Late-stage trial boost for Argenx’s myasthenia gravis drug Vyvgart

Argenx SE’s antibody drug Vyvgart has become the first myasthenia gravis treatment to improve disease activity across all three subtypes of the rare autoimmune disease in a late-stage trial.

The drug showed clinically meaningful improvements in disease activity for the muscle-specific tyrosine kinase (MuSK)+, LRP4+ and triple seronegative subtypes of AChR-Ab seronegative generalised myasthenia gravis (gMG) in the Phase III study.

The topline data from the pivotal ADAPT SERON study also demonstrated that Vyvgart (IV: efgartigimod alfa-fcab) enabled improvements in MG-ADL (Myasthenia Gravis Activities of Daily Living) total score compared to placebo.

In the ADAPT SERON trial, Vyvgart was well tolerated and no new safety concerns were identified.

The new study findings are significant because there are currently no approved treatments available for individuals with anti-LRP4 antibodies or for triple seronegative patients.

However, notable progress has been made across the treatment landscape. For example, last year, the European Commission approved a first-of-a-kind drug for adults with anti-acetylcholine receptor (AChR)  or anti-MuSK antibody positive generalised myasthenia gravis.

Addressing unmet need in generalised myasthenia gravis

Dr James Howard Jr, Professor of Neurology (Neuromuscular Disease), Medicine and Allied Health, Department of Neurology, The University of North Carolina and Principal Investigator for the ADAPT SERON trial, said: “The results of the ADAPT SERON study, the largest study to date of AChR-Ab seronegative gMG, confirm that Vyvgart now has the potential to be a targeted, effective, safe, and necessary treatment for patients living with gMG, regardless of autoantibody status.

“Paired with our existing knowledge, these data demonstrate that pathogenic IgGs are underlying drivers of gMG across patient subtypes. This is a critical advancement in the management of this debilitating and unpredictable disease for patients with limited treatment options.”

Detailed results from the ADAPT SERON study will be presented at an upcoming medical meeting.

Argenx plans to submit a Supplemental Biologics License Application (sBLA) to the US Food and Drug Administration (FDA) by end of the year, to expand use of Vyvgart in adults with AChR-Ab seronegative generalised myasthenia gravis across all three subtypes.