Higher Response with Bone Mineral Density Increase with Monthly Injectable Ibandronate 1 mg Compared with Oral Risedronate in the MOVER Study

We examined response to bone mineral density (BMD) gains in the MOVER study following treatment with intravenous (IV) ibandronate 1 mg/month, and investigated the characteristics of a non-responder group. At 1 year, responder rates for patients with BMD increases >0 % were similar with IV ibandronate 0.5 or 1 mg/month and oral risedronate 2.5 mg/day. However, after 3 years, responder rates with BMD increases ≥3 % were highest with ibandronate 1 mg at all bone sites (>80 % at the lumbar spine [L2-L4] and >50 % at all femur sites, which was significantly higher than with risedronate). Non-responders were defined by BMD increases ≤3 % at L2-L4 or ≤0 % at total hip, and ≤50 % reduction in creatinine-corrected urinary collagen type 1 cross-linked C-telopeptide (uCTX) from baseline to 1 year. There were a small number of non-responders in the ibandronate 1 mg group: 3.3 % (10/299) with ≤0 % total hip BMD increase and ≤50 % uCTX reduction from baseline. These non-responders had lower 25-hydroxyvitamin D (25[OH]D) levels than responders, but no differences in kidney function, L2-L4 BMD or bone turnover marker baseline values. Throughout the study, non-responders failed to show any increases in BMD. Our analysis demonstrates significantly higher responder rates with IV ibandronate 1 mg/month than with risedronate at 3 years. A small number of non-responders in the ibandronate group had lower 25(OH)D baseline levels than responders, suggesting that 25(OH)D levels could be a useful indicator of BMD response to therapy.