For most people with IgA nephropathy, the kidneys lose function on a slow, predictable slide that ends, often within a couple of decades, in dialysis or a transplant. Otsuka's two-year data on sibeprenlimab, sold as VOYXACT, describe something the disease rarely does on its own: a stop [1].
In the Phase 3 VISIONARY trial, presented as a late-breaker at the GlomCon meeting on August 3, the annualized rate of kidney-function decline was +0.3 mL/min/1.73m2 per year for patients on the drug, against -4.2 for those on placebo, a treatment difference of +4.5 with a p-value below 0.0001 [1]. Measured across the full two years, the eGFR change was +1.3 for the treated group and -7.9 for placebo, a gap of +9.2 [1]. A positive number means kidney function held roughly steady rather than falling.
The trial's investigators tie that to a specific benchmark. The 2025 KDIGO guidelines set a treatment goal of holding decline below 1 mL/min/1.73m2 per year, a rate close to ordinary age-related loss, and the VISIONARY slope clears it [1].
Dr. Dana Rizk of the University of Alabama at Birmingham, a site investigator, described the result as a change in the disease's direction. "The VISIONARY two-year eGFR results achieved the KDIGO treatment goal of reducing kidney function decline to near physiological level, fundamentally altering the disease progression," she said [1].
John Kraus, Otsuka's executive vice president and chief medical officer, put it in comparative terms. "These transformative results deliver the largest treatment effect reported in a Phase 3 IgAN trial, with a magnitude of benefit demonstrating stabilization of kidney function," he said [1].
The safety profile the company released on August 3 tracks closely between arms. Any adverse event occurred in 90.7 percent of treated patients versus 90.0 percent on placebo, infections in 51.4 versus 51.0 percent, and injection-site reactions in 35.1 versus 32.2 percent; serious infections were lower on the drug, 1.9 versus 4.0 percent [1].
What the numbers do not yet carry is a finished approval. VOYXACT reached the market in November 2025 under the FDA's accelerated pathway, cleared on nine-month proteinuria data that stand in as an early signal, and Otsuka is now filing on a rolling basis for traditional approval on the strength of these eGFR results [1]. The distinction matters: accelerated approval is a promise that the confirmatory data will follow, not a closed case. The drug also manages the disease rather than curing it, the eGFR record runs two years rather than a patient's remaining decades, and the company has released two different safety datasets, a July interim set and these August 3 figures, that an editor should see reconciled before either is repeated as final.
For a young person handed an IgA nephropathy diagnosis, a slope that reads near zero is the difference between counting down to dialysis and holding steady. That is worth reporting exactly as far as the data reach, and no farther.
