Objective: To evaluate the budget impact to a health plan after introducing Ixabepilone as a treatment option for metastatic breast cancer patients who have previously failed Anthracycline and Taxane based regimens. Methods: The analysis was conducted from a U.S. payer's perspective over a three-year time horizon. The model specifically considered 2 segments of MBC patients for which Ixabepilone is indicated: 1) patients pretreated with Anthracycline and Taxane (AT_p); and 2) patients pretreated with Anthracycline, Taxane, and Capecitabine (ATC_p). After combining epidemiological data (SEERs, NCI), market uptake assumptions from market research forecasting, and current drug treatment costs (based on WAC price and average number of treatment cycles a patient received), the model estimated the incremental budget impact after adopting Ixabepilone as a treatment option. The model assumed that during the first year, 9.41% of AT_p patients receive Ixabepilone and Capecitabine combination therapy; and 62.7% of ATC_p patients are treated with Ixabepilone monotherapy. A plausible range of parameter values were considered in the sensitivity analysis. Results: In a hypothetical health plan with approximately 0.06% of members estimated to be diagnosed with MBC, it was assumed that 37% were AT_p and 5% were ATC_p patients. In the year after introduction of Ixabepilone, the overall incremental cost per member per month (PMPM) was estimated to be approximately $0.03. For the AT_p patient segment, the incremental PMPM cost was estimated to be $0.03. However, for the ATC_p population, the model estimated a savings of $0.002 in PMPM. The incremental cost per treated MBC member per year is estimated at $545.29 for Year 1, and $640.76 and $668.01 for Years 2 and 3, respectively. Conclusion: In patients with MBC who have few viable treatment options after failing AT or ATC treatments, the budgetary impact of adding Ixabepilone to a health plan was estimated to be minimal.