A systematic review and economic model of the clinical effectiveness and cost-effectiveness of docetaxel in combination with prednisone or prednisolone for the treatment of hormone-refractory metastatic prostate cancer.

OBJECTIVES A systematic review was undertaken and an economic model constructed to evaluate the clinical effectiveness and cost-effectiveness of docetaxel (Taxotere, Sanofi-Aventis) in combination with prednisone/prednisolone for the treatment of metastatic hormone-refractory prostate cancer (mHRPC). The main comparators considered were other established chemotherapy regimens and best supportive care. DATA SOURCES Twenty-one resources (including MEDLINE, EMBASE and the Cochrane Library) were searched to April 2005. REVIEW METHODS Two reviewers independently assessed studies for inclusion. Data from included studies were extracted and quality assessed. Where appropriate, outcomes were synthesised using formal analytic approaches. A new economic model was developed in order to establish the cost-effectiveness of docetaxel compared with a range of potential comparators. A separate review was undertaken to identify sources of utility data required to estimate quality-adjusted life-years (QALYs). Sensitivity analyses were also undertaken to explore the robustness of the main analysis to alternative assumptions related to quality of life. Monte Carlo simulation was used to propagate uncertainty in input parameters through the model in such a way that the results of the analysis could be presented with their uncertainty. The impact of uncertainty surrounding the decision was established using value of information and implementation approaches. RESULTS Seven randomised controlled trials were identified that met the inclusion criteria. A direct comparison of docetaxel plus prednisone versus mitoxantrone plus prednisone in an open-label randomised trial showed improved outcomes for docetaxel plus prednisone in terms of overall survival, quality of life, pain and prostate-specific antigen decline. Two other chemotherapy regimens that included docetaxel: docetaxel plus estramustine and docetaxel plus prednisone plus estramustine, also showed improved outcomes in comparison with mitoxantrone plus prednisone. Indirect comparison suggested that docetaxel plus prednisone seems to be superior to corticosteroids alone in terms of overall survival. Conclusions on cost-effectiveness were primarily informed by the results of the in-house model. This indicated that mitoxantrone plus a corticosteroid is probably cheaper and more effective than corticosteroid alone. Compared with mitoxantrone plus prednisone/prednisolone, the use of docetaxel plus prednisone/prednisolone (3-weekly) appears cost-effective only if the NHS is prepared to pay 33,000 pounds per QALY. The incremental cost-effectiveness ratio associated with docetaxel plus prednisone (3-weekly) remained fairly robust to these variations with estimates ranging from 28,000 pounds to 33,000 pounds per QALY. Value of information analysis revealed that further research is potentially valuable. Given a maximum acceptable ratio of 30,000 pounds per QALY, the expected value of information was estimated to be approximately 13 million pounds. CONCLUSIONS This systematic review of the research suggests that docetaxel plus prednisone seems to be the most effective treatment for men with mHRPC. The economic model suggests that treatment with docetaxel plus prednisone/prednisolone is cost-effective in patients with mHRPC provided the NHS is prepared to pay 33,000 pounds per additional QALY. Future research should include the direct assessment of quality of life and utility gain associated with different treatments, including the effect of adverse events of treatment, using generic instruments, which are suitable for the purposes of cost-effectiveness analyses.