Otsuka Pharmaceutical Development & Commercialization announced on July 27, 2026, that it will present two-year kidney-function and safety results from the Phase 3 VISIONARY trial of VOYXACT, or sibeprenlimab-szsi, at GlomCon Hawaii 2026. The presentation will provide the first detailed look at the 24-month estimated glomerular filtration rate results supporting Otsuka’s rolling supplemental Biologics License Application for traditional U.S. approval in adults with primary immunoglobulin A nephropathy at risk for disease progression.
The announcement is significant because VOYXACT is already commercially available in the United States, but under an accelerated approval that is based on proteinuria reduction rather than confirmed preservation of long-term kidney function. The U.S. Food and Drug Administration granted that accelerated approval on November 25, 2025, while explicitly stating that it had not yet been established whether VOYXACT slows kidney-function decline over the long term.
Otsuka has reported that the final VISIONARY analysis showed statistically significant stabilization of kidney function, with evidence of improvement against placebo over two years. However, neither the July 27 conference announcement nor the earlier topline disclosure provided the actual 24-month eGFR slopes, treatment difference, confidence intervals, discontinuation-adjusted analyses or kidney-failure event counts. The result therefore appears encouraging, but the evidence available before GlomCon remains a company-reported topline conclusion rather than a fully assessable clinical dataset.
Why does the 24-month eGFR endpoint matter more than another proteinuria update?
VISIONARY was designed with proteinuria reduction at nine months as its primary efficacy endpoint and the annualized rate of eGFR change over approximately 24 months as a key secondary endpoint. Mean eGFR change from baseline at month 24 was also evaluated, giving regulators two complementary ways to assess whether the treatment effect extended beyond reducing protein leakage into the urine.
Proteinuria is an important marker of disease activity and future risk in IgA nephropathy, but a reduction does not automatically demonstrate that a therapy will preserve kidney filtration or prevent kidney failure. That distinction is why the FDA label continues to state that VOYXACT’s effect on long-term kidney-function decline has not been established, despite the substantial proteinuria reduction supporting accelerated approval.
The two-year eGFR analysis therefore moves closer to the outcome that matters most clinically, the rate at which kidney function is being lost. It still does not directly measure every patient-centred outcome, such as dialysis initiation, transplantation or survival without kidney failure, but a consistent and statistically robust slowing of eGFR decline would provide stronger evidence of durable clinical benefit than proteinuria alone.
Otsuka has used unusually forceful language in describing the topline result, including assertions that VOYXACT halted disease progression and reduced the risk of progression to kidney failure. Those conclusions may eventually prove supportable, but the company has not yet disclosed enough information to independently evaluate the magnitude, statistical certainty or clinical interpretation of the kidney-failure analyses.
What has Otsuka disclosed before the GlomCon Hawaii presentation?
Otsuka said the forthcoming presentation will cover key 24-month eGFR and safety data from adults with primary IgA nephropathy at risk for progression. The central oral presentation, titled “Sibeprenlimab in IgA Nephropathy: Topline 24-Month eGFR Results,” is scheduled for August 3, 2026, and will be delivered by VISIONARY investigator Dana Rizk of the University of Alabama at Birmingham.
The company has also scheduled an investor and media briefing for later on August 3 in the United States, corresponding to August 4 in Japan. Otsuka executives are expected to review the results and answer questions, while the company has indicated that a more complete analysis will subsequently be presented at another scientific congress.
This sequencing suggests that GlomCon may provide considerably more detail than the current topline release without necessarily delivering the final peer-reviewed evidence package. Investors and nephrologists should consequently distinguish between a conference presentation, a completed regulatory submission, an FDA assessment and eventual publication. Each step can strengthen confidence, but none should be treated as interchangeable.
The ClinicalTrials.gov record lists VISIONARY as a completed, global, randomized, double-blind and placebo-controlled Phase 3 study with actual enrolment of 530 participants. The study began in March 2022 and reached both primary completion and study completion on May 13, 2026.
How strong was the earlier VISIONARY evidence supporting accelerated approval?
The accelerated approval was based on an interim efficacy analysis involving the first 320 participants who had the opportunity to complete nine months of treatment. The FDA reported that proteinuria fell by approximately 50% in the VOYXACT group, compared with a roughly 2% increase in the placebo group. Otsuka’s statistical presentation described the placebo-adjusted reduction as 51.2%, with a p-value below 0.0001.
That result was supported by the randomized and double-blind design, a clinically relevant population with biopsy-confirmed IgA nephropathy and consistent biological findings involving galactose-deficient IgA1. The interim Phase 3 analysis was subsequently published in the New England Journal of Medicine, giving the proteinuria evidence greater maturity than an unpublished corporate announcement alone.
The earlier 12-month kidney-function analysis also provided a promising bridge toward the final result. Otsuka reported a mean eGFR change from baseline of positive 0.7 mL/min/1.73 m² with VOYXACT, compared with a decline of 4.8 mL/min/1.73 m² with placebo, producing an estimated treatment difference of 5.5 mL/min/1.73 m².
The annualized eGFR slope in that interim analysis was negative 3.0 mL/min/1.73 m² per year with VOYXACT and negative 7.6 with placebo, corresponding to a treatment difference of 4.6 mL/min/1.73 m² per year. Although the confidence intervals supported a statistically persuasive difference at 12 months, longer follow-up is necessary because eGFR can fluctuate and early treatment differences do not always remain unchanged through a full two-year analysis.
Can selective APRIL inhibition translate its biological rationale into durable kidney protection?
VOYXACT is a humanized monoclonal antibody designed to bind and block A Proliferation-Inducing Ligand, commonly known as APRIL. This pathway contributes to the production of galactose-deficient IgA1, an abnormal immunoglobulin involved in the immune-complex formation and kidney deposition associated with IgA nephropathy.
Otsuka’s therapeutic argument is that selective APRIL inhibition can reduce pathogenic antibody production without broadly depleting B cells. The biological rationale has been supported by reductions in galactose-deficient IgA1, proteinuria and microscopic haematuria, but the decisive question is whether those upstream and intermediate effects translate into sustained preservation of filtration over several years.
The two-year VISIONARY data are therefore important beyond VOYXACT itself. A convincing result would strengthen the case for APRIL as a validated target in IgA nephropathy, while also informing the development of other selective APRIL and combined BAFF-APRIL therapies. It would not establish superiority over those approaches because the drugs have not been compared in a head-to-head study and their trials differ in populations, background treatments, endpoints and follow-up.
VOYXACT’s once-every-four-weeks subcutaneous administration could become a practical differentiator. It requires less frequent dosing than Vera Therapeutics’ weekly injectable TRUTAKNA, although frequency alone does not establish better adherence, persistence or patient preference in real-world care.
Which safety details could shape interpretation of the two-year results?
The current prescribing information warns that VOYXACT suppresses antibody production and may increase infection risk. In the clinical data supporting approval, infections occurred in 49% of VOYXACT recipients and 45% of placebo recipients, while injection-site reactions occurred in 24% and 23%, respectively.
The label also advises assessment for active infections before treatment, monitoring during therapy and avoidance of live vaccines within 30 days before initiation and during treatment. The most common infection was an upper respiratory infection, reported in 15% of VOYXACT-treated participants and 14% of placebo recipients.
Those percentages were relatively balanced, but the 24-month analysis must show whether prolonged APRIL inhibition changes the frequency or severity of serious infections, immunoglobulin reductions, treatment discontinuations or other immune-related events. Longer exposure is especially relevant for a therapy intended to be used against a chronic disease that may require sustained treatment.
The GlomCon presentation will be more informative if it separates overall adverse events from treatment-related events, serious infections and discontinuations. The absence of a new safety signal would be reassuring, but it would not mean that the therapy carries no immunological risk.
How has the IgA nephropathy market changed ahead of Otsuka’s presentation?
VOYXACT is entering a considerably more competitive market than the one that existed when the VISIONARY programme began. On July 16, 2026, the FDA granted traditional approval to Novartis’ oral complement inhibitor Fabhalta to slow kidney-function decline in adults with primary IgA nephropathy at risk for progression. The supporting study showed an annualized eGFR decline of 3.0 mL/min/1.73 m² with Fabhalta and 5.7 with placebo over two years.
Fabhalta now has the regulatory language that VOYXACT is seeking, although it also carries a boxed warning concerning serious infections caused by encapsulated bacteria and is distributed through a Risk Evaluation and Mitigation Strategy programme. That creates a more complicated competitive equation involving efficacy, mechanism, safety management, dosing, reimbursement and clinician familiarity rather than a simple ranking based on one efficacy percentage.
Vera Therapeutics received accelerated FDA approval for TRUTAKNA on July 7, 2026. That weekly injectable inhibits both BAFF and APRIL and achieved a statistically significant 42% proteinuria reduction relative to placebo at 36 weeks, while its kidney-function analysis is expected during the third quarter of 2026.
Novartis’ Vanrafia, Travere Therapeutics’ Filspari and other approved or emerging treatments further expand the therapeutic choices available to nephrologists. The expanding field could support earlier, mechanism-based treatment, but it will also make comparative positioning difficult because there is little head-to-head evidence showing which sequence or combination produces the best balance of kidney preservation, tolerability and treatment burden.
Why does traditional FDA approval matter commercially for Otsuka Holdings?
Traditional approval would remove a central uncertainty from VOYXACT’s U.S. regulatory position by establishing a kidney-function benefit within the approved label, subject to the FDA’s assessment of the full application. It could support stronger discussions with nephrologists and payers because the therapy would no longer rely solely on proteinuria as the basis for continued approval.
Sibeprenlimab is also one of the assets identified by Otsuka Holdings as part of its “Next 8” growth pipeline. The group is attempting to create new revenue drivers while managing the loss of exclusivity affecting established products, making successful execution in nephrology strategically important beyond a single regulatory event.
Market sentiment toward Otsuka has remained constructive but does not show a clean reaction that can be attributed solely to the GlomCon announcement. Otsuka Holdings closed at ¥11,325 on July 27, up 1.52%, before trading around ¥11,305 by midday in Tokyo on July 28 after opening at ¥11,545. The shares were roughly 2% above their July 21 close and remained close to a reported 52-week high of ¥11,910.
Otsuka is also scheduled to report its second-quarter financial results on July 31, three days before the VISIONARY presentation. The close proximity of the earnings announcement and GlomCon disclosure means investors will be evaluating VOYXACT alongside broader guidance, launch execution and the company’s pipeline priorities.
What must the GlomCon data establish for VOYXACT’s regulatory case?
The most important disclosure will be the actual annualized eGFR slope in each treatment group, followed by the placebo-adjusted difference, confidence interval, statistical methodology and consistency across sensitivity analyses. Mean eGFR change at month 24 will provide a useful second view, but agreement between the slope and fixed-timepoint analyses would make the result more persuasive.
Investigators will also need to explain how missing measurements, treatment discontinuations, rescue medications and changes in supportive therapy were handled. Prespecified subgroup results involving baseline eGFR, proteinuria, sodium-glucose cotransporter-2 inhibitor use, geography and disease severity could help assess consistency, but none should replace the overall randomized result.
Any claim involving prevention of kidney failure will require particular scrutiny. Event definitions, numbers of events, hazard ratios, follow-up and statistical testing must be disclosed before the market can determine whether the finding represents a reliable clinical outcome or an encouraging but immature secondary analysis.
Otsuka has already crossed the first regulatory threshold by demonstrating a large proteinuria reduction and obtaining accelerated approval. The two-year VISIONARY presentation must now show that VOYXACT’s biological and surrogate effects translate into durable kidney preservation without an emerging long-term safety trade-off. That is the evidence needed to turn an important IgA nephropathy launch into a more firmly established disease-modifying franchise.
