Amgen announced that the US Food and Drug Administration (FDA) has approved Uplizna (inebilizumab-cdon) for the treatment of generalised Myasthenia Gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) and anti-muscle specific tyrosine kinase (MuSK) antibody positive. The approval offers patients a new targeted treatment option that has the potential for long-term disease control with just two doses a year, after two initial loading doses.

"This approval marks a significant advancement for people living with gMG. By selectively targeting CD19-positive B cells, Uplizna offers a new approach to treatment that addresses a biological root cause of disease. Uplizna is conveniently dosed twice a year and delivers durable efficacy, helping people manage debilitating symptoms that can compromise daily function – including trouble breathing, speaking and seeing," said Jay Bradner, MD, Executive Vice President, Research and Development, Amgen.

gMG is a rare, unpredictable, chronic, B-cell-mediated autoimmune disorder that impairs neuromuscular communication and can cause fluctuating muscle weakness. The disease is thought to be primarily driven by AChR and MuSK autoantibodies, which are produced by CD19+ B cells, particularly plasmablasts and some plasma cells. Myasthenia Gravis impacts approximately 80,000 to 100,000 people in the US.

The approval of Uplizna for gMG is supported by data from the Myasthenia Gravis Inebilizumab Trial (MINT), the largest phase III biologic study to include both AChR+ and MuSK+ patients, and the first to successfully incorporate a steroid taper into its protocol. Patients on steroids at baseline began tapering at Week 4 to reach prednisone 5 mg per day by Week 24. By Week 26, 87.4 percent of patients taking Uplizna and 84.6 percent of those taking placebo had reduced their steroid dose to 5 mg or less per day.

"Uplizna showed strong efficacy at 26 weeks in both AChR+ and MuSK+ patients, with AChR+ patients continuing to improve through 52 weeks in MINT. MINT also required steroid tapering, recognising that long-term steroid use adds to the overall burden of disease. This approval brings a new first-in-class approach to gMG, expanding treatment options for clinicians and patients," said Richard J Nowak, MD, MS, Global Principal Investigator and Director, Myasthenia Gravis Clinic, Yale University.

At Week 26, Uplizna demonstrated a 1.9-point difference in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score compared with placebo (-4.2 vs. -2.2; p<0.0001). Benefits in the AChR+ patient subgroup continued through Week 52 – the longest randomised-controlled period for a Phase III trial in gMG – with an exploratory analysis of AChR+ patients showing a 2.8-point difference in MG-ADL for Uplinza compared with placebo (-4.7 vs. -1.9; 95% CI: −3.9 to −1.7).

"Managing a rare and chronic illness can mean facing unpredictable relapsing symptoms and demanding treatment schedules. This approval marks an important milestone, offering durable efficacy and a dosing schedule that provides people living with generalised Myasthenia Gravis six months of treatment-free time between maintenance doses," said Samantha Masterson, President and Chief Executive Officer, Myasthenia Gravis Foundation of America.