RARE Daily

EC Approve UCB’s gMG Drug Rystiggo

January 8, 2024

Rare Daily Staff

The European Commission granted marketing authorization to UCB’s Rystiggo as an add-on to standard therapy for the treatment of the rare, autoimmune disease generalized myasthenia gravis.

The approval is for generalized myasthenia gravis in adults who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.

Generalized myasthenia gravis (gMG) can cause people to experience a variety of symptoms, including severe muscular weakness that can result in double vision, drooping eyelids, difficulty with swallowing, chewing and talking, as well as life-threatening weakness of the muscles of respiration. In gMG, pathogenic autoantibodies can impair synaptic transmission at the neuromuscular junction by targeting specific proteins on the post-synaptic membrane. This disrupts the ability of the nerves to stimulate the skeletal muscle and results in a weaker contraction. The condition can occur in any race, gender, or age.

Rystiggo is a humanized IgG4 monoclonal antibody that binds to the neonatal Fc receptor resulting in the reduction of circulating IgG. It is the first therapy approved in Europe for adults with anti-AChR or anti-MuSK antibody-positive gMG, the two most common subtypes of gMG.

Orphan designation was granted by the European Commission in 2020 to Rystiggo for the treatment of myasthenia gravis and maintained after having received the positive CHMP Opinion. The approval of Rystiggo from the EC is valid in all EU member states, as well as in the European Economic Area countries Iceland, Liechtenstein, and Norway.

EC approval of Rystiggo is supported by safety and efficacy data from the pivotal phase 3 MycarinG study, published in The Lancet Neurology in May 2023. The primary efficacy endpoint was the comparison of the change from baseline between treatment groups versus placebo in the MG-ADL score at Day 43. MG-ADL is a measurement tool that assesses the impact of gMG on daily functions of eight items that are typically affected in gMG. These include activities such as breathing, talking, swallowing, and being able to rise from a chair.  Secondary efficacy endpoints included change from baseline to Day 43 in the Myasthenia Gravis Composite (MG-C) and the Quantitative Myasthenia Gravis (QMC) scores.

The most commonly reported adverse reactions were headache (48.4 percent), diarrhea (25.0 percent) and pyrexia (12.5 percent).

In December 2023, the EC also granted a marketing authorization for UCB’s Zilbrysq as an add-on to standard therapy for the treatment of gMG in adult patients who are anti-AChR antibody-positive. Zilucoplan is a once-daily subcutaneously injected, self-administered peptide C5 inhibitor.

“With the European Commission approval of [Rystiggo], alongside their recent approval of zilucoplan, I’m very excited that our gMG portfolio is now approved for use by healthcare professionals across Europe. This represents another important milestone in our ambition to deliver new and additional patient value to the gMG community and continues our launch trajectory,” explained Jean-Christophe Tellier, CEO, UCB. “We believe there is still a significant unmet need within the gMG community which can be addressed by bringing differentiated, generally well-tolerated, and effective treatment options to patients that address key aspects of gMG pathophysiology.”


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