OTSKY VOYXACT: GlomCon Data Locks In +0.3 eGFR Slope

Otsuka (OTSKY) presented the full 24-month VISIONARY Phase 3 dataset at GlomCon Hawaii, and the numbers deliver on the July topline. VOYXACT (sibeprenlimab-szsi) showed an annualized eGFR slope of +0.3 mL/min/1.73 m²/year versus -4.2 on placebo, a treatment effect of +4.5 (95% CI, 3.6 to 5.4; p<0.0001). Kidney function essentially stabilized at a near-physiologic rate of decline. For a disease where patients typically lose 3-5 mL/min/year on optimized supportive care, a slope that rounds to zero is a new standard.

OTSKY, the ADR for Otsuka Holdings, closed at $40.49 on volume of roughly 18,000 shares. The ADR trades over the counter. Otsuka’s primary listing is the Tokyo Stock Exchange.

What the GlomCon data adds

The topline in July confirmed eGFR stabilization. The GlomCon presentation put exact numbers on it. The least square mean change from baseline at 24 months was +1.3 mL/min/1.73 m² with VOYXACT versus -7.9 for placebo, a treatment difference of +9.2 (95% CI, 7.1 to 11.4; p<0.0001). Patients on VOYXACT gained kidney function over two years. Patients on placebo lost nearly 8 points.

The safety profile through 24 months remained comparable to placebo. Overall adverse events were 90.7% versus 90.0%. Infection rates were 51.4% versus 51.0%. Serious infections were lower on VOYXACT, at 1.9% versus 4.0%, and both serious adverse events and discontinuations favored the drug.

VOYXACT is the only selective APRIL inhibitor on the market, reducing pathogenic galactose-deficient IgA1 production without broad B-cell depletion. The FDA granted accelerated approval in November 2025. Otsuka has started a rolling sBLA submission for traditional approval.

The IgAN competitive field just got a data leader

The IgAN market now has four entrants with distinct mechanisms. Vera’s Trutakna (atacicept) blocks BAFF and APRIL but has reported only 9-month proteinuria data, with eGFR results still pending. Novartis’ Fabhalta (iptacopan), a complement factor B inhibitor, holds traditional approval with eGFR data maturing. Vertex’s povetacicept, another BAFF/APRIL inhibitor, has a November 30 PDUFA date with 36-week proteinuria data but 2-year eGFR still outstanding. VOYXACT is the only one with 24-month eGFR results in hand, and the numbers beat the KDIGO treatment target of under 1 mL/min/1.73 m²/year.

The caveat is the accelerated approval gap. Fabhalta already has traditional approval. VOYXACT and Trutakna both need confirmatory eGFR data to convert; VOYXACT just delivered. The sBLA timeline is not yet public, but the dataset gives Otsuka the most mature filing package in the APRIL inhibitor class.

For the setup to these results, see the earlier preview of the VISIONARY dataset.

Source: Otsuka press release | VISIONARY on ClinicalTrials.gov