New therapeutic options in metastatic castration-resistant prostate cancer: Can cost-effectiveness analysis help in treatment decisions?

Objective: To evaluate the cost-effectiveness of abiraterone, cabazitaxel, and enzalutamide compared to placebo for treatment of metastatic castration-resistant prostate cancer.
Material and Methods: A decision-tree model compared three treatment options for metastatic castration-resistant prostate cancer patients over 18 months from a societal perspective in 2012 USD. Chance nodes included baseline pain as a severity indicator, significant adverse effects (neutropenia, cardiac events, or seizures), and survival. Probabilities, survival rates, and health utilities were from clinical trials (COU-AA, TROPIC, and AFFIRM) and other published studies. Survival of enzalutamide was adjusted to match placebo groups across trials. Probabilistic sensitivity analyses, acceptability curves and net benefit calculations were performed.
Results: Abiraterone was the most cost-effective of the treatments ($123.4 K/quality-adjusted life year) compared to placebo, enzalutamide was $437.6 K/quality-adjusted life year compared to abiraterone, and cabazitaxel was $351.9 K/quality-adjusted life year compared to enzalutamide. Enzalutamide and cabazitaxel were not cost-effective compared to placebo at $154.3 K/quality-adjusted life year and $163.2 K/quality-adjusted life year, respectively. Acceptability curves showed abiraterone was cost-effective 29.3% of the time with a willingness to pay threshold of $100 K. The model was sensitive to changes in cost of the drugs, life expectancy, and survival rate. Sensitivity analysis shows that enzalutamide can become the most cost-effective option if the price of the medication decreased by 26% and other drug costs remained the same.
Conclusion: Based on the cost-effective analysis, and survival adjustments necessary to match placebo groups, we would recommend abiraterone for treatment of metastatic castration-resistant prostate cancer despite not quite falling under the usually accepted willingness to pay threshold. Further analysis should examine comparative survival across the three drugs.
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