OBJECTIVES

To assess the cost-utility of abiraterone versus enzalutamide in the treatment of metastatic castration-resistant prostate cancer (mCRPC) in asymptomatic or mildly symptomatic patients, after failure of androgen deprivation therapy (ADT) in Portugal.

METHODS

: A lifetime individual-patient simulation model was used to predict time in each health state, according to survival functions that include as explanatory variables the baseline profile and the history of each patient. In each health state, patients face competing risks of death and transition to the next state. Health states are defined by the therapeutic algorithm (pre-docetaxel, docetaxel and post-docetaxel), including periods without any active treatment or on best supportive care. Survival functions were based in the reference clinical trial of abiraterone in the treatment of mCRPC after ADT failure (COU-AA-302), with the treatment coefficient for enzalutamide’s survival functions being adjusted according to median time on treatment from PREVAIL trial. Health state utilities were obtained from the COU-AA-302 trial, the literature and an Oxford Outcomes’ study that assessed quality of life on this population. Resource consumption was based on an expert panel with six specialists on mCRPC treatment in Portugal. Unit costs were based on official sources. The payer’s perspective was considered and costs and consequences were discounted at a 5% annual rate.

RESULTS

: Compared to enzalutamide, abiraterone was associated to an average saving of €12,564 per patient, with incremental 0.102 life years or 0.003 quality adjusted life years (QALY). Cost differences are mainly due to the lower time on treatment (1.784 years) when compared to enzalutamide (2.118 years).

CONCLUSIONS

: Abiraterone in the treatment of metastatic castration-resistant prostate cancer in asymptomatic or mildly symptomatic patients is a less expensive and more effective option than enzalutamide, being considered a dominant alternative in the Portuguese setting.