In this study, 250 women with osteoporosis were randomized to 12 months with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly, then crossed over to the other treatment. The primary endpoint, treatment adherence at 12 months, was 76.6% for alendronate and 87.3% for denosumab.
Introduction: The purpose of this study is to evaluate treatment adherence with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly.
Methods: In this multicenter, randomized, open-label, 2-year, crossover study, 250 postmenopausal women with low bone mineral density received denosumab or alendronate for 12 months, then the other treatment for 12 months. The alendronate bottle had a medication event monitoring system cap to monitor administration dates. Definitions were as follows: compliance, receiving both denosumab doses 6 (± 1) months apart or 80-100% of alendronate doses; persistence, receiving both denosumab doses and completing the month 12 visit within the visit window or ≥ 2 alendronate doses in the final month; adherence, achieving both compliance and persistence. This report includes data from the first 12 months.
Results: The primary study endpoint, adherence in the first 12 months, was 76.6% (95/124) for alendronate and 87.3% (110/126) for denosumab. Risk ratios for denosumab compared with alendronate at 12 months were 0.58 (p = 0.043) for non-adherence, 0.48 (p = 0.014) for non-compliance, and 0.54 (p = 0.049) for non-persistence. Subject ratings for treatment necessity, preference, and satisfaction were significantly greater for denosumab and ratings for treatment bother were significantly greater for alendronate. Adverse events were reported by 64.1% of alendronate-treated subjects and 72.0% of denosumab-treated subjects (p = 0.403). The most common adverse events were arthralgia, back pain, pain in extremity, cough, and headache (each in <10% of subjects in each group).
Conclusions: Significantly greater treatment adherence was observed for subcutaneous administration of denosumab every 6 months than for oral alendronate once weekly.