Management of castration-resistant prostate cancer: bisphosphonates and emerging therapies

Addition of Docetaxel and/or Zoledronic Acid to Standard of Care for Hormone-naive Prostate Cancer: A Cost-effectiveness Analysis

Background

The effectiveness of the addition of docetaxel and/or zoledronic acid to the standard of care (SOC) for hormone-naive prostate cancer has been evaluated in the STAMPEDE trial. The object of the present analysis was to evaluate the cost-effectiveness of these treatment options in the treatment of advanced hormone-naive prostate cancer in China.

Methods

A cost-effectiveness analysis using a Markov model was carried out from the Chinese societal perspective. The efficacy data were obtained from the STAMPEDE trial and health utilities were derived from previous studies. Transition probabilities were calculated based on the survival in each group. The primary endpoint in the analysis was the incremental cost-effectiveness ratio (ICER), and model uncertainties were explored by 1-way sensitivity analysis and probabilistic sensitivity analysis.

Results

SOC alone generated an effectiveness of 2.65 quality-adjusted life years (QALYs) at a lifetime cost of $20,969.23. At a cost of $25,001.34, SOC plus zoledronic acid was associated with 2.69 QALYs, resulting in an ICER of $100,802.75/QALY compared with SOC alone. SOC plus docetaxel gained an effectiveness of 2.85 QALYs at a cost of $28,764.66, while the effectiveness and cost data in the SOC plus zoledronic acid/docetaxel group were 2.78 QALYs and $32,640.95.

Conclusions

Based on the results of the analysis, SOC plus zoledronic acid, SOC plus docetaxel, and SOC plus zoledronic acid/docetaxel are unlikely to be cost-effective options in patients with advanced hormone-naive prostate cancer compared with SOC alone.

Clodronate inhibits tumor angiogenesis in mouse models of ovarian cancer

PURPOSE

Bisphosphonates have been shown to inhibit and deplete macrophages. The effects of bisphosphonates on other cell types in the tumor microenvironment have been insufficiently studied. Here, we sought to determine the effects of bisphosphonates on ovarian cancer angiogenesis and growth via their effect on the microenvironment, including macrophage, endothelial and tumor cell populations.

EXPERIMENTAL DESIGN

Using in vitro and in vivo models, we examined the effects of clodronate on angiogenesis and macrophage density, and the overall effect of clodronate on tumor size and metastasis.

RESULTS

Clodronate inhibited the secretion of pro-angiogenic cytokines by endothelial cells and macrophages, and decreased endothelial migration and capillary tube formation. In treated mice, clodronate significantly decreased tumor size, number of tumor nodules, number of tumor-associated macrophages and tumor capillary density.

CONCLUSIONS

Clodronate is a potent inhibitor of tumor angiogenesis. These results highlight clodronate as a potential therapeutic for cancer.

Celecoxib plus hormone therapy versus hormone therapy alone for hormone-sensitive prostate cancer: first results from the STAMPEDE multiarm, multistage, randomised controlled trial

Background

Long-term hormone therapy alone is standard care for metastatic or high-risk, non-metastatic prostate cancer. STAMPEDE—an international, open-label, randomised controlled trial—uses a novel multiarm, multistage design to assess whether the early additional use of one or two drugs (docetaxel, zoledronic acid, celecoxib, zoledronic acid and docetaxel, or zoledronic acid and celecoxib) improves survival in men starting first-line, long-term hormone therapy. Here, we report the preplanned, second intermediate analysis comparing hormone therapy plus celecoxib (arm D) with hormone therapy alone (control arm A).

Methods

Eligible patients were men with newly diagnosed or rapidly relapsing prostate cancer who were starting long-term hormone therapy for the first time. Hormone therapy was given as standard care in all trial arms, with local radiotherapy encouraged for newly diagnosed patients without distant metastasis. Randomisation was done using minimisation with a random element across seven stratification factors. Patients randomly allocated to arm D received celecoxib 400 mg twice daily, given orally, until 1 year or disease progression (including prostate-specific antigen [PSA] failure). The intermediate outcome was failure-free survival (FFS) in three activity stages; the primary outcome was overall survival in a subsequent efficacy stage. Research arms were compared pairwise against the control arm on an intention-to-treat basis. Accrual of further patients was discontinued in any research arm showing safety concerns or insufficient evidence of activity (lack of benefit) compared with the control arm. The minimum targeted activity at the second intermediate activity stage was a hazard ratio (HR) of 0·92. This trial is registered with ClinicalTrials.gov, number NCT00268476, and with Current Controlled Trials, number ISRCTN78818544.

Findings

2043 patients were enrolled in the trial from Oct 17, 2005, to Jan 31, 2011, of whom 584 were randomly allocated to receive hormone therapy alone (control group; arm A) and 291 to receive hormone therapy plus celecoxib (arm D). At the preplanned analysis of the second intermediate activity stage, with 305 FFS events (209 in arm A, 96 in arm D), there was no evidence of an advantage for hormone therapy plus celecoxib over hormone therapy alone: HR 0·98 (95% CI 0·90–1·06). 2-year FFS was 51% (95% CI 46–56) in arm A and 51% (95% CI 43–58) in arm D. There was no evidence of differences in the incidence of adverse events between groups (events of grade 3 or higher were noted at any time in 123 [23%, 95% CI 20–27] patients in arm A and 64 [25%, 19–30] in arm D). The most common grade 3–5 events adverse effects in both groups were endocrine disorders (55 [11%] of patients in arm A vs 19 [7%] in arm D) and musculoskeletal disorders (30 [6%] of patients in arm A vs 15 [6%] in arm D). The independent data monitoring committee recommended stopping accrual to both celecoxib-containing arms on grounds of lack of benefit and discontinuing celecoxib for patients currently on treatment, which was endorsed by the trial steering committee.

Interpretation

Celecoxib 400 mg twice daily for up to 1 year is insufficiently active in patients starting hormone therapy for high-risk prostate cancer, and we do not recommend its use in this setting. Accrual continues seamlessly to the other research arms and follow-up of all arms will continue to assess effects on overall survival.

Funding

Cancer Research UK, Pfizer, Novartis, Sanofi-Aventis, Medical Research Council (London, UK).