Otsuka Pharmaceutical Development and Commercialisation and Otsuka Pharmaceutical have announced positive two-year results from the Phase 3 VISIONARY trial, demonstrating that Voyxact (sibeprenlimab-szsi) significantly stabilised kidney function in adults with primary IgA nephropathy (IgAN) who are at risk of disease progression.

The findings, presented during a late-breaking oral session at the GlomCon Hawaii 2026 conference, showed that the study met its key secondary endpoint by significantly improving the annual rate of kidney function decline, measured by estimated Glomerular Filtration Rate (eGFR). Patients treated with Voyxact achieved an annualised eGFR slope of +0.3 mL/min/1.73 m²/year, compared with -4.2 mL/min/1.73 m²/year in the placebo group, representing a statistically significant treatment benefit.

According to Otsuka, Voyxact is the first therapy for IgA nephropathy to achieve the Kidney Disease: Improving Global Outcomes (KDIGO) therapeutic goal of slowing kidney function decline to a near-physiological rate of less than one mL/min/1.73 m² per year for most adults.

The study also reported sustained improvements in overall kidney function after 24 months. Patients receiving Voyxact experienced a least-square mean increase of 1.3 mL/min/1.73 m² in eGFR from baseline, while those receiving placebo recorded a decline of 7.9 mL/min/1.73 m², resulting in a treatment difference of 9.2 mL/min/1.73 m².

The safety profile remained favourable throughout the two-year study period. Overall adverse events, infections and injection-site reactions occurred at rates comparable to placebo, while serious infections, severe adverse events and treatment discontinuations were reported less frequently in the Voyxact arm. No new safety concerns were identified.

Dr. Dana Rizk, Professor of Medicine in the Division of Nephrology at the University of Alabama at Birmingham and co-chair of the VISIONARY steering committee, said the results represent a major advance in the treatment of IgA nephropathy. She noted that achieving the KDIGO treatment goal has the potential to fundamentally alter disease progression and improve long-term outcomes for patients.

John Kraus, Executive Vice President and Chief Medical Officer at Otsuka, said the VISIONARY trial represents the largest Phase 3 study conducted in IgA nephropathy, with 24 months of follow-up in a patient population representative of real-world clinical practice. He added that the magnitude of kidney function preservation observed in the study supports Voyxact's potential to redefine the treatment landscape by addressing the underlying drivers of the disease rather than only managing symptoms.

Voyxact received accelerated approval from the US Food and Drug Administration (FDA) in November 2025 after meeting the VISIONARY trial's primary endpoint of significantly reducing proteinuria at nine months. The newly reported two-year data build on earlier evidence demonstrating reductions in proteinuria, galactose-deficient IgA1 (Gd-IgA1) and haematuria, further supporting the therapy's disease-modifying potential.

Otsuka said the complete two-year Phase 3 analysis will be presented at an upcoming scientific congress and will form part of its rolling supplemental Biologics License Application (sBLA) seeking traditional FDA approval for Voyxact.

IgA nephropathy is a chronic immune-mediated kidney disease that primarily affects adults between 20 and 40 years of age and can progressively lead to kidney failure. Voyxact is a humanised monoclonal antibody that selectively inhibits APRIL (A Proliferation-Inducing Ligand), an immune pathway involved in the production of pathogenic galactose-deficient IgA1, a key driver of IgAN. Administered as a once-every-four-weeks subcutaneous injection, Voyxact is currently the first and only FDA-approved selective APRIL inhibitor for adults with primary IgA nephropathy at risk of disease progression.