A cost-utility analysis of apalutamide for metastatic castration-sensitive prostate cancer

Introduction: Earlier application of oral androgen receptor-axis targeted therapies in patients with metastatic castration-sensitive prostate cancer (mCSPC) has established improvements in overall survival, as compared to androgen deprivation therapy (ADT) alone. Recently, the use of apalutamide plus ADT has demonstrated improvement in mCSPC-related mortality vs. ADT alone, with an acceptable toxicity profile. However, the cost-effectiveness of this therapeutic option remains unknown. Methods: We used a state-transition model with probabilistic analysis to compare apalutamide plus ADT, as compared to ADT alone, for mCSPC patients over a time horizon of 20 years. Primary outcomes included expected life-years (LY), quality-adjusted life-years (QALY), lifetime cost (2020 Canadian dollars), and incremental cost-effectiveness ratio (ICER). Parameter and model uncertainties were assessed through scenario analyses. Health outcomes and cost were discounted at 1.5%, as per Canadian guidelines. Results: For the base-case analysis, expected LY for ADT and apalutamide plus ADT were 4.11 and 5.56, respectively (incremental LY 1.45). Expected QALYs were 3.51 for ADT and 4.84 for apalutamide plus ADT (incremental QALYs 1.33); expected lifetime cost was $36 582 and $255 633, respectively (incremental cost $219 051). ICER for apalutamide plus ADT, as compared to ADT alone, was $164 700/QALY. Through scenario analysis, price reductions >50% were required for apalutamide in combination with ADT to be considered cost-effective, at a cost-effectiveness threshold of $100 000/QALY. Conclusions: Apalutamide plus ADT is unlikely to be cost-effective from the Canadian healthcare perspective unless there are substantial reductions in the of treatment.