Otsuka's Voyxact Slows Kidney Function Loss in Interim Phase 3 VISIONARY Analysis
Patients on sibeprenlimab held their eGFR steady over 12 months while the placebo group declined, Otsuka said, though STAT reported the benefit was smaller than expected.
These results come from a Phase 3 trial, the large trial usually needed before approval.
Key points
- Otsuka said on June 4 that Voyxact (sibeprenlimab-szsi) produced a mean eGFR change of +0.7 mL/min/1.73 m² at 12 months versus -4.8 on placebo in an interim analysis of the Phase 3 VISIONARY trial in IgA nephropathy.
- The annualized eGFR slope was -3.0 with sibeprenlimab and -7.6 with placebo; STAT reported the benefit was less than expected.
- Otsuka has begun a rolling supplemental BLA seeking traditional FDA approval based on the trial's 24-month eGFR data.
Otsuka said on June 4 that its antibody Voyxact (sibeprenlimab-szsi) preserved kidney function over 12 months in adults with primary IgA nephropathy (IgAN), in a pre-specified interim analysis of the Phase 3 VISIONARY trial presented at the European Renal Association (ERA) Congress 2026 in Glasgow, according to the company's release. The results are company-reported interim data; the full final analysis has not yet been presented.
The interim results
In the analysis of 320 patients, 152 on sibeprenlimab and 168 on placebo, the mean change in estimated glomerular filtration rate (eGFR) from baseline was +0.7 mL/min/1.73 m² with sibeprenlimab, compared with a decline of -4.8 mL/min/1.73 m² with placebo. Otsuka put the treatment effect at 5.5 mL/min/1.73 m² (95% CI, 3.4 to 7.6).
The annualized slope of eGFR over 12 months was -3.0 mL/min/1.73 m² per year with sibeprenlimab and -7.6 with placebo, a treatment effect of 4.6, the company said. eGFR is a lab measure of how well the kidneys filter waste from the blood.
Otsuka said the overall safety profile was comparable to placebo, with infections and injection site reactions the most common adverse events.
"These data are very encouraging and suggest that selective inhibition of APRIL may slow eGFR decline, helping patients preserve kidney function and improve long-term outcomes," said Vlado Perkovic, provost at the University of New South Wales, in the company's release.
A smaller effect than expected
STAT reported that the benefit was less than expected and "left room for competing treatments to perform better," pointing to the annualized loss of 3 points on Voyxact against 7.6 points on placebo after one year.
Sibeprenlimab is a humanized monoclonal antibody that blocks APRIL (A PRoliferation-Inducing Ligand), a protein that promotes production of the galactose-deficient IgA1 implicated in the disease. It is self-administered as a subcutaneous injection once every four weeks.
The regulatory path
The FDA granted Voyxact accelerated approval on November 25, 2025, to reduce proteinuria in adults with primary IgAN at risk for disease progression. Its label states that it has not been established whether the drug slows kidney function decline over the long term, and that continued approval may depend on a confirmatory trial.
VISIONARY is designed to provide that evidence. The trial is ongoing and will assess the annualized eGFR slope, a key secondary efficacy endpoint, and eGFR change from baseline over 24 months. Otsuka said it has begun a rolling submission of a supplemental Biologics License Application to the FDA for traditional approval, including the 24-month eGFR data, and that full results from the final analysis will be presented at a future medical meeting.
Sources
- Otsuka Presents Positive Interim Phase 3 VISIONARY eGFR Data Showing VOYXACT (sibeprenlimab-szsi) Preserved Kidney Function Over 12 Months in IgA Nephropathy (IgAN), Otsuka America Pharmaceutical, June 4, 2026
- Otsuka kidney drug slowed loss of function, but less than expected, in late-stage trial, STAT, June 4, 2026