Date

2026-07-10

Protocol

Protocol changed

Item Changed

Secondary outcome

Previous Version

Efficacy: • To evaluate the long-term efficacy of sibeprenlimab in subjects with IgAN. • To evaluate the treatment effect of sibeprenlimab on the progression to a composite kidney failure endpoint (as measured by time to event or proportion of subjects). Pharmacodynamics: • To evaluate Ig response in subjects with IgAN. Other: • To evaluate immunogenicity in subjects with IgAN.

Next Version

Secondary: Efficacy: • The slope of eGFR over the course of approximately 12 and 24 months. • Mean change of eGFR from baseline at 12 and 24 months. • Estimate the time-normalized area under curve (AUC) for eGFR at 12 and 24 months. • Relative change from baseline in terms of uPCR at 12 and 24 months, based on 24 hour urine collection. • Overall rate of proteinuric remission, based on 24 hour urine collection, and defined as the proportion of subjects achieving urine total protein < 0.5 g/day at 12 and 24 months. • Progression to CKF, as assessed by: o Time to progression to CKF (time from first IMP date to first occurrence of CKF). o Proportion of subjects with progression to CKF. Composite kidney failure is defined as meeting 1 or more of the following criteria based on observed assessments or therapy: sustained doubling of serum creatinine compared with baseline based on 2 measurements at least 4 weeks apart, sustained 40% reduction in eGFR compared with baseline based on 2 measurements at least 4 weeks apart, sustained eGFR < 15 mL/min/1.73 m2 based on 2 measurements at least 4 weeks apart, or the requirement of renal replacement therapy (chronic dialysis for ? 4 weeks or kidney transplantation). Pharmacodynamics: Change from baseline in total serum IgA, IgG, and IgM concentrations. Other: Evaluation of serum ADA levels.