Telitacicept for IgA Nephropathy — Interim Analysis of a Phase 3 Trial

BACKGROUND: The pathogenesis of IgA nephropathy is mediated by B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL). Telitacicept is a fusion protein that targets and neutralizes both BAFF and APRIL and, as such, might be effective in IgA nephropathy. METHODS: We now report a prespecified interim analysis of a phase 3, multicenter, double-blind, randomized, placebo-controlled trial, which enrolled adults with biopsy-proven IgA nephropathy and persistent proteinuria (protein level, ≥1.0 g per day), despite appropriate supportive care. Patients were randomly assigned in a 1:1 ratio to receive subcutaneous once-weekly telitacicept (240 mg) or matching placebo. The primary end point was the geometric mean ratio of the 24-hour urinary protein-to-creatinine ratio at 39 weeks relative to baseline. Safety was also evaluated. RESULTS: A total of 318 patients were assigned to receive telitacicept or placebo (159 in each group). At week 39, the percentage change in the 24-hour urinary protein-to-creatinine ratio was -58.9% with telitacicept and -8.8% with placebo, which corresponded to a relative difference (based on the ratio of geometric mean reductions between the two groups) of -55.0% (95% confidence interval [CI], -61.3 to -47.6; P