A retrospective cost-effectiveness analysis of interferon as adjuvant therapy in high-risk resected cutaneous melanoma

To assess the cost per life year gained of alpha interferon (IFN) as adjuvant therapy for patients with high-risk resected melanoma, we conducted a retrospective, incremental cost-effectiveness analysis on clinical data from a previously published ECOG trial [9]. The Gompertz model was used to estimate the total Lifetime values of patient-gears of subjects receiving IFN in comparison with subjects given no adjuvant treatment. The ECOG trial involved 143 patients treated with high-dose IFN and 137 given no adjuvant treatment. Estimated drug expenditures were based on the assumption of a cost of $109.25 per 10 MU of IFN. Our analysis of the ECOG results showed that the adjuvant treatment of 100 subjects with high-dose IFN improved survival expectancy by 133.6 discounted life years or 308 undiscounted life years. The use of IFN (compared with no adjuvant treatment) implied an incremental cost of $16467 per discounted life year saved (95% Cl of $4752-50000) or $7143 per undiscounted life year saved (95% CI of $3226-33846). Sensitivity testing, in which variations were introduced in the main factors influencing cost and effectiveness, showed that this value always remained below $50000. Our pharmacoeconomic analysis indicates that adjuvant treatment with high-dose IFN in patients with high-risk resected melanoma implies a favourable cost-effectiveness ratio. Because two other studies showed no significant survival benefit in patients receiving adjuvant IFN at lower values of total dose per patient, the controversy remains and confirmation data are needed for the ECOG trial's results. If these clinical results are confirmed, our analysis shows that the dosage of IFN given in this trial has a favourable pharmacoeconomic profile. (C) 1997 Elsevier Science Ltd.