Sparsentan in Posttransplant Immunoglobulin A Nephropathy or Focal Segmental Glomerulosclerosis

Prior treatment

• Immunosuppressive therapy (IST) regimen for kidney transplant or other systemic chronic ISTs including enteric budesonide that is not stable for \>6 weeks prior to Day 1. Exceptions include routine changes in the dose of CNIs to meet target level.
• Active bacterial, fungal or viral infection and/or active treatment of infection including BK virus (BKV), cytomegalovirus (CMV), human immunodeficiency virus (HIV), Hepatitis B and C \<3 months prior to and during the screening period.
• Current treatment for surgical complications.
• Participant requires any of the prohibited concomitant medications.
• Treatment with sparsentan \<12 weeks prior to screening.
• Participant has participated in a study of another investigational product \<28 days prior to screening or plans to participate in such a study during the course of this study.

Other illness

• History of heart failure (New York Heart Association \[NYHA\] Class II-IV).
• Jaundice, hepatitis, or known hepatobiliary disease.
• Malignancy within the past 2 years with the exception of adequately treated basal cell carcinoma or non-metastatic squamous cell carcinoma of the skin, with no evidence or recurrence.
• History of alcohol or illicit drug use disorder (as defined in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition).
• History of serious side effects or allergic response to any angiotensin II antagonist or ERA.

Lab values

• Hematocrit \<27%, hemoglobin \<90 g/L (9 g/dL), or potassium \>5.5 mmol/L (5.5 mEq/L).
• The participant, in the opinion of the Investigator, has a medical condition or abnormal clinically significant laboratory screening value not listed above that may interfere with the evaluation of sparsentan safety or activity.

Other

• Participant has multiorgan transplants (with the exception of pancreas and corneal transplants).
• \<3 months after antirejection treatment and active rejection.
• The participant is pregnant, plans to become pregnant during the course of the study, or is breastfeeding.
• The participant, in the opinion of the Investigator, is unable to adhere to the requirements of the study, including the ability to swallow the study IMP whole.

• Willing and capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the ICF and in the protocol.
• Male and female aged ≥18 years
• Participants with a kidney transplant with biopsy-proven IgAN or FSGS histological pattern in the graft.
• A period of ≥12 months since kidney transplantation.
• UPCR ≥0.5 g/g and eGFR (CKD-EPI creatinine-based formula ≥30 mL/min/1.73 m2.
• Participants who can become pregnant, must agree to the use of 1 highly reliable method of contraception from 7 days prior to the first dose of study intervention until 30 days after the last dose of study intervention.
• Systolic BP ≤160 mmHg and ≥100 mmHg, and diastolic BP ≤100 mmHg and ≥60 mmHg at screening.
• For participants on an ACEI and/or ARB, and/or sodium glucose cotransporter-2 (SGLT2) inhibitor, the dosing regimen(s) is stable for ≥6 weeks prior to screening.