Economic impact of mortality risk reduction with first-line imatinib (IM) versus interferon-α (IFN) in patients newly diagnosed with chronic phase (CP) chronic myeloid leukemia (CML) under the Brazilian public healthcare system perspective over a 5-year period

Abstract

17068 Background: Patients receiving imatinib had a significant survival advantage compared with patients receiving IFN therapy (Roy et al. Blood 2006; Kantarjian et al. Blood 2006). Although reimbursed as second line therapy for CP CML patients who did not respond to INF-a, IM was not considered for public reimbursement as first line treatment in Brazil based on drug costs. An economic evaluation considering the mortality risk reduction with first line IM versus INF was performed under the Brazilian Public Healthcare System perspective, comparing the costs to avoid one death of a chronic phase CML patient over a 5-year period. Methods: Risk of death in 5 years was defined by survival rates in the 60 month follow-up of IRIS for IM (Rim= 10%) (Druker et al. JCO 2006), MD Anderson cohort of CML patients treated with INF-a for INF-a (RINF-a= 38%) (Cortes et al. American J. Med 1996) and a population based-survey in Norway for the natural course of the disease (Rnon-treatment= 67%). IRIS INF group survival rate was not used due to high crossover to IM in the trial. Risk of death in the natural course of the disease was the basis for the absolute risk reduction (ARR) calculation (ARRim= 57%; ARRINF-a= 29%). Number need to treat (NNT) was obtained by the inverse of ARR value for each first line treatment (NNT =1/ARR). Costs were estimated based on the Brazilian public healthcare reimbursement payment (APAC-SUS) for chronic phase CML treatment. A base case economic model of 100 patients for each treatment option was constructed focused on drug costs and adverse events (AE) from the IRIS study for both groups. Clinical guidelines from two public hematology centers were used to estimate AE treatment costs. Costs were discounted at a 6% annual rate. Results: The treatment costs and NNTs for a 5-year period are US$ 62,135 and 3.45 for INF-a, and US$ 93,397 and 1.75 for IM, respectively. The costs to avoid one death over a 5-year period are US$ 214,368 for INF-a and US$ 163,445 for IM. Conclusions: The costs for avoiding one death of a chronic phase CML patient over a 5-year period is US$ 50,923 higher with first line INF-a than it would be with first line imatinib. [Table: see text]