OBJECTIVES: THE AIM OF THIS STUDY IS TO COMPARE BUDGET IMPACT WITH TWO TREATMENT SEQUENCES FOR METASTATIC CASTRATION RESISTANT PROSTATE CANCER (MCRPC): ABIRATERONE ACETATE PLUS PREDNISO(LO)NE (AA+P) FOLLOWED BY DOCETAXEL (DOC) CHEMOTHERAPY AND THEN ENZALUTAMIDE (ENZ) (‘AA+P-DOC-ENZ SEQUENCE’) VERSUS ENZ FOLLOWED BY DOC CHEMOTHERAPY AND THEN AA+P (‘ENZ-DOC-AA+P SEQUENCE’) UNDER THE BRAZILIAN PRIVATE HEALTHCARE SYSTEM PERSPECTIVE. METHODS: A health economic model has been developed to estimate and compare cost consequences of these two treatment sequences in Brazil. hypothetically, a private plan with 100.000 lives was used as an example, with 5 years of impact.  Seven health states were considered in the model: prechemotherapy (AA+P or ENZ), active monitoring (before and after chemotherapy separately), DOC chemotherapy, post-chemotherapy (AA+P or ENZ), best supportive care, and death. Clinical input data (duration of treatment, time to chemotherapy) for the model were derived from published pivotal trial results. Costs parameters were derived from available literature and cmed’s official price list. For each treatment sequence, the model estimated total costs and total costs per health state. matching adjustment of full trial population was done.  RESULTS: the model estimated 3 patients (PT) starting treatment in 1^st year, reaching an incidence of 6 at the end of the 5^th year. Total costs were estimated to be R$ 256,459 for ‘AA+P-DOC-ENZ sequence’ in the 1^st year and R$ 258,129 for ‘ENZ-DOC-AA+P sequence’ resulting in total difference of -R$ 1,670. the difference between the two sequences was in each year: -R$ 1,670; -R$ 15,498; -R$ 38,307; -R$ 64,136 and -R$ 85,072 resulting in a total SAVINGS of R$ 204,683 in the end of 5 years FOR THE ‘AA+P-DOC-ENZ sequence’. CONCLUSIONS: ‘AA+P-DOC-ENZ sequence’ has a lower impact for the private plan compared to ‘ENZ – DOC-AA+ P sequence’. therefore starting treatment with AA+P may result in savings.