Economic Impact of Adverse Events in Chronic Myelogenous Leukemia: A Cost of Treatment Analysis of Dasatinib.

OBJECTIVES: With a greater focus on costs in today’s health care markets, it is important to evaluate overall costs and quality of care associated with new therapies in cost-effectiveness analyses. Adverse events (AEs) associated with cancer therapies often result in substantial economic costs and negative impacts on patient quality of life. AEs may also affect adherence to therapy and result in suboptimal treatment outcomes. Important AEs of dasatinib in chronic myelogenous leukemia (CML) patients who are resistant to imatinib include neutropenia, thrombocytopenia, anemia, gastrointestinal hemorrhage, central nervous system hemorrhage, and fluid retention leading to effusions and heart dysfunction. This study evaluated the total cost of treatment with dasatinib in patients with chronic, accelerated, and myeloid blast phase CML, taking into account both drug and AE-associated costs. METHODS: A literature-based economic model was developed to examine the short-term potential impact of AEs in patients with CML treated with dasatinib. The incidence rates of Grade 3/4 AEs were obtained from the SPRYCEL™ (dasatinib) package insert. The AEs were assumed to occur within the first 6 months of treatment. The costs associated with the AEs were obtained from published medical literature and the 2003 Healthcare Cost and Utilization Project database of mean hospital charges by principal diagnosis, converting to costs using a Medicare cost-to-charge ratio of 0.55. Dasatinib dosing assumptions were based on the FDA briefing documents of the SPRYCEL™ filing submission presented at the June 2, 2006 Oncology Drug Advisory Committee meeting. The initial dose for dasatinib was 70 mg twice daily based on the package insert. Patients were assumed to remain on treatment for 6 months. However, dose interruption of 7–14 days during the first 3 months of treatment and dose reduction to 50 mg twice daily in the second 3 months of treatment were assumed in 46–55% and 9–10% of patients, respectively. Drug costs were based on wholesale acquisition cost. Univariate and multivariate sensitivity analyses were conducted. All costs were adjusted to 2006 U.S. dollars using the medical care component of the consumer price index. RESULTS: In the base case analysis, the expected 6-month per-patient cost of treatment for dasatinib was $31,528 for chronic phase, $44,340 for accelerated phase, and $48,666 for myeloid blast phase. Six-month drug cost alone was $22,284 per patient in each phase. Grade 3/4 AEs accounted for approximately 29%, 50%, and 54% of the total cost of care for chronic, accelerated, and myeloid blast phases, respectively. Sensitivity analysis showed that the 6-month cost of Grade 3/4 AEs may range from $5,235–$10,696 for chronic, $16,109–$23,723 for accelerated, and $12,971–$27,551 for myeloid blast phases. Primary cost drivers were the hematologic AEs. CONCLUSIONS: This study provides an estimate for the total cost of treatment with dasatinib that considers treatment costs for severe AEs associated with therapy. These results highlight the importance of including treatment-related AEs in addition to drug costs when assessing the economic value of treatment options for CML. Future studies should expand the time horizon of the analysis and include recurring AEs to more comprehensively evaluate the overall economic impact of AEs with dasatinib.