Roche said its investigational sefaxersen was associated with a 43.1% lower 24-hour urine protein-to-creatinine ratio (UPCR) than placebo at Week 37 in adults with primary IgA nephropathy (IgAN) receiving optimized standard care. The Phase 3 interim result, presented at the American Society of Nephrology's Kidney Week 2026, had a 95% confidence interval of 32.5% to 52.0% and a P value below 0.0001. Proteinuria is a marker of kidney damage, but this finding does not show whether treatment preserves kidney function over time.
The primary endpoint tracked geometric mean changes in 24-hour UPCR from baseline at Week 37. Because the trial numbers its first week as Week 1, the Week 37 label corresponds to 36 weeks of data.
Roche said the effect was consistent across prespecified subgroups. Among participants with blood in their urine at baseline, Roche said a higher proportion of sefaxersen recipients than placebo recipients had resolution by Week 37; its announcement did not give the proportions.
The study is randomized, double-blind and placebo-controlled, and tests the medicine alongside optimized care. The presentation says background care included renin-angiotensin system blockers at the maximum tolerated dose, with some other blood pressure or kidney medicines allowed.
Sefaxersen is a liver-directed antisense oligonucleotide intended to reduce production of complement factor B and regulate the alternative complement pathway. Roche is developing it as a monthly injection under the skin for self-administration. Roche said adverse-effect findings remained in line with its Phase 2 experience and that no new safety concerns had emerged.
Roche Chief Medical Officer Levi Garraway said the results pointed to the potential to “meaningfully reduce protein in the urine.” Roche announced Sept. 23 that the study had met its primary endpoint, but did not provide the effect size then.
The blinded trial is scheduled to measure estimated glomerular filtration rate (eGFR), a kidney-function measure, at Week 105. Roche said it plans to share the study data with health authorities.
