Roche reports Phase 3 data showing sefaxersen cut proteinuria in IgA nephropathy

On October 23, 2026, Ionis Pharmaceuticals disclosed that its partner Roche presented late-breaking Phase 3 results for investigational sefaxersen in adults with primary IgA nephropathy (IgAN) who were also receiving optimized standard of care. Sefaxersen achieved a statistically significant and clinically meaningful 43.1% reduction in proteinuria (95% confidence interval: 32.5 to 52.0, P<0.0001) relative to placebo at 37 weeks, as measured by 24-hour urine protein-to-creatinine ratio.¹ The company noted that proteinuria reflects kidney damage and that lowering UPCR is closely tied to preserving kidney function over time.¹

The data, presented at the American Society of Nephrology Kidney Week 2026, also covered patients with blood in their urine at baseline. Among that subgroup, more patients on sefaxersen than on placebo saw their hematuria resolve by week 37.¹ Ionis said the benefit held across all prespecified patient subgroups, matching the main proteinuria finding.¹

On safety, the company said the drug's tolerability profile matched what was seen in the earlier Phase 2 trial, with no new issues identified. Sefaxersen is dosed as a once-monthly subcutaneous shot meant for patients to give themselves at home. The IMAgINATION trial remains blinded and will keep tracking kidney function for two years, measuring estimated glomerular filtration rate at week 105.¹ Roche said it plans to share the results with health regulators.¹

Roche licensed sefaxersen from Ionis to develop treatments for complement-mediated diseases, with Ionis receiving upfront, license, and development milestone payments and eligibility for further regulatory and sales milestones plus royalties on future sales.¹ The Phase 3 IMAgINATION study (NCT05797610) enrolled 459 patients randomized 1:1 to sefaxersen or placebo for 105 weeks.¹