Pharmacoeconomic evaluation of using enzalutamide for treatment of patients with metastatic hormone-sensitive prostate cancer

Abstract

Background. The addition of enzalutamide to standard androgen deprivation therapy (ADT) significantly increases overall survival and progression-free survival in patients with metastatic hormone-sensitive prostate cancer (mHSPC) compared with ADT.Objective: to evaluate the incremental cost/effectiveness ratio (ICER) of enzalutamide use in patients with mHSPC and the ICER of enzalutamide as the first-line therapy for metastatic castration-resistant prostate cancer (mCRPC) from the Russian healthcare system perspective and to assess the contribution of enzalutamide into the reduction of mortality of mHSPC patients in the Russian Federation on the horizon until 2024.Materials and methods. Standard ADT regimens for mHSPC were used as a comparator as it is the most common treatment for mHSPC in Russia. We proposed a Markov model of mHSPC progression on enzalutamide + ADT (hereinafter enzalutamide) or ADT + 1st generation antiandrogen (hereinafter ADT) based on ENZAMET trial data. Model was used to calculate the average life-years gained (LYG) and costs of mHSPC and post-progression mCRPC treatment. Simulation period was 15 years with one cycle of 1 month. In the “cost–effectiveness” analysis, we calculated enzalutamide ICER compared to ADT. In addition, we calculated ICER for enzalutamide plus ADT vs ADT in the first-line therapy of mCRPC as a benchmark based on PREVAIL trial data. In both cases, the average LYG over a 15-year period was used as an efficacy criteria. To assess the contribution of the enzalutamide into the reduction of mortality rate of mHSPC patients, the potential number of patients who could be treated with enzalutamide on the horizon of 2021–2024 was taken into account.Results. According to the Markov model, the average LYG over a period of 15 years for enzalutamide was 7.59 years compared to 5.12 for ADT. The average enzalutamide therapy costs were 11,193,802 rubles per patient for 15 years, which were 8,597,131 rubles higher than when using ADT (2,596,672 rubles). ICER for enzalutamide (vs ADT) in mHSPC treatment was 3,484,362 rubles per one life-year gained. ICER for enzalutamide in the first line of mCRPC treatment (vs ADT) was 5,899,418 rubles per one life-year gained. The combination therapy with enzalutamide + ADT in Russia can be started annually by 2,410 mHSPC patients. If they all receive enzalutamide a total of 561 averted deaths among prostate cancer patients can be expected in 2021–2024.Conclusion. In the Russian healthcare system, ICER for enzalutamide in mHSPC was 3,484,362 rubles and the ICER for enzalutamide in mCRPC was 5,899,418 rubles. Enzalutamide can make a significant contribution to achieving the target cancer mortality rates by 2024.