No abstract

This substudy finds no clinically important benefit to BMD from untargeted vitamin D supplementation of older, community-dwelling adults. Exploratory analyses suggest meaningful benefit in those with baseline 25-hydroxyvitamin D ≤ 30 nmol L . This represents a significant step towards a trial-based definition of vitamin D deficiency for bone health in older adults.

Romosozumab and denosumab are monoclonal antibodies for the treatment of osteoporosis. Both have a rapid offset of effect resulting in loss of bone density (BMD) gained on-treatment and, in some cases, multiple vertebral fractures following treatment cessation. We recently reported disappointing results from transitioning patients from denosumab to intravenous zoledronate at the time the next denosumab injection is due. The present report re-assesses the role of bisphosphonates following the use of denosumab. In the FRAME trial, osteoporotic women were randomized to romosozumab or placebo for 1 year, then both groups were provided with open-label denosumab for the subsequent 2 years. In women completing this study at our center, we offered treatment with either oral or intravenous bisphosphonates. In the eleven women opting for intravenous treatment, zoledronate was given after a median delay of 65 days from trial-end, in the hope that this might increase skeletal uptake of the drug and, thereby, its efficacy to maintain bone density. In these women, spine BMD was 17.3% above baseline at trial-end, and still 12.3% above baseline a year later, a 73% (CI: 61%, 85%) retention of the treatment benefit. The comparable BMD figures for the total hip were 10.7 and 9.2% above baseline, a 87% (CI: 77%, 98%) retention of treatment effect. In contrast, those not receiving treatment after the conclusion of the FRAME trial lost 80-90% of the BMD gained on-trial in the following 12 months. Women treated with risedronate showed an intermediate response. In the zoledronate group, mean PINP 6 months post-FRAME was 23 ± 4 µg/L and at 12 months it was 47 ± 8 µg/L, suggesting that repeat zoledronate dosing is needed at 1 year to maintain the BMD gains. In conclusion, delaying administration of intravenous bisphosphonate when transitioning from short-term denosumab appears to increase the extent to which the gains in BMD are maintained.

A case series of six women with postmenopausal osteoporosis who had received continuous denosumab for 7 years and were then given a single infusion of zoledronate (5 mg) is reported. During denosumab treatment, bone mineral density (BMD) in the spine increased 18.5% (P = 0.006), and total hip BMD by 6.9% (P = 0.03). Post-zoledronate BMDs were measured 18-23 months after treatment, and there were significant declines at each site (P = 0.043, P = 0.005). Spine BMD remained significantly above the pre-denosumab baseline (+9.3%, P = 0.003), but hip BMD was not significantly different from baseline (-2.9%). At the time of post-zoledronate BMD measurements, serum PINP levels were between 39 and 60 μg/L (mean 52 μg/L), suggesting that the zoledronate treatment had not adequately inhibited bone turnover. It is concluded that this regimen of zoledronate administration is not adequate to preserve the BMD gains that result from long-term denosumab treatment.

Ca supplements are used for bone health; however, they have been associated with increased cardiovascular risk, which may relate to their acute effects on serum Ca concentrations. Microcrystalline hydroxyapatite (MCH) could affect serum Ca concentrations less than conventional Ca supplements, but its effects on bone turnover are unclear. In the present study, we compared the acute and 3-month effects of MCH with conventional Ca supplements on concentrations of serum Ca, phosphate, parathyroid hormone and bone turnover markers. We randomised 100 women (mean age 71 years) to 1 g/d of Ca as citrate or carbonate (citrate -carbonate), one of two MCH preparations, or a placebo. Blood was sampled for 8 h after the first dose, and after 3 months of daily supplementation. To determine whether the acute effects changed over time, eight participants assigned to the citrate dose repeated 8 h of blood sampling at 3 months. There were no differences between the citrate and carbonate groups, or between the two MCH groups, so their results were pooled. The citrate -carbonate dose increased ionised and total Ca concentrations for up to 8 h, and this was not diminished after 3 months. MCH increased ionised Ca concentrations less than the citrate -carbonate dose; however, it raised the concentrations of phosphate and the Ca -phosphate product. The citrate -carbonate and MCH doses produced comparable decreases in bone resorption (measured as serum C-telopeptide (CTX)) over 8 h and bone turnover (CTX and procollagen type-I N-terminal propeptide) at 3 months. These findings suggest that Ca preparations, in general, produce repeated sustained increases in serum Ca concentrations after ingestion of each dose and that Ca supplements with smaller effects on serum Ca concentrations may have equivalent efficacy in suppressing bone turnover.

We recently showed that zoledronate prevented fractures in older women with osteopenia (hip T-scores between −1.0 and −2.5). In addition to fewer fractures, this study also suggested that women randomized to zoledronate had fewer vascular events, a lower incidence of cancer, and a trend to lower mortality. The present analysis provides a more detailed presentation of the adverse event data from that study, a 6-year, double-blind trial of 2000 women aged >65 years recruited using electoral rolls. They were randomly assigned to receive four infusions of either zoledronate 5 mg or normal saline at 18-month intervals. Supplements of vitamin D, but not calcium, were provided. There were 1017 serious adverse events in 443 participants in the placebo group, and 820 events in 400 participants in those randomized to zoledronate (relative risk = 0.90; 95% CI, 0.81 to 1.00). These events included fractures resulting in hospital admission. Myocardial infarction occurred in 39 women (43 events) in the placebo group and in 24 women (25 events) in the zoledronate group (hazard ratio 0.60 [95% CI, 0.36 to 1.00]; rate ratio 0.58 [95% CI, 0.35 to 0.94]). For a prespecified composite cardiovascular endpoint (sudden death, myocardial infarction, coronary artery revascularization, or stroke) 69 women had 98 events in the placebo group, and 53 women had 71 events in the zoledronate group (hazard ratio 0.76 [95% CI, 0.53 to 1.08]; rate ratio 0.72 [95% CI, 0.53 to 0.98]). Total cancers were significantly reduced with zoledronate (hazard ratio 0.67 [95% CI, 0.51 to 0.89]; rate ratio 0.68 [95% CI, 0.52 to 0.89]), and this was significant for both breast cancers and for non-breast cancers. Eleven women had recurrent or second breast cancers during the study, all in the placebo group. The hazard ratio for death was 0.65 (95% CI, 0.40 to 1.06; p = 0.08), and 0.51 (95% CI, 0.30 to 0.87) in those without incident fragility fracture. These apparent beneficial effects justify further appropriately powered trials of zoledronate with these nonskeletal conditions as primary endpoints.

Annual intravenous administration of 5 mg zoledronate decreases fracture risk, but the optimal dosing regimen for zoledronate has not been determined. We set out to evaluate the antiresorptive effects of a single administration of lower doses of zoledronate. A total of 180 postmenopausal women with osteopenia enrolled in a double-blind, randomized, placebo-controlled trial over 2 years at an academic research center. Participants were randomized to a single baseline administration of intravenous zoledronate in doses of 1 mg, 2.5 mg, or 5 mg, or placebo. The primary endpoint was change in bone mineral density(BMD) at the lumbar spine. Secondary endpoints were change in BMD at the proximal femur and total body, and changes in biochemical markers of bone turnover. After 2 years, the change in spine BMD was greater in each of the zoledronate groups than in the placebo group; values are mean (95% confidence interval [CI]) difference versus placebo: zoledronate 1 mg 4.4% [2.7% to 6.1%]; 2.5 mg 5.5% [3.9% to 7.2%]; 5 mg 5.3% [3.8% to 6.7%], p < 0.001 for each dose). Change in BMD at the total hip was greater in each of the zoledronate groups than the placebo group (mean [95% CI] difference versus placebo: zoledronate 1 mg 2.6% [1.5% to 3.7%]; 2.5 mg 4.4% [3.5% to 5.3%]; 5 mg 4.7% [3.7% to 5.7%], p < 0.001 for each dose). Each of the bone turnover markers, b-C-terminal telopeptide of type I collagen (b-CTX) and procollagen type-I N-terminal propeptide (P1NP), was lower in each of the 2.5-mg and 5-mg zoledronate groups than the placebo group throughout the trial (p < 0.001 versus placebo for each marker for each dose at each time point). For each endpoint, changes were similar in the 2.5-mg and 5-mg zoledronate groups, whereas those in the 1-mg group were smaller than those in the other zoledronate groups. These data demonstrate that single administrations of zoledronate 1 mg or 2.5 mg produce antiresorptive effects that persist for at least 2 years. Trials assessing the antifracture efficacy of intermittent low doses of zoledronate, in particular the 2.5-mg dose, are justified.

Zoledronate is an intravenously administered bisphosphonate that has been shown in randomized clinical trials to reduce fracture risk in osteoporosis.1,2 A notable feature of zoledronate is its prolonged activity in bone, such that it is approved for annual administration for treatment of osteopor osis and administration every 2 years for prevention of bone loss. 3Despite being in clinical use for almost a decade, the optimal dosing regimen for zoledronate is uncertain. The dose approved for clinical practice, 5 mg, is greater than any studied in the phase II zoledronate trial. 4 That trial, which lasted only 1 year, did not identify the optimal dose and dosing interval for zoledronate. It studied the effects of total zoledronate doses of 1 mg, 2 mg and 4 mg, administered at intervals including 3 months, 6 months and 12 months. 4 The zoledronate treatments produced effects on bone mineral density (BMD) and biochemical markers of bone turnover that were superior to placebo, were indistinguishable from one another and remained substantial after 1 year. These effects on surrogate markers for fracture suggest that smaller or less frequent doses of zoledronate than 5 mg annually may also have efficacy in preventing fractures.Evidence that less frequent administration of the currently recommended 5-mg dose of zoledronate might reduce fracture risk includes data from randomized clinical trials conducted in postmenopausal women, 5 older women in institutional care 6 and men with HIV infection, 7 which have indicated that 4-mg and 5-mg doses of zoledronate produce antiresorptive activity that persists for up to 5 years. A post hoc analysis of the zoledronate phase III trials reported similar reductions in fracture risk after 3 years in response to 3 annual administrations of 5 mg zoledronate and a single baseline administration of 5 mg. ABSTRACT BACKGROUND: Intravenous zoledronate 5 mg annually reduces fracture risk, and 5 mg every 2 years prevents bone loss, but the optimal dosing regimens for these indications are uncertain.