Long-term trends in androgen-directed therapy in advanced prostate cancer: a 29-year national analysis.

[BACKGROUND] Androgen deprivation therapy (ADT) has been pivotal in advanced prostate cancer (PCa) for decades. The introduction of androgen-receptor pathway inhibitors (ARPIs) has transformed treatment paradigms. However, their real-world adoption over time has not been comprehensively characterised. We examined prescribing trends for androgen-directed therapies in Australia over a 29-year period.

[METHODS] A retrospective population-based analysis of Pharmaceutical Benefits Scheme (PBS) dispensing data (1996-2024) was performed. PBS-listed anti-androgen therapies-luteinising hormone-releasing hormone (LHRH) agonists (goserelin, leuprorelin, triptorelin), combined androgen blockage (CAB) (LHRH + bicalutamide), ARPIs (enzalutamide, apalutamide, darolutamide, abiraterone)-were included. Annual prescription counts were standardised per 100,000 men. Outcomes included temporal trends, proportional contribution of each drug class, and the effect of ARPI introduction using interrupted time-series (ITS) analysis.

[RESULTS] Anti-androgen prescriptions rose from 146 to 228,707 between 1996 and 2024, respectively. LHRH monotherapy accounted for > 94% of prescriptions prior to ARPI approval, declining to 51.61% in 2024 despite continued absolute growth (+ 65.16 prescriptions/100,000/year, p < 0.0001). ARPIs expanded following PBS listing, increasing from 2.44% in 2013 to 47.28% in 2024 (+ 131.9 prescriptions/100,000/year, p < 0.0001). ITS modelling demonstrated a significant immediate level increase of + 9.85 percentage points (p < 0.0001) and sustained a post-intervention slope increase of + 3.04 percentage points per year (p < 0.0001) following ARPI introduction, closely mirroring observed proportional and absolute growth 3.44-47.28% between 2013 and 2024, respectively.

[CONCLUSION] Australia has transitioned from predominately LHRH-based therapy to widespread use of ARPIs. Health-system structures enabling timely clinical access appears pivotal to the rapid and equitable diffusion of high-value androgen-targeted therapies.