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Purpose: The International Randomized Study of Interferon-α vs. STI571 (imatinib) (IRIS) demonstrated significantly improved clinical measures among patients newly diagnosed with chronic myeloid leukemia (CML) in the chronic phase who were initially randomized to imatinib relative to those initially randomized to interferon-α plus low-dose cytarabine (IFN-α + LDAC). The aim of our study was to estimate the incremental cost per life-year saved (LYS) and the incremental cost per quality-adjusted life-year (QALY) of first-line treatment with imatinib relative to IFN-α + LDAC in chronic phase CML patients. Methods: A simulation model was developed to incorporate clinical, resource utilization and utility data collected in IRIS with data from the literature to estimate lifetime costs, survival and quality adjusted survival. The model was designed so that patients initially treated with imatinib could switch to IFN-α + LDAC, and then to hydroxyurea. Patients initially treated with IFN-α + LDAC could switch to hydroxyurea. Long-term survival estimates were based on proportional hazards relationships estimated between age- and gender-matched individuals from the general population and historical CML patients who attained or did not attain complete cytogenetic response on treatment with IFN-α. The simulation model incorporated first and second order uncertainty. Probabilistic and traditional sensitivity analyses were undertaken to evaluate uncertainty. Results: In the base-case analysis, undiscounted mean survival was estimated at 15.30 years for patients receiving first-line imatinib and 9.07 years for patients receiving first-line IFN-α + LDAC. Undiscounted lifetime costs were estimated at approximately $424,600 for imatinib-treated patients and $182,800 for IFN-α + LDAC-treated patients. With an annual discount rate of 3%, the incremental gain in survival among patients treated with imatinib was 3.93 LYS and 3.89 QALYs. The incremental cost-effectiveness ratios (ICERs) were estimated at $43,100/LYS (95%CI: 37,600 to 51,100) and $43,300/QALY (95%CI: 38,300 to 49,100). The model’s results were most sensitive to changes in assumptions affecting the relative duration or costs of the treatments. Because lifetime costs closely tracked with survival, the ICERs were relatively consistent when varying assumptions used in survival estimation. Conclusions: When used as first-line therapy for newly diagnosed CML patients, imatinib appears to be an economically attractive therapy relative to first-line treatment with IFN-α + LDAC.
See more of Oral Concurrent Session B - Clinical Effectiveness and Quality of Life
See more of The 26th Annual Meeting of the Society for Medical Decision Making (October 17-20, 2004)