oral phosphate + active vitamin D

The combination of oral phosphate supplements and active vitamin D analogs (such as calcitriol, alfacalcidol, or paricalcitol) represents the conventional therapy for X-linked hypophosphatemia (XLH). In clinical trials sponsored by Kyowa Kirin, such as the Phase 3 Study CL301, this regimen served as the active control arm against which the FGF23 inhibitor burosumab (Crysvita) was compared. The therapy aims to compensate for the renal phosphate wasting characteristic of XLH by providing exogenous inorganic phosphate salts and enhancing intestinal absorption of calcium and phosphate through vitamin D receptor activation. While it helps manage rickets and growth in pediatric patients, the regimen requires frequent daily dosing and is associated with long-term complications including nephrocalcinosis and secondary hyperparathyroidism.

Other names

conventional therapystandard therapyoral phosphate and active vitamin Doral phosphate supplement