Otsuka's sibeprenlimab (Voyxact) has delivered statistically significant eGFR stabilization with evidence showing preservation of kidney function over two years in the full dataset from the Phase III VISIONARY trial, completing the confirmatory evidence Otsuka needs to convert its November 2025 accelerated approval into a traditional FDA approval. The two-year eGFR results are the critical piece of data the agency has been waiting for, and Otsuka has already initiated a rolling supplemental Biologics License Application submission. The outcome directly determines whether sibeprenlimab retains its market position or faces the withdrawal risk that accompanies all accelerated approvals.
The VISIONARY trial is a global, randomized, double-blind, placebo-controlled study enrolling adults with primary IgAN at risk of disease progression. The key secondary endpoint — annualized eGFR slope over 24 months — was met with statistical significance, as was the mean change from baseline in eGFR at month 24. Otsuka reported that the eGFR decline was reduced to near physiological levels of less than 1 mL/min/1.73 m² per year, aligning with the KDIGO 2025 IgAN treatment target. Specific numerical values for the eGFR slope and mean change were not disclosed in the announcement; full data are to be submitted for presentation at an upcoming scientific congress.
Interim 12-month data presented at the ERA Congress in June 2026 showed a 5.5 mL/min/1.73 m² treatment difference in eGFR change versus placebo, findings now reinforced by the completed 24-month analysis.
The IgAN treatment landscape has become intensely competitive in a short period, and sibeprenlimab's two-year eGFR data land amid a cluster of similar confirmatory readouts from rival programs. Novartis's Fabhalta (iptacopan), an oral complement factor B inhibitor, reported a 49.3% slowing of eGFR slope decline over two years in the APPLAUSE-IgAN Phase III trial, also now under FDA priority review for traditional approval. Vertex Pharmaceuticals' povetacicept, a dual BAFF/APRIL TACI-Fc fusion protein, met its proteinuria primary endpoint in the Phase III RAINIER trial at 36 weeks and has a BLA under rolling review. Cross-trial comparisons are limited by differences in patient populations, background therapy, and study design.