Amgen announced FDA approval of a label expansion for Uplinza (inebilizumab-cdon) to include treatment of generalized myasthenia Gravis (gMG), a B-cell mediated autoimmune disorder, on December 11th, 2025. Adult patients who are anti-acetylcholine receptor (AChr) and anti-muscle specific tyrosine kinase (MuSK) antibody positive are eligible for the treatment.
According to a company press release, gMG is thought to be primarily driven by AChR and MuSK autoantibodies, which are produced by CD19+ B cells. Inebilizumab-cdon is a humanized monoclonal antibody (mAb) designed for targeted and sustained depletion of autoantibody-producing CD19+ B cells, including plasmablasts and some plasma cells. This is the third FDA approval granted to inebilizumab-cdon, which has also been indicated for the treatment of anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder and immunoglobulin G4-related disease.
According to the release, FDA approval was based on results from the Phase III MINT study, which studied inebilizumab-cdon in both AChR+ and MuSK+ patients. The primary endpoint of the study was change in baseline Myasthenia Gravis Activities of Daily Living (MG-ADL) score at Week 26. The combined patient population treated with inebilizumab-cdon had an MG-ADL score approximately 1.9 points lower than the placebo group at Week 26 (-4.2 vs. -2.2). Additionally, the AChR+ patient subgroup continued to demonstrate benefits from the treatment, with an MG-ADL score approximately 2.8 points lower than that of the placebo at Week 52 (-4.7 vs. -1.9).
“This approval marks a significant advancement for people living with gMG,” said Jay Bradner, M.D., Executive Vice President of Research and Development, Amgen, in the release. “By selectively targeting CD19-positive B cells, [inebilizumab-cdon] offers a new approach to treatment that addresses a biological root cause of disease. [Inebilizumab-cdon] 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.”
“Managing a rare and chronic illness can mean facing unpredictable relapsing symptoms and demanding treatment schedules,” said Samantha Masterson, President and CEO, Myasthenia Gravis Foundation of America, in the release. “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.”
