Otsuka reported two-year kidney function data from the Phase III VISIONARY trial showing that sibeprenlimab (Voyxact) significantly slowed kidney function decline in patients with IgA nephropathy (IgAN), providing the confirmatory evidence needed to support conversion of the drug's US accelerated approval to traditional approval. The findings were presented at GlomCon Hawaii 2026, and the company said it has initiated a rolling supplemental Biologics License Application (sBLA) submission with the US FDA.
Patients treated with sibeprenlimab achieved an annualized estimated glomerular filtration rate (eGFR) slope of +0.3 mL/min/1.73 m²/year compared with −4.2 mL/min/1.73 m²/year for placebo, corresponding to a statistically significant treatment difference of +4.5 mL/min/1.73 m²/year (95% CI, 3.6–5.4; p<0.0001). The observed rate of kidney function decline also met the Kidney Disease: Improving Global Outcomes (KDIGO) 2025 therapeutic target of limiting annual eGFR decline to less than 1 mL/min/1.73 m²/year.
Sibeprenlimab is a humanized monoclonal antibody that selectively neutralizes APRIL (A PRoliferation-Inducing Ligand), a cytokine that drives B-cell production of pathogenic galactose-deficient IgA1 — the initiating event in IgAN's four-hit pathogenic cascade. Voyxact received FDA accelerated approval in November 2025 based on a statistically significant 51% placebo-adjusted reduction in proteinuria at nine months in the VISIONARY interim analysis. The two-year eGFR data are intended to serve as the confirmatory evidence the agency requires, and Otsuka has initiated a rolling supplemental Biologics License Application (sBLA) submission for traditional approval.
The complementary secondary endpoint — least square mean change from baseline in eGFR at month 24 — showed +1.3 mL/min/1.73 m² with sibeprenlimab versus -7.9 mL/min/1.73 m² with placebo, a treatment difference of +9.2 mL/min/1.73 m² (95% CI, 7.1 to 11.4; p<0.0001). Safety at 24 months remained consistent with prior data and comparable to placebo; rates of serious infections were lower with sibeprenlimab than placebo (1.9% vs 4.0%), and no new safety signals were identified.