Breakthrough CD19+ B-Cell Targeted Therapy Delivered an 87% Reduction in the Risk of Flares Versus Placebo
UPLIZNA Shown to Deliver Corticosteroid-Free, Flare-Free, Complete Remission for Patients in the MITIGATE Trial
Advances Amgen's Leadership in CD19 Directed, B-Cell Depletion Therapies for Serious Autoimmune Diseases Including NMOSD, IgG4-RD and gMG
THOUSAND OAKS, Calif., April 3, 2025 /PRNewswire/ -- Amgen (NASDAQ:AMGN) announced today that the U.S. Food and Drug Administration (FDA) has approved UPLIZNA as the first and only treatment for adults living with Immunoglobulin G4-related disease (IgG4-RD). IgG4-RD is a chronic and debilitating immune-mediated inflammatory condition that can affect multiple organs. The FDA granted Breakthrough Therapy Designation to UPLIZNA for the treatment of IgG4-RD, recognizing the high unmet medical need in this serious condition and the medicine's potential to benefit patients.
"The FDA approval of UPLIZNA marks a significant turning point for IgG4-RD patients and physicians who now have a proven treatment that targets a key driver of the disease, reducing the risk of flares and reliance on harmful long-term steroid use," said Jay Bradner, M.D., executive vice president of Research and Development at Amgen. "We are proud to deliver a therapy that has the potential to significantly improve care for patients with IgG4-RD and remain encouraged by UPLIZNA's broader potential in other immune-mediated diseases, including neuromyelitis optica spectrum disorder and generalized myasthenia gravis. This approval underscores Amgen's ongoing commitment and leadership in developing innovative treatments targeting CD19+ B-cells across multiple therapeutic areas."
IgG4-RD can occur in multiple organs and lead to fibrosis and permanent organ damage.1,2 Understanding how organ damage manifests is critically important to inform the timely diagnosis of IgG4-RD. The disease mimics other diseases due to the heterogeneous and unpredictable inflammatory flares that can occur.3 Over time, IgG4-RD can affect virtually any organ system.1
"Targeting CD19+ B cells with UPLIZNA has proven to be a highly effective approach to help address the pathophysiology of IgG4-RD," said John Stone, M.D., M.P.H., principal investigator, and a professor of medicine at Harvard Medical School and the Edward A. Fox Chair in Medicine at the Massachusetts General Hospital. "The clinical community now has an FDA-approved therapeutic innovation for patients that targets underlying disease mechanisms and helps to control disease activity by reducing flares in IgG4-RD. Now, our work begins in raising awareness of this disease so that patients can access the right treatment as early as possible, avoiding a long and often harmful diagnostic journey."
The approval of UPLIZNA for IgG4-RD is supported by data from the MITIGATE trial, the first randomized, double-blind, placebo-controlled trial conducted in IgG4-RD.1 This trial demonstrated the potential of UPLIZNA to decrease disease activity by reducing flares in patients, while maintaining its efficacy and established safety profile.1
This is the second approved indication for UPLIZNA, which was previously approved by the FDA for the treatment of adult patients with AQP4-IgG+ Neuromyelitis Optica Spectrum Disorder (NMOSD) in June 2020. The FDA also granted UPLIZNA Orphan Drug Designation for the treatment of generalized myasthenia gravis (gMG). Regulatory filing activities are underway for gMG with submission anticipated to be complete in H1 2025.
Amgen is committed to supporting patients with IgG4-RD and helping appropriate patients with access to UPLIZNA. Patients and caregivers who need support, tools or resources can contact Amgen By Your Side.
About the MITIGATE Trial MITIGATE is a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial designed to evaluate the efficacy and safety of UPLIZNA compared to placebo in reducing the risk of flares in adults with IgG4-RD.1
The primary endpoint was time to first treated and adjudicated IgG4-RD flare.1 The three key secondary endpoints were annualized flare rate; flare-free, treatment-free complete remission; and flare-free, corticosteroid-free complete remission.1 The MITIGATE trial also includes an optional three-year open-label treatment period and a safety follow-up period after UPLIZNA discontinuation of up to two years.
Key findings from the MITIGATE trial include (p values are formatted to align with New England Journal of Medicine standards):1
- An 87% reduction in the risk of IgG4-RD flare compared to placebo (Hazard Ratio 0.13, p

