Safety and Efficacy of AT-1501 in Patients With IgA Nephropathy (IgAN)

Inclusion Criteria: 1. Male or female ≥ 18 years of age 2. Biopsy proven IgAN 3. Urine protein ≥ 0.75g/24 hours at Screening despite optimization with ACE inhibitors or angiotensin receptor blockers (ARB) 4. eGFR ≥ 45 mL/min per 1.73 m2 or eGFR \< 45 mL/min per 1.73 m2 and ≥ 30 mL/min per 1.73 m2 with a kidney biopsy within 2 years of Screening showing \< 50% tubulointerstitial fibrosis 5. Agree to comply with contraception requirements during and for 90 days after study completion. Exclusion Criteria: 1. Any secondary IgAN as defined by the investigator 2. Patients who have undergone a kidney transplant 3. Any history of kidney disease other than IgAN 4. Any history of diabetes (Type 1 or Type 2) 5. Seated blood pressure \> 140 mmHg (systolic) or \> 90 mmHg (diastolic) at the Screening Visit. Patients must be on a stable dose and regimen of an ACE inhibitor or ARB for at least 90 days 6. Pregnancy or breastfeeding.