Role of perspective and other uncertainties in cost-effectiveness assessments in advanced prostate cancer

Individualized strategy for dosing luteinizing hormone-releasing hormone agonists for androgen-independent prostate cancer: identification of outcomes and costs

PURPOSE

Continuing androgen suppression is the current standard in men with androgen-independent prostate cancer (AIPC). An individualized strategy, wherein luteinizing hormone-releasing hormone agonists (LH-RHas) are redosed when serum testosterone approaches a non-castrate level, may decrease costs without worsening outcomes. To understand possible outcomes, we performed a cost-utility analysis comparing individualized and fixed LH-RHa dosing strategies in men with AIPC.

METHODS

The model used a societal perspective, a 5-year time horizon, and 3% annual cost discounting. The model accounted for direct costs of androgen suppression. Utilities were varied in accordance with published preference data.

RESULTS

Under base-case assumptions, individualized LH-RHa dosing yielded 1.089 expected quality-adjusted life years (QALYs), compared with 1.094 expected QALYs for fixed LH-RHa dosing. In cost analysis, lifetime per-patient costs for androgen suppression were estimated to be $5,694 for individualized LH-RHa dosing and $9,157 for fixed LH-RHa dosing. Applied to the total population, a strategy of individualized LH-RHa dosing would cost $170 million for androgen suppression, compared with $274 million for fixed LH-RHa dosing. Under these assumptions, adopting the individualized strategy resulted in $692,600 gained from a societal perspective for each QALY lost (the decremental cost utility).

CONCLUSION

The results suggest that an individualized LH-RHa dosing strategy would be associated with moderate savings on an individual basis but substantial savings on a population basis, and would not adversely affect quality of life or life expectancy. Further research is needed to establish the effects of this strategy on symptoms and survival, as well as patient satisfaction and true costs.

Role of androgen deprivation treatment in patients with castration-resistant prostate cancer, receiving docetaxel-based chemotherapy

OBJECTIVES

To assess the impact of continued androgen deprivation therapy (ADT) in patients with castration-resistant prostate cancer (CRPC) receiving first-line docetaxel-based chemotherapy.

METHODS

A retrospective review was performed on 78 patients fulfilling the criteria for CRPC who were treated with docetaxel-based chemotherapy over 5 years.

RESULTS

Thirty-nine patients received concurrent ADT (ADT group), whereas 39 patients discontinued ADT (No-ADT group). PSA response rates were 66.7% for ADT patients and 48.7% for No-ADT patients (P = 0.27). The median progression-free survival and overall survival were 5.0 months and 24.8 months for ADT patients and 4.9 months and 22.1 months for No-ADT patients, respectively (P = 0.57, P = 0.94). Follow-up testosterone levels were available in 13 patients of the No-ADT group and none of them recovered a normal serum testosterone level over a median follow-up duration of 8.3 months from ADT discontinuation. ADT was recommenced in 21 of 39 patients in the No-ADT group and, of these, 6 (29%) achieved a PSA response.

CONCLUSION

Clinical outcomes were not significantly different when patients with CRPC received concurrent ADT, or were not so treated, when receiving first-line docetaxel-based chemotherapy. Despite ADT withdrawal, serum testosterone level did not recover to the noncastrated level during the period of chemotherapy, and reinduction of hormone sensitivity occurred in about one-quarter of patients.

Pharmacoeconomics of available treatment options for metastatic prostate cancer

The resources devoted to managing metastatic prostate cancer are enormous, yet little attention has been given to directly measuring the economic consequences of treatment alternatives. The purpose of this article was to evaluate the pharmacoeconomics of available treatments for metastatic prostate cancer, including hormone-sensitive disease, androgen-independent prostate cancer and locally advanced/progressive disease. We identified 58 articles addressing economic issues related to metastatic prostate cancer. Treatment alternatives with considerably different costs are available in many areas of disease management, most notably, medical androgen deprivation therapy (ADT) versus surgical castration; combined androgen blockage (CAB) versus monotherapy for initial treatment of hormone-sensitive disease; as well as bisphosphonates and bone-targeted radioisotopes for palliation. The few available pharmacoeconomic studies indicate that the additional costs are not supported by clear and compelling evidence of differences in survival or quality-of-life (QOL) outcomes. Our review revealed that authors often use considerably different assumptions about efficacy and survival outcomes in their analyses, which may be due to the inconsistency of available clinical evidence. Although there have been many clinical trials comparing various therapies, we identified only three trials that included economic assessments. Thus, few sources of economic data are available and most pharmacoeconomic studies rely on information mined from indirect sources. We note that, while there has been considerable enthusiasm about the role of docetaxel regimens in the past 2 years, no study has yet examined the costs of these therapies. Survival remains poor for metastatic disease, thus QOL is the primary consideration for many therapies. However, QOL for treatment of metastatic disease is poorly measured and, in most analyses, the impact of therapy on QOL was inferred based on speculation by the authors. Given the large cost burdens of these treatments, it is essential that we more fully understand the true QOL gains potentially offered by more expensive therapies. The economic studies of advanced prostate cancer highlight several aspects of clinical care that are filled with considerable uncertainty and remain guided by forces other than optimal resource allocation. It is essential that we address the weaknesses in our understanding of the economic consequences of therapies for prostate cancer, and find ways to include economic information into the process of determining optimal therapy.

Is combined androgen blockade with bicalutamide cost-effective compared with combined androgen blockade with flutamide?

OBJECTIVES

To determine the cost-effectiveness of combined androgen blockade (CAB) with bicalutamide versus CAB with flutamide in men with Stage D2 prostate cancer. Both bicalutamide and flutamide are commonly used in CAB for prostate cancer. Although the cost of bicalutamide is more than that of flutamide, it is important that the efficacy, quality of life, and side effects are also considered when determining whether CAB with bicalutamide is a cost-effective option.

METHODS

A decision model was created to compare treatment strategies. Survival and side-effect information was based on a randomized trial that directly compared bicalutamide and flutamide. The costs and quality-of-life effects related to therapy were determined from published sources.

RESULTS

The incremental cost per quality-adjusted life year gained for bicalutamide versus flutamide was 22,000 dollars and 16,000 dollars at 5 and 10 years, respectively. If a quality adjustment was not included, the incremental cost-effectiveness ratio for CAB with bicalutamide compared with CAB with flutamide was even more favorable (20,000 dollars/life year gained at 5 years). One-way sensitivity analysis demonstrated that the cost-effectiveness estimates were most sensitive to drug costs and survival (baseline survival was not significantly different between therapies). Multi-way uncertainty analysis revealed that the median value of the incremental cost-effectiveness ratio at 5 years was 13,637 dollars/quality-adjusted life year when all the parameters were varied over a clinically reasonable range.

CONCLUSIONS

Bicalutamide is cost-effective compared with flutamide when used for androgen blockade as part of CAB for men with advanced prostate cancer.