Cost-effectiveness analyses have focused on aromatase inhibitors (AIs), but the results are inconsistent and disease-free survival has often been extrapolated to overall survival. The present study calculates the cost-effectiveness of 5 years of letrozole versus tamoxifen versus anastrozole in the context of the German health care system, using survival data from the Breast International Group (BIG) 1–98 study and the Arimidex, Tamoxifen, Alone or in Combination (ATAC) study and generic prices.
Materials and Methods
A hybrid model was developed that incorporates recurrence rates, overall survival, treatment costs and treatment-associated adverse events and the resulting costs. The basic assumption was that generic anastrozole would lead to a price reduction to 75% of the original price. Further analyses were carried out with 50% and 25% of the original prices for anastrozole and letrozole.
The cost-benefit model showed a gain of 0.3124 or 0.0659 quality-adjusted life years (QALYs) for letrozole or anastrozole. Incremental costs of € 29,375.15/QALY for letrozole (100% of original price) were calculated and € 94,648.03/QALY for anastrozole (75% of original price). Marked increases in cost-effectiveness are observed with further decreases in price (anastrozole: 50% price € 54,715.17/QALY, 25% price € 14,779.57/QALY; letrozole 75% price € 20,988.59/QALY, 50% price € 12,602.03/QALY, 25% price € 4,215.46/QALY).
The present model including the inverse probability of censoring weighted analysis (IPCW) for letrozole and generic prices for both AIs shows that letrozole is cost effective.