R. Wagman

The Effect of Three or Six Years of Denosumab Exposure in Women With Postmenopausal Osteoporosis: Results From the FREEDOM Extension

Context: The Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) extension is evaluating the long-term efficacy and safety of denosumab for up to 10 years. Objective: The objective of the study was to report results from the first 3 years of the extension, representing up to 6 years of denosumab exposure. Design, Setting, and Participants: This was a multicenter, international, open-label study of 4550 women. Intervention: Women from the FREEDOM denosumab group received 3 more years of denosumab for a total of 6 years (long-term) and women from the FREEDOM placebo group received 3 years of denosumab (crossover). Main Outcome Measures: Bone turnover markers (BTMs), bone mineral density (BMD), fracture, and safety data are reported. Results: Reductions in BTMs were maintained (long-term) or achieved rapidly (crossover) after denosumab administration. In the long-term group, BMD further increased for cumulative 6-year gains of 15.2% (lumbar spine) and 7.5% (total hip). During the first 3 years of denosumab treatment, the crossover group had significant gains in lumbar spine (9.4%) and total hip (4.8%) BMD, similar to the long-term group during the 3-year FREEDOM trial. In the long-term group, fracture incidences remained low and below the rates projected for a virtual placebo cohort. In the crossover group, 3-year incidences of new vertebral and nonvertebral fractures were similar to those of the FREEDOM denosumab group. Incidence rates of adverse events did not increase over time. Six participants had events of osteonecrosis of the jaw confirmed by adjudication. One participant had a fracture adjudicated as consistent with atypical femoral fracture. Conclusion: Denosumab treatment for 6 years remained well tolerated, maintained reduced bone turnover, and continued to increase BMD. Fracture incidence remained low.

A Randomized, Placebo-Controlled Study of the Effects of Denosumab for the Treatment of Men with Low Bone Mineral Density

CONTEXT Men with low bone mineral density (BMD) were treated with denosumab. OBJECTIVE Our objective was to investigate the effects of denosumab compared with placebo in men with low BMD after 1 yr of treatment. DESIGN, SUBJECTS, AND INTERVENTION This was a placebo-controlled, phase 3 study to investigate the efficacy and safety of denosumab 60 mg every 6 months vs. placebo in men with low BMD. MAIN OUTCOME MEASURE The primary endpoint was the percent change from baseline in lumbar spine (LS) BMD at month 12. RESULTS Of the 242 randomized subjects (mean age 65 yr), 228 (94.2%) completed 1 yr of denosumab therapy. After 12 months, denosumab resulted in BMD increases of 5.7% at the LS, 2.4% at the total hip, 2.1% at the femoral neck, 3.1% at the trochanter, and 0.6% at the one third radius (adjusted P ≤ 0.0144 for BMD percent differences at all sites compared with placebo). Sensitivity analyses done by controlling for baseline covariates (such as baseline testosterone levels, BMD T-scores, and 10-yr osteoporotic fracture risk) demonstrated that the results of the primary endpoint were robust. Subgroup analyses indicate that treatment with denosumab was effective across a spectrum of clinical situations. Treatment with denosumab significantly reduced serum CTX levels at d 15 (adjusted P < 0.0001). The incidence of adverse events was similar between groups. CONCLUSIONS One year of denosumab therapy in men with low BMD was well tolerated and resulted in a reduction in bone resorption and significant increases in BMD at all skeletal sites assessed.

10 years of denosumab treatment in postmenopausal women with osteoporosis: results from the phase 3 randomised FREEDOM trial and open-label extension

BACKGROUND Long-term safety and efficacy of osteoporosis treatment are important because of the chronic nature of the disease. We aimed to assess the long-term safety and efficacy of denosumab, which is widely used for the treatment of postmenopausal women with osteoporosis. METHODS In the multicentre, randomised, double-blind, placebo-controlled, phase 3 FREEDOM trial, postmenopausal women aged 60-90 years with osteoporosis were enrolled in 214 centres in North America, Europe, Latin America, and Australasia and were randomly assigned (1:1) to receive 60 mg subcutaneous denosumab or placebo every 6 months for 3 years. All participants who completed the FREEDOM trial without discontinuing treatment or missing more than one dose of investigational product were eligible to enrol in the open-label, 7-year extension, in which all participants received denosumab. The data represent up to 10 years of denosumab exposure for women who received 3 years of denosumab in FREEDOM and continued in the extension (long-term group), and up to 7 years for women who received 3 years of placebo and transitioned to denosumab in the extension (crossover group). The primary outcome was safety monitoring, comprising assessments of adverse event incidence and serious adverse event incidence, changes in safety laboratory analytes (ie, serum chemistry and haematology), and participant incidence of denosumab antibody formation. Secondary outcomes included new vertebral, hip, and non-vertebral fractures as well as bone mineral density (BMD) at the lumbar spine, total hip, femoral neck, and one-third radius. Analyses were done according to the randomised FREEDOM treatment assignments. All participants who received at least one dose of investigational product in FREEDOM or the extension were included in the combined safety analyses. All participants who enrolled in the extension with observed data were included in the efficacy analyses. The FREEDOM trial (NCT00089791) and its extension (NCT00523341) are both registered with ClinicalTrials.gov. FINDINGS Between Aug 3, 2004, and June 1, 2005, 7808 women were enrolled in the FREEDOM study. 5928 (76%) women were eligible for enrolment in the extension, and of these, 4550 (77%) were enrolled (2343 long-term, 2207 crossover) between Aug 7, 2007, and June 20, 2008. 2626 women (1343 long-term; 1283 crossover) completed the extension. The yearly exposure-adjusted participant incidence of adverse events for all individuals receiving denosumab decreased from 165·3 to 95·9 per 100 participant-years over the course of 10 years. Serious adverse event rates were generally stable over time, varying between 11·5 and 14·4 per 100 participant-years. One atypical femoral fracture occurred in each group during the extension. Seven cases of osteonecrosis of the jaw were reported in the long-term group and six cases in the crossover group. The yearly incidence of new vertebral fractures (ranging from 0·90% to 1·86%) and non-vertebral fractures (ranging from 0·84% to 2·55%) remained low during the extension, similar to rates observed in the denosumab group during the first three years of the FREEDOM study, and lower than rates projected for a virtual long-term placebo cohort. In the long-term group, BMD increased from FREEDOM baseline by 21·7% at the lumbar spine, 9·2% at total hip, 9·0% at femoral neck, and 2·7% at the one-third radius. In the crossover group, BMD increased from extension baseline by 16·5% at the lumbar spine, 7·4% at total hip, 7·1% at femoral neck, and 2·3% at one-third radius. INTERPRETATION Denosumab treatment for up to 10 years was associated with low rates of adverse events, low fracture incidence compared with that observed during the original trial, and continued increases in BMD without plateau. FUNDING Amgen.

Discontinuation of denosumab and associated fracture incidence: Analysis from the Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) Trial

Osteoporosis is a chronic disease and requires long‐term treatment with pharmacologic therapy to ensure sustained antifracture benefit. Denosumab reduced the risk for new vertebral, nonvertebral, and hip fractures over 36 months in the Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) trial. Whereas discontinuation of denosumab has been associated with transient increases in bone remodeling and declines in bone mineral density (BMD), the effect on fracture risk during treatment cessation is not as well characterized. To understand the fracture incidence between treatment groups after cessation of investigational product, we evaluated subjects in FREEDOM who discontinued treatment after receiving two to five doses of denosumab or placebo, and continued study participation for ≥7 months. The off‐treatment observation period for each individual subject began 7 months after the last dose and lasted until the end of the study. This subgroup of 797 subjects (470 placebo, 327 denosumab), who were evaluable during the off‐treatment period, showed similar baseline characteristics for age, prevalent fracture, and lumbar spine and total hip BMD T‐scores. During treatment, more placebo‐treated subjects as compared with denosumab‐treated subjects sustained a fracture and had significant decreases in BMD. During the off‐treatment period (median 0.8 years per subject), 42% versus 28% of placebo‐ and denosumab‐treated subjects, respectively, initiated other therapy. Following discontinuation, similar percentages of subjects in both groups sustained a new fracture (9% placebo, 7% denosumab), resulting in a fracture rate per 100 subject‐years of 13.5 for placebo and 9.7 for denosumab (hazard ratio [HR] 0.82; 95% confidence interval [CI], 0.49–1.38), adjusted for age and total hip BMD T‐score at baseline. There was no apparent difference in fracture occurrence pattern between the groups during the off‐treatment period. In summary, there does not appear to be an excess in fracture risk after treatment cessation with denosumab compared with placebo during the off‐treatment period for up to 24 months.

Sustained Modeling‐Based Bone Formation During Adulthood in Cynomolgus Monkeys May Contribute to Continuous BMD Gains With Denosumab

Denosumab (DMAb) administration to postmenopausal women with osteoporosis is associated with continued bone mineral density (BMD) increases and low fracture incidence through 8 years, despite persistently reduced bone turnover markers and limited fluorochrome labeling in iliac crest bone biopsies. BMD increases were hypothesized to result from additional accrual of bone matrix via modeling‐based bone formation—a hypothesis that was tested by examining fluorochrome labeling patterns in sections from ovariectomized (OVX) cynomolgus monkeys (cynos) treated with DMAb for 16 months. Mature OVX or Sham cynos were treated monthly with vehicle for 16 months, whereas other OVX cynos received monthly 25 or 50 mg/kg DMAb. DMAb groups exhibited very low serum bone resorption and formation biomarkers and near‐absent fluorochrome labeling in proximal femur cancellous bone. Despite these reductions, femoral neck dual‐energy X‐ray absorptiometry (DXA) BMD continued to rise in DMAb‐treated cynos, from a 4.6% increase at month 6 to 9.8% above baseline at month 16. Further examination of cortical bone in the proximal femur demonstrated consistent and prominent labeling on the superior endocortex and the inferior periosteal surface, typically containing multiple superimposed labels from month 6 to 16 over smooth cement lines, consistent with continuous modeling‐based bone formation. These findings were evident in all groups. Quantitative analysis at another modeling site, the ninth rib, demonstrated that DMAb did not alter the surface extent of modeling‐based labels, or the cortical area bound by them, relative to OVX controls, while significantly reducing remodeling‐based bone formation and eroded surface. This conservation of modeling‐based formation occurred concomitantly with increased femoral neck strength and, when coupled with a reduction in remodeling‐based bone loss, is likely to contribute to increases in bone mass with DMAb treatment. Thus, this study provides preclinical evidence for a potential mechanism that could contribute to the clinical observations of continued BMD increases and low fracture rates with long‐term DMAb administration.

Denosumab or Zoledronic Acid in Postmenopausal Women With Osteoporosis Previously Treated With Oral Bisphosphonates

Context: Denosumab and zoledronic acid (ZOL) are parenteral treatments for patients with osteoporosis. Objective: The objective of the study was to compare the effect of transitioning from oral bisphosphonates to denosumab or ZOL on bone mineral density (BMD) and bone turnover. Design and Setting: This was an international, multicenter, randomized, double-blind trial. Participants: A total of 643 postmenopausal women with osteoporosis previously treated with oral bisphosphonates participated in the study. Interventions: Subjects were randomized 1:1 to sc denosumab 60 mg every 6 months plus iv placebo once or ZOL 5 mg iv once plus sc placebo every 6 months for 12 months. Main Outcome Measures: Changes in BMD and bone turnover markers were measured. Results: BMD change from baseline at month 12 was significantly greater with denosumab compared with ZOL at the lumbar spine (primary end point; 3.2% vs 1.1%; P < .0001), total hip (1.9% vs 0.6%; P < .0001), femoral neck (1.2% vs −0.1%; P < .0001), and one-third radius (0.6% vs 0.0%; P < .05). The median decrease from baseline was greater with denosumab than ZOL for serum C-telopeptide of type 1 collagen at all time points after day 10 and for serum procollagen type 1 N-terminal propeptide at month 1 and at all time points after month 3 (all P < .05). Median percentage changes from baseline in serum intact PTH were significantly greater at months 3 and 9 with denosumab compared with ZOL (all P < .05). Adverse events were similar between groups. Three events consistent with the definition of atypical femoral fracture were observed (two denosumab and one ZOL). Conclusions: In postmenopausal women with osteoporosis previously treated with oral bisphosphonates, denosumab was associated with greater BMD increases at all measured skeletal sites and greater inhibition of bone remodeling compared with ZOL.

A 24-Month Study Evaluating the Efficacy and Safety of Denosumab for the Treatment of Men With Low Bone Mineral Density: Results From the ADAMO Trial

CONTEXT One in 4 men in the United States aged >50 years will have an osteoporosis-related fracture. Fewer data are available on osteoporosis treatment in men than in women. OBJECTIVE The purpose of this study was to evaluate denosumab therapy in men with low bone mineral density (BMD). DESIGN This was a phase 3 study with 2 treatment periods: a previously reported 12-month double-blind, placebo-controlled phase and a 12-month open-label phase. SETTING This was a multicenter study conducted in North America and Europe. PARTICIPANTS A total of 228 men entered the open-label phase and 219 completed the study. INTERVENTION Men from the original denosumab (long-term) and placebo (crossover) groups received 60 mg of denosumab sc every 6 months. MAIN OUTCOME MEASURES BMD, serum collagen type I C-telopeptide, and safety were measured. RESULTS During the open-label phase, continued BMD increases occurred with long-term denosumab treatment (2.2% lumbar spine, 0.9% total hip, 1.3% femoral neck, 1.3% trochanter, and 0.2% 1/3 radius), resulting in cumulative 24-month gains from baseline of 8.0%, 3.4%, 3.4%, 4.6%, and 0.7%, respectively (all P < .01). The crossover group showed BMD gains after 12 months of denosumab treatment similar to those of the long-term denosumab group during the first treatment year. Significant reductions in serum collagen type I C-teleopeptide were observed after denosumab administration. Adverse event rates were similar between groups, and no new safety signals were identified. CONCLUSIONS In men with low BMD, denosumab treatment for a second year continued to increase BMD, maintained reductions in bone resorption, and was well tolerated. BMD increased in men initiating denosumab during the second year. These effects were similar to those previously seen in postmenopausal women with osteoporosis and in men with prostate cancer receiving androgen deprivation therapy.

The development of denosumab for the treatment of diseases of bone loss and cancer‐induced bone destruction

Denosumab is a fully human monoclonal antibody against RANK ligand (RANKL), an essential cytokine for the formation, function, and survival of osteoclasts. The role of excessive RANKL as a contributor to conditions characterized by bone loss or bone destruction has been well studied. With its novel mechanism of action, denosumab offers a significant advance in the treatment of postmenopausal osteoporosis; bone loss associated with hormone ablation therapy in women with breast cancer and men with prostate cancer; and the prevention of skeletal‐related events in patients with bone metastases from solid tumors by offering clinical benefit to these patients in need.

Effects of Up to 5 Years of Denosumab Treatment on Bone Histology and Histomorphometry: The FREEDOM Study Extension

Denosumab reduced bone resorption, increased bone mineral density (BMD), and decreased new vertebral, hip, and nonvertebral fracture risk in postmenopausal women with osteoporosis in the FREEDOM trial. Consistent with its mechanism of action, transiliac crest bone biopsies from subjects treated with denosumab for 1 to 3 years demonstrated reduced bone turnover that was reversible upon treatment cessation. Long‐term denosumab treatment for up to 6 years in the FREEDOM extension provides sustained bone turnover reduction and continued low fracture incidence. Here, we evaluate 5 years of denosumab treatment on bone remodeling at the tissue level. Transiliac crest bone biopsies were obtained from 41 subjects (13 cross‐over and 28 long‐term from the FREEDOM placebo and denosumab groups, respectively) at year 2 of the FREEDOM extension, representing up to 5 years of denosumab treatment. Demographics for this subset were comparable to the overall extension cohort. The mean (SD) duration from the last denosumab dose to the first dose of tetracycline was 5.7 (0.5) months. Qualitative bone histology assessed in all biopsy samples was unremarkable, showing normally mineralized lamellar bone. Structural indices, including trabecular bone volume, number, and surface, were similar between cross‐over and long‐term groups. Bone resorption was decreased as reflected by eroded surface in cross‐over and long‐term subjects. A total of 11 of 13 (85%) cross‐over subjects and 20 of 28 (71%) long‐term subjects had specimens with double or single tetracycline label in trabecular and/or cortical compartments; specimens from 5 cross‐over subjects and 10 long‐term subjects were evaluable for dynamic trabecular bone parameters. Dynamic remodeling indices were low for both groups and consistent with reduced bone turnover with denosumab. In conclusion, denosumab treatment through 5 years resulted in normal bone quality with reduced bone turnover. These observations are consistent with its mechanism of action and associated with continued BMD increases and low fracture incidence.

Design and methods of a postmarketing pharmacoepidemiology study assessing long-term safety of Prolia ® (denosumab) for the treatment of postmenopausal osteoporosis ‡

To describe the rationale and methods for a prospective, open‐cohort study assessing the long‐term safety of Prolia® for treatment of postmenopausal osteoporosis (PMO) in postmarketing settings.