This study is for people aged 16 to 75 with certain kidney diseases called primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD). It aims to find out how three medicines (frexalimab, brivekimig, or rilzabrutinib) affect proteinuria, which is a condition where there's too much protein in urine, and help with remission of nephrotic syndrome. Nephrotic syndrome is a kidney disorder that causes your body to pass too much protein in your urine. The study lasts up to 52 weeks, with 24 weeks of treatment and up to 16 visits to the study site.

• The study requires up to 16 visits over a year.
• Participants will receive treatment for 24 weeks.
• Participants should have a stable weight (45-120 kg) and cannot be on certain medications or in severe kidney failure.

Participants must have a biopsy report showing primary FSGS or MCD and meet specific health criteria. It's important to talk with your doctor to see if joining this study is right for you.