A Study to Test BI 764198 in People With a Type of Kidney Disease Called Primary Focal Segmental Glomerulosclerosis

Open to people ages 18-75

1. Signed and dated informed consent in accordance with ICH-GCP and local legislation prior to admission to the study.
2. Male and female patients 18 years to 75 years (both inclusive) of age on the day of signing informed consent.
3. Patients diagnosed with biopsy proven primary Focal Segmental Glomerulosclerosis (FSGS) or documented Transient Receptor Potential Cation subfamily C Member 6 (TRPC6) gene mutation causing FSGS prior to screening visit.
4. Urine Protein-Creatinine Ratio (UPCR) ≥ 1000 mg/g based on first morning void urine sample during screening.
5. Patients treated with corticosteroids must be on a stable dose for at least 4 weeks prior to screening visit with no plan to change the dose until end of trial treatment.
6. Patients treated with Angiotensin Converting Enzyme (ACE) inhibitors, Angiotensin II Receptor Blockers (ARBs), finerenone, aldosterone inhibitors, or Sodium-Glucose Cotransporter-2 (SGLT2) inhibitors should be on a stable dose for at least 4 weeks prior to screening visit with no plan to change the dose until end of trial treatment.
7. Body Mass Index (BMI) of ≤ 40 kg/m2 at screening visit.
8. Women of childbearing potential (WOCBP1) must be willing and able to use highly effective methods of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly. A list of contraception methods meeting these criteria is provided in the protocol. Men must be willing and able to use condom if their partner is a WOCBP.

1. Known monogenic (with the exception of TRPC6 gene mutations) or clinical or histologic evidence of secondary FSGS.
2. Documented Alport syndrome, Nail Patella syndrome, diabetic nephropathy, Immunoglobulin A (IgA) nephropathy, lupus nephritis, or monoclonal gammopathy (e.g., multiple myeloma).
3. Genito-urinary malformations with vesicoureteral reflux or renal dysplasia.
4. A history of organ transplantation or planned transplantation during the course of the study.
5. Uncontrolled hypertension defined as an average resting systolic blood pressure >160 mmHg calculated from the last two of the triplicate sitting blood pressure measurements at screening visit. Patients with a documented history of white coat hypertension may be included.
6. Concomitant use of calcineurin inhibitors within 5 half-lives before screening visit.

7. Concomitant treatment with cytotoxic agents (cyclophosphamide, chlorambucil), or CD20 monoclonal antibody, e.g., rituximab, within 5 half-lives before screening visit.

   Note: use of other immunosuppression therapies considered as standard of care may be allowed as long as the patient remains on stable dose throughout the study.

8. Treatment with metformin or dofetilide (Multidrug and Toxin Extrusion 1 (MATE1) or Organic Cation Transporter 2 (OCT2) substrates); dabigatran or digoxin (Permeability Glycoprotein (P-gp) substrates with narrow therapeutic window) within 5 half-lives before screening visit.

   Further exclusion criteria apply.