Sparsentan in Posttransplant Immunoglobulin A Nephropathy or Focal Segmental Glomerulosclerosis

This is a 46-week, open-label, multicenter, single-group Phase 4 study to determine the safety and efficacy of sparsentan for the treatment of patients post kidney transplantation with IgAN or FSGS with proteinuria (≥ 0.5 g/g).

Eligible participants with a kidney transplant receiving stable standard of care (SOC) therapy, including standard immunosuppressive therapy (IST) to prevent graft rejection, will be enrolled to receive sparsentan treatment for 36 weeks. Participants will remain on standard IST for the duration of the study and will stop RAASi prior to initiating sparsentan treatment. The final dose of a RAASi should be taken on the day before the Day 1 visit.

Participants with a kidney transplant, at least one year prior to screening, with biopsy-proven IgAN will take 200 mg orally once daily (QD) for 2 weeks, then 400 mg QD through Week 36. Participants with a kidney transplant with FSGS histological pattern in the graft, or a biopsy finding of both IgAN and glomeruli with FSGS patterns will take 400 mg orally QD for 2 weeks, then 800 mg QD through Week 36.

Study visits will be conducted at Day 5 and Weeks 2, 4, 6, 12, 24, and 36 following Day 1. Following the 36 week treatment period, all participants will complete a 4 week off-sparsentan treatment follow-up period (ie, no study drug), during which time treatment will be at the discretion of the investigator. Participants will have a telephone visit at Week 40.