Amgen says the U.S. 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 two doses a year, after two initial loading doses.
“This approval marks a significant advancement for people living with gMG,” said Jay Bradner, executive vice president of Research and Development at Amgen.
“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.”
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 affects 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 3 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% of patients taking UPLIZNA and 84.6% 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,” said Richard J. Nowak, global principal investigator and director of the Myasthenia Gravis Clinic at Yale University.
“MINT also uniquely required steroid tapering, recognizing 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.”
At Week 26, UPLIZNA demonstrated a 1.9-point difference in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score compared with placebo. Benefits in the AChR+ patient subgroup continued through Week 52 – the longest randomized-controlled period for a phase 3 trial in gMG – with an exploratory analysis of AChR+ patients showing a 2.8-point difference in MG-ADL for UPLIZNA compared with placebo.
“Managing a rare and chronic illness can mean facing unpredictable relapsing symptoms and demanding treatment schedules,” said Samantha Masterson, president and chief executive officer of the Myasthenia Gravis Foundation of America.
“This approval marks an important milestone, offering durable efficacy and a dosing schedule that provides people living with generalized myasthenia gravis six months of treatment-free time between maintenance doses.”
This is the third indication for UPLIZNA, which was previously approved by the FDA for the treatment of adult patients with anti-aquaporin-4 (AQP4) antibody positive neuromyelitis optica spectrum disorder (NMOSD) in June 2020, and for the treatment of adult patients with immunoglobulin G4-related disease (IgG4-RD) in April 2025.
The most common adverse reactions in gMG were headache and infusion-related reactions.
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