ObjectivesThe aim of this study was to perform a budget impact analysis (BIA) of introducing olaparib treatment for adult patients with metastatic castration-resistant prostate cancer in Argentina.MethodsA BIA model was used to estimate the cost difference between the current scenario (without olaparib) and the new scenario (incorporation of olaparib) for a third-party payer over a 5-year time horizon. The budgetary impact is estimated at the national health system level and by healthcare sectors in Argentina. Input parameters were obtained from the literature and validated by local expert opinion. Direct medical costs were obtained from both the Institute for Clinical Effectiveness and Health Policy (IECS) unit cost database and public data in Argentina. The microcosting estimation was used for key variables of the analysis. All costs are reported in US dollars (US$) as for October 2022 (1 US$ = 152.59 Argentine pesos). One-way sensitivity analyses and scenario analyses were conducted to evaluate the model robustness.ResultsThe incorporation of olaparib, with a wholesale price per pack of US$3176, was associated with a weighted average of the budget impact per member per month (PMPM) of US$0.0191 for the national health system, being slightly higher than the estimated budgeted high impact threshold (US$0.0153). The PMPM budget impact for a 5-year average ranged between US$0.007 (public sector) and US$0.033 (private sector). The duration of treatment with olaparib was the most influential parameter in the budget impact results.ConclusionsThe introduction of olaparib for the treatment of metastatic castration-resistant prostate cancer has a high budget impact for Argentina's health system. These findings are informative to support policy decisions aimed to expand the current treatment landscape for prostate cancer.