OBJECTIVES: The advent of novel targeted therapies, such as ibrutinib, has altered the treatment paradigm for Chronic Lymphocytic Leukemia (CLL) in the recent years. The aim of this study was to estimate the budget impact of ibrutinib, a first-in-class once daily Bruton’s Tyroskine Kinase inhibitor, for the treatment of relapsed/refractory (R/R) CLL in the Brazilian private healthcare system (BPHS). METHODS: A budget impact analysis (BIA) was developed to project investments over the years from 2016 to 2019. An approach based on Brazilian age-adjusted incidence rate (IR) for R/R CLL patients was used to estimate the population eligible for analysis. Two scenarios were simulated: (1) current setting, in which patients are treated either with fludarabine-cyclophosphamide-rituximab (FCR) or ofatumumab monotherapy; (2) proposed setting, with introduction of ibrutinib monotherapy. Annual treatment costs were calculated following doses/intervals defined in the guidelines. Final costs were calculated considering drug acquisition costs and prices were gathered from the official Brazilian government website (CMED-ANVISA). Expected ibrutinib adoption rates were assumed over ofatumumab. RESULTS: Based on projected Brazilian total population (2016-2019) and employing proportion of patients in BPHS (24.70%), the BIA estimated eligible patient cohort with R/R CLL ranging from 158 (2016) to 166 (2019). Considering that all drugs would be considered tax-exempt, incorporation of ibrutinib would incur higher expenses for the treatment of R/R CLL, a budget impact of R$7,400,062 in 2016 and R$15,656,728 in 2019 and cumulative budget impact of R$45,801,929 (2016-2019). Considering the present population in BPHS, incorporation of ibrutinib would produce budget impact ranging from R$0.012 to R$0.025 per month, per life insured. CONCLUSIONS: In this BIA, the introduction of ibrutinib in BPHS as an option for R/R CLL patients would bring a small budget impact for private payers over the next 4 yrs, albeit with potentially superior outcomes over traditional chemoimmunotherapy as shown in studies of relapsed CLL.