A Study of the Effect and Safety of Sparsentan in the Treatment of Patients With IgA Nephropathy

Prior treatment

• Require any prohibited medications
• Treatment of systemic immunosuppressive medications (including corticosteroids) for \>2 weeks within 3 months of screening
• History of heart failure or previous hospitalization for heart failure or unexplained dyspnea, orthopnea, paroxysmal nocturnal dyspnea, ascites, and/or peripheral edema
• Participation in a study of another investigational product within 28 days of screening
• Development of any criteria for discontinuation of study medication or discontinuation from the study, between Week 110 and Week 114
• Patient was unable to initiate, or developed contraindications to, treatment with RAAS inhibitors between Week 110 and Week 114
• Initiated or changed dose of a systemic immunosuppressive medication (including systemic steroids) within 12 weeks
• Taking an SGLT2 inhibitor within 12 weeks

Other illness

• IgAN secondary to another condition
• Chronic kidney disease (CKD) in addition to IgAN
• History of organ transplantation, with exception of corneal transplants
• Clinically significant cerebrovascular disease or coronary artery disease within 6 months of screening
• History of malignancy other than adequately treated basal cell or squamous cell skin cancer or cervical carcinoma within the past 2 years
• History of alcohol of illicit drug use disorder
• History of serious side effect or allergic response to any angiotensin II antagonist or endothelin receptor antagonist, including sparsentan or irbesartan, or has a hypersensitivity to any of the excipients in the study medications
• Progression to end-stage renal disease (ESRD) requiring renal replacement therapy (RRT)

Lab values

• Jaundice, hepatitis, or known hepatobiliary disease or elevations of transaminases (ALT/AST) \>2 times upper limit of normal at screening
• Hematocrit value \<27% (0.27 V/V) or hemoglobin value \<9 g/dL (90 g/L) at Screening
• Potassium \>5.5 mEq/L (5.5 mmol/L) at Screening
• eGFR ≤20 mL/min/1.73 m2 at Week 110

Other

• Presence of cellular glomerular crescents in \>25% of glomeruli on renal biopsy (if biopsy available within 6 months of screening)
• For female: Pregnancy, or planning to become pregnant during the course of the study, or breastfeeding
• Female patient is pregnant or breastfeeding
• Progressed to ESRD requiring RRT

• Age 18 years or older at screening
• Biopsy-proven primary IgAN
• Proteinuria of ≥1 g/day at screening
• eGFR ≥30 mL/min/1.73 m2 at screening
• Currently on stable dose of ACEI and/or ARB therapy, for at least 12 weeks prior to screening (maximum tolerated dose and at least one-half of the maximum labeled dose)
• Systolic BP ≤150 mmHg and diastolic BP ≤100 mmHg at screening
• Willing to undergo change in ACEI and/or ARB and anti-hypertensive medications
• Agree to contraception
• Completed participation in the double-blind period, including the Week 114 visit
• Did not permanently discontinue study medication during the double-blind period
• Agree to contraception
• Participating in the open-label extension and is willing and able to provide signed informed consent for participation in the open-label extension period Sub study
• A urine protein excretion value of ≥0.3 g/day.
• An eGFR of ≥25 mL/min/1.73m2
• On a stable dose of sparsentan for ≥8 weeks in the open-label extension period that is the maximum tolerated dose.