The burden of symptomatic skeletal events in castrate-resistant prostate cancer patients with bone metastases at three Canadian uro-oncology centres

Treatment landscape and burden of disease in metastatic castration-resistant prostate cancer: systematic and structured literature reviews

Purpose

Metastatic castration-resistant prostate cancer (mCRPC) is a lethal disease that imposes a major burden on patients and healthcare systems. Three structured literature reviews (treatment guidelines, treatment landscape, and human/clinical/patient burden) and one systematic literature review (economic burden) were conducted to better understand the disease burden and unmet needs for patients with late-stage mCRPC, for whom optimal treatment options are unclear.

Methods

Embase®, MEDLINE®, MEDLINE® In-Process, the CENTRAL database (structured and systematic reviews), and the Centre for Reviews and Dissemination database (systematic review only) were searched for English-language records from 2009 to 2021 to identify mCRPC treatment guidelines and studies related to the treatment landscape and the humanistic/economic burden of mCRPC in adult men (aged ≥18 years) of any ethnicity.

Results

In total, six records were included for the treatment patterns review, 14 records for humanistic burden, nine records for economic burden, three records (two studies) for efficacy, and eight records for safety. Real-world treatment patterns were broadly aligned with treatment guidelines and provided no optimal treatment sequencing beyond second line other than palliative care. Current post-docetaxel treatments in mCRPC are associated with adverse events that cause relatively high rates of treatment discontinuation or disruption. The humanistic and economic burdens associated with mCRPC are high.

Conclusion

The findings highlight a lack of treatment options with novel mechanisms of action and more tolerable safety profiles that satisfy a risk-to-benefit ratio aligned with patient needs and preferences for patients with late-stage mCRPC. Treatment approaches that improve survival and health-related quality of life are needed, ideally while simultaneously reducing costs and healthcare resource utilization.

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.

Use of bisphosphonates and other bone supportive agents in the management of prostate cancer-A UK perspective

AIM

To explore the practice and views of uro-oncologists in the UK regarding their use of bone supportive agents in patients with prostate cancer.

METHODS

An expert-devised online questionnaire was completed by members of the British Uro-oncology Group (BUG).

RESULTS

Of 160 uro-oncologists invited, 81 completed the questionnaire. Approximately 70% of respondents never use a bone supportive agent in patients with metastatic hormone-naïve prostate cancer on androgen deprivation therapy (ADT). However, use was more frequent in men with metastatic castration-resistant prostate cancer, from first-line treatment onwards. The majority of uro-oncologists do not use a bone supportive agent to prevent skeletal-related events in men with non-metastatic disease unless the individual patient is at an increased risk of osteoporosis. In men with more advanced disease, respondents would use an oral or intravenous (IV) bisphosphonate in 41% and 61% of patients, respectively. Zoledronic acid is the first-choice bone supportive treatment in 77% of cases, with the lack of clinical data cited as a barrier to use for other IV bisphosphonates. Local guidelines also have a significant influence on the use of bone supportive agents, especially with respect to denosumab. Bone mineral density measurement is conducted in approximately 40% of men with ADT exposure of 2 years or longer, or those with metastatic prostate cancer.

CONCLUSION

Uro-oncologists in the UK generally do not use bone supportive agents for men with metastatic hormone-naïve prostate cancer or those with non-metastatic disease. However, increasing the duration of ADT and the presence of castration-resistant metastatic prostate cancer increases use.

Incidence of Skeletal-Related Events in Patients with Castration-Resistant Prostate Cancer: An Observational Retrospective Cohort Study in the US

Background and Objective

Skeletal-related events (SREs) are common in men with bone metastases and have negative consequences for patients with castration-resistant prostate cancer (CRPC), including pain, reduced quality of life, and increased mortality. We estimated incidence rates of first SREs in a cohort of men with CRPC in the Surveillance, Epidemiology, and End Results-Medicare database.

Methods

We included men aged ≥ 65 years with a prostate cancer diagnosis in 2000-2011 if they had no prior malignancy (other than nonmelanoma skin cancer) and had surgical or medical castration with subsequent second-line systemic therapy, which was used to infer castration resistance. The first occurrence of an SRE (fracture, bone surgery, radiation therapy, or spinal cord compression) in Medicare claims was identified. Incidence rates of SREs were estimated in all eligible person-time and, in secondary analyses, stratified by any use of bone-targeted agents (BTAs) and history of SRE.

Results

Of 2,234 men with CRPC (84% white, mean age = 76.6 years), 896 (40%) had an SRE during follow-up, with 74% occurring within a year after cohort entry. Overall, the incidence rate of SREs was 3.78 (95% CI, 3.53-4.03) per 100 person-months. The incidence rate of SREs before any BTA use was 4.16 (95% CI, 3.71-4.65) per 100 person-months, and after any BTA use was 3.60 (95% CI, 3.32-3.91) per 100 person-months. The incidence rate in patients with no history of SRE was 3.33 (95% CI 3.01-3.68) per 100 person-months, and in patients who had such a history, it was 4.20 (95% CI 3.84-4.58) per 100 person-months.

Conclusions

In this large cohort of elderly men with CRPC in the US, SREs were common. A decrease in incidence of SREs after starting BTA is suggested, but the magnitude of the effect may be confounded by indication and other factors such as age and prior SRE.

Denosumab treatment in the management of patients with advanced prostate cancer: clinical evidence and experience

Osteoprotective therapies have become an essential component in the management of advanced prostate cancer (PC) patients as bone metastases (BMs) have a major impact on morbidity and mortality. Denosumab is a fully humanized antibody targeting the receptor activator of nuclear factor κB ligand (RANKL), which has been approved by the European Medicines Agency (EMA) in Europe and the United States (US) Food and Drug Administration (FDA) in the US for prevention of skeletal-related events (SREs) in patients with solid tumors and BMs, including PC. The clinical settings in which PC patients should be treated with denosumab are still discussed controversially. In a phase III study, denosumab significantly delayed SREs compared with zoledronic acid (ZA) in patients with metastatic castration-resistant PC (CRPC). In addition, denosumab showed superior effects on pain and health-related quality of life (QoL) in these patients. In patients with nonmetastatic CRPC, denosumab has been proven to significantly increase bone metastases-free survival. However, no significant benefits on cancer-specific and overall survival were observed and denosumab was not approved by the US FDA and EMA in this context. The effectiveness of denosumab in patients with castration-sensitive PC (CSPC) and BMs is also under discussion, as clinical trials with ZA in these patients have not shown significant benefits. Clinical data on the use of denosumab in CSPC are urgently needed.