Amgen's Uplizna Wins FDA and European Approval for Generalized Myasthenia Gravis
Amgen received FDA and European Commission approval for Uplizna to treat generalized myasthenia gravis in adults who are anti-AChR or anti-MuSK antibody positive, offering twice-yearly maintenance dosing after initial loading doses.
The U.S. Food and Drug Administration approved Uplizna (inebilizumab-cdon) in December 2025 for the treatment of generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) and anti-muscle specific tyrosine kinase (MuSK) antibody positive. The European Commission also approved Uplizna as an add-on treatment to standard therapy for adults living with generalized myasthenia gravis who are anti-AChR or anti-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.
Generalized myasthenia gravis 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 U.S. and an estimated 56,000-123,000 people in Europe.
Uplizna works by selectively targeting CD19-positive B cells, which play a key role in disease pathology. The vice president of medical affairs at Amgen stated that the approval represents an important advancement for adults with gMG in Europe, helping address debilitating symptoms and potentially reduce the long-term use of steroids where clinically appropriate.
The approval 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 structured steroid-tapering protocol. The trial enrolled 238 adults with gMG, including 190 patients who are AChR+ and 48 patients who are MuSK+. Patients receiving steroids at baseline began tapering at Week 4 with a goal of reaching 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.
Eligibility criteria at screening and randomization included a Myasthenia Gravis Foundation of America classification of II, III or IV disease, MG-ADL score between 6 and 10 with greater than 50% of this score attributed to non-ocular items, or an MG-ADL score of at least 11, and a Quantitative Myasthenia Gravis (QMG) score of at least 11. Participants had to have been receiving a stable dose of steroids and/or nonsteroidal immunosuppressive therapy (or both) at the time of randomization.
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 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 (-4.7 vs. -1.9; 95% CI: −3.9 to −1.7).
Key secondary endpoints included a 2.5-point difference in the QMG score for Uplizna (-4.8) compared to placebo (-2.3) (p=0.0002) at Week 26 for the combined treated population. For the AChR+ population, there was a 1.8-point difference in the MG-ADL score for Uplizna (-4.2) compared to placebo (-2.4) (p=0.0015) at Week 26, and a 2.5-point difference in the QMG score for Uplizna (-4.4) compared to placebo (-2.0) (p=0.0011) at Week 26. For the MuSK+ population, there was a 2.2-point difference in the MG-ADL score for Uplizna (-3.9) compared to placebo (-1.7) (p=0.0297) at Week 26.
The most common adverse reactions in gMG were headache and infusion-related reactions. MINT also includes an optional three-year open-label treatment period.
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 in June 2020, and for the treatment of adult patients with Immunoglobulin G4-related disease in April 2025. Uplizna was also previously approved in Europe in April 2022 as a monotherapy for adult patients with neuromyelitis optica spectrum disorder who are anti-aquaporin-4 immunoglobulin G seropositive, and received European Commission approval in November 2025 as the first and only treatment for adults living with active immunoglobulin G4-related disease.
Uplizna has received regulatory approvals across multiple indications from Health Canada and the Brazilian Health Regulatory Agency (ANVISA), among others.