Otsuka Pharmaceutical has reported that its approved kidney disease drug Voyxact (sibeprenlimab) preserved kidney function over 12 months in a late-stage clinical study, marking a significant milestone in the treatment of immunoglobulin A nephropathy (IgAN), a serious autoimmune condition that progressively damages the kidneys.
In the Phase 3 VISIONARY trial involving 320 participants, patients who received Voyxact showed an increase in kidney function as measured by estimated glomerular filtration rate (eGFR), a key indicator of how effectively the kidneys filter toxins from the blood, while those on placebo experienced a decline. The 12-month eGFR data build on earlier interim results that had demonstrated a 51% placebo-adjusted reduction in proteinuria at nine months, which supported the drug’s accelerated FDA approval in November 2025.
“This stability of eGFR over that time is incredibly encouraging. And it demonstrates that the reduction we saw in proteinuria did indeed translate to maintaining or preserving the kidney function of those patients that had been randomized to sibeprenlimab,” said John Kraus, Chief Medical Officer at Otsuka.
Voyxact, a monoclonal antibody, works by blocking a protein called A-Proliferation-Inducing-Ligand (APRIL), which plays a central role in the immune mechanism driving IgAN. The drug is administered as a subcutaneous injection every four weeks and can be self-administered by the patient or a caregiver at home, offering a convenient treatment option for a disease with limited targeted therapies.
IgAN occurs when an abnormal form of the antibody immunoglobulin A deposits in the kidneys, triggering inflammation, tissue damage, and leakage of blood and protein into the urine, eventually risking complete organ failure. It is considered the most common primary glomerulonephritis and a leading cause of kidney failure globally.
Otsuka has already commenced a rolling submission to the U.S. Food and Drug Administration seeking traditional, full approval for the drug, based on the anticipated 24-month data from the same VISIONARY trial. Kraus confirmed the 24-month data is expected within two months, which will be the cornerstone of the confirmatory package required as a condition of the earlier accelerated approval.
The VISIONARY trial, the largest IgAN study ever conducted, also demonstrated that treatment benefits were consistent across patient subgroups, including those already on SGLT2 inhibitors, suggesting Voyxact may offer additional benefit beyond the current standard of care. Voyxact had received both Priority Review and Breakthrough Therapy designation from the FDA, underscoring the unmet medical need in this patient population.
The IgAN treatment space is growing increasingly competitive. Rival companies, including Vera Therapeutics and Vertex Pharmaceuticals, are also developing drugs targeting the same disease, making Otsuka’s 24-month eGFR data a critical differentiator as the company moves toward securing unconditional regulatory approval for its first-in-class APRIL inhibitor.
