Cost-effectiveness of interferon alfa in chronic myelogenous leukemia

Purpose: To evaluate the cost-effectiveness of interferon alfa (IFN alpha) treatment of patients with chronic myelogenous leukemia relative to conventional chemotherapy. Materials and Methods: A decision-analysis model that involved a multistate Markov process was designed to estimate the expected cost and quality-adjusted life expectancies for two cohorts of patients to be administered conventional chemotherapy or IFN alpha. Two IFN alpha strategies were modeled: prolonged treatment for patients who achieved a hematologic response (scenario A) or only for patients who achieved a cytogenetic remission in a 2-year period (scenario B). Delta on response and transition probabilities between health states were obtained from the literature by a MEDLINE search and pooled with a meta-analytic method, Costs were based on local charges. Expected survival was adjusted for quality of life on the basis of an expert panel judgment. Results: Baseline analysis showed IFN alpha treatment to increase the quality-adjusted life expectancy by 15.5 and 12.5 months relative to conventional chemotherapy, in scenarios A and B, respectively. Marginal cost-effectiveness was $89,500 and $63,500 per quality-adjusted life-year (QALY) gained. Sensitivity analysis confirmed IFN alpha as the most effective approach. Cost-effectiveness results were sensitive to the cost of IFN alpha therapy and to the assumptions about the rate of cytogenetic remission. Reducing the drug dose, as suggested by a recent report, would decrease the marginal cost-effectiveness to less than $20,000. Conclusion: IFN alpha is substantially superior to conventional chemotherapy in terms of quality-adjusted survival, but, at the current doses, marginal cost-effectiveness ranges from $50,000 to $100,000 per QALY gained under most of our assumptions. (C) 1997 by American Society of Clinical Oncology.