Rifampin Treatment for High Blood and Urine Calcium in Patients With CYP24A1 Gene Mutations

What this Trial Is About

This research investigates the use of rifampin for treating hypercalcemia and hypercalciuria in patients with at least one inactivating mutation in the CYP24A1 gene. This genetic condition, called idiopathic infantile hypercalcemia IIH, causes abnormal calcium metabolism due to impaired vitamin D breakdown, leading to high blood and urine calcium levels. The study aims to assess the effect, safety, and tolerability of rifampin, which may activate alternative liver and intestinal enzymes to help manage vitamin D metabolism. Participants will receive oral rifampin once daily for a total of 16 weeks, starting with a dose of 5 mgkg up to 300 mg daily for 8 weeks, followed by an increased dose of 10 mgkg up to 600 mg daily for another 8 weeks. The study includes a single group receiving escalating doses of rifampin. Before treatment, participants will be observed for 8 weeks, followed by 16 weeks of rifampin treatment, and then 8 weeks of further observation after treatment ends. Throughout the study, participants will undergo regular monitoring of calcium levels in blood and urine, parathyroid hormone levels, and vitamin D metabolism. Researchers will also study how rifampin is processed in the body and its effect on intestinal calcium absorption. Assessments include laboratory tests and imaging to evaluate kidney calcification at baseline and week 32. The total study duration for each participant is up to 32 weeks.

Rifampin in CYP24A1-related Hypercalcemia and Hypercalciuria