THOUSAND OAKS, Calif., April 3, 2025 – Hansoh Pharma’s collaborator Amgen (NASDAQ: AMGN) announced that the U.S. Food and Drug Administration (FDA) has approved inebilizumab 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 inebilizumab 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 approval of inebilizumab 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 inebilizumab to decrease disease activity by reducing flares in patients, while maintaining its established safety profile.1This is the second approved indication for inebilizumab, 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 inebilizumab 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.
On May 24, 2019, Hansoh Pharma entered into a license agreement with Viela Bio (Viela Bio was acquired by Horizon Therapeutics in 2021, which was acquired by Amgen in 2023), and has been granted an exclusive license to develop and commercialize the inebilizumab in Chinese mainland, Hong Kong and Macao. On March 14, 2022, inebilizumab was approved to be launched in China by the NMPA under the Chinese brand name 昕越® (XINYUE).
On March 4, 2025, Hansoh Pharma announced that the second Biologics License Application (BLA) of XINYUE has been accepted by the NMPA, which is for the treatment of IgG4-RD. On February 8, 2025, this indication has been included in the Priority Review and Approval Procedure by the NMPA.
About MITIGATE Trial
MITIGATE is a randomized, double-blind, placebo-controlled, parallel-group, multicenter trial designed to evaluate the efficacy and safety of inebilizumab 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 inebilizumab 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<0.001) during the 52-week placebo-controlled period; 10.3% (7 of 68) of participants receiving inebilizumab experienced a flare compared to 59.7% (40 of 67) of participants receiving placebo.
· A reduction in annualized flare rate for treated and adjudication committee-determined flares during the placebo-controlled period; 0.10 for participants receiving inebilizumab compared to 0.71 for participants receiving placebo (p<0.001).
· 57.4% (39 of 68) of participants receiving inebilizumab achieved flare-free, treatment-free, and complete remission at Week 52 compared to 22.4% (15 of 67) of participants receiving placebo (p<0.001).
· 58.8% (40 of 68) of participants receiving inebilizumab achieved flare-free, corticosteroid-free, and complete remission at Week 52 compared to 22.4% (15 of 67) of participants receiving placebo (p<0.001).
· 89.7% (61 of 68) of inebilizumab -treated patients required no glucocorticoid treatment for disease control during the placebo-controlled period, outside of the planned glucocorticoid tapering, compared to 37.3% (25 of 67) of patients on placebo.
· Inebilizumab -treated patients experienced a ten-fold reduction in mean total glucocorticoid use for disease control per patient relative to placebo (118 mg vs. 1385 mg, respectively) during the placebo-controlled period.
The most common adverse reactions in patients with IgG4-RD (at least 10% of patients treated with inebilizumab and greater than placebo) were urinary tract infection (12%) and lymphopenia (16%).
About IgG4-RD
Immunoglobulin G4-related disease (IgG4-RD) is a chronic, systemic, immune-mediated, fibroinflammatory disease which can affect numerous and generally multiple organs of the body.1 It is a progressive disease that can affect a variety of organ systems and often affects multiple organs over time. It is characterized by periods of remission and unpredictable disease flares.4,5 IgG4-RD can cause permanent organ damage with or without the presence of symptoms.2 Awareness of how organ damage manifests is critically important to inform the timely diagnosis of IgG4-RD. B cells are central to the pathogenesis of IgG4-RD.1 In IgG4-RD, CD19-expressing (CD19+) B cells are thought to drive inflammatory and fibrotic processes and interact with other immune cells that contribute to disease activity.1,2
The prevalence is estimated at 20,000 people in the United States (5 in 100,000 worldwide), although the number of IgG4-RD patients is difficult to determine based on limited epidemiology data.1,2 The typical age of onset of IgG4-RD is between 50 and 70 years old and, unlike many other immune-mediated diseases, IgG4-RD is more likely to occur in men than women.4
