Anifrolumab Treatment Leads to Rapid Reduction in Urinary Biomarkers of Intrarenal Inflammation in Lupus Nephritis: Results From the Phase 2 Randomized Trial.
OBJECTIVE: Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus (SLE) and is partially driven by type I interferon signaling. Anifrolumab, an approved treatment for patients with SLE, has been investigated in a phase 2 trial in patients with LN receiving standard therapy (TULIP-LN, ClinicalTrials.gov identifier NCT02547922). We studied the impact of anifrolumab treatment on urinary biomarker expression in patients with LN through proteomic analysis of samples from TULIP-LN. METHODS: Urine samples were collected at weeks 0, 12, and 48 from patients treated with the anifrolumab basic regimen (n = 35), intensified regimen (n = 42), or placebo (n = 35), in addition to standard therapy, and analyzed for the presence of 197 proteins. The impact of anifrolumab relative to placebo on prespecified biomarkers linked to histologic activity was assessed, and a comparison of responders versus nonresponders was conducted on proteins detected in ≥75% of samples. RESULTS: Anifrolumab treatment significantly reduced urinary CD163 and monocyte chemoattractant protein 1 expression at week 12 versus placebo, including in patients classified as proteinuric nonresponders across all regimens. By week 48, biomarker levels declined in all groups, indicating that standard therapy alone can eventually suppress intrarenal inflammation but with slower kinetics. Proteomic analyses further revealed that anifrolumab was superior to placebo in reducing the proteomic inflammatory signature, regardless of responder status. CONCLUSION: Compared with placebo, anifrolumab treatment significantly reduced urinary biomarkers of renal histologic activity in patients with LN, which may accelerate the resolution of intrarenal inflammation, potentially preventing damage accrual.