Vitamin D levels and busulphan kinetics in patients undergoing hematopoietic stem cell transplantation, a multicenter study

Vitamin D (Vit-D), an essential nutrient, interacts with different drugs including chemotherapeutic agents like busulphan, an alkylating agent used for conditioning prior to stem cell transplantation. The correlation between Vit-D plasma levels and busulphan clearance was investigated in an uncontrolled prospective study in patients and mice. Plasma 25(OH)D levels were measured and busulphan pharmacokinetics calculated in 81 patients. Adults received oral busulphan ( n = 34) while children received busulphan orally ( n = 19) or intravenously ( n = 28). Patients received no Vit-D supplementation. To confirm our findings, pharmacokinetics after a single dose of busulphan (oral or intravenous) were evaluated in two groups of mice ( n = 60) receiving high or standard-level Vit-D supplementation. Both busulphan clearance ( P