Pharmacoeconomics of bisphosphonates for skeletal-related event prevention in metastatic non-breast solid tumours

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.

Canadian health care institution resource utilization resulting from skeletal-related events

PURPOSE

We describe the types of major institution health care resources consumed as a result of skeletal-related events (SREs) [ie, pathological fracture, bone surgery, radiation to bone, spinal cord compression].

METHODS

A retrospective multicenter chart review of cancer patients with bone metastases who experienced SREs was conducted. Patients with multiple SREs occurring during the same hospitalization within 21 days of each other were grouped into SRE clusters.

RESULTS

We reviewed 156 patient charts from 4 Canadian institutions, accounting for 358 SREs and 259 SRE clusters. Of the total patients, 63% experienced 1 SRE; 19%, 2 SREs; 10%, 3 SREs; and 8%, ≥ 4 events. Health care resource utilization was captured for ≥ 90 days following each SRE: 54% of all SRE events resulted in an inpatient stay; 34% in an emergency visit; 85% of SREs required the use of diagnostic procedures (including radiography, magnetic resonance imaging, Computerized Axial Tomography scans, and radio scans); 57% required radiation treatment; 34% required a surgical procedure; 35% received outpatient treatment visits (ie, physiotherapy or occupational therapy). Bone surgery and spinal cord compression were more often associated with hospitalization than were other SRE types. Spinal cord compression was associated with the greatest number of inpatients stays (1.09 per SRE), longest duration of hospital stay (mean 26.18 days per SRE), and more outpatient visits, relative to other SRE types.

CONCLUSION

Results of our Canadian retrospective study clearly demonstrate that SREs occur in cancer patients and each SRE is associated with considerable institutional consumption of health care resources.

The economics of abiraterone acetate for castration-resistant prostate cancer

Abiraterone acetate is an oral medication that has recently been granted approval for the treatment of metastatic castration resistant prostate cancer (mCRPC) prior and/or after chemotherapy with docetaxel. In this article we assess the economics of abiraterone acetate in mCRPC. Relevant studies demonstrated that abiraterone acetate had a minimal budget impact on health plans. A relevant advantage was the cost savings due to the lack of chemotherapy-related side effects as well as the ease of administration. The results of cost/benefit comparative studies with other novel agents (i.e. cabazitaxel, enzalutamide, sipuleucel-T) are warranted as well as the close collaboration between urologists and medical oncologists.

Early inhibitory effects of zoledronic acid in tooth extraction sockets in dogs are negated by recombinant human bone morphogenetic protein

PURPOSE

This study was conducted with 2 purposes. The first was to determine the effect of a single dose of zoledronic acid (ZA) on the healing of a tooth extraction socket in dogs. The second was to determine if placement of recombinant human bone morphogenetic protein-2 (rhBMP-2)/absorbable collagen sponge (ACS) - INFUSE, (Medtronic, Memphis, TN) into these extraction sockets would inhibit the inhibition on bone healing and remodeling by ZA.

MATERIALS AND METHODS

Nine adult female beagle dogs (2 to 3 yr old) were placed into 3 groups of 3 dogs each. Group I received 15 mL of sterile saline intravenously; group II received 2.5 mg of ZA intravenously; and group III received 5 mg of ZA intravenously. Forty-five days after treatment, all dogs underwent extraction of noncontiguous right and left mandibular first molars and second premolars. In group I, the right mandibular extraction sockets had nothing placed in them, whereas the left mandibular sockets had only ACS placed in them. In groups II and III, the right mandibular sockets had rhBMP-2/ACS placed in them, whereas the left mandibular sockets had only ACS placed. All extraction sockets were surgically closed. Tetracycline was given intravenously 5 and 12 days later, and all animals were euthanized 15 days after tooth extraction. The extraction sockets and rib and femur samples were harvested immediately after euthanasia, processed, and studied microscopically.

RESULTS

A single dose of ZA significantly inhibited healing and bone remodeling in the area of the tooth extractions. The combination of rhBMP-2/ACS appeared to over-ride some of the bone remodeling inhibition of the ZA and increased bone fill in the extraction sites, and remodeling activity in the area was noted. The effects of rhBMP-2/ACS were confined to the area of the extraction sockets because bone activity at distant sites was not influenced.

CONCLUSIONS

A single dose of ZA administered intravenously inhibits early healing of tooth extraction sockets and bone remodeling in this animal model. The combination of rhBMP-2/ACS significantly increased bone fill and bone remodeling in these areas, negating much of the effect of the ZA.

Bisphosphonates in the treatment of patients with lung cancer and metastatic bone disease: a systematic review and meta-analysis

PURPOSE

Bisphosphonates are known to prevent skeletal-related events (SREs) in advanced breast cancer, prostate cancer, and multiple myeloma. This systematic review assessed the efficacy of bisphosphonates in preventing SREs, controlling pain, and overall survival in patients with bone metastases from lung cancer.

METHODS

We searched MEDLINE, EMBASE, Web of Science, and the Cochrane Library databases through November 10, 2011 for controlled trials that included lung cancer patients with bone metastases treated with bisphosphonates. Two reviewers independently extracted data on pain control, survival, and SREs and evaluated the quality of each study. Meta-analyses were performed when there were two or more trials with similar outcomes.

RESULTS

Twelve trials met our inclusion criteria and included 1,767 patients. Studies were placebo-controlled, or had compared bisphosphonates with other modalities (chemotherapy, radiation therapy, or radioisotope therapy), or had used different bisphosphonates as active controls. Randomized controlled trials did not report adequate descriptions of randomization procedures, allocation concealment, and blinding, resulting in low-quality scores. Patients treated with zoledronic acid + chemotherapy had fewer SREs than those receiving chemotherapy alone (relative risk (RR) 0.81, 95 % confidence interval (CI) 0.67-0.97). Pain control improved when a bisphosphonate was added to another treatment modality (chemotherapy or radiation; RR 1.18, 95 %CI 1.0-1.4). Bisphosphonate therapy improved survival compared to controls, but the difference failed to reach statistical significance (mean of 72 days, 95 %CI -8.9 to 152.9).

CONCLUSIONS

Treatment with bisphosphonates reduced SREs, improved pain control, and showed a trend to increased survival. Bisphosphonates should be used in the treatment of patients with lung cancer and bone metastases.