Cost-Utility Analysis Of Enzalutamide For Patients With Chemotherapy-Naïve Metastatic Castration-Resistant Prostate Cancer (Mcrpc) After Failure Of Androgen Deprivation Therapy (Adt).

PCN248 Cost-Utility ANAlysis of ENzAlUtAmidE for PAtiENts With ChEmothErAPy-NAïvE mEtAstAtiC CAstrAtioN-rEsistANt ProstAtE CANCEr (mCrPC) AftEr fAilUrE of ANdrogEN dEPrivAtioN thErAPy (Adt) Vicente C1, Loblaw A2, North S3, Kassouf W4, Naidoo S5, Husein F6, Nakhaipour HR6 1PIVINA Consulting Inc., Mississauga, ON, Canada, 2University of Toronto, Toronto, ON, Canada, 3University of Alberta, Edmonton, AB, Canada, 4McGill University Health Centre, Montreal, QC, Canada, 5Astellas, Chertsey, UK, 6Astellas, Markham, ON, Canada Objectives: Enzalutamide prolonged overall survival and radiographic progression-free survival (rPFS), delayed initiation of cytotoxic chemotherapy and maintained quality of life in patients with chemotherapy-naïve mCRPC after failure of ADT (PREVAIL; Beer et al 2014). The cost-effectiveness of enzalutamide, compared with abiraterone plus prednisone (ABI+P) for patients with chemotherapy-naïve mCRPC, was evaluated from the perspective of the Canadian Ministries of Health (MoH). MethOds: A Markov model was developed to capture time spent by patients in various health states: stable, progression and death. Results were reported as incremental costs per additional quality-adjusted life year (QALY) gained over a 10-year period. Transition probabilities were derived from patient-level data from PREVAIL and a network meta-analysis (NMA) of available trials. Base case analysis focused on direct medical costs from the Canadian MoH perspective. Cost data was obtained from a variety of Canadian sources, valued in 2015 Canadian dollars. A 5% discount rate was applied to costs and outcomes. Multiple sensitivity analyses were performed. Results: NMA results suggested no difference between enzalutamide and ABI+P for overall survival, but indicated that enzalutamide is superior to ABI+P for rPFS (hazard ratio 0.35; credible interval 0.27, 046). The improvement in rPFS translated into a longer mean duration of stable disease with enzalutamide (36.7 months) than with ABI+P (16.4 months), and greater total QALYs (enzalutamide 2.65; ABI+P 2.23). From the Canadian MoH perspective, enzalutamide had an incremental cost-effectiveness ratio (ICER) of $92,690 per additional QALY gained versus ABI+P. The ICER was robust over a wide range of sensitivity analyses. In the probabilistic sensitivity analysis, the mean ICER was $110,036 per QALY gained versus ABI+P, with > 60% of iterations falling below a willingness-to-pay threshold of $100,000 per QALY gained. cOnclusiOns: Enzalutamide is considered a costeffective treatment option compared to ABI+P in patients with chemotherapy-naïve mCRPC after failure of ADT.