Eldecalcitol, in Combination with Bisphosphonate, Is Effective for Treatment of Japanese Osteoporotic Patients.

Alfacalcidol (ALF) and eldecalcitol (ELD) are vitamin D analogues that can be combined with anti-resorption drugs, such as bisphosphonate (BP) for the treatment of osteoporosis (OP). There has been no report comparing the effects of those vitamin D analogs in combination with BPs. Twenty female patients with OP were enrolled, and all of them were treated with ALF and BPs. After switching from ALF to ELD, we examined the effectiveness of ALF and ELD. The averaged age was 69.4 years and the period of BP usage was between 1 to 13.4 years (mean period was 3.7 years). Serum corrected calcium, serum inorganic phosphorus, serum bone specific alkaline phosphatase (BAP), and serum tartrate-resistant acid phosphatase (TRACP)-5b were measured prior to ELD and at 6 months afterwards. Bone mineral density (BMD) of the lumbar spine (L-BMD), femoral neck, and total hip BMD were assessed one year before, prior to, and one year after ELD therapy commencement. Six months after switching from ALF to ELD, BAP and TRACP-5b values significantly decreased. After one year of ALF therapy, L-BMD, total hip BMD and femoral neck H-BMD values slightly increased. In contrast, a year following the change from ALF to ELD, L-BMD significantly increased and femoral neck BMD slightly increased, but total hip BMD did not. These results suggest that the treatment with ELD after ALF significantly suppressed bone turnover and increased L-BMD. Thus, the combined therapy with ELD is more effective for OP treatment than that with ALF.