Key clinical point: Zoledronate after denosumab discontinuation prevented the complete return of bone mineral density to baseline levels.

Major finding: Women with osteoporosis who received a single infusion of zoledronate after discontinuing denosumab retained 66% of bone mineral density gains at the lumbar spine, 49% at the total hip, and 57% at the femoral neck.

Study details: The data come from a review of 120 women with postmenopausal osteoporosis who received three or more injections of 60 mg denosumab administered at 6-month intervals over 2-5 years, followed by a single infusion of 5 mg zoledronate 6 months after the final denosumab injection.

Disclosures: The study was funded by OsteoRheuma Bern. The researchers reported having no financial conflicts.

Commentary

"Defining the optimal treatment regimen to preserve bone mineral density (BMD) after discontinuation of denosumab represents a significant knowledge gap in osteoporosis care. In this retrospective observational study, the authors investigated the effect of a single dose of zoledronate administered at 6 months after the last denosumab injection on BMD among women with postmenopausal osteoporosis. A total of 120 women who received > 2 injections of denosumab every 6 months for an average of 3 years were included. BMD was measured and vertebral fracture assessment was performed before the first and the last denosumab injection and at 2.5 years (median) after denosumab discontinuation. In this population, two-thirds of BMD gained during denosumab was maintained at the lumbar spine and half at the total hip. These findings suggest that zoledronate at 6 months after denosumab discontinuation is associated with partial decrease in BMD loss. Future studies including randomized clinical trials are needed to determine the appropriate sequence of zoledronate administration post-denosumab."