Cost comparison of different forms of androgen ablative therapies in metastatic castration-resistant prostate cancer in Canada

Objectives: Androgen ablation (ADT) maintenance is recommended during castration- resistant prostate cancer; however the overall cost of medications during this phase is dramatically increasing with ADT accounting for almost 21% of the total cost. The objective of this study was to perform a cost comparison of different forms of ADT, including luteinizing hormone releasing hormone agonists (LHRHa) medications and surgical castration, over the phase of metastatic castration-resistant prostate cancer (mCRPC). Methods: Two Markov models were developed in order to simulate survival in mCRPC, and the cost of ADT as per Quebec's public health care system. The models include recently approved additional lines of treatment after and/or before docetaxel (i.e. abiraterone and cabazitaxel). Survival was based on clinical trial results and clinical practice guidelines found in a literature review. Costs are in Canadian dollars ($). Results: The mean cost of ADT per patient in mCRPC over an average period of 28.1 months was estimated at: $1,413 for surgical castration, $8,346 for Leuprolide (Eligard), $8,514 for Triptorelin (Trelstar), $9,891 for Buserelin (Suprefact Depot), $10,032 Leuprolide (Lupron Depot), and $10,172 for Goserelin (Zoladex). The corresponding values obtained with the alternate model (which includes abiraterone initiation prior to docetaxel therapy) over a 37.2 months were: $1,413, $11,078, $11,302, $13,130, $13,316 and $13,503, respectively. For each annual Canadian cohort of 4,000 mCRPC patients, for a 28.1 months period, the total cost of ADT was estimated at $ 5.6 million for surgical castration, and between $33.4 and $40.7 million for LHRHa therapy. For a 37.2 months period, the total cost for surgical castration remained the same and was between $44.3 and $54.0 million for LHRHa therapy. Conclusions: Our study estimates the costs associated with the use of different ADT in mCRPC. Increasing the use of least costly forms of ADT will result in potential cost savings during the mCRPC phase.