Eldecalcitol for the treatment of osteoporosis.

Eldecalcitol [1α,25-dihydroxy-2β-(3-hydroxypropyloxy)-vitamin D₃] is an analogue of 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], bearing a hydroxypropyloxy residue at the 2β position. Eldecalcitol shows stronger effects than alfacalcidol to increase bone mineral density and reduce bone resorption markers in osteoporotic patients, and oral once-daily 0.75 μg eldecalcitol reduced vertebral fracture incidence by 26% compared to 1.0 μg alfacalcidol in a 3-year randomized, double-blind, active-comparator clinical trial. The effect of eldecalcitol on vertebral fracture incidence was sustained throughout the 3-year study period, and the annual incidence of vertebral fracture during the third year was significantly lower with eldecalcitol rather than with alfacalcidol treatment (3.9% vs 7.0%, respectively). Eldecalcitol also reduced the incidence of wrist fractures by 71% compared to alfacalcidol. Eldecalcitol is well tolerated and is not associated with serious side effects including sustained hypercalcemia. Eldecalcitol was approved for the treatment of osteoporosis in Japan in 2011.