Lanthanum Carbonate (Fosrenol®) to Reduce Oxalate Excretion in Patients With Secondary Hyperoxaluria and Nephrolithiasis

Inclusion Criteria:

• able to give written informed consenct
• hyperoxaluria (defined as urinary oxalate > 45 mg/24 hours), demonstrated on 24-hoururine collection within 18 months prior to baseline visit
• history of nephrolithiasis eGFR > 60 mL/min/1.73m² (CKD-EPI formula)

Exclusion Criteria:

• primary hyperoxaluria, diagnosed by genetic testing
• known allergy to Lanthanum Carbonate
• hypophosphatemia (defined as serum phosphorus < 0.81 mmol/L)
• severe known liver insufficiency of biliary obstruction
• rectocolitis ulcerohaemorraghica, Crohn's disease, bowel obstruction, stomach/duodenalulceration
• glucose/galactose malabsorption
• severe diarrhea or other gastrointestinal disorder, which might interfere with theability to absorb oral medication
• pregnancy or breast-feeding
• female participant of childbearing potential unwilling to take efficient contraceptivemeasures for the duration of the study
• female participant without negative serum or urine pregnancy test
• psychological illness or condition, interfering with the patient's compliance orability to understand the requirements of the study
• currently participating in another clinical trial