Estimating the cost effectiveness of total androgen blockade with flutamide in M1 prostate cancer

Abstract

Objectives: Although combined androgen blockade with flutamide plus medical or surgical castration is effective in metastatic prostate cancer, debate exists over whether it is cost effective.

Methods: Decision analysis model of hypothetical cohorts of 70-year-old men presenting with metastatic prostate cancer, using a societal perspective, calculated anticipated survival and incremental cost per life-year gained. Time to progression and survival rate were from the Intergroup 0036 trial. Costs were based on Medicare data and wholesale drug pricing. Flutamide was estimated to reduce the relative risk of progressive disease by 25% (range, 0 to 50%). Costs and survival benefits were discounted at a 5% annual rate.

Results: In our model for minimal disease, median survival increased from 42.3 to 49.4 months with flutamide and average survival by 5.2 months at an incremental cost of $25,300 per life-year gained. If the efficacy were as high as 50%, the benefit would be 12 months at a cost of $13,700 per life-year gained. At a 10% efficacy, the benefit would be 1.9 months at a cost of $60,900 per life-year gained. For severe disease, the model estimated the median survival increased from 29.5 to 34.3 months with flutamide and average survival by 4.0 months at an incremental cost of $20,000 per life-year gained. At worst-case 10% efficacy, the benefit decreased to 1.5 months at an incremental cost of $47,500 per life-year gained. Total costs for patients treated with an orchiectomy and flutamide compared to leuprolide alone were similar if severe disease was present and actually lowered costs if there was minimal disease.

Conclusions: Flutamide has an incremental cost effectiveness more favorable than most accepted therapies. If drug costs are covered under health care reform, flutamide should be initiated and covered for all good performance status patients.