Atrasentan in Patients With Proteinuric Glomerular Diseases

Inclusion Criteria:

* Age 18 years and older for patients in the IgAN, FSGS, and Alport Syndrome cohorts
* Age 18-70 years for patients in the DKD cohort
* Receiving a maximally tolerated dose of RAS inhibitor therapy (ACEi or ARB) that has been stable for at least 12 weeks.
* For patients enrolling in IgAN Cohort:

1. Biopsy-proven IgA nephropathy
2. UPCR between 0.5 to less than 1.0 g/g
3. Screening eGFR ≥ 30 mL/min/1.73 m2
* For patients enrolling in FSGS Cohort:

1. Biopsy-proven FSGS or documented genetic mutation in a podocyte protein associated with FSGS
2. UPCR \> 1.0 g/g
3. Screening eGFR ≥ 30 mL/min/1.73 m2
4. Subjects receiving systemic corticosteroids or other immunosuppressants must be on a stable dose for at least 12 weeks.
5. BMI ≤ 40 kg/m2
* For patients enrolling in Alport syndrome Cohort:

1. Diagnosis of Alport syndrome by genetic testing
2. UPCR \> 0.5 g/g
3. Screening eGFR ≥ 30 mL/min/1.73 m2
* For patients enrolling in DKD Cohort:

1. Diagnosis of type 2 diabetes mellitus
2. UACR ≥ 0.5 g/g
3. Screening eGFR ≥ 45 mL/min/1.73 m2
4. Receiving a stable dose of SGLT2 inhibitor for at least 12 weeks
* Willing and able to provide informed consent and comply with all study requirements

Exclusion Criteria:

* Current diagnosis of another cause of chronic kidney disease or another primary glomerulopathy.
* History of kidney transplantation or other organ transplantation.
* Except for FSGS patients, use of systemic immunosuppressant medications, such as steroids, for more than 2 weeks in the past 3 months.
* Blood pressure above 150 mmHg systolic or 95 mmHg diastolic as evaluated by the Investigator.
* History of heart failure or a previous hospital admission for fluid overload.
* Clinically significant history of liver disease as assessed by the Investigator.
* Hemoglobin below 9 g/dL as measured by the Investigator or blood transfusion for anemia within the past 3 months.
* Clinical diagnosis of nephrotic syndrome
* Malignancy within the past 5 years. Exception to the criteria include nonmelanoma skin cancer and curatively treated cervical carcinoma in situ.
* For women, pregnant, breastfeeding, or intent to become pregnant during the study.
* For men, intent to father a child or donate sperm during the study.
* Recently received an investigational agent.
* Clinically significant unstable or uncontrolled medical condition as assessed by the Investigator.