The estimated 6-year fracture rate was about 10% in the denosumab group and 20% in the placebo group. “Please note that the frequency of clinical fractures reported in this trial that is focusing on bone health is markedly higher than fracture rates reported in previous large AI trials. Obviously, we had a tendency to underreport them in those trials,” Dr. Gnant commented. “The true magnitude of the problem in clinical practice is likely reflected in the placebo group … with approximately one out of five patients experiencing a new clinical fracture within 5-6 years of adjuvant AI treatment.”
Benefit was similar across numerous patient subgroups studied, including the subgroups of women who had a baseline bone mineral density T-score of less than –1 and women who had a baseline bone mineral density T-score of –1 or greater.
Additionally, the denosumab group had improvements from baseline in bone mineral density of the lumbar spine, total hip, and femoral neck, whereas the placebo group had worsening at all sites (P less than .0001 between groups for each site). And at 36 months, the denosumab group had significantly lower risks of both new vertebral fractures and new or worsening vertebral fractures.
“Adjuvant denosumab at this dose and schedule is safe,” Dr. Gnant maintained. The two groups had similar rates of various adverse events, with musculoskeletal disorders and vascular disorders (including hot flashes) predominating. “This means that we are in essence reporting the side effects of the underlying adjuvant AI treatment,” he noted.
There were 31 cases of dental issues, but none met diagnostic criteria for osteonecrosis of the jaw. “We can safely say that at this dose of denosumab, 60 mg twice yearly, ONJ is not an issue,” Dr. Gnant commented. Additionally, none of the women experienced atypical fractures.
Dr. Gnant disclosed employment of an immediate family member with Sandoz; receipt of honoraria from Amgen, AstraZeneca, GlaxoSmithKline, NanoString Technologies, Novartis, and Roche Pharma AG; a consulting or advisory role with Accelsiors, AstraZeneca, and Novartis; and receipt of research funding from GlaxoSmithKline, Novartis, Pfizer, Roche Pharma AG, Sanofi, and Smiths Medical. The trial was sponsored by Amgen.