This is a phase 2b open-label trial to characterize histopathological biomarkers of disease in immunoglobulin A nephropathy (IgAN) and demonstrate potential changes in response to sibeprenlimab.
Participants must be at least 16 years of age or older at the time of signing the informed consent/assent.
Source-verified kidney biopsy confirmed diagnosis of IgAN.
Participant has estimated glomerular filtration rate (eGFR) > 45 mL/min/1.73 m2 using serum creatinine (Chronic Kidney Disease-Epidemiology Collaboration [CKD EPI] creatinine eGFR 2021 equation for those 18 years and older; Chronic Kidney Disease in Children under age 25 [CKiD U25] eGFR equation for those younger than 18 years)
Participants who are breast-feeding and/or who have a positive pregnancy test result prior to receiving sibeprenlimab.
Participant has coexisting chronic kidney disease, other than IgAN.
Participant has a serum IgG value <600 mg/dL at screening.
Participant has uncontrolled hypertension (defined as systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg).