Additive effects of eldecalcitol in poorly responding long-term bisphosphonate treatment for osteoporosis

ABSTRACT

OBJECTIVES: We examined whether eldecalcitol (ELD) provided additive bone mineral density (BMD) and bone turnover marker gains in patients undergoing long-term bisphosphonate (BP) usage, especially in osteoporotic individuals exhibiting a poor response to BPs. METHODS: Forty-two post-menopausal patients with primary osteoporosis and low lumbar BMD (L-BMD) and/or bilateral total hip BMD (H-BMD) values receiving long-term BP treatment were prospectively enrolled. Serum bone alkaline phosphatase (BAP) was measured as a bone formation marker and urinary N-terminal telopeptide of type I collagen (NTX) was assessed as a bone resorption marker. L-BMD, H-BMD, and femoral neck BMD (N-BMD) were recorded before, at the commencement of, and during ELD administration. RESULTS: BAP and urinary NTX were significantly decreased by BP therapy prior to ELD. ELD addition further significantly decreased the bone turnover markers (both p < 0.01). The mean L-BMD increase rate was 0.2% (p = 0.81) from 2 to 1 years before ELD administration, −0.7% (p = 0.30) during the year before ELD, and 2.9% (p < 0.01) during 1 year of ELD. Similar findings were observed for the mean increase rate of H-BMD, with values of 0.2% (p = 0.55), −0.7% (p < 0.01), and 1.2% (p < 0.01), respectively. The mean N-BMD increase rate was significantly increased after ELD administration (1.1%, p = 0.03) despite no gains by BP therapy alone. CONCLUSIONS: This study suggests that ELD addition may be useful for osteoporotic patients exhibiting a diminished long-term BP therapy response.