Amgen announced the presentation of new data across rare autoimmune and inflammatory diseases at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, taking place from June 3-6 in London. New data from the Phase 3 MITIGATE trial of UPLIZNA (inebilizumab) provide insights into the biology of immunoglobulin G4-related disease (IgG4-RD), while additional analyses support its long-term safety profile and sustained results in IgG4-RD. Additionally, new real-world evidence on TAVNEOS (avacopan) further support its established efficacy and safety profile with reduced steroid use in people living with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis.

Key presentations include: Long-term Efficacy and Safety of Inebilizumab in IgG4-Related Disease: Primary Results from Year 1 of the Open-Label Period (OLP) of the Phase 3 MITIGATE Trial. IgG4-RD is a chronic and debilitating condition, marked by recurrent, unpredictable flares that can potentially impact multiple organs. New Phase 3 MITIGATE data further support the longer-term clinical profile of UPLIZNA.

In the first year of the OLP, these data demonstrated sustained results and disease control with continued UPLIZNA treatment in patients with IgG4-RD. No patients (0%) who received UPLIZNA in the randomized controlled period (RCP) and continued with UPLIZNA in the OLP (N=56) experienced a flare, and 71.4% achieved flare-free, glucocorticoid-free complete remission at year 1 of the OLP. 5.9% of patients who received placebo in the RCP and transitioned to UPLIZNA in the OLP (N=51) experienced a flare, and 41.2% achieved flare-free, glucocorticoid-free complete remission at year 1 of the OLP.

Safety results were consistent with the established safety profile of UPLIZNA. The most common adverse events in the OLP were COVID-19, upper respiratory tract infection, cough and influenza. Across the combined RCP and OLP period, median total UPLIZNA treatment exposure was 2.2 years among participants who received =1 dose of inebilizumab.

The new MITIGATE data reinforce the long-term safety and efficacy profile of UPLIZNA while advancing understanding of how IgG4-RD progresses over time. Natural History of IgG4-RD: Patterns of Organ Involvement and Flare-associated Biomarker Changes in the Phase 3 MITIGATE Trial. The first-of-its-kind natural history analysis reinforced the chronic and unpredictable nature of IgG4-RD, underscoring widespread and diverse multi-organ involvement and the need for earlier intervention and more comprehensive monitoring and risk stratification.

Dynamic patterns of organ involvement over time, including the emergence of new organ manifestations and biological signals that may precede disease flares. CD19+ B cells were the first biomarker to rise ahead of a flare, followed by increases in total IgG and IgG subsets within the 30-day window preceding a flare. An additional exploratory combined analysis (Abstract #POS0089) of clinical trial RCP and OLP data in MITIGATE (N=119) showed how long-term use of UPLIZNA resulted in mostly mild immunoglobulin (Ig) reduction, with no significant association between these Ig reductions and occurrence of infections or serious infections.

The incidence of infections and serious infections did not increase with each additional year of UPLIZNA treatment. The AQUARIUS analyses (Abstracts #POS01356 and #POS08673), conducted at Massachusetts General Hospital and Northwestern University, evaluated the largest U.S. real-world cohort to date of patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) treated with TAVNEOS (n=159). The findings provide new insights into clinical outcomes in patients with ANCA-associated vasculitis and are consistent with the established clinical efficacy and safety profile of TAVNEOS in patients with severe active GPA or MPA.

Results highlighted variability in glucocorticoids (GCs) tapering strategies in real world practice and showed that many patients were able to taper to very low or no doses of GCs quickly. Observations underscored the complexity of managing ANCA-associated vasculitis and pointed to opportunities to further optimize treatment approaches to reduce steroid exposure while maintaining disease control. The safety profile observed in this real-world setting was consistent with the established safety profile in patients with severe active GPA or MPA.

Among patients who experienced hepatic adverse events, all hepatic abnormalities were resolved. These new data reinforce that TAVNEOS can help patients achieve disease control with reduced steroid use. For more information on the full list of Amgen abstracts and presentation times, see below.

All Amgen-sponsored abstracts being presented at EULAR: UPLIZNA (inebilizumab): Long-term Efficacy and Safety of Inebilizumab in IgG4-Related Disease: Primary Results from Year 1 of the Open-Label Period of the Phase 3 MITIGATE Trial. Immunogenicity and Impact of Anti-drug Antibodies on the Efficacy and Pharmacokinetics of Inebilizumab In MITIGATE, a Phase 3 Trial in IgG4-Related Disease. Atypical IgG4-Related Disease: Re-Examining the Entry Criteria of the2019 ACR/EULAR Classification Criteria.

Natural History of IgG4-RD: Patterns of Organ Involvement and Flare-associated Biomarker Changes in the MITIGATE Trial. Serum IgG4 Elevation in IgG4-Related Disease: A Marker of Disease Phenotype and Organ Involvement. Long-term Inebilizumab Treatment Results in Mild Immunoglobulin Reduction but No Increase in Infection Risk.

TAVNEOS (avacopan): Reliability and Content Validity of a Definition of Severe Active Granulomatosis with Polyangiitis and Microscopic Polyangiitis. Clinical Outcomes by Glucocorticoid Duration in Individuals with Granulomatosis with Polyangiitis and Microscopic Polyangiitis Treated with Avacopan in a Real-World Setting in Two Large Healthcare Systems. One Year Real-World Effectiveness and Safety with Avacopan in Granulomatosis with Polyangiitis and Microscopic Polyangiitis in Two Large Healthcare Systems. KRYSTEXXA (pegloticase): Association of Pegloticase-Induced Remission with Patient-Reported Quality of Life Outcomes in the MIRROR Randomized Controlled Trial. Reduction of Gout Flares with Pegloticase in Patients with or without Tophi at Baseline: A Post Hoc Analysis of the MIRROR Trial.

Differences in Gout Management and Outcomes in Patients Referred From Primary Care to Rheumatology. Baseline Predictors of Gout Remission During Intensive Urate-Lowering with Pegloticase: Post Hoc Analysis of the MIRROR Randomized Trial.