the NMJ. People with gMG can suffer from initial symptoms, such as slurred speech, droopy eyelids, double vision, and lack of balance, which can often lead to more severe symptoms like choking, impaired swallowing, extreme fatigue and even episodes of respiratory failure.gMG can occur at any age, but it most commonly begins for women before the age of 40 and for men after the age of 60.

The supplemental Biologics License Application (sBLA) for Ultomiris (ravulizumab-cwvz) in adults with generalised myasthenia gravis (gMG) has been accepted for Priority Review by the US Food and Drug Administration (FDA).

gMG is a rare, debilitating, chronic, autoimmune neuromuscular disease that leads to a loss of muscle function and severe weakness. The diagnosed prevalence of gMG in the US is estimated at 64,000.

The sBLA submission in the US is based on results from the Phase III trial of Ultomiris in gMG, which were announced by Alexion in July 2021, and showed efficacy as early as Week 1 and sustained for 52 weeks (26 weeks randomised controlled period + 26 weeks of open-label extension). In the trial, the safety profile of Ultomiris was consistent with that observed in Phase III trials of Ultomiris in paroxysmal nocturnal haemoglobinuria (PNH) and atypical haemolytic uraemic syndrome (aHUS).

The global Phase III randomised, double-blind, placebo-controlled, multicentre 26-week trial evaluated the safety and efficacy of Ultomiris in adults with gMG who were not previously treated with a complement inhibitor medicine. The trial enrolled 175 patients across North America, Europe, Asia-Pacific and Japan. Patients were randomised 1:1 to receive Ultomiris or placebo for a total of 26 weeks. Patients received a single weight-based loading dose on Day 1, followed by regular weight-based maintenance dosing beginning on Day 15, every eight weeks. The primary endpoint of change from baseline in the MG-ADL total score at Week 26 was assessed along with multiple secondary endpoints evaluating improvement in disease-related and quality-of-life measures.

Patients who completed the randomised controlled period were eligible to continue into an open-label extension period evaluating the safety and efficacy of Ultomiris for up to two years, which is ongoing. At the time of the preliminary analysis of the open-label extension period, 75 patients had completed 26 weeks of treatment, for a total of 52 weeks of treatment.

Regulatory submissions for Ultomiris for the treatment of gMG are also currently under review with health authorities in the European Union (EU) and Japan.