Randomized, Double-blind, Placebo-controlled, Crossover Study of Atrasentan in Subjects With IgA Nephropathy

Approximately 52 patients with biopsy-proven IgAN who are on a background SGLT2i and a maximally tolerated and stable dose of a renin-angiotensin system inhibitor (RASi) [such as angiotensin converting enzyme inhibitor (ACEi) or angiotensin-receptor antagonist (ARB)] as part of standard of care, will be randomized to either sequence AB or sequence BA in which they will receive 0.75 mg atrasentan once daily during one period (period A), complete a 12-week washout period, and then receive matching placebo during the other period (period B) as determined by the randomization schema. Subjects who are not on background SGLT2i therapy must be willing to undergo a run-in period of 8 weeks with an SGLT2i with a 24-hour total urine protein of > 0.85 grams/day at screening prior to the run-in period and have 24-hour total urine protein of > 0.5 grams/day at the end of the run-in period to be eligible for randomization. Subjects will remain on their maximally tolerated and stable dose of RASi and stable dose of SGLT2i therapies for the duration of the study following randomization. The primary objective of the study is to evaluate the efficacy of atrasentan vs. placebo while on background therapy with SGLT2i. Subjects will have safety and efficacy assessments for 1 year (52 weeks).