Health-economic review of zoledronic acid for the management of skeletal-related events in bone-metastatic prostate cancer

Real-world use of bone modifying agents in metastatic, castration-resistant prostate cancer

BACKGROUND

Bone modifying agents (BMAs) prevent skeletal related events among patients with metastatic, castration-resistant prostate cancer (mCRPC) involving bone and prevent osteoporotic fractures among patients at high risk. BMA utilization for patients with mCRPC has not been well quantified.

METHODS

We used linked SEER registry and Medicare claims data. We included men diagnosed with stage IV prostate adenocarcinoma during 2007-2015, aged > = 66 at diagnosis, with sufficient continuous enrollment in Medicare Parts A, B, and D, who received androgen deprivation therapy. We limited to those who subsequently received a CRPC-defining treatment (CDT). We identified patients with evidence of bone metastasis using claims. Our primary outcome was receipt of a BMA (zoledronic acid or denosumab) within 180 days of initiating CDT.

RESULTS

Among 1292 included patients, 1034 (80%) had bone metastasis. BMA use within 180 days of initiating CDT was higher among patients with bone metastases than those without (705/1034 [68%] vs 56/258 [22%]). Among patients without bone metastasis, those with high osteoporotic fracture risk were more likely than those without to receive a BMA (OR = 2.48, 95% CI: 1.17, 5.29); however, only 26% of patients with high fracture risk received a BMA. Among patients who received BMAs, most (62%) first initiated them >90 days before initiating CDT.

CONCLUSIONS

Two-thirds of patients with mCRPC and bone metastases received BMAs within 180 days after initiating CDT. A greater proportion of patients without bone metastasis may warrant BMA therapy for osteoporotic fracture prevention. Some patients with bone metastasis may be able to delay BMA initiation until CRPC.

The burden of skeletal-related events in four Latin American countries: Argentina, Brazil, Colombia, and Mexico

AIM

Skeletal-related events (SREs) are major bone complications that frequently occur in patients with solid tumors (ST) and bone metastases, and in patients with multiple myeloma (MM). SREs include pathological fracture, spinal cord compression, radiation to bone, and surgery to bone. Limited data are available regarding the burden of SREs in Latin America. We built an economic model to quantify the current and future economic burden of SREs among adults in four Latin American countries: Argentina, Brazil, Colombia, and Mexico.

METHODS

A comprehensive literature review with a systematic search strategy was conducted to parameterize the economic burden of illness (BOI) model. Economic analyses were conducted using a prevalence-based model. Aggregate SRE costs obtained from country-specific sources were used. We also included patient productivity losses. Costs were expressed in 2020 USD for the total annual burden, annual burden per 1,000 at risk, and projected five-year burden.

RESULTS

The estimated total number of SREs was 251,503 in 2020, amounting to a total annual cost of USD 1.4 billion. The total projected five-year cost was USD 6.9 billion. Annual costs were highest in Brazil (USD 779.1 million), followed by Mexico (USD 281.8 million), Argentina (USD 174.6 million), and Colombia (USD 120.1 million). The average financial burden per 1,000 at risk was greatest in Brazil (USD 3.6 million), followed by Mexico (USD 3.4 million), Colombia (USD 2.9 million), and Argentina (USD 2.7 million).

CONCLUSION

Despite recommendations by medical societies for the use of bone-targeted agents in patients with solid tumors and bone metastasis or with multiple myeloma and bone lesions, a large proportion of patients at risk of experiencing SREs are not treated. Early detection of bone metastases and SREs and the use of the most effective preventative treatments are needed to decrease the clinical and economic burden of SREs in Latin America.

Regulation of the Notch-ATM-abl axis by geranylgeranyl diphosphate synthase inhibition

Notch proteins drive oncogenesis of many cancers, most prominently T-cell acute lymphoblastic leukemia (T-ALL). Because geranylgeranylated Rab proteins regulate Notch processing, we hypothesized that inhibition of geranylgeranyl diphosphate synthase (GGDPS) would impair Notch processing and reduce viability of T-ALL cells that express Notch. Here, we show that GGDPS inhibition reduces Notch1 expression and impairs the proliferation of T-ALL cells. GGDPS inhibition also reduces Rab7 membrane association and depletes Notch1 mRNA. GGDPS inhibition increases phosphorylation of histone H2A.X, and inhibitors of ataxia telangiectasia-mutated kinase (ATM) mitigate GGDPS inhibitor-induced apoptosis. GGDPS inhibition also influences c-abl activity downstream of caspases, and inhibitors of these enzymes prevent GGDPS inhibitor-induced apoptosis. Surprisingly, induction of apoptosis by GGDPS inhibition is reduced by co-treatment with γ-secretase inhibitors. While inhibitors of γ-secretase deplete one specific form of the Notch1 intracellular domain (NICD), they also increase Notch1 mRNA expression and increase alternate forms of Notch1 protein expression in cells treated with a GGDPS inhibitor. Furthermore, inhibitors of γ-secretase and ATM increase Notch1 mRNA stability independent of GGDPS inhibition. These results provide a model by which T-ALL cells use Notch1 to avoid DNA-damage-induced apoptosis, and can be overcome by inhibition of GGDPS through effects on Notch1 expression and its subsequent response.

A cost-effectiveness analysis of denosumab for the prevention of skeletal-related events in patients with multiple myeloma in four European countries: Austria, Belgium, Greece, and Italy

Aim: The approved indication for denosumab (120 mg) was expanded in 2018 to include skeletal-related event (SRE) prevention in patients with multiple myeloma (MM). Therefore, a cost-effectiveness analysis was conducted comparing denosumab with zoledronic acid (ZA) for SRE prevention in patients with MM from the national healthcare system perspective in a representative sample of European countries: Austria, Belgium, Greece, and Italy. Methods: The XGEVA global economic model for patients with MM was used to calculate incremental cost-effectiveness ratios (ICERs) for denosumab vs ZA over a lifetime horizon. Clinical inputs were derived from the denosumab vs ZA randomized, phase 3 study ("20090482") in patients newly-diagnosed with MM, and comprised real-world adjusted SRE rates, serious adverse event (SAE) rates, treatment duration, dose intensity, progression-free survival (PFS), and overall survival (OS). Economic inputs comprised country-specific denosumab and ZA acquisition and administration costs, SRE and SAE management costs, and discount rates. Health utility decrements associated with MM disease progression, SRE and SAE occurrence, and route of administration were included. Results: Estimated ICERs (cost per quality-adjusted life-year [QALY] gained) for denosumab vs ZA in Austria, Belgium, Greece, and Italy were €26,294, €17,737, €6,982, and €27,228, respectively. Using 1-3 times gross domestic product (GDP) per capita per QALY as willingness to pay thresholds, denosumab was 69-94%, 84-96%, 79-96%, and 50-92% likely to be cost-effective vs ZA, respectively. Limitations: Economic inputs were derived from various sources, and time to event inputs were extrapolated from 20090482 study data. Conclusions: Denosumab is cost-effective vs ZA for SRE prevention in patients with MM in Austria, Belgium, Greece, and Italy, based on often-adopted World Health Organization thresholds. This conclusion is robust to changes in model parameters and assumptions. Cost-effectiveness estimates varied across the four countries, reflecting differences in healthcare costs and national economic evaluation guidelines.

Denosumab versus bisphosphonates for the treatment of bone metastases from solid tumors: a systematic review

BACKGROUND

Bone metastases are highly prevalent in breast, prostate, lung and colon cancers. Their symptoms negatively affect quality of life and functionality and optimal management can mitigate these problems. There are two different targeted agents to treat them: bisphosphonates (pamidronate and zoledronic acid) and the monoclonal antibody denosumab. Estimates of cost-effectiveness are still mixed.

OBJECTIVE

To conduct a systematic review of economic studies that compares these two options.

METHOD

Literature search comprised eight databases and keywords for bone metastases, bisphosphonates, denosumab, and economic studies were used. Data were extracted regarding their methodologic characteristics and cost-effectiveness analyses. All studies were evaluated regarding to its methodological quality.

RESULTS

A total of 263 unique studies were retrieved and six met inclusion criteria. All studies were based on clinical trials and other existing literature data, and they had high methodological quality. Most found unfavorable cost-effectiveness for denosumab compared with zoledronic acid, with adjusted ICERS that ranged from $4638-87,354 per SRE avoided and from US$57,274-4.81 M. per QALY gained, which varied widely according to type of tumor, time horizon, among others. Results were sensitive to drug costs, time to first skeletal-related event (SRE), time horizon, and utility.

CONCLUSIONS

Denosumab had unfavorable cost-effectiveness compared with zoledronic acid in most of the included studies. New economic studies based on real-world data and longer time horizons comparing these therapeutic options are needed.

Treatment patterns and trends in patients dying of prostate cancer in Quebec: a population-based study

INTRODUCTION

Since just after the year 2000 in Quebec, the management of metastatic castration-resistant prostate cancer (mcrpc) has evolved considerably, with the inclusion of docetaxel-based chemotherapy, bone-targeted therapies (zoledronic acid and denosumab), and more recently, abiraterone, enzalutamide, and cabazitaxel for docetaxel-refractory patients. In the present study, we aimed to analyze contemporary mcrpc management patterns and therapy utilization trends in Quebec.

METHODS

The study cohort consisted of patients dying of prostate cancer (pca) between January 2001 and December 2013, selected from Quebec public health care insurance databases. Patient selection was based on death from a pca-related cause or therapy used according to the Canadian Urological Association guidelines on mcrpc management. Treatments included chemotherapy (mitoxantrone before 2005 and docetaxel after 2005), abiraterone, bone-targeted therapy (zoledronic acid or denosumab, or both), and palliative radiation therapy (rt). During the study period, neither enzalutamide nor cabazitaxel was publicly reimbursed in Quebec, and as a result, no capture of their use was possible for this study. Multivariate logistic regression was used to identify factors associated with the probability of receiving chemotherapy, bone-targeted therapies, and palliative rt before death from pca.

RESULTS

Overall, the database search identified 3106 patients who died of pca between January 2001 and December 2013. Median age of death was 78 years. Of those 3106 patients, just 2568 (83%) received mcrpc-specific treatments: chemotherapy, abiraterone, palliative rt, or bone-targeted therapy; the other 17% of the patients were managed solely with maximum androgen blockade (androgen deprivation therapy plus anti-androgens) despite a record of pca-related death. Logistic regression analyses indicate that patients dying after 2005 were more likely to have received chemotherapy [odds ratio (or): 1.51; 95% ci: 1.22 to 1.85] and bone-targeted therapy (or: 1.97; 95% ci: 1.64 to 2.37). Age was a significant predictor for the use of chemotherapy, bone-targeted therapy, and palliative rt (ors in the range 0.96-0.98, p < 0.05).

CONCLUSIONS

Patient age seems to be a strong determinant in the of selection mcrpc therapy, affecting the probability of the use of chemotherapy, bone-targeted therapy, or palliative rt. Although chemotherapy is still used only in a small percentage of patients, the introduction of new therapies-such as bone-targeted therapy, docetaxel, and abiraterone-affected treatment selection over time. The availability of enzalutamide since February 2014 will likely produce additional changes in mcrpc management.

Effect of a local, one time, low-dose injection of zoledronic acid on titanium implant osseointegration in ovariectomized rats

INTRODUCTION

Local application of bisphosphonates has been proven to be safer than systemic administration to promote implant fixation. The objective of this study was to introduce such a simple, convenient and efficient method to enhance titanium (Ti) implant osseointegration in ovariectomized (OVX) rats.

MATERIAL AND METHODS

Twenty female Sprague-Dawley rats sequentially underwent bilateral ovariectomy and tibia implantation, and injection of 30 µg/implant zoledronic acid (ZOL) at the site of implantation was performed. At the end of the study, the tibiae, mandibles, femurs and vertebrae were harvested for dual energy X-ray absorptiometry, histology and micro-computed tomography examination.

RESULTS

Ovariectomized rats showed poor bone density, bone mass and trabecular microstructure. OVX + ZOL rats were characterized by significantly improved peri-implant bone area (1.72-fold), bone contact (2.30-fold), bone mineral density (1.57-fold) and bone mineral content (1.67-fold), as well as moderately increased bone volume to total volume ratio (1.34-fold), percentage osteointegration (1.54-fold), connectivity density (1.45-fold), and trabecular number (1.43-fold), but decreased trabecular separation (57.69%) when compared with the control levels (p < 0.05). No histological signs of jaw osteonecrosis were observed in the rats treated with ZOL, and there was no significant difference between the OVX group and OVX + ZOL group in the bone mass of the mandible, femur and 5^th lumbar vertebra (p > 0.05). In addition, the overproduction of osteoporosis-induced advanced glycation end-products (AGEs) was completely prevented by local treatment with 30 µg/implant ZOL.

CONCLUSIONS

A local, one time, low-dose injection of ZOL at the site of implantation is able to promote the osseointegration of Ti implants following postmenopausal osteoporosis, and this action may be partly mediated by inhibition of the osteoporosis-induced AGE overproduction in the bone marrow.

Current Patterns of Management of Advanced Prostate Cancer in Routine Clinical Practice in Spain

Objective. To describe urologists' practice patterns when managing patients with advanced prostate cancer (PCa) in Spain. Methods. This was an observational study conducted by 120 urologists using retrospective data of advanced PCa patients attending hospitals and outpatient centers. Results. Urologists evaluated a total of 375 patients (mean age: 75 years; ECOG 0-1: 77%; mean serum PSA levels at study entry: 50.5 ng/Ml). Approximately 50% of patients had bone metastases, and 60.6% experienced pain as the main symptom of progressive disease. Primary androgen deprivation therapy (ADT) use was 99.7%, with continuous ADT as the dominant strategy (91.9%). After failure of initial ADT, antiandrogen withdrawal was the next method most commonly used in 57% of patients. Choice of secondary hormonal treatment was made mostly by urologists (96%), who continued to monitor patients. Patient follow-up after chemotherapy and supportive care were mainly done in urology units, although responsibility was shared with medical oncologists and radiologists. Conclusion. The urologists' attitudes towards management of PCa in the routine practice in Spain show the urologist as an integral component even when patients progress to advanced stages of the disease.

Enzalutamide in European and North American men participating in the AFFIRM trial

Objective

To explore any differences in efficacy and safety outcomes between European (EU) (n = 684) and North American (NA) (n = 395) patients in the AFFIRM trial (NCT00974311).

Patients and Methods

Phase III, double-blind, placebo-controlled, multinational AFFIRM trial in men with metastatic castration-resistant prostate cancer (mCRPC) after docetaxel. Participants were randomly assigned in a 2:1 ratio to receive oral enzalutamide 160 mg/day or placebo. The primary end point was overall survival (OS) in a post hoc analysis.

Results

Enzalutamide significantly improved OS compared with placebo in both EU and NA patients. The median OS in EU patients was longer than NA patients in both treatment groups. However, the relative treatment effect, expressed as hazard ratio and 95% confidence interval, was similar in both regions: 0.64 (0.50, 0.82) for EU and 0.63 (0.47, 0.83) for NA. Significant improvements in other end points further confirmed the benefit of enzalutamide over placebo in patients from both regions. The tolerability profile of enzalutamide was comparable between EU and NA patients, with fatigue and nausea the most common adverse events. Four EU patients (4/461 enzalutamide-treated, 0.87%) and one NA patient (1/263 enzalutamide-treated, 0.38%) had seizures. The difference in median OS was related in part to the timing of development of mCRPC and baseline demographics on study entry.

Conclusion

This post hoc exploratory analysis of the AFFIRM trial showed a consistent OS benefit for enzalutamide in men with mCRPC who had previously progressed on docetaxel in both NA- and EU-treated patients, although the median OS was higher in EU relative to NA patients. Efficacy benefits were consistent across end points, with a comparable safety profile in both regions.

Bone-targeted therapies for elderly patients with renal cell carcinoma: current and future directions

Bone metastases are very common in advanced renal cell carcinoma (RCC) and can have a huge impact on quality of life by leading to skeletal-related events (SREs), including pain, pathologic fractures and spinal cord compression with need for surgery or radiotherapy. Because of their osteolytic aspect and biologic behaviour, these SREs are more common in patients with bone metastases from RCC than from other malignancies. As overall survival is increased by new anti-angiogenic drugs like tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors, the incidence of SREs is rising, making the clinical management of bone metastases in RCC ever more important, especially in the more vulnerable elderly patient. In this review we discuss the current advances and future directions in bone-targeted therapies in patients with RCC with a special focus on the elderly population. Recently, two bone-targeted agents have been approved in the prevention of SREs in advanced RCC: zoledronic acid and denosumab. To date, there is no specific data on the use of bisphosphonates or denosumab in the elderly and specific studies in this setting are warranted. We compare the available evidence for the use and implications of both agents in the elderly patient and give general information on safety concerns that could be more important in these patients.

Drug costs in the management of metastatic castration-resistant prostate cancer in Canada

BACKGROUND

For Canadian men, prostate cancer (PCa) is the most common cancer and the 3rd leading cause of cancer mortality. Men dying of PCa do so after failing castration. The management of metastatic castration-resistant prostate cancer (mCRPC) is complex and the associated drug treatments are increasingly costly. The objective of this study was to estimate the cost of drug treatments over the mCRPC period, in the context of the latest evidence-based approaches.

METHODS

Two Markov models with Monte-Carlo microsimulations were developed in order to simulate the management of the disease and to estimate the cost of drug treatments in mCRPC, as per Quebec's public healthcare system. The models include recently approved additional lines of treatment after or before docetaxel (i.e. abiraterone and cabazitaxel). Drug exposure and survival were based on clinical trial results and clinical practice guidelines found in a literature review. All costs were assigned in 2013 Canadian dollars ($). Only direct drug costs were estimated.

RESULTS

The mean cost of mCRPC drug treatments over an average period of 28.1 months was estimated at $48,428 per patient (95% Confidence Interval: $47,624 to $49,232). The mean cost increased to $104,071 (95% CI: $102,373 - $105,770) per patient when one includes abiraterone initiation prior to docetaxel therapy. Over the mCRPC period, luteinizing hormone-releasing hormone agonists (LHRHa) prescribed to maintain castrate testosterone levels accounted for 20.4% of the total medication cost, whereas denosumab prescribed to decrease bone-related events accounted for 30.5% of costs. When patients received cabazitaxel in sequence after abiraterone and docetaxel, the mCRPC medications cost per patient per month increased by 60.2%. The total cost of medications for the treatment of each annual Canadian cohort of 4,000 mCRPC patients was estimated at $ 193.6 million to $416.3 million.

CONCLUSIONS

Our study estimates the direct drug costs associated with mCRPC treatments in the Canadian healthcare system. Recently identified effective yet not approved therapies will become part of the spectrum of mCRPC treatments, and may potentially increase the cost.

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.

Comparing cost-effectiveness analyses of denosumab versus zoledronic acid for the treatment of bone metastases

BACKGROUND

Bone metastases from various cancers have been traditionally treated with bisphosphonates, such as zoledronic acid (ZA), to prevent future skeletal-related events (SREs). Denosumab (Dmab) has been shown to have more advantages in preventing SREs in clinical trials than ZA, but the cost to administer Dmab is significantly higher.

METHODS

A literature review was conducted to investigate the methodologies used to compare the cost-effectiveness of Dmab and ZA. MEDLINE and EMBASE were searched systematically for all cost-effectiveness analyses published between January week 1, 2006 to August week 1, 2012. Search strategies were designed to retrieve articles analyzing the cost-effectiveness and cost utility of Dmab compared to ZA in patients with bone metastases. From 12 references obtained in the initial database search, eight satisfied the predetermined criteria for full article review. Articles were analyzed for incremental costs per skeletal-related event avoided or incremental cost per quality-adjusted life year gained.

RESULTS

All the studies identified received funding from Novartis Pharmaceuticals (the manufacturer of ZA) or Amgen Incorporated (the manufacturer of Dmab). The studies looked at the economic analysis using different associated costs and over various time periods, ranging from a 1-year to a lifetime time horizon.

CONCLUSION

It is not clear whether the methods used across studies are consistent, which may account for the differences between estimated costs and effects. Future research is suggested to explore the cost-effectiveness between Dmab and ZA using a standardize time frame and endpoint.