A new Phase 3 clinical trial has found that Otsuka Pharmaceutical's kidney disease treatment VOYXACT (sibeprenlimab-szsi) slowed the loss of kidney function in adults with IgA nephropathy (IgAN) to levels close to normal ageing over two years, raising hopes for patients living with the progressive disease.

The findings, presented in a late-breaking session at the GlomCon Hawaii 2026 conference, showed that patients receiving sibeprenlimab maintained stable kidney function, while those given a placebo continued to experience a marked decline. The study met its key secondary endpoint, with a statistically significant improvement in the annual rate of change in estimated glomerular filtration rate (eGFR)—a blood test that measures how well the kidneys remove waste from the body.

Researchers reported an annualised eGFR slope of +0.3 mL/min/1.73 m² per year in the treatment group compared with −4.2 mL/min/1.73 m² per year in the placebo group over 24 months. According to the investigators, this brings kidney function decline close to the physiological rate expected in healthy adults and meets the treatment goal outlined by the Kidney Disease: Improving Global Outcomes (KDIGO) clinical guidelines.

"IgAN patients achieving stabilisation of kidney function represents a major advancement in the clinical management of this disease," said Dana Rizk, professor of medicine at the University of Alabama at Birmingham and co-chair of the VISIONARY trial steering committee. She said the consistency of benefit across patient groups, together with a reassuring safety profile, "delivers new hope for better long-term outcomes."

IgA nephropathy is a chronic autoimmune kidney disease in which abnormal immune deposits gradually damage the kidneys' filtering units. Persistent loss of kidney function can eventually lead to kidney failure, requiring dialysis or transplantation.

VOYXACT is the first US-approved medicine that selectively blocks APRIL, an immune system protein believed to drive the disease process. The drug received accelerated approval from the US Food and Drug Administration in 2025 after reducing proteinuria—the leakage of protein into urine, an early sign of kidney damage. The latest findings suggest the treatment may also preserve kidney function over time.

Safety results remained comparable to placebo after two years, with no new safety concerns identified. Serious infections and treatment discontinuations were reported less frequently in patients receiving sibeprenlimab.

Experts cautioned, however, that although slowing the decline in eGFR is an important marker of disease progression, longer-term follow-up and real-world studies will be needed to confirm whether the benefits translate into fewer cases of kidney failure and reduced need for dialysis or transplantation, outcomes that remain the ultimate goal in managing IgA nephropathy.