OBJECTIVES: The introduction of novel hormonal agents (NHAs) such as abiraterone acetate (ABI) and enzalutamide (ENZ) for metastatic castration-resistant prostate cancer (mCRPC) was an important milestone given their survival benefits and tolerability relative to taxane chemotherapies. This descriptive study examined the utilization trends of NHAs in patients with mCRPC in the early years after approval in the province of Quebec in Canada.

METHODS: A retrospective population-based cohort was extracted from Quebec public healthcare administrative databases. The cohort included first-time users of NHAs (ABI or ENZ) from 2011-2016. The primary analysis aims to describe the overall temporal trends (2011-2016) of NHA use by chemotherapy status (chemotherapy-naïve versus post-chemotherapy), and prescribing specialty (medical oncology versus urology versus others). In secondary analyses, we described the trends in the years when both ABI and ENZ were available from 2014-2016 (ENZ-era) stratified by NHA type.

RESULTS: The cohort comprises 2,183 patients, with 1,562 (72%) in the chemotherapy-naïve group and 621 (28%) in the post-chemotherapy group. While the majority of patients were post-chemotherapy NHA users in 2012, this proportion decreased over time and accounted for only 13% of NHA users by the end of 2016. Medical oncologists were the most frequent prescribers of NHAs (upwards of 60%) throughout 2012 but fell to 45% by the end of 2016. Conversely, the proportion of prescriptions by urologists increased from 22% in 2012 to 42% in 2016. Adjusted analyses show that urologists were more likely to prescribe ENZ over ABI, relative to medical oncologists.

CONCLUSIONS: Over time, there was an increasing proportion of patients who (1) initiated NHAs without prior chemotherapy treatment, (2) NHA prescribing by urologists, and (3) of ENZ users. Further research examining how exactly the introduction of NHAs has impacted disease management and referral patterns in advanced PCa may be of interest to clinicians and policy-makers.