The purpose of this study is to evaluate the efficacy, safety, and pharmacokinetics of sefaxersen (RO7434656), a novel Antisense Oligonucleotide (ASO) therapy in participants with primary IgA nephropathy (IgAN) who are at high risk of progressive kidney disease despite optimized supportive care.
Primary IgAN, as evidenced by a kidney biopsy performed within 10 years prior to or during screening, without known secondary cause
Treatment with maximum tolerated doses of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) for at least 90 days immediately prior to screening, and without an intent to modify the dose during the study, except for interruptions due to illness (not greater than 7 consecutive days), unless the potential participant is intolerant to these medications
Urine Protein-to-Creatinine Ratio (UPCR) ≥ 1 gram per gram (g/g) or urine protein excretion ≥ 1 gram per day (g/day) (with UPCR ≥ 0.8 g/g), all measured from a 24-hour urine collection during screening
eGFR ≥ 20 mL/min/1.73 m², as calculated by the 2021 CKD-EPI creatinine equation (Inker et al. 2021a)
Pregnancy or breastfeeding, or intention of becoming pregnant during the study or within 12 weeks after the final dose of sefaxersen
Histopathologic or other evidence of another autoimmune glomerular disease
Presence of ≥ 50% crescents on kidney biopsy, sustained doubling of serum creatinine within 3 months prior to screening, or rapidly progressive glomerulonephritis in the opinion of the investigator
History of kidney transplantation