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 hasbeen 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 proteinassociated 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 beon 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 primaryglomerulopathy.

• History of kidney transplantation or other organ transplantation.

• Except for FSGS patients, use of systemic immunosuppressant medications, such assteroids, for more than 2 weeks in the past 3 months.

• Blood pressure above 150 mmHg systolic or 95 mmHg diastolic as evaluated by theInvestigator.

• 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 foranemia within the past 3 months.

• Clinical diagnosis of nephrotic syndrome

• Malignancy within the past 5 years. Exception to the criteria include nonmelanomaskin 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 theInvestigator.