,10 By binding FGF23, burosumab improves phosphate reabsorption in the proximal renal tubules and also increases the production of 1,25(OH)2D.2,11–13 Treatment with burosumab has also demonstrated improved healing of osteomalacic fractures compared to placebo at week 24 of the pivotal randomized phase 3 study in adults with XLH.11 Here, FGF23 is linked to X-linked hypophosphatemia.