Otsuka Pharmaceutical’s VOYXACT (active ingredient: sibeprenlimab) demonstrated long-term kidney protection by maintaining kidney function over a two-year period in patients with immunoglobulin A nephropathy (IgA nephropathy), according to Phase 3 clinical trial results. The findings provide critical evidence that the therapy can slow disease progression beyond its established ability to reduce proteinuria.
Otsuka presented the two-year data from its Phase 3 VISIONARY trial at the international glomerular disease conference, GlomCon Hawaii 2026. Over the two-year study period, patients in the VOYXACT group recorded an average annual change in estimated glomerular filtration rate (eGFR) of +0.3 mL/min/1.73m², compared to an annual decline of -4.2 mL/min/1.73m² in the placebo group. eGFR is a primary indicator of kidney function, measuring how effectively the organs filter waste from the blood.
Slowing Disease Progression to Rates of Normal Aging
By the second year of treatment, overall eGFR from baseline had increased by 1.3 mL/min/1.73m² in the VOYXACT group, whereas it dropped by 7.9 mL/min/1.73m² in the placebo arm.
The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines define successful treatment goals for IgA nephropathy as lowering proteinuria and reducing the annual rate of eGFR loss to below 1 mL/min/1.73m²—a threshold considered equivalent to normal physiologic aging in adults. The trial results indicate that VOYXACT kept kidney function loss well within this natural range over two years.
Researchers noted that while the data reflects "preservation" rather than a recovery of lost kidney tissue—with a 95% confidence interval for annual eGFR change of -0.4 to 0.9 mL/min/1.73m²—the ability to stabilize a chronic, progressive condition that often leads to dialysis or kidney transplantation marks a significant clinical outcome.
Targeting the Underlying Cause of IgA Nephropathy
IgA nephropathy is a chronic autoimmune disease in which abnormal IgA antibodies build up in the kidney's glomeruli, triggering inflammation and irreversible tissue damage. It frequently affects young adults and often continues to worsen despite standard blood pressure and proteinuria management.
VOYXACT is a monoclonal antibody that selectively blocks APRIL (a proliferation-inducing ligand), a signaling protein required for the survival of specific B cells and antibody production. By inhibiting APRIL, the drug reduces the upstream generation of the abnormal IgA antibodies driving the disease. It is administered as a 400 mg subcutaneous injection every four weeks.
The U.S. Food and Drug Administration (FDA) previously granted VOYXACT accelerated approval based on nine-month data showing a 51.2% reduction in proteinuria compared to placebo. The new two-year eGFR findings fulfill the requirement for demonstrating long-term clinical benefit.
Full Approval Push and Strong Commercial Growth
The safety profile of VOYXACT remained comparable to placebo, with treatment-related adverse event rates of 35% in the VOYXACT arm and 33% in the placebo group. The most common adverse reactions reported were mild infections and injection-site reactions.
Otsuka plans to submit the two-year VISIONARY data to the FDA to convert its accelerated approval into full approval, while also seeking regulatory clearance for an autoinjector formulation alongside its existing prefilled syringe.
Driven by strong clinical adoption, VOYXACT recorded first-half sales of 17.1 billion yen (approximately 155 billion KRW). Citing faster-than-anticipated uptake, Otsuka significantly raised its full-year sales forecast from 25.0 billion yen to 60.0 billion yen (approximately 543 billion KRW).
