Bone Mineral Density Changes After 1 Year of Denosumab Discontinuation in Postmenopausal Women with Long-Term Denosumab Treatment for Osteoporosis

The aim of the present study was to document the changes in bone mineral density (BMD) 1 year after denosumab loss-of-effect following long-term treatment with subcutaneous denosumab 60 mg Q6M during 7 or 10 years and in the absence of any treatment with a bone active substance. All postmenopausal women with osteoporosis who participated to the randomized placebo-controlled FREEDOM core trial and its open-label extension at the University Hospital of Bern, Switzerland, and who accepted to undergo off-treatment follow-up during 1 year after discontinuation, were included (N = 12). After 10 years of denosumab, mean lumbar spine (LS) BMD had increased by 21.2% vs. baseline. One year after discontinuation LS BMD had decreased by - 9.1% vs. Year 10, resulting in a net gain of 10.2% vs. baseline. At total hip (TH) and femoral neck (FN), BMD had increased by 8.3 and 8.1% in Year 10 vs. baseline, respectively. 1 Year after discontinuation, BMD had decreased by - 12.7 and - 11.0% vs. Year 10, respectively, corresponding to net BMD losses of - 5.5 and - 3.8% vs. baseline, respectively. Similar albeit less pronounced changes were observed in those treated with denosumab during 7 years. Stopping denosumab after long-term exposure resulted in BMD losses of large order of magnitude at all measured sites, suggesting that treatment duration may predict the rate and amount of bone lost.