Effects of denosumab on bone mineral density in men receiving androgen deprivation therapy for prostate cancer

Role of osteoclast inhibitors in prostate cancer bone metastasis; a narrative review

OBJECTIVE

To study the role of Osteoclast inhibitors in advanced prostate cancer metastasis treatment and their efficacy in reducing skeletal related events.

METHODS: DATA SOURCE

A comprehensive search was done using search terms as "osteoclast inhibitors" "Bisphosphonates" "Zoledronic acid" " pamidronate" " Alendronate" "Denosumab" " Prostate cancer metastasis" in pubmed and Google scholar. Relevant articles were screened and collected . The collected articles were used to frame the review and data showing use of Osteoclast inhibitors In prostate cancer bone metastasis was collected.

DATA SUMMARY

Prostate cancer metastasizes most commonly to the skeleton thus leading to significant morbidity ranging from pain, pathological fractures to spinal cord compression and are the primary cause of patient disability and reduced quality of life.Initially, radiation therapy and radiopharmaceuticals were the mainstay of treatment however the role of Bisphosphonates and denosumab has become an integral part of therapy to manage metastatic prostate cancer. These agents significantly decrease skeletal related events and enhance patients quality of life. Emerging therapies like Radium-223 have also shown promise in reducing skeletal related events and also improving survival rates in patients with bone metastasis. Other treatment options which are being used are systemic agents like Docetaxel, cabazitaxel, hormonal therapies like abiraterone and enzalutamide. Immunotherapy with sipuleucel-T has demonstrated a reduction in mortality among prostate cancer patients with metastasis, highlighting the need for further research in this area. Ongoing studies are investigating novel agents that target both tumor cells and the bone microenvironment.

CONCLUSION

Osteoclast inhibitors are effective in reducing skeletal related events in advanced bone metastasis and improve the quality of life of patients.

Development of a Multidisciplinary Care Pathway for Fracture Prevention in Men with Prostate Cancer at Initiation of Androgen Deprivation Therapy

Fracture risk is increased in men with prostate cancer (PCa) receiving Androgen Deprivation Therapy (ADT). However, routine assessment of fracture risk is often not systematically applied. We aimed to establish a comprehensive care pathway for fracture prevention in men with PCa starting ADT. Therefore, a multidisciplinary working group designed and implemented a care pathway using the 'Knowledge to Action' framework, based on current Dutch guidelines for PCa, osteoporosis and fracture prevention, and an extensive literature review of other guidelines. The pathway was developed according to a five-step clinical approach including case finding, fracture risk assessment based on risk factors, bone mineral density test, vertebral fracture assessment, differential diagnosis, treatment, and annual follow-up. Our fracture prevention care pathway for patients with PCa at the time of ADT initiation was designed to promote a patient-centered, multidisciplinary approach to facilitate the implementation of early fracture prevention measures.

Testosterone recovery after androgen deprivation therapy in localised prostate cancer: Long-term data from two randomised trials

BACKGROUND AND PURPOSE

To determine the rate and time of testosterone (T) recovery in patients (pts) with localised prostate cancer treated with radiotherapy plus 0-, 6-, 18- or 36-month of androgen deprivation therapy (ADT).

MATERIALS AND METHODS

In 1230 pts with prostate cancer randomised into two phase III trials, serum T was measured at baseline, then regularly. T recovery rate was compared between normal vs. abnormal baseline T and with ADT duration with Chi-square test or Fisher's exact test. A multivariable logistic regression model to predict the probability of recovering normal T was performed.

RESULTS

Overall, 87.4 % (167/191), 75.9 % (293/386), 54.8 % (181/330) and 43.2 % (80/185) of pts, recovered normal T on the 0-, 6-, 18- or 36-month schedule, respectively (p < 0.001). In patients recovering normal T, the median time to T recovery increased with ADT duration ranging from 0.31, 1.64, 3.06 to 5.0 years for the 0-, 6-, 18- or 36-month schedules, respectively (p < 0.001) and was significantly faster for those with a normal T at baseline (p < 0.001). On multivariable analysis, older age and longer ADT duration are associated with a lower T recovery.

CONCLUSIONS

Testosterone recovery rate after ADT depends on several factors including hormonal duration, normal baseline T, age and medical comorbidities. A longer ADT duration is the most important variable affecting T recovery. The data from this report might be a valuable tool to help physicians and patients in evaluating risks and benefits of ADT.

Discontinuation of denosumab in men with prostate cancer

In patients with non-metastatic prostate cancer, treated with radiation therapy and androgen deprivation therapy for 3 years and DMAB on average for 5 years, BMD was in the normal or osteopenic range. Discontinuation of DMAB led to a bone loss of 2-5%. In men with osteopenia, the bone loss was prevented by zoledronate.

PURPOSE

Patients with prostate cancer receiving androgen deprivation therapy (ADT) are treated with denosumab (DMAB) to prevent fractures and preserve bone mass. We wanted to investigate the change in BMD in men with non-metastatic prostate cancer discontinuing DMAB.

METHODS

We conducted a retrospective cohort study based on medical records from patients referred to the Department of Endocrinology from the Department of Urology, Aarhus University Hospital between June 1, 2018, and June 1, 2021. We retrieved information on biochemistry and DXA performed 0-6 months after the last DMAB injection and a second DXA performed approximately 12 months after the first. In case of a BMD T-score ≤ - 1 at the lumbar spine or total hip at the first DXA, the patients were treated with zoledronate. The primary endpoint was change in lumbar spine BMD.

RESULTS

We included 50 patients with non-metastatic prostate cancer. The mean DMAB treatment duration was 5 ± 0.1 years. Among the patients treated with zoledronate (n = 9), BMD was maintained at the spine and femoral neck after a mean of 16 months. We found a significant decrease in BMD; - 4.9 ± 4.2%, - 1.9 ± 3.5%, and - 2.4 ± 3.6% at the spine, total hip, and femoral neck between the first and second DXA in the patients not treated with zoledronate (n = 24) (p ≤ 0.01 for all). One patient who did not receive ZOL sustained multiple fragility vertebral fractures after DMAB discontinuation.

CONCLUSION

In men with non-metastatic prostate cancer, discontinuation of DMAB after stopping ADT led to an average bone loss of 2-5%. Zoledronate prevented bone loss in men with osteopenia.

[Effect of different schemes of androgen deprivation therapy on bone mass density in prostate cancer patients]

OBJECTIVES

To evaluate the aspects of the basal bone health status in prostate cancer patients. Furthermore, to evaluate in a real-world setting the effect of different schemes (intermittent or continuous) of androgen deprivation therapy (ADT) and the effect of denosumab in bone mass density (BMD).

METHODS

Observational, retrospective study of a cohort of prostate cancer patients in treatment with luteinizing hormone-releasing hormone (LH-RH) agonists, evaluated in the rheumatology department of a tertiary center. Demographics, FRAX score, LH-RH treatment scheme, osteoporosis treatment, laboratory data and BMD were collected. Mixed effect regression models to analyze the interaction between LH-RH treatment scheme, denosumab and BMD evolution were used.

RESULTS

Eighty-three patients (mean age 71±8years) were included. At the basal evaluation, 16% of patients presented densitometric osteoporosis and 27% of patients presented high fracture risk. Eighty percent of patients had inadequate vitaminD levels. VitaminD >30ng/mL was correlated with higher T-scores. There was no association between LH-RH treatment scheme and BMD evolution, however there was a positive association with denosumab.

CONCLUSION

A high proportion of patients presented elevated fracture risk or inadequate vitaminD levels, not previously recognized. Bone health assessment and fracture risk evaluation are convenient in these patients. In a real-world setting, the effect of denosumab in BMD is detected, however the effect of intermittent LH-RH schema treatment is less evident.

Pharmacological Prevention and Management of Skeletal-Related Events and Bone Loss in Individuals with Cancer

OBJECTIVE

To provide a literature review of the clinical efficacy and safety data of various pharmacological agents used to manage bone health in people affected by cancer.

DATA SOURCES

Peer-reviewed articles and research publications identified from PubMed and relevant clinical guidelines were used in this evidence synthesis.

CONCLUSION

Individuals with cancers such as breast and prostate cancers, multiple myeloma, and other malignancies are at a high risk of developing skeletal-related events such as bone fracture, bone metastasis, and osteoporosis. Pharmacologic agents such as bisphosphonates and RANK-L inhibitor (denosumab) are the mainstay therapy options for managing bone health in this population.

IMPLICATIONS FOR NURSING PRACTICE

Nurses and nurse practitioners should be aware of the efficacy data of bisphosphonates and denosumab but also should be well-versed in the appropriate administration of these agents, potential side effect profiles, timely assessment, and interventions to optimize quality of life.

Cancer Treatment–Induced Bone Loss and Role of Denosumab in Nonmetastatic Prostate Cancer: A Narrative Review

Bone loss is an important complication of prostate cancer and its associated treatments, especially androgen-deprivation therapy (ADT). There is a 5 to 10 times increased loss of bone mineral density (BMD) in men receiving ADT with yearly 4 to 13% BMD loss. The risk of fracture increases yearly by 5 to 8% with ADT. ADT associated bone loss of 10 to 15% of BMD doubles the risk of fractures. Hence, BMD evaluation through dual-energy X-ray absorptiometry and evaluation of individual fracture risk assessed before initiating ADT. The use of vitamin D, calcium, bisphosphonates, and denosumab has shown improved bone health in men with prostate cancer receiving ADT. Denosumab 60 mg is approved to increase bone mass in men at high risk for fractures receiving ADT for nonmetastatic prostate cancer. Denosumab has shown improvement of 5.6% BMD at 2 years in nonmetastatic prostate cancer patients, with significant improvements seen at the total hip, femoral neck, and distal third of the radius. Denosumab has shown a 62% decreased incidence of new vertebral fractures at 36 months. Furthermore, denosumab delays the onset of bone metastases in high-risk nonmetastatic prostate cancer patients. Denosumab can be preferred over other bone modifying agents owing to several advantages, such as subcutaneous administration and no requirement of hospitalization, no dose modifications in renal impairment and less incidence of acute phase anaphylactic reactions. We review the available evidence of denosumab for managing bone loss in nonmetastatic prostate cancer patients. The relevant articles used in this narrative review were obtained through general search on google and PubMed using the key terms “non-metastatic prostate cancer,” “denosumab,” “bone loss,” “bone mineral density,” “fracture,” “CTIBL,” and “chemotherapy induced bone loss.”

Real-world incidence of symptomatic skeletal events and bone-modifying agent use in castration-resistant prostate cancer - an Australian multi-centre observational study

INTRODUCTION

Bone metastases occur frequently in castration-resistant prostate cancer (CRPC) and may lead to skeletal-related events (SREs), including symptomatic skeletal events (SSEs). Bone-modifying agents (BMAs) delay SREs and SSEs. However, the real-world use of BMAs is debated given the absence of demonstrated survival advantage and potential adverse events (AEs). Our retrospective study examined BMA use and SSE rates in Australian patients with CRPC.

METHODS

Patients with CRPC and bone metastases were identified from the electronic CRPC Australian Database. Patient characteristics, treatment patterns and AEs were analysed. Descriptive statistics reported baseline characteristics, SSE rates and BMA use. Comparisons between groups used t-tests and Chi-square analyses. Overall survival was calculated by the Kaplan-Meier method.

RESULTS

A total of 532 eligible patients were identified with a median age of 73 years (range: 44-97 years). BMAs were prescribed in 232 men (46%), 183 of whom received denosumab. Patients receiving first-line docetaxel for CRPC were more likely to commence BMAs than those receiving abiraterone or enzalutamide (51% vs 31% vs 38%; p = 0.004). SSEs occurred in 148 men (28%), most commonly symptomatic lesions requiring intervention (75%). At the time of initial SSEs, only 28% were receiving BMAs. Patients treated at sites with lower BMA use (<median) had higher SSE rates (32% vs 22%, p = 0.019).

CONCLUSION

In our real-world cohort, SSEs occurred in almost one-third of patients with CRPC and bone metastases, whereas less than half of patients received BMAs. The lower rate of SSEs in treatment sites with increased BMA use supports their benefit in this setting.

The comparative efficiency of denosumab treatment in patients with postmenopausal osteoporosis, primary hyperparathyroidism and glucocorticoid-induced osteoporosis in real clinical practice

Background: Denosumab is a highly effective and safe first-line treatment for osteoporosis. Primary hyperparathyroidism is a prevalent condition found in patients with osteoporosis. However, data regarding effectiveness of denosumab treatment in patients with PHPT are scarce.

Aims: To estimate the comparative effects of denosumab to treat postmenopausal osteoporosis (PMO) and osteoporosis caused by primary hyperparathyroidism (PHPT) or glucocorticoid-induced osteoporosis (GIOP) in postmenopausal women in routine clinical practice. Materials and methods: Retrospective study based on the medical card records. Patients over 50 years of age with verified osteoporosis (based on bone mineral density (BMD) T-score ≤ -2.5 SD and/or low-trauma fracture), who had at least 3 denosumab injections were included in the study.

Results: 162 patients were included and divided into three groups according to the etiology of osteoporosis. The first group consisted of postmenopausal women with osteoporosis (PMO) [(n=85); median age 70 [64;78]]. Patients with glucocorticoid-induced osteoporosis (GIOP) were enrolled in the second group [(n=16); male to female ratio =1:15; median age 60 [57,8; 66,3]]. The third group consisted of patients with PHPT and osteoporosis [(n=61); male to female=2:59; median age 68 [63; 75]]. Among all patients, denosumab treatment significantly increased BMD and decreased serum levels of calcium and CTx compared with baseline. PMO: the median increase in BMD according to the T-score was L1-L4 0,6 (p<0,001), femoral neck 0,2 (p<0,001); serum calcium -0,04 (p=0,004). PHPT: the median increase in BMD according to the T-score was L1-L4 0,6 (p<0,001), femoral neck 0,2 (p<0,001); radius 33% 0,25 (p=0,002), serum calcium -0,04 (p<0,001). In patients with GIOP, denosumab increased BMD in the lumbar spine L1-L4 0,5 (p=0,004). There was no difference in BMD increase or in levels of bone turnover suppression between the groups. A marked decline in levels of serum calcium was noted among patients with GFR less than 60 ml / min / 1.73 m2 (median Δ Са serum=0,24 p<0,001), compared to patients without CKD (median Δ Са serum=0,08 p<0,001).

Conclusion: Denosumab treatment is similarly effective for increasing BMD and decreasing bone turnover markers in patients with PMO and PHPT among postmenopausal women. The hypocalciemic effect of denosumab is most significant in subjects with PHPT.

Bisphosphonates or RANK-ligand-inhibitors for men with prostate cancer and bone metastases: a network meta-analysis

BACKGROUND

Different bone-modifying agents like bisphosphonates and receptor activator of nuclear factor-kappa B ligand (RANKL)-inhibitors are used as supportive treatment in men with prostate cancer and bone metastases to prevent skeletal-related events (SREs). SREs such as pathologic fractures, spinal cord compression, surgery and radiotherapy to the bone, and hypercalcemia lead to morbidity, a poor performance status, and impaired quality of life. Efficacy and acceptability of the bone-targeted therapy is therefore of high relevance. Until now recommendations in guidelines on which bone-modifying agents should be used are rare and inconsistent.

OBJECTIVES

To assess the effects of bisphosphonates and RANKL-inhibitors as supportive treatment for prostate cancer patients with bone metastases and to generate a clinically meaningful treatment ranking according to their safety and efficacy using network meta-analysis.

SEARCH METHODS

We identified studies by electronically searching the bibliographic databases Cochrane Controlled Register of Trials (CENTRAL), MEDLINE, and Embase until 23 March 2020. We searched the Cochrane Library and various trial registries and screened abstracts of conference proceedings and reference lists of identified trials.

SELECTION CRITERIA

We included randomized controlled trials comparing different bisphosphonates and RANKL-inihibitors with each other or against no further treatment or placebo for men with prostate cancer and bone metastases. We included men with castration-restrictive and castration-sensitive prostate cancer and conducted subgroup analyses according to this criteria.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of trials. We defined proportion of participants with pain response and the adverse events renal impairment and osteonecrosis of the jaw (ONJ) as the primary outcomes. Secondary outcomes were SREs in total and each separately (see above), mortality, quality of life, and further adverse events such as grade 3 to 4 adverse events, hypocalcemia, fatigue, diarrhea, and nausea. We conducted network meta-analysis and generated treatment rankings for all outcomes, except quality of life due to insufficient reporting on this outcome. We compiled ranking plots to compare single outcomes of efficacy against outcomes of acceptability of the bone-modifying agents. We assessed the certainty of the evidence for the main outcomes using the GRADE approach.

MAIN RESULTS

Twenty-five trials fulfilled our inclusion criteria. Twenty-one trials could be considered in the quantitative analysis, of which six bisphosphonates (zoledronic acid, risedronate, pamidronate, alendronate, etidronate, or clodronate) were compared with each other, the RANKL-inhibitor denosumab, or no treatment/placebo. By conducting network meta-analysis we were able to compare all of these reported agents directly and/or indirectly within the network for each outcome. In the abstract only the comparisons of zoledronic acid and denosumab against the main comparator (no treatment/placebo) are described for outcomes that were predefined as most relevant and that also appear in the 'Summary of findings' table. Other results, as well as results of subgroup analyses regarding castration status of participants, are displayed in the Results section of the full text. Treatment with zoledronic acid probably neither reduces nor increases the proportion of participants with pain response when compared to no treatment/placebo (risk ratio (RR) 1.46, 95% confidence interval (CI) 0.93 to 2.32; per 1000 participants 121 more (19 less to 349 more); moderate-certainty evidence; network based on 4 trials including 1013 participants). For this outcome none of the trials reported results for the comparison with denosumab. The adverse event renal impairment probably occurs more often when treated with zoledronic acid compared to treatment/placebo (RR 1.63, 95% CI 1.08 to 2.45; per 1000 participants 78 more (10 more to 180 more); moderate-certainty evidence; network based on 6 trials including 1769 participants). Results for denosumab could not be included for this outcome, since zero events cannot be considered in the network meta-analysis, therefore it does not appear in the ranking. Treatment with denosumab results in increased occurrence of the adverse event ONJ (RR 3.45, 95% CI 1.06 to 11.24; per 1000 participants 30 more (1 more to 125 more); high-certainty evidence; 4 trials, 3006 participants) compared to no treatment/placebo. When comparing zoledronic acid to no treatment/placebo, the confidence intervals include the possibility of benefit or harm, therefore treatment with zoledronic acid probably neither reduces nor increases ONJ (RR 1.88, 95% CI 0.73 to 4.87; per 1000 participants 11 more (3 less to 47 more); moderate-certainty evidence; network based on 4 trials including 3006 participants). Compared to no treatment/placebo, treatment with zoledronic acid (RR 0.84, 95% CI 0.72 to 0.97) and denosumab (RR 0.72, 95% CI 0.54 to 0.96) may result in a reduction of the total number of SREs (per 1000 participants 75 fewer (131 fewer to 14 fewer) and 131 fewer (215 fewer to 19 fewer); both low-certainty evidence; 12 trials, 5240 participants). Treatment with zoledronic acid and denosumab likely neither reduces nor increases mortality when compared to no treatment/placebo (zoledronic acid RR 0.90, 95% CI 0.80 to 1.01; per 1000 participants 48 fewer (97 fewer to 5 more); denosumab RR 0.93, 95% CI 0.77 to 1.11; per 1000 participants 34 fewer (111 fewer to 54 more); both moderate-certainty evidence; 13 trials, 5494 participants). Due to insufficient reporting, no network meta-analysis was possible for the outcome quality of life. One study with 1904 participants comparing zoledronic acid and denosumab showed that more zoledronic acid-treated participants than denosumab-treated participants experienced a greater than or equal to five-point decrease in Functional Assessment of Cancer Therapy-General total scores over a range of 18 months (average relative difference = 6.8%, range -9.4% to 14.6%) or worsening of cancer-related quality of life.

AUTHORS' CONCLUSIONS

When considering bone-modifying agents as supportive treatment, one has to balance between efficacy and acceptability. Results suggest that Zoledronic acid likely increases both the proportion of participants with pain response, and the proportion of participants experiencing adverse events However, more trials with head-to-head comparisons including all potential agents are needed to draw the whole picture and proof the results of this analysis.

The skeletal impact of cancer therapies

Both cancer and therapies used in the treatment of cancer can have significant deleterious effects on the skeleton, increasing the risks for both bone loss and fracture development. While advancements in cancer therapies have resulted in enhanced cancer survivorship for patients with many types of malignancies, it is increasingly recognized that efforts to reduce bone loss and limit fractures must be considered for nearly all patients undergoing cancer therapy in order to diminish the anticipated future skeletal consequences. To date, most studies examining the impact of cancer therapies on skeletal outcomes have focused on endocrine-associated cancers of the breast and prostate, with more recent advances in our understanding of bone loss and fracture risk in other malignancies. Pharmacologic efforts to limit the adverse effects of cancer therapies on bone have nearly universally employed anti-resorptive approaches, although studies have frequently relied on surrogate outcomes such as changes in bone mineral density or bone turnover markers, rather than on fractures or other skeletal-related events, as primary study endpoints. Compounding current deficiencies for the provision of optimal care is the recognition that despite clearly written and straightforward society-based guidelines, vulnerable eligible patients are very often neither identified nor provided with appropriate treatments to limit the skeletal impact of their cancer therapies.

The Current Role of Osteoclast Inhibitors in Patients with Prostate Cancer

Purpose

Prostate cancer (PCa) is one of the most frequently diagnosed malignancies worldwide. Hormonal deprivation therapy is a well-established treatment for locally advanced or metastatic diseases but exposes patients to the risk of osteoporosis and fragility fractures. Furthermore, the tropism of the PCa cells to osseous metastases increases the incidence of skeletal-related events (SREs).

Methods

A nonsystematic review of the international literature was performed in respect to the use of osteoclast inhibitors zoledronic acid (ZA) and denosumab (DEN) in PCa patients.

Results

DEN and ZA have proved their efficacy in preventing osteoporosis and bone mass loss in patients treated with hormonal therapy with no proven superiority of one agent over the other. However, the effectiveness in reducing fragility fractures has been proved only for DEN so far. In metastatic-free castrate-sensitive high-risk PCa patients, ZA has not shown any efficacy in preventing osseous metastasis, and evidence is lacking in favor or against the use of DEN. The use of osteoclasts inhibitors had no evident positive effect in overall and disease-specific survival in this group of patients. In advanced castrate-refractory malignancy, DEN has shown clinical superiority over ZA in preventing new SRE but not in overall survival.

Conclusion

Superiority of DEN over ZA has been proved only in advanced castrate refractory disease in terms of preventing new SRE. In the rest of the cases, the selection of either agent should be based on the clinical condition of each patient and the cost of the treatment.

Harnessing the potential of therapeutic agents to safeguard bone health in prostate cancer

Background

Patients with prostate cancer are at risk of impaired bone health. Prostate cancer has a propensity to metastasize to bone, after which patients are at risk of skeletal-related events (SREs). These complications are associated with increased mortality, substantial pain, and reduced quality of life. Patients are also at risk of bone loss due to androgen deprivation therapy (ADT), which can be compounded in elderly patients with reduced bone density. It is essential, therefore, that aspects of bone health and therapies able to prevent the occurrence of SREs are considered throughout the clinical course of prostate cancer.

Methods

We reviewed the literature regarding the molecular mechanisms underpinning bone lesion formation, the modes of action of therapies that prevent SREs, and the efficacy and safety of these therapies in patients with hormone-sensitive or castration-resistant prostate cancer (CRPC).

Results

Therapies such as denosumab (a RANKL inhibitor) and zoledronic acid (a bisphosphonate) were indicated for prevention of SREs. Radium-223 dichloride also has proven efficacy in delaying symptomatic SREs, as well as in improving overall survival through effects on bone metastases. Before development of bone metastases, low-dose denosumab may also be used for treatment of ADT-associated bone loss. Denosumab may also have the potential to delay bone metastases development in patients with CRPC, although this is not currently an approved indication. The safety profile of therapies to prevent SREs should be considered. This review consolidates the available evidence on use of denosumab and bisphosphonates in prostate cancer, differentiated by hormone-sensitive and castration-resistant disease.

Conclusions

There is convincing evidence to support the use of denosumab and bisphosphonates to maintain bone health in patients with prostate cancer. Clinicians should be mindful of the adverse event risk profile of these therapies.

Pharmacokinetics, pharmacodynamics, safety, and tolerability of single-dose denosumab in healthy Chinese volunteers: A randomized, single-blind, placebo-controlled study

Background

Denosumab is a fully human monoclonal antibody against receptor activator of nuclear factor kappa-B ligand, a cytokine essential for the formation, function and survival of osteoclasts. This study assessed the pharmacokinetics, pharmacodynamics, safety and tolerability of single-dose denosumab (60 and 120 mg) in healthy Chinese volunteers.

Methods

This randomized (3:3:2), single-blind, placebo-controlled study enrolled healthy Chinese volunteers to receive single subcutaneous injection of denosumab 60 mg, 120 mg, or placebo. Study consisted of screening period (up to 21 days), treatment and assessment period (19 weeks), and an end-of-study visit (at week 26). Denosumab pharmacokinetics and pharmacodynamics parameters were estimated using non-compartmental analysis. Safety and tolerability were assessed throughout the study.

Results

A total of 63 volunteers received the study treatment and 62 (98.4%) completed the study. Denosumab serum concentrations peaked at around Day 10 with dose-proportional increase from 60 mg to 120 mg. The mean terminal half-life of denosumab 60 mg and 120 mg was 15 days and 26 days, respectively. The serum C-terminal cross-linking telopeptide of type I collagen concentration-time profiles were similar (>80% decrease within 5 days) between denosumab 60 mg and 120 mg groups. The most commonly reported adverse event (AE) was decreased blood calcium levels (denosumab 60 mg, n = 13; denosumab 120 mg, n = 13; placebo, n = 1); however only one volunteer had calcium level below the abnormality value of potential clinical importance and none of the volunteers developed symptoms of hypocalcemia. The majority of AEs were of mild to moderate intensity. There were no deaths, serious AEs, or withdrawal from study due to AEs. No clinically significant findings in vital signs or electrocardiogram were observed.

Conclusions

Both denosumab 60 mg and 120 mg were well tolerated with no new safety concerns identified in healthy Chinese volunteers with similar pharmacokinetics and pharmacodynamics profiles to that of Caucasians.

Trial registration

ClinicalTrial.gov NCT02135640

Cancer Treatment and Bone Health

Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies.

223Ra α-Therapy in Patients with Bone Metastases from Castration-resistant Prostate Cancer

In developed countries such as Canada, the lifetime risk of prostate cancer is about one in six, with a 30% chance of relapse with bone metastases in each case. Bone involvement not only decreases prognosis, but also increases the likelihood of many other medical ailments. There currently exist numerous treatment options for pain palliation for these patients. Common options include chemotherapy, external beam radiotherapy, bisphosphonates, and radionuclide therapy with strontium 89. Each variation, however, shows clear drawbacks. A type of radionuclide therapy, newly approved in Canada, using alpha particles from radium 223 is showing promise. Unlike the previously mentioned therapies, radium 223 is the only one that excels in all desirable aspects for palliation therapy. Radium 223 not only decreases or eliminates metastases-related bone pain, but also has a great safety profile, increases the average length of survival, and exhibits areas of cost-effectiveness. Radium 223 also delays skeletal-related events and prostate-specific antigen elevation, representing a noteworthy breakthrough for bone-targeted radionuclide therapies.

Antiresorptive therapy in the management of cancer treatment-induced bone loss

Cancer treatment-induced bone loss treatment has an important role to prevent bone loss-related events like fracture, significant morbidity, mortality, disfigurement and loss of self-esteem, and health-care expenditure. Numerous factors, including treatment regimens and bone metastasis, increase the risk of osteoporosis or local bone destruction in most breast and prostate cancer patients. Cytotoxic chemotherapies, radiation, and hormonal therapies can lead to premature menopause and decrease bone mineral density. Over 60 % of breast cancer patients within 1 year of beginning postoperative adjuvant chemotherapy experience ovarian failure. Also, ovarian ablation and aromatase inhibitors used to treat breast cancer and orchiectomy and androgen deprivation therapy (ADT; to treat prostate cancer) cause substantial bone loss. In this article, we will focus mainly on antiresorptive therapy in the management of cancer treatment-induced bone loss (CTIBL). An understanding of CTIBL is critical for determining how to assess the risk and identify which patients may benefit from preventive therapy.

Beyond peptides and mAbs--current status and future perspectives for biotherapeutics with novel constructs

Biotherapeutics are attractive anti-cancer agents due to their high specificity and limited toxicity compared to conventional small molecules. Antibodies are widely used in cancer therapy, either directly or conjugated to a cytotoxic payload. Peptide therapies, though not as prevalent, have been utilized in hormonal therapy and imaging. The limitations associated with unmodified forms of both types of biotherapeutics have led to the design and development of novel structures, which incorporate key features and structures that have improved the molecules' abilities to bind to tumor targets, avoid degradation, and exhibit favorable pharmacokinetics. In this review, we highlight the current status of monoclonal antibodies and peptides, and provide a perspective on the future of biotherapeutics using novel constructs.

Systemic therapy for the treatment of hormone-sensitive metastatic prostate cancer: from intermittent androgen deprivation therapy to chemotherapy

Treatment of advanced prostate cancer has changed considerably in recent years, but the vast majority of advances have been made in patients with metastatic castration-resistant disease. There have been relatively fewer advances in the earlier, hormonally responsive stage of metastatic disease. Since the empiric establishment of androgen deprivation therapy as first-line therapy for metastatic prostate cancer decades ago, there have been multiple studies looking at variations of suppressing testosterone, but the overall paradigm has not been strongly challenged until more recently. In particular, the dramatic results reported by the CHAARTED trial not only bring chemotherapy to an arena historically dominated solely by hormonal therapy but also stimulate renewed efforts into improving upon our management of metastatic hormone-sensitive prostate cancer.

Bisphosphonates for osteoporosis in nonmetastatic prostate cancer patients receiving androgen-deprivation therapy: a systematic review and meta-analysis

This systematic review was conducted to assess the efficacy and safety of bisphosphonates for prevention and treatment of osteopenia or osteoporosis in men with non-metastatic prostate cancer receiving androgen- deprivation therapy. We searched for randomised controlled trials (RCTs) of bisphosphonates compared with placebo from Pubmed, Embase, the Cochrane Library, and ISI - Science Citation Index. Meta-analyses of pre- specified outcomes (bone mineral density, fractures, and adverse events) were performed using Review Manager. Ten RCTs with a total patient population of 1,017 were identified. There was generally more improvement in bone mineral density of the lumbar spine for patients who received bisphosphonate treatment than placebo or other medical treatment at 12 months (WMD 6.02,95%CI 5.39 to 6.65). Similar effects were also observed for total hip, trochanter or femoral neck bone mineral density. However, there was no significant reduction in fractures. Fever and gastrointestinal symptoms were the most common adverse events (10.4% vs. 1.2%; 0.10% vs. 0.03%). Currently, our meta-analysis suggested that oral and intravenous bisphosphonates caused a rapid increase in spine and hip or femoral BMD in non-metastatic prostate cancer patients receiving androgen-deprivation therapy. Fever and gastrointestinal symptoms were common with the use of bisphosphonates. These short-term trials (maximum of 12 months) did not show fracture reduction. In future, more efficient performance of higher quality, more rigorous, large sample, long-term randomised controlled trials (>12 months) are needed where outcomes are detailed.

Bone targeted therapies for the prevention of skeletal morbidity in men with prostate cancer

Men with prostate cancer suffer substantially from bone-related complications. Androgen deprivation therapy itself is a cause of loss of bone mineral density and is associated with an increased incidence of osteoporotic fractures. In advanced disease, bone is by far the most common site of metastasis. Complications of bone metastases prominently include pain and the potential for skeletal events such as spinal cord compression and pathologic fractures. Elevated osteoclast activity is an important aspect of the pathophysiology of both treatment-related osteoporosis and skeletal complications due to metastases. The osteoclast is therefore a therapeutic target. Denosumab is a fully human monoclonal antibody to receptor activator of nuclear factor-κ-B ligand that was designed to potently inhibit osteoclast activity and is the central focus of this review. Bisphosphonates, radiopharmaceuticals and systemically-active hormonal agents such as abiraterone acetate and enzalutamide have each been shown to improve skeletal morbidity in specific clinical situations. Denosumab is the only agent that has been shown to prevent osteoporotic fractures in men receiving androgen deprivation therapy and at elevated risk for fracture. It has also demonstrated superiority to the potent bisphosphonate zoledronic acid for the prevention of skeletal-related events in men with castration-resistant prostate cancer metastatic to bone. Efficacy and toxicity data will be discussed.

Medication-induced osteoporosis: screening and treatment strategies

Drug-induced osteoporosis is a significant health problem and many physicians are unaware that many commonly prescribed medications contribute to significant bone loss and fractures. In addition to glucocorticoids, proton pump inhibitors, selective serotonin receptor inhibitors, thiazolidinediones, anticonvulsants, medroxyprogesterone acetate, aromatase inhibitors, androgen deprivation therapy, heparin, calcineurin inhibitors, and some chemotherapies have deleterious effects on bone health. Furthermore, many patients are treated with combinations of these medications, possibly compounding the harmful effects of these drugs. Increasing physician awareness of these side effects will allow for monitoring of bone health and therapeutic interventions to prevent or treat drug-induced osteoporosis.

Muscle and bone effects of androgen deprivation therapy: current and emerging therapies

Prostate cancer and treatment with androgen deprivation therapy (ADT) affect significant numbers of the male population. Endocrine effects of ADT are a critical consideration in balancing the benefits and risks of treatment on long-term survival and quality of life. This review highlights the latest advances in androgen manipulation in prostate cancer with an emphasis on the effects of ADT on muscle and bone, which universally affects the health and well-being of men undergoing ADT for prostate cancer. Muscle mass declines with ADT; however, the evidence that this correlates with a decrease in muscle strength or a decrease in physical performance is discordant. Cortical bone decay also occurs in association with an increase in fracture risk, hence optimization of musculoskeletal health in men undergoing ADT is crucial. The role of exercise, and current and emerging anabolic therapies for muscle as well as various new strategies to prevent loss of bone mass in men undergoing ADT are discussed. Future well-designed, prospective, controlled studies are required to elucidate the effects of ADT on physical performance, which are currently lacking, and larger randomized controlled trials are required to test the efficacy of medical therapies and exercise interventions to target proven deficits and to ensure safety in men with prostate cancer.

Contemporary pharmacotherapy for the prevention of skeletal complications in patients with prostate cancer

INTRODUCTION

Bones represent the most common metastatic sites in prostate cancer (PCa) patients, and in addition with androgen deprivation therapy, they represent the causative reasons of bone mineral density loss and the onset of skeletal-related events.

AREAS COVERED

An extensive search of PubMed/Medline was performed to identify randomized, Phase II/III controlled trials reporting results regarding the prevention of skeletal morbidity in patients with PCa.

EXPERT OPINION

Preventing bone health is an imperative issue for preserving quality of life and elongate survival and, thus, a concerted effort should be made to monitor skeletal changes and to apply treatment for preventing bone loss. Although several agents have received approval for routine use, it is of paramount importance to identify the appropriate patients who would mostly be benefited by the use of these agents with attention to documenting the toxicity and economic implications. Additionally, it remains to be justified the frequency of administration in order to balance the efficacy and the potential complications.

Targeting receptor-activator of nuclear kappaB ligand in aneurysmal bone cysts: verification of target and therapeutic response

Aneurysmal bone cyst (ABC) is a benign tumor of bone presenting as a cystic, expansile lesion in both the axial and appendicular skeleton. Axial lesions demand special consideration, because treatment-related morbidity can be devastating. In similar lesions, such as giant cell tumor of bone (GCTB), the receptor-activator of nuclear kappaB ligand (RANKL)-receptor-activator of nuclear kappaB (RANK) signaling axis is essential to tumor progression. Although ABC and GCTB are distinct entities, they both contain abundant multinucleated giant cells and are osteolytic characteristically. We hypothesize that ABCs express both RANKL and RANK similarly in a cell-type specific manner, and that targeted RANKL therapy will mitigate ABC tumor progression. Cellular expression of RANKL and RANK was determined in freshly harvested ABC samples using laser confocal microscopy. A consistent cell-type-specific pattern was observed: fibroblastlike stromal cells expressed RANKL strongly whereas monocyte/macrophage precursor and multinucleated giant cells expressed RANK. Relative RANKL expression was determined by quantitative real-time polymerase chain reaction in ABC and GCTB tissue samples; no difference in relative expression was observed (P > 0.05). In addition, we review the case of a 5-year-old boy with a large, aggressive sacral ABC. After 3 months of targeted RANKL inhibition with denosumab, magnetic resonance imaging demonstrated tumor shrinkage, bone reconstitution, and healing of a pathologic fracture. Ambulation, and bowel and bladder function were restored at 6 months. Denosumab treatment was well tolerated. Post hoc analysis demonstrated strong RANKL expression in the pretreatment tumor sample. These findings demonstrate that RANKL-RANK signal activation is essential to ABC tumor progression. RANKL-targeted therapy may be an effective alternative to surgery in select ABC presentations.

Androgen deprivation therapy for prostate cancer: long-term safety and patient outcomes

Androgen deprivation therapy (ADT) constitutes the first-line treatment for patients with locally advanced tumors, recurrent or metastatic disease. Given its widespread use, clinicians should be familiar with common side effects of this treatment. This review focuses on common side effects of ADT and available treatment options to control the side effects. Also, it briefly compares continuous ADT with other therapeutic approaches for androgen deprivation in prostate cancer patients. Similar to hormonal medications, newer non-hormonal therapeutic options including gabapentin and acupuncture have at best moderate effect in controlling hot flashes in patients on ADT. Supervised and/or home exercise programs significantly improve ADT-related fatigue, metabolic/cardiovascular side effects, and cognitive dysfunction. Denosumab, a human monoclonal antibody against RANK-L, is more effective than bisphosphonates in preventing skeletal-related events in patients with metastatic or castrate-resistant prostate cancer and unlike bisphosphonates, it can also reduce the risk of vertebral fractures in men receiving ADT for non-metastatic prostate cancer. Toremifene, a selective estrogen receptor inhibitor, has dual beneficial effects on ADT-related osteoporosis and metabolic dysfunction. Metformin coupled with lifestyle modification is also a well-tolerated treatment for metabolic changes during ADT. While producing similar oncological outcomes, intermittent ADT is associated with higher quality of life in patients under ADT by improving bone health, less metabolic and hematologic complications, and fewer hot flashes and sexual dysfunction events.

Palliative Oncology

Bone metastases cause devastating clinical complications leading patients to have pain, poor quality of life, loss of mobility, and autonomy. Complications from osseous metastases cause a big economic burden reflected by repeated admissions for uncontrolled symptoms. Management of symptoms associated with bone metastasis includes systemic analgesics, glucocorticoids, radiation (external beam radiation and radiopharmaceuticals), ablative techniques (radiofrequency ablation and cryoablation), chemotherapeutic agents, hormonal therapies, interventional techniques (eg, kyphoplasty), and surgical approaches. Bisphosphonates have become a standard therapy for bony metastasis. They bind to bone eventually inhibiting osteoclast action. Bisphosphonates decrease fractures when given routinely. Adverse effects of bisphosphonates include osteonecrosis of the jaw and renal insufficiency. Late last year, the Food and Drug Administration approved denosumab to prevent skeletal-related events (SREs) associated with metastatic solid tumors. This drug is a monoclonal antibody that inhibits the receptor activator of nuclear factor κB (RANK)–RANK ligand interaction. Clinical trials have shown superiority over bisphosphonates for the prevention of SREs. This article reviews the mechanism of action, pharmacology, adverse effects, and clinical trial evidence for this new drug.

Bone health care for patients with prostate cancer receiving androgen deprivation therapy

Patients with prostate cancer often receive androgen deprivation therapy (ADT) as part of their treatment regimen. However, treatment with ADT causes multiple side effects, including reduced bone mineral density (BMD), lower lean body mass, and a higher risk for fractures. Several organizations provide clinical practice guidelines for osteoporosis screening, prevention, and treatment in this population, but adherence to these guidelines remains low. Areas for improvement in provider adherence include baseline and follow-up BMD testing, as well as counseling regarding healthy bone behaviors such as calcium/vitamin D intake, lifestyle changes, and physical exercise. Comparison of osteoporosis care in breast cancer and non-oncology populations shows that suboptimal bone health care is not isolated to prostate cancer. A summary of the literature examining improvements in patient adherence and provider delivery of bone health care is included in this review, but high-quality studies are lacking. Patients may be the most receptive to written educational information delivered at or near the time of ADT initiation. Involvement of a primary care practitioner and oncologist in care delivery is associated with higher BMD test use. Institution-level programs that automatically initiate osteoporosis screening and management may be effective at reducing the incidence of hip fracture. Lastly, suggestions are provided for future approaches to knowledge translation and quality of care studies to improve bone health.

Managing bone metastases and reducing skeletal related events in prostate cancer

Advanced-stage prostate cancer is associated with skeletal complications related to metastatic disease and its treatment. On the one hand, metastatic disease to bone is commonly associated with skeletal-related events (SREs); on the other hand, treatment with androgen-deprivation therapy (ADT) leads to loss in bone mineral density (BMD) and increased risk of fracture. Despite osteoblastic appearance on radiography, bone metastases from prostate cancer are associated with increased osteoblast and osteoclast activity providing the rationale for treatment with osteoclast-targeted agents. The bisphosphonate zoledronic acid and the monoclonal antibody denosumab reduce the incidence of SREs in metastatic castration-resistant prostate cancer (mCRPC). A number of agents prevent loss of BMD associated with ADT, but only denosumab is approved to reduce fractures in patients with non-metastatic prostate cancer. Another recently approved agent-radium-223-improves survival and delays SREs in mCRPC. The inhibitors of androgen receptor signalling, abiraterone and enzalutamide, improve survival in mCRPC and delay SREs, although the latter is likely related to control of disease rather than a direct effect on bone. Finally, the tyrosine kinase inhibitor cabozantinib shows promising activity in bone metastases from mCRPC. This Review addresses the skeletal morbidity associated with prostate cancer and the therapeutic options that exist to treat it.

Future of bisphosphonates and denosumab for men with advanced prostate cancer

Prostate cancer is the most common cancer occurring in American men of all races. It is also the second leading cause of cancer death among men in the USA. Bone metastasis is a frequent occurrence in men with advanced prostate cancer, with skeletal-related events being a common complication and having negative consequences, leading to severe pain, increased health care costs, increased risk of death, and decreased quality of life for patients. Bone loss can also result from antiandrogen therapy, which can further contribute to skeletal-related events. Treatment with antiresorptive agents bisphosphonates, and the newly approved denosumab, a receptor activator of nuclear factor kappa-B ligand (RANK-L) inhibitor, has been shown to reduce the risk of skeletal-related complications and prevent treatment-induced bone loss in patients with advanced prostate cancer. This review discusses the role of antiresorptive agents bisphosphonates and RANK-L inhibitor in the current treatment of advanced prostate cancer by examining the primary literature and also focuses on the likely role of the bisphosphonates in the treatment of advanced prostate cancer in the future.

Current treatments and novel therapeutic targets for castration resistant prostate cancer with bone metastasis

Prostate cancer is a leading cause of cancer death in men in developed countries. While early stage disease can often be cured, many patients eventually develop castration resistant prostate cancer (CRPC). The majority of CRPC patients have bone metastases, which cause significant morbidity and mortality. Although there is no cure for prostate cancer metastatic to bone, several bone-targeted agents have been approved to prevent skeletal-related events (SREs). Among them, bisphosphonates were the first class of drugs investigated for prevention of SREs. Denosumab is a recently approved agent that binds to the receptor activator of nuclear factor-κB ligand (RANKL) as a humanized monoclonal antibody. Both agents target prostate cancer skeletal metastasis through the inhibition of bone resorption. Alpharadin is the first radiopharmaceutical agent that has significant overall survival benefit. It has benefits in pain palliation and SREs as well. Another newly approved drug is Abiraterone acetate, which decreases circulating levels of testosterone by targeting an enzyme expressed in the testis and the adrenal, as well as in prostate cancer tissues. This review outlines the clinical and preclinical data supporting the use of these and new agents in development for CRPC with bone metastasis.

A new antiresorptive approach to the treatment of fragility fractures: long-term efficacy and safety of denosumab

An imbalance of the remodeling process for bone resorption leads to a loss of tissue with consequent microarchitectural damage, evident in conditions such as osteoporosis and related fragility fractures. Currently, pharmacological therapies are able to prevent or slow down bone resorption by inhibiting osteoclast activity. An innovative and targeted anti-resorptive approach is represented by the inhibition of RANK ligand (RANK-L), essential for the proliferation and activity of osteoclastic cells. The human monoclonal antibody against RANK-L (denosumab) has been approved for the treatment of osteoporosis. In clinical trials of patients with osteoporosis, inhibition of RANK-L has reduced bone loss and damage to the microarchitecture and was associated with an increase in mass and resistance at different skeletal sites, with most significant effects than those demonstrated by any other antiresorptive drugs. In addition, after 3 years of treatment, it showed a reduction in vertebral and non-vertebral fracture risk. Denosumab treatment also has not revealed any alteration in the physiological processes of fracture repair, showing no increase in the onset of complications 3 years after the fracture. The data show that denosumab offers an effective alternative therapeutic approach for the treatment of severe osteoporosis, with positive effects on BMD and reduction of fragility fractures risk. So, promising results in terms of therapeutic efficacy and reliability make desirable the wide clinical use of denosumab for the treatment of osteoporotic fractures in the near future.

Prostate cancer and osteoporosis

Adenocarcinoma of the prostate is one of the commonest cancers in the world. Due to a combination of earlier detection and better treatments, survival has increased dramatically. Prostate cancer itself is associated with lower bone density and increased fractures. This is compounded by the use of androgen deprivation therapy, which causes dramatic falls in circulating testosterone and estrogen, resulting in rapid falls in bone density, decreased muscle mass, and increased fracture rates. Bisphosphonates have been demonstrated to prevent and reverse this bone loss, but there are no anti-fracture data. Denosumab, a monoclonal antibody to RANKL, has recently been shown to increase bone density and reduce fracture rates. Prostate cancer also commonly metastasizes to bone where it can cause complications such as fracture and pain. Both zoledronic acid and denosumab have been demonstrated to reduce skeletal related events. Comparative studies would suggest that densosumab may have an advantage over zoledronic acid.

[Treatment effect of breast cancer and prostate cancer on bone]

Aromatase inhibitors are used in the treatment of breast cancer and androgen deprivation therapy is used in prostate cancer. Both of them induce bone loss and increase fracture incidence. Early detection is important for patients with increased risk of osteoporotic fractures. In this article we review the available treatments and their indication to prevent the onset of osteoporosis and osteoporotic fractures in this patient group.

Responder analysis of the effects of denosumab on bone mineral density in men receiving androgen deprivation therapy for prostate cancer

BACKGROUND

Denosumab, a fully human monoclonal antibody against RANK ligand, increased bone mineral density (BMD) and reduced fracture risk vs placebo in a phase 3 trial in men with prostate cancer on androgen deprivation therapy (ADT). The present analysis of this study evaluated BMD changes after 36 months in responder subgroups and in individual patients for three key skeletal sites (lumbar spine (LS), femoral neck (FN) and total hip (TH)) and the distal radius.

METHODS

Men with nonmetastatic prostate cancer receiving ADT were treated with subcutaneous denosumab 60 mg (n=734) or placebo (n=734) every 6 months for up to 36 months in a phase 3, randomized, double-blind study. Patients were instructed to take supplemental calcium and vitamin D. For this BMD responder analysis, the primary outcome measure was the percentage change in BMD from baseline to month 36 at the LS, FN and TH as measured by dual-energy X-ray absorptiometry. BMD at the distal 1/3 radius at 36 months was measured in a substudy of 309 patients.

RESULTS

At 36 months, significantly more patients in the denosumab arm had increases of >3% BMD from baseline at each site studied compared with placebo (LS, 78 vs 17%; FN, 48 vs 13%; TH, 48 vs 6%; distal 1/3 radius, 40 vs 7% (P<0.0001 for all)). BMD loss at the LS, FN and TH occurred in 1% of denosumab-treated patients vs 42% of placebo patients, and BMD gain at all three sites occurred in 69% of denosumab patients vs 8% of placebo patients. Lower baseline BMD was associated with higher-magnitude BMD responses to denosumab at the LS, FN and TH.

CONCLUSIONS

In men with prostate cancer receiving ADT, significantly higher BMD response rates were observed with denosumab vs placebo. Patients with lower baseline T-scores benefited the most from denosumab treatment.

Two-year survival follow-up of the randomized, double-blind, placebo-controlled phase II study of radium-223 chloride in patients with castration-resistant prostate cancer and bone metastases

BACKGROUND

This phase II randomized, placebo-controlled study was conducted to evaluate efficacy and safety of radium-223 in patients with castration-resistant prostate cancer (CRPC) and painful bone metastases. Twelve- and 18-month survival results were reported previously. Here we report 24-month overall survival (OS) and safety data from the period 12 to 24 months after the first injection of study medication.

METHODS

Patients with CRPC and bone pain were randomized 1:1 to receive 4 injections of radium-223 (50 kBq/kg [n = 33]) or placebo (n = 31) after external-beam radiotherapy; each injection was given every 4 weeks. Endpoints for this report were 24-month OS, long-term safety, and treatment-related adverse events (AEs) occurring in the 12- to 24-month period.

RESULTS

After 24 months, 10 (30%) patients were alive in the radium-223 group compared with 4 patients (13%) in the placebo group. Patients who received at least 1 dose of study medication had a median OS of 65 weeks in the radium-223 group vs. 46 weeks in the placebo group (log-rank P = .056). The hazard ratio (HR) for OS, adjusted for baseline covariates, was 0.476 (95% confidence interval [CI], 0.258-0.877; Cox regression P = .017). The most frequent cause of death for both arms was disease progression. There were no reports of treatment-related AEs or long-term hematologic toxicity during the 12- to 24-month follow-up.

CONCLUSION

Radium-223 had a highly favorable safety profile, with no evidence of second malignancies at 24-month follow-up. The significant improvement in OS observed in patients receiving radium-223 vs. placebo suggests that treatment of bone disease with radium-223 has survival benefits.

Bone-targeted agents: preventing skeletal complications in prostate cancer

In men, prostate cancer is the most common non-cutaneous malignancy and the second most common cause of cancer death. Skeletal complications occur at various points during the disease course, either due to bone metastases directly, or as an unintended consequence of androgen deprivation therapy (ADT). Bone metastases are associated with pathologic fractures, spinal cord compression, and bone pain and can require narcotics or palliative radiation for pain relief. ADT results in bone loss and fragility fractures. This review describes the biology of bone metastases, skeletal morbidity, and recent advances in bone-targeted therapies to prevent skeletal complications of prostate cancer.

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.

Treatment-induced bone loss and fractures in cancer patients undergoing hormone ablation therapy: efficacy and safety of denosumab

Hormone ablation therapy (HALT) for breast or prostate cancer accelerates the development of osteoporosis in both men and women by causing estrogen deficiency, which increases the risk for fracture by promoting bone resorption mediated by osteoclasts. Denosumab, a fully human monoclonal antibody that inhibits osteoclast formation and function, increases bone mass in patients undergoing hormone ablation therapy. In the HALT study of 1,468 men with prostate cancer on androgen-deprivation therapy, denosumab significantly reduced the risk of new vertebral fractures, increased bone mineral density (BMD), and reduced markers of bone turnover. In a study of 252 women with breast cancer undergoing adjuvant aromatase inhibitor (AI) therapy, denosumab increased BMD at 12 and 24 months, overall and in all patient subgroups. The overall rates of adverse events were similar to placebo. Clinicians should consider fracture risk assessment and therapies such as denosumab to increase bone mass in patients on hormone ablation therapy who are at high risk for fracture.

Anti-RANKL therapy for bone tumours: Basic, pre-clinical and clinical evidences

Bone remodelling is related to coordinated phases of bone resorption and bone apposition allowing the maintenance of bone integrity, the phosphocalcic homoeostasis all along the life and consequently the bone adaptation to mechanical constraints or/and to endocrine fluctuations. Unfortunately, bone is a frequent site of tumour development originated from bone cell lineages (primary bone tumours: bone sarcomas) or from nonosseous origins (bone metastases: carcinomas). These tumour cells disrupt the balance between osteoblast and osteoclast activities resulting in a disturbed bone remodelling weakening the bone tissue, in a strongly altered bone microenvironment and consequently facilitating the tumour growth. At the early stage of tumour development, osteoclast differentiation and recruitment of mature osteoclasts are strongly activated resulting in a strong bone matrix degradation and release of numerous growth factors initially stored into this organic/calcified matrix. In turn these soluble factors stimulate the proliferation of tumour cells and exacerbate their migration and their ability to initiate metastases. Because Receptor Activator of NFκB Ligand (RANKL) is absolutely required for in vivo osteoclastogenesis, its role in the bone tumour growth has been immediately pointed out and has consequently allowed the development of new targeted therapies of these malignant diseases. The present review summarises the role of RANKL in the bone tumour microenvironment, the most recent pre-clinical and clinical evidences of its targeting in bone metastases and bone sarcomas. The following sections position RANKL targeted therapy among the other anti-resorptive therapies available and underline the future directions which are currently under investigations.

Local delivery of recombinant osteoprotegerin enhances postorthodontic tooth stability

Relapse after orthodontic tooth movement is a significant problem in orthodontics. The purpose of this study was to examine the efficacy of the osteoclast inhibitor osteoprotegerin-Fc (OPG-Fc) for inhibiting postorthodontic relapse. Rat maxillary molars were moved mesially and allowed to relapse for 24 days. Low-dose (1 mg/kg) or high-dose (5 mg/kg) OPG-Fc or saline was injected adjacent to the molars during relapse. Tooth movement, micro-CT, histologic bone quality, and serum OPG and TRAP-5b were measured. OPG-Fc injections significantly diminished postorthodontic relapse from 63% (0.78/1.20 mm) of total movement in vehicle control rats to 31% (0.31/1.00 mm) in low-dose and 24% (0.28/1.16 mm) in high-dose OPG-Fc groups 24 days after appliance removal. Normalization of bone and periodontal tissues occurred as early as 8 and 16 days in the high- and low-dose OPG-Fc-treated groups, respectively, while the vehicle-treated group showed only partial tissue recovery 24 days following tooth movement. After 24 days of relapse, there was complete recovery to pre-tooth-movement values for bone volume fraction (BVF) and tissue mineral density (TMD) in both the low- and high-dose OPG-Fc groups, while BVF recovered only partially and TMD did not recover in the vehicle control group. Greatly elevated serum OPG levels and reduced serum TRAP-5b levels in OPG-Fc-treated animals indicated systemic exposure to locally injected drug. The profound decrease in postorthodontic relapse by local OPG-Fc administration indicates that osteoclasts are critical to bone maturation following tooth movement and points to the potential pharmacologic use of OPG-Fc or other RANKL inhibitors for orthodontic retention.