Twice-weekly teriparatide improves lumbar spine BMD independent of pre-treatment BMD and bone turnover marker levels.

Background: There have been no reports of the effects of baseline lumbar spine bone mineral density (LS-BMD) and bone turnover marker levels on the therapeutic effect of a 28.2-μg teriparatide formulation for twice-weekly use (2/W-TPTD).

Methods: An analysis was performed using data from a double-blind, randomized, non-inferiority trial (TWICE study) conducted with patients who received 2/W-TPTD or a 56.5-μg teriparatide formulation for once-weekly use (1/W-TPTD) for 48 weeks. The patients were divided into tertile groups based on baseline LS-BMD, urinary type I collagen cross-linked N-telopeptide (u-NTX), and serum type I procollagen-N-propeptide (P1NP) levels, respectively. Time profiles of these measurements were analyzed. Furthermore, whether a change in P1NP is a predictor for percentage change in BMD was assessed.

Results: Across all tertile groups divided based on baseline LS-BMD and levels of bone turnover markers, the LS-BMD increased significantly. The u-NTX level decreased throughout the study period in the high- and middle-u-NTX-level groups. The P1NP level increased after 4 weeks, but subsequently decreased after 12 weeks and thereafter in the high-P1NP-level group; it increased after 4 weeks and subsequently fluctuated near the baseline level in the middle-P1NP-level group. A cut-off value of 12.0 µg/L for change in P1NP after 4 weeks of 2/W-TPTD as a predictor for percentage change in LS-BMD of 3% or more after 48 weeks gave a positive predictive value of 89.6%.

Conclusions: 2/W-TPTD, just like 1/W-TPTD, improved LS-BMD significantly, regardless of baseline LS-BMD and bone turnover marker levels.