Leerink analysts noted, however, that Uplizna’s slow onset of therapeutic efficacy compares unfavorably to would-be competitors in generalized myasthenia gravis.
Amgen’s anti-CD19 antibody Uplizna showed durable and deepening treatment effects for patients with generalized myasthenia gravis, maintaining improved function and disease activity through 1 year of follow-up, according to a data drop on Wednesday.
Leerink analysts in a Wednesday note said that responses to Uplizna “progressively improved out to week 52,” adding that its end response is “comparable” to other drugs in the same therapeutic class, such as UCB’s Rystiggo and argenx’s Vyvgart.
However, Leerink noted that Uplizna has a more “gradual effectiveness” than its would-be competitors in generalized myasthenia gravis (gMG), a neuromuscular autoimmune condition that causes muscle weakness. In particular, patients on Uplizna “only began to show initial separation from placebo” in terms of activities of daily living after 8 weeks, before reaching statistically significant separation at 26 weeks.
“This compares unfavorably vs. Vyvgart,” the analysts wrote, adding that argenx’s asset, significantly distinguishes itself from placebo as early as week 1.
Amgen’s data, which were presented at the 2025 Annual Meeting of the American Academy of Neurology and simultaneously published in the New England Journal of Medicine, showed that patients on Uplizna saw significant improvements in activities of daily living compared to those on placebo at 26 weeks. Uplizna also significantly lowered quantitative disease activity over this same time span.
In terms of safety, Uplizna was not associated with more frequent serious toxicities than placebo. Common side effects included headache, cough, urinary tract infections and infusion-related reactions.
Amgen plans to file for approval of Uplizna in gMG in the first half of 2025, according to a March 13 press release.
Uplizna is an intravenous monoclonal antibody designed to target and bind the CD19 protein, typically found on the surface of mature and immature B cells. The biologic was first approved in 2020 for neuromyelitis optica spectrum disorder, a rare autoimmune condition that affects nerves in the eye and spinal cord.
Last week, the FDA signed off on the use of Uplizna for IgG4-related disease, a condition that involves the infiltration of B cells into various organs, causing widespread damage. In this indication, Uplizna has shown the ability to reduce disease-related flares by 87% versus placebo, according to the Phase III MITIGATE trial. Uplizna likewise eliminated the need for glucocorticoids for nearly 90% of patients.
Amgen is also proposing Uplizna for gMG, with an approval filing planned for the first half of 2025.
