FDA Approval of Amgen's UPLIZNA for IgG4-related Disease Opens New Market Opportunity in Rare Autoimmune Segment | DelveInsight
With UPLIZNA receiving a label expansion that opens the door to a previously untapped rare disease market, Amgen is seeing strong returns on its USD 27.8 billion acquisition of Horizon Therapeutics. The drug has become the first to receive FDA approval specifically for treating immunoglobulin G4-related disease (IgG4-RD).
LAS VEGAS, April 14, 2025 /PRNewswire/ -- IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory condition marked by the accumulation of IgG4-positive plasma cells in affected tissues, sometimes accompanied by elevated blood levels of IgG4. The disease can impact nearly any organ, with common sites including the pancreas, bile ducts, salivary and lacrimal glands, orbits, kidneys, lungs, and the retroperitoneal space.
Due to its relatively recent identification, lack of widespread clinical awareness, and often subtle or slow-developing symptoms, IgG4-RD is likely underdiagnosed and underreported. It occurs more frequently in men, with most diagnoses in adults between their 30s and 50s, though cases have also been documented in children. In 2024, there were ~149K diagnosed prevalent cases of IgG4-RD across the 7MM, with the United States representing the largest share of these cases.
In patients with IgG4-related disease, treatment may not always be necessary. In cases where individuals are asymptomatic, a watchful waiting approach can be appropriate. However, when vital organs are involved or symptoms are present, timely treatment becomes crucial, as IgG4-RD can lead to significant organ damage and dysfunction.
Glucocorticoids are considered the first-line treatment, as outlined in the International Consensus Statement on IgG4-RD management. They typically produce rapid and substantial clinical improvement in both pancreatic and extra-pancreatic manifestations. To help maintain remission and reduce long-term steroid use, various glucocorticoid-sparing agents—such as azathioprine, mycophenolate mofetil, methotrexate, cyclophosphamide, and bortezomib—have been utilized across different organ systems, though their effectiveness varies.
Steroid-sparing drugs like azathioprine, mycophenolate mofetil, and methotrexate are used to minimize the side effects of prolonged steroid therapy and support long-term disease control. However, the evidence supporting their efficacy remains limited. Rituximab has emerged as a promising newer option; it targets CD20-positive plasmablast precursors, leading to a reduction in plasmablasts and a subsequent decline in IgG4 production.
To know more about IgG4-RD treatment options, visit @ New Treatment for IgG4-related Disease
Recently, in April 2025, the FDA approved Amgen's anti-CD19 therapy, UPLIZNA, for the treatment of IgG4-related disease, making it the first and only approved treatment specifically for this condition, according to the company's announcement. This label expansion is supported by data from the Phase III MITIGATE trial, initially presented by Amgen in November 2024.
The study showed that UPLIZNA reduced the risk of disease-related flares by 87% compared to placebo. Over the 52-week study period, only 7 out of 68 patients receiving UPLIZNA experienced flares, compared to 40 out of 67 in the placebo group—a difference Amgen highlighted as statistically significant.
Additionally, 57.4% of patients treated with UPLIZNA achieved complete remission at the one-year mark versus just 22.4% of those on placebo. Nearly 90% of patients in the UPLIZNA arm were able to stop using glucocorticoids, compared to 37.3% in the placebo group. Within just 8 weeks of treatment, UPLIZNA recipients had a tenfold reduction in total glucocorticoid usage compared to placebo.
Administered via intravenous infusion, UPLIZNA is a humanized monoclonal antibody that targets the CD19 protein found on specific immune cells. By binding to CD19, it depletes both immature and mature B cells, thereby addressing a key disease mechanism in IgG4-RD, which involves the widespread infiltration of B cells into affected tissues, leading to organ damage.
Amgen recorded USD 379 million in UPLIZNA sales in 2024 from its original indication alone. However, the recent approval for IgG4-related disease presents a significant growth opportunity, as this new market includes a treatable patient population that is roughly twice as large as that for NMOSD.
Learn more about the FDA-approved IgG4-RD drugs @ Drugs for IgG4-related Disease Treatment
Apart from Amgen, key players such as Zenas Biopharma, Bristol Myers Squibb and Sanofi are also evaluating their lead candidates in different stages of clinical development, respectively. They aim to investigate their products to treat IgG4-RD.
The treatment pipeline for IgG4-RD includes several promising therapies in advanced stages of development, such as ZB012 (obexelimab) and Rilzabrutinib, among others. These emerging treatments hold the potential to significantly improve patient outcomes and address existing gaps in care.
Discover which therapies are expected to grab major IgG4-RD market share @ IgG4-related Disease Market Report
Obexelimab (XmAb5871) is a dual-function monoclonal antibody that targets both CD19 and FcγRIIb—proteins found widely on B cells—aiming to suppress B-cell activity involved in various autoimmune disorders without destroying the cells. Its distinctive mechanism and subcutaneous self-injection format position it as a promising therapy to effectively address the role of B cells in chronic autoimmune conditions.
Zenas is currently advancing obexelimab through multiple Phase II and III clinical trials for a range of autoimmune diseases, including IgG4-related disease, multiple sclerosis, systemic lupus erythematosus, and warm autoimmune hemolytic anemia. In August 2023, The Lancet Rheumatology published Phase II trial results showing its potential in treating IgG4-RD. These findings have led to an ongoing Phase III trial focused on evaluating the safety and efficacy of obexelimab via subcutaneous injection in patients with IgG4-RD.
Rilzabrutinib (also known as PRN1008) is a selective, orally available, reversible covalent inhibitor of Bruton's Tyrosine Kinase (BTK), exhibiting a potent IC50 of 1.3 nM. It targets a cysteine residue on BTK, resulting in a slow dissociation rate—about 79% of BTK binding remains in peripheral blood mononuclear cells (PBMCs) 18 hours after the compound is washed out in vitro. This covalent binding is fully reversible upon denaturation of the protein.
Functionally, rilzabrutinib suppresses anti-IgM-induced human B-cell proliferation and inhibits CD69 expression on B cells, with IC50 values of 5 ± 2.4 nM and 123 ± 38 nM, respectively, under 10% serum conditions.
In August 2020, Sanofi entered into a definitive agreement to acquire Principia Biopharma, a deal approved unanimously by both companies' boards. The acquisition strengthened Sanofi's pipeline in immunology by integrating Principia's BTK inhibitors—including rilzabrutinib—into its broader strategy to develop next-generation therapies for autoimmune diseases.
Discover more about drugs for IgG4-RD in development @ IgG4-related Disease Clinical Trials
The anticipated launch of these emerging therapies for IgG4-RD are poised to transform the market landscape in the coming years. As these cutting-edge therapies continue to mature and gain regulatory approval, they are expected to reshape the IgG4-RD market landscape, offering new standards of care and unlocking opportunities for medical innovation and economic growth.
DelveInsight estimates that the market size for IgG4-RD is expected to grow from USD 170 million in 2024, with a significant CAGR by 2034. This growth can be attributed to the approval of new therapies with improved safety and tolerability, which will significantly impact the treatment landscape in the coming years.
DelveInsight's latest published market report, titled as IgG4-related Disease Market Insight, Epidemiology, and Market Forecast – 2034, will help you to discover which market leader is going to capture the largest market share. The report provides comprehensive insights into the IgG4-RD country-specific treatment guidelines, patient pool analysis, and epidemiology forecast to help understand the key opportunities and assess the market's underlying potential. The IgG4-RD market report proffers epidemiological analysis for the study period 2020–2034 in the 7MM segmented into:
- Total Diagnosed Prevalent Cases of IgG4-RD
- Gender-specific Diagnosed Prevalent Cases of IgG4-RD
- Age-specific Diagnosed Prevalent Cases of IgG4-RD
The report provides an edge while developing business strategies by understanding trends shaping and driving the 7MM IgG4-RD market. Highlights include:
- 10-year Forecast
- 7MM Analysis
- Epidemiology-based Market Forecasting
- Historical and Forecasted Market Analysis upto 2034
- Emerging Drug Market Uptake
- Peak Sales Analysis
- Key Cross Competition Analysis
- Industry Expert's Opinion
- Access and Reimbursement
Download this IgG4-RD market report to assess the epidemiology forecasts, understand the patient journeys, know KOLs' opinions about the upcoming treatment paradigms, and determine the factors contributing to the shift in the IgG4-RD market. Also, stay abreast of the mitigating factors to improve your market position in the IgG4-RD therapeutic space.
Related Reports
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IgG4-related Disease Epidemiology Forecast – 2034 report delivers an in-depth understanding of the disease, historical and forecasted IgG4-RD epidemiology in the 7MM, i.e., the United States, EU4 (Germany, Spain, Italy, and France), the United Kingdom, and Japan.
IgG4-related Disease Pipeline Insight – 2025 report provides comprehensive insights about the pipeline landscape, pipeline drug profiles, including clinical and non-clinical stage products, and the key IgG4-RD companies, including Amgen, Sanofi, Zenas Biopharma, Bristol-Myers Squibb, among others.
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SOURCE DelveInsight Business Research, LLP