Cost-effectiveness analysis of exemestane compared with megestrol in patients with advanced breast carcinoma

The objective of this study was to determine the potential economic implications resulting from using exemestane (EXE), a new steroidal, irreversible aromatase inactivator, compared with megestrol acetate (MA) in patients with advanced breast carcinoma.

The model used the clinical results from the manufacturer-sponsored, international, randomized, controlled, double-blind trial of patients with postmenopausal, tamoxifen-refractory advanced breast carcinoma. Seven hundred sixty-nine women were randomized to EXE 25 mg per day or MA 40 mg four times daily EXE was well tolerated, significantly delayed tumor progression (relative risk [RR], 0.82; 95% confidence interval [95% CI], 0.70-0.97), and prolonged survival (RR, 0.77; 95% CI, 0.59-0.99). Lifetime effectiveness projections were made using the trial efficacy results to the U.S. market using a 1000-day ( approximately 3-year) time frame. Because the median survival of patients who received EXE was not reached, it was projected from the Cox model. There were no differences in the rate of hospitalization. The average wholesale prices for EXE and MA were used.

Patients who received EXE were projected to have a mean survival benefit of 53.5 days (estimated 95% CI, 2-100 days) and to incur at an additional cost of $1559 per patient (estimated 95% CI, 880-2075 dollars). The incremental cost effectiveness (CE) ratio using EXE was 10,600 dollars per life year gained (estimated 95% CI, 6200-209,000 dollars). If MA had no costs, then the CE ratio increased to 12,200 dollars per life year. Using a 5-year projection, the CE ratio for EXE was 5900 dollars per life year. The projected survival at 1000 days was 53.9% in the EXE cohort compared with 44.8% in the MA cohort.

EXE, compared with MA, is projected to increase survival at a modest added cost. If treatment with EXE delays or defers initiating more costly therapies, then it may even be cost saving.