TOKYO, Japan, August 4, 2026

Otsuka Pharmaceutical Co., Ltd. and Otsuka Pharmaceutical Development & Commercialization, Inc. announced new two-year Phase 3 VISIONARY trial results demonstrating that VOYXACT® (sibeprenlimab-szsi) significantly stabilized kidney function in adults with primary IgA nephropathy (IgAN) who are at risk of disease progression. The study achieved its key secondary endpoint, showing an annualized estimated glomerular filtration rate (eGFR) slope of +0.3 mL/min/1.73 m²/year in patients treated with VOYXACT compared with -4.2 mL/min/1.73 m²/year for placebo, representing a highly significant treatment difference of +4.5 mL/min/1.73 m²/year (p<0.0001). According to the company, these findings indicate that VOYXACT reduced kidney function decline to near the normal physiological rate, making it the first and only U.S. FDA-approved IgAN therapy to demonstrate this level of kidney function stabilization. The new data complete the Phase 3 VISIONARY study and further support Otsuka’s rolling supplemental Biologics License Application (sBLA) seeking traditional FDA approval for VOYXACT.

Phase 3 VISIONARY Trial Demonstrates Disease-Modifying Potential

The global, randomized, double-blind, placebo-controlled VISIONARY Phase 3 trial evaluated adults with primary IgA nephropathy at risk for progressive kidney disease. Beyond meeting its primary endpoint of proteinuria reduction that supported the therapy’s accelerated FDA approval in November 2025, the study has now demonstrated durable kidney protection over 24 months. Patients receiving VOYXACT achieved a least-square mean increase of +1.3 mL/min/1.73 m² in eGFR, while placebo-treated patients experienced a decline of -7.9 mL/min/1.73 m², resulting in a treatment difference of +9.2 mL/min/1.73 m² (p<0.0001). Investigators noted that the treatment met the KDIGO therapeutic goal of reducing kidney function decline to a near physiological level. Researchers also reported consistent clinical benefit across predefined patient subgroups, reinforcing selective APRIL inhibition as a disease-modifying strategy that addresses one of the key biological drivers responsible for IgA nephropathy progression rather than simply controlling symptoms.

Safety Profile Supports Long-Term Treatment Use

The two-year analysis confirmed that VOYXACT maintained a safety profile comparable to placebo, supporting its long-term clinical use. Overall adverse event rates were similar between treatment groups, while serious infections occurred less frequently with sibeprenlimab than placebo (1.9% vs. 4.0%). The study also showed comparable rates of infections, injection-site reactions, and overall treatment tolerability, with no new safety signals identified during the 24-month follow-up period. Investigators emphasized that these findings strengthen confidence in the therapy’s long-term benefit-risk profile while supporting its potential role as a foundational treatment for patients with progressive IgA nephropathy, a chronic immune-mediated kidney disease that frequently leads to kidney failure despite current standard supportive care.

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VOYXACT Strengthens Otsuka’s Leadership in IgA Nephropathy

The latest VISIONARY results further reinforce VOYXACT’s position as a potentially transformative therapy for IgA nephropathy, building upon previously reported reductions in proteinuria, galactose-deficient IgA1 (Gd-IgA1), and hematuria. As the first selective APRIL inhibitor approved by the U.S. FDA, VOYXACT targets an underlying immune mechanism responsible for disease progression rather than providing symptomatic management alone. Otsuka stated that completion of the Phase 3 dataset marks another major milestone in its regulatory strategy as it continues the rolling sBLA submission for traditional FDA approval. The company also plans to continue evaluating long-term outcomes through an ongoing open-label extension study, with the goal of further demonstrating durable kidney protection and improving long-term clinical outcomes for patients living with IgA nephropathy, an area of significant unmet medical need worldwide.

Source:Otsuka press release