Cost-effectiveness of enzalutamide with androgen-deprivation therapy (ADT) versus ADT alone for the treatment of high-risk biochemically recurrent non-metastatic castration-sensitive prostate cancer in Canada

Abstract

Aim: The EMBARK (NCT02319837) trial demonstrated that enzalutamide with androgen-deprivation therapy (ADT; enzalutamide combination) or without ADT (enzalutamide monotherapy) significantly improved metastasis-free survival compared with ADT alone in high-risk biochemically recurrent (BCR) non-metastatic castration-sensitive prostate cancer (nmCSPC; also known as non-metastatic hormone-sensitive prostate cancer [nmHSPC]). No new safety signals were observed during the trial. The findings of EMBARK led to Health Canada's approval of enzalutamide for this patient population. The aim of this analysis was to assess the cost-effectiveness of enzalutamide combination versus ADT alone in patients with high-risk BCR nmCSPC from the Canadian payer's perspective.

Material and methods: A semi-Markov model was created to represent the treatment and disease progression of patients with high-risk BCR nmCSPC over a 30-year horizon. Costs and outcomes were discounted at 1.5% annually. Treatment effects for high-risk BCR nmCSPC were informed by data from the EMBARK trial. Life-years (LYs), quality-adjusted life-years (QALYs), lifetime costs and incremental cost-effectiveness ratio (ICER) were estimated for enzalutamide combination and ADT alone. A one-way sensitivity analysis (OWSA) and scenario analyses were conducted to assess the robustness of results.

Results: In the base-case deterministic analysis over the modeled time horizon, enzalutamide combination accumulated 11.85 LYs and 8.96 QALYs versus 8.75 LYs and 6.24 QALYs for ADT alone. The total cost for enzalutamide combination was Canadian dollars (CAD) 166,199, compared with CAD 95,146 for ADT alone. When combining cost and clinical outcome data, enzalutamide combination was associated with an ICER of CAD 26,129 per QALY gained. The OWSA and scenario analysis results were consistent with the base-case results.

Conclusion: The study findings suggest that enzalutamide combination was associated with an ICER of CAD 26,129 per QALY gained, which is within the standard Canadian thresholds for willingness-to-pay (i.e. <CAD 50,000 per QALY gained), making enzalutamide combination a preferred treatment option for patients with high-risk BCR nmCSPC in Canada.

Keywords: Canada; Enzalutamide; I11; I15; androgen-deprivation therapy; biochemically recurrent; cost-effectiveness; cost-utility analysis; non-metastatic hormone-sensitive prostate cancer.