Atrasentan in Patients With Proteinuric Glomerular Diseases

The AFFINITY Study is a phase 2, open-label, basket study to evaluate the efficacy and safety of atrasentan in patients with proteinuric glomerular disease who are at risk of progressive loss of renal function. Cohorts will consist of patients with: * IgA nephropathy (IgAN) with urine protein:creatinine ratio (UPCR) of 0.5 to less than 1.0 g/g * Focal segmental glomerulosclerosis (FSGS) * Alport syndrome * Diabetic kidney disease (DKD) on top of background care of a RAS inhibitor and SGLT2 inhibitor Additional cohorts may be added as data is available. Approximately 100 patients will be enrolled in the study. Approximately 20 patients will be enrolled in each cohort to receive 0.75 mg atrasentan QD for 52 weeks. The study will also evaluate efficacy and safety of 1.5 mg atrasentan QD in FSGS subjects who received 0.75 mg atrasentan and it was well tolerated. Patients will be allowed to continue into treatment extension and receive oral atrasentan QD for up to an additional 84 weeks (total maximum treatment of 188 weeks), The primary objective of the study is to evaluate the effect of atrasentan on proteinuria (for IgAN, FSGS, and Alport syndrome patients) or albuminuria (for DKD patients) levels. Exploratory objectives include evaluating the change in kidney function over time as measured by eGFR, safety and tolerability. To facilitate study participation over this time period, where allowed by local regulations, options for remote study visits using telemedicine and home health may be offered.