A cost-utility analysis of apalutamide for the treatment of patients with metastatic castration-sensitive prostate cancer (mCSPC).

Abstract

e19369 Background: The therapeutic landscape for patients with mCSPC has evolved over the last decade given the growing body of evidence demonstrating efficacy for the earlier application of oral androgen receptor signaling inhibitors, such as with abiraterone and enzalutamide. Recently the success of the TITAN trial established the superior efficacy of apalutamide combined with androgen deprivation therapy (ADT), with a 33% reduction in mortality versus ADT alone, and a tolerable toxicity profile. However, with substantially higher costs than ADT alone, the cost-effectiveness of this combination is critical to evaluate. Methods: A cost-utility analysis of apalutamide+ADT versus ADT alone was conducted from the Canadian healthcare perspective. A state-transition model with probabilistic analysis was used to compare the two strategies over a lifetime horizon. Model inputs were informed by the TITAN trial (transition probabilities, adverse events [AE], subsequent therapy), published literature (utilities) and Canadian costing resources (systemic therapy [initial and subsequent], routine care [physician visits, imaging], AE, end-of-life care costs). Primary outcomes included expected life-year gains (LYG), quality-adjusted life-years (QALY), lifetime cost (in 2018 Canadian dollars), and the incremental cost-effectiveness ratio (ICER). Multiple scenario analyses were conducted to assess parameter and model uncertainty. Cost and effectiveness were discounted at 1.5% as per Canadian guidelines. Results: From the base-case analysis expected LYG and QALY for ADT and apalutamide+ADT were 4.11, 5.57 and 3.50, 4.85, respectively. Expected cost over a lifetime horizon was $37,553 and $254,205, respectively. The ICER for apalutamide+ADT as compared to ADT alone was $160,483/QALY. Through scenario analysis, cost-effectiveness of apaluatmide+ADT was achieved with apalutamide price reductions of >50%, relative to a cost-effectiveness threshold (CET) of $100,000/QALY. Scenario analysis of alternative long-term survival expectations with apalutamide+ADT demonstrated cost-effectiveness (relative to CET $100,000/QALY) with expected improvements in the 5-year survival rate of 29% as compared to ADT (versus base-case expected improvement in 5-year survival of 15%). Conclusions: Apalutamide+ADT is unlikely to be cost-effective from the Canadian healthcare perspective at current list prices. Improvement in cost-effectiveness is most likely to be achieved through price reductions in apalutamide drug costs.