Patients with bone metastases from solid tumors initiating treatment with a bone-targeted agent in 2011: a descriptive analysis using oncology clinic data in the US

Bone-targeting agents in major solid tumour metastases: a multinational cohort study

OBJECTIVE

To describe the epidemiology, clinical characteristics and utilisation patterns of bone-targeting agents (BTAs) in patients with bone metastases from breast, prostate and lung cancer.

METHODS

This is a multinational retrospective cohort study including patients with three major solid tumours (breast, prostate and lung cancer) and newly initiated on BTAs (ie, denosumab, zoledronic acid and pamidronate). Records were retrieved from nationwide health databases from Hong Kong and Taiwan (HK and TW: 2013-2017) and Korea (KR: 2012-2016). Descriptive analyses included the annual incidence rates of bone metastases and the cumulative incidence curves of BTA initiation. We used Sankey diagrams to visualise the dynamic BTA utilisation patterns.

RESULTS

The annual incidence rate of bone metastases ranged from 3.5% to 4.5% in TW, from 9.6% to 10.3% in HK and from 2.9% to 3.8% in KR. We identified 14.1% (5127), 9.3% (883) and 9.4% (4800) of patients with bone metastases newly initiated on BTAs in TW, HK and KR, respectively. The most frequently used BTA in TW (67.1%) and HK (51.9%) was denosumab, while in KR (84.8%) it was zoledronic acid. Sankey diagrams indicated the proportion of patients remaining on denosumab was highest in TW and HK, while it was zoledronic acid in KR. Specifically, in TW, patients who were on bisphosphonates or had discontinued treatment frequently switched to or reinitiated denosumab.

CONCLUSIONS

We found the rate of BTA utilisation remained low across all sites and tumour types in recent years. The dynamic utilisation patterns of BTAs provide better understanding of the treatment landscape for future evaluation of associated outcomes of patients.

Comparative Treatment Persistence with Bone-Targeting Agents Among Asian Patients with Bone Metastases from Solid Tumors: A Multinational Retrospective Cohort Study

BACKGROUND

The efficacy of bone-targeting agents has been confirmed, but the generalizability of results to Asia is in question.

OBJECTIVE

We aimed to evaluate and compare treatment persistence and re-initiation with different bone-targeting agents among patients with bone metastases from solid tumors.

METHODS

This population-based cohort study included patients with bone metastasis with breast, lung, or prostate cancer who initiated bone-targeting agents, including denosumab, zoledronic acid, and pamidronate in Taiwan (2013-17), Hong Kong (2013-17), and Korea (2012-16). We described the patients' persistence with bone-targeting agents, by evaluating the interruption probability, and compared risks of treatment interruption. The rates of re-initiation with index bone-targeting agents were evaluated.

RESULTS

We included 5127 patients (denosumab: 3440, zoledronic acid: 1210, pamidronate: 477) from Taiwan, 883 patients (denosumab: 458, zoledronic acid: 357, pamidronate: 68) from Hong Kong, and 4800 patients (zoledronic acid: 4068, pamidronate: 732) from Korea. Compared with zoledronic acid, denosumab had a lower risk of interruption in Taiwan (adjusted hazard ratio: 0.44; 95% confidence interval 0.40-0.48) and Hong Kong (0.36; 0.28-0.45). However, pamidronate was more likely to be interrupted than zoledronic acid in Taiwan (1.31; 1.11-1.54) and Korea (2.06; 1.83-2.32), but not in Hong Kong (1.13; 0.71-1.78). After discontinuation, original treatments with denosumab in Taiwan and zoledronic acid in Hong Kong were more likely to be resumed, while in Korea, the rates were similar among the bisphosphonates.

CONCLUSIONS

Denosumab was associated with a lower risk of interruption than bisphosphonates in patients with bone metastases in Taiwan and Hong Kong. Further investigations may be required to verify patients' actual reasons for discontinuation.

Real-world use of denosumab and bisphosphonates in patients with solid tumours and bone metastases in Germany

PURPOSE

Bisphosphonates and denosumab prevent bone complications in patients with bone metastases from solid tumours. This retrospective, longitudinal, cohort study provides data on their real-world use in this setting in Germany.

METHODS

Adults with bone metastases from breast, prostate or lung cancer who were newly initiated on a bisphosphonate or denosumab between 1 July 2011 and 31 December 2015 were identified from a German healthcare insurance claims database. Primary outcomes included persistence, compliance, discontinuation and switch rates at 12 months.

RESULTS

This study included 1130 patients with bone metastases: 555 (49%) had breast cancer, 361 (32%) prostate cancer and 242 (21%) lung cancer. Mean age was 65 years for patients with breast or lung cancer and 74 years for those with prostate cancer. Across all tumour types, compared with any bisphosphonate, 12-month persistence was higher with denosumab (breast cancer 78% vs 54-58%, prostate cancer 58% vs 50%, lung cancer 68% vs 34-60%), median time to discontinuation was longer with denosumab and switch rates were lower for denosumab (breast cancer 5% vs 14-19%, prostate cancer 2% vs 11%, lung cancer 3% vs 7-12%). Compliance at 12 months was longer for denosumab than for any bisphosphonate in breast cancer (75% vs 42-48%) and in prostate cancer (47% vs 36%).

CONCLUSIONS

Patients initiated on denosumab following a diagnosis of bone metastases from breast, prostate or lung cancer had greater medication persistence, longer time to discontinuation, improved compliance and lower switch rates than those initiated on a bisphosphonate.

Treatment dynamics of bone-targeting agents among men with bone metastases from prostate cancer in the United States

PURPOSE

To examine the dynamics of treatment with 2 bone-targeting agents (BTAs)-denosumab and zoledronic acid-among men with bone metastases from prostate cancer.

METHODS

Using electronic health record data from oncology practices across the US, we identified prostate cancer patients diagnosed with bone metastasis in 2012/2013 without evidence of BTA use within 6 months prior to diagnosis. We examined the risk and predictors of BTA initiation, interruption, and re-initiation.

RESULTS

Among 897 men diagnosed with prostate cancer, the cumulative incidence of BTA initiation after bone metastasis diagnosis was 34% (95% confidence interval [CI], 31-37%) at 30 days, 64% (95% CI, 61-68%) at 180 days, and 88% (95% CI, 85-91%) at 2 years. Denosumab was initiated more frequently than zoledronic acid. Men with diabetes, more bone lesions, history of androgen deprivation therapy, or no hospice enrollment were more likely to initiate treatment. Following initiation, the cumulative incidence of treatment interruption was 17% (95% CI, 14-19%) at 60 days and 70% (95% CI, 66-74%) at 2 years, with interruption more likely among patients receiving emerging therapies for prostate cancer or enrolling in hospice. The cumulative incidence of re-initiation following interruption was 36.3% (95% CI, 32.7-40.2%) at 15 days, 49.8% (95% CI, 45.9-54.1%) at 30 days, and 81.0% (95% CI, 77.5-84.7%) at 1 year.

CONCLUSIONS

Bone-targeting agent therapy is initiated by the majority of men living with bone metastases following a prostate cancer diagnosis; however, the timing of initiation is highly variable. Once on treatment, gaps or interruptions in therapy are common.

Cost-effectiveness of denosumab versus zoledronic acid for preventing skeletal-related events in the Czech Republic

AIMS

This study assessed the cost-effectiveness of the subcutaneous RANKL inhibitor, denosumab, vs the intravenous bisphosphonate, zoledronic acid, for the prevention of skeletal-related events (SREs) in patients with prostate cancer, breast cancer, and other solid tumors (OST) in the Czech Republic.

MATERIALS AND METHODS

A lifetime Markov model was developed to compare the effects of denosumab and zoledronic acid on costs (including drug costs and administration, patient management, SREs, and adverse events), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios from a national payer perspective. Different discount rates, time horizons, SRE rates, distributions, and nature (asymptomatic vs all SREs), and the inclusion of treatment discontinuation were considered in scenario analyses. The robustness of the model was tested using deterministic and probabilistic sensitivity analyses.

RESULTS

Across tumor types, denosumab was associated with fewer SREs, improved QALYs, and higher total costs over a lifetime. The incremental cost per QALY gained for denosumab vs zoledronic acid was 382,673 CZK for prostate cancer, 408,450 CZK for breast cancer, and 608,133 CZK for OST. Incremental costs per SRE avoided for the same tumor type were 54,007 CZK, 51,765 CZK, and 94,426 CZK, respectively. In scenario analyses, the results remained similar to baseline, when different discount rates and time horizons were considered. At a non-official willingness-to-pay threshold of 1.2 million CZK, the probabilities of denosumab being cost-effective vs zoledronic acid were 0.64, 0.67, and 0.49 for prostate cancer, breast cancer, and OST, respectively.

LIMITATIONS

The SRE rates used were obtained from clinical trials; studies suggest rates may be higher in clinical practice. Additional evidence on real-world SRE rates could further improve the accuracy of the modeling.

CONCLUSIONS

Compared with zoledronic acid, denosumab provides a cost-effective treatment option for the prevention of SREs in patients with prostate cancer, breast cancer, and OST in the Czech Republic.

Longitudinal patterns of bone-targeted agent use among patients with solid tumors and bone metastases in the United States

Purpose

This study examined real-world long-term use of guideline-recommended bone targeted agents (BTA) among patients with metastatic solid tumors.

Methods

Adults with a solid tumor diagnosis followed by a bone metastasis diagnosis in 2012–2014 were identified from electronic medical records in the Oncology Services Comprehensive Electronic Records (OSCER) database. Patients initiated zoledronic acid (ZA) or denosumab on or after the bone metastasis diagnosis and were followed through last clinic visit by 30 June 2015. We describe time to BTA initiation, compliance (≥12 administrations in a year), switching, and non-persistence (switch or ≥90 day gap in therapy), by agent and follow-up period.

Results

The majority of the 14,881 study patients (50% female, 65% age ≥65 years) had breast (33%), prostate (26%), or lung (26%) tumors. Half of all patients initiated on each agent, with denosumab initiations exceeding ZA initiations in 2014. Most (91% denosumab, 93% ZA) initiations occurred within 3 months of bone metastasis diagnosis. At 1, 2, and 3 years post-initiation, denosumab patients were less likely to switch agents (4, 3, and 1% versus 14, 12, and 11%) and more likely to be compliant (50, 37, and 31% versus 41, 26, and 6%). Median time to non-persistence was 25.9 months for denosumab and 17.2 months for ZA, p < 0.0001.

Conclusions

This is the first study reporting long-term treatment patterns for the two primary BTAs used in the USA. The greater compliance and longer persistence observed among denosumab patients may improve treatment effectiveness achieved in the real-world setting.

Electronic supplementary material

The online version of this article (doi:10.1007/s00520-017-3583-1) contains supplementary material, which is available to authorized users.

Annual patient and caregiver burden of oncology clinic visits for granulocyte-colony stimulating factor therapy in the US

OBJECTIVE

Prophylactic treatment with granulocyte-colony stimulating factors (G-CSFs) is indicated for chemotherapy patients with a significant risk of febrile neutropenia. This study estimates the annual economic burden on patients and caregivers of clinic visits for prophylactic G-CSF injections in the US.

METHODS

Annual clinic visits for prophylactic G-CSF injections (all cancers) were estimated from national cancer incidence, chemotherapy treatment and G-CSF utilization data, and G-CSF sales and pricing information. Patient travel times, plus time spent in the clinic, were estimated from patient survey responses collected during a large prospective cohort study (the Prospective Study of the Relationship between Chemotherapy Dose Intensity and Mortality in Early-Stage (I-III) Breast Cancer Patients). Economic models were created to estimate travel costs, patient co-pays and the economic value of time spent by patients and caregivers in G-CSF clinic visits.

RESULTS

Estimated total clinic visits for prophylactic G-CSF injections in the US were 1.713 million for 2015. Mean (SD) travel time per visit was 62 (50) min; mean (SD) time in the clinic was 41 (68) min. Total annual time for travel to and from the clinic, plus time at the clinic, is estimated at 4.9 million hours, with patient and caregiver time valued at $91.8 million ($228 per patient). The estimated cumulative annual travel distance for G-CSF visits is 60.2 million miles, with a total transportation cost of $28.9 million ($72 per patient). Estimated patient co-pays were $61.1 million, ∼$36 per visit, $152 per patient. The total yearly economic impact on patients and caregivers is $182 million, ∼$450 per patient.

LIMITATIONS

Data to support model parameters were limited. Study estimates are sensitive to the assumptions used.

CONCLUSIONS

The burden of clinic visits for G-CSF therapy is a significant addition to the total economic burden borne by cancer patients and their families.

Prevalence of bone metastases and bone-targeting agent use among solid tumor patients in the United States

Purpose

Patients with bone metastases are at an increased risk of experiencing morbidity due to bone complications, and bone-targeting agents (BTA) are indicated for the prevention of these complications. Population-based estimates of the prevalence of bone metastases associated with solid tumors, and current treatment patterns for these patients, are limited. This study was undertaken to estimate the prevalence of bone metastases from solid tumors and to describe recent trends in the use of BTA in the US.

Methods

We estimated the prevalence of bone metastases in the US in 2012 using data from Medicare fee-for-service and PharMetrics Plus, a large commercial claims database. We evaluated the proportion of patients with bone metastases who were treated with BTA in 2012, timing of initiation of BTA relative to bone metastasis diagnosis, and persistence on BTA, overall and by primary tumor type and treatment.

Results

There were ~330,000 (168,063 Medicare fee-for-service; 162,239 other) patients aged ≥18 years living with solid tumors and bone metastases in 2012. BTA were used by 43% (Commercial) to 47% (Medicare) of patients in 2012, with the greatest use among breast cancer patients. Over half (Medicare: 57%; Commercial: 53%) of BTA-treated patients initiated BTA after experiencing a bone complication.

Conclusion

Of the estimated 330,000 solid tumor patients living with bone metastases in the US in 2012, many may have received less than optimal care to prevent bone complications during the calendar year.