(026) Real-world effectiveness of oral novel hormonal agents in patients with advanced prostate cancer: a head-to-head comparison using longitudinal, territory-wide electronic medical records

Background: This study provided evidence addressing unreported direct comparison of effectiveness and health resource utilisation (HRU) of novel hormonal agents (NHAs) against chemotherapy for prostate cancer (PCa) for clinical decision-making.

Objectives: Evaluating the overall survival, prostate specific antigen (PSA) progression-free survival of adjunct treatments and their impact on HRU in a real-world context.

Methods:

Design: A territory-wide, retrospective cohort study using electronic medical records (EMR) in Hong Kong.
Setting: EMRs data sourced from the Hong Kong Hospital Authority. The study population comprised patients diagnosed with PCa between 2001 and 2021. We include individuals prescribed any of the adjunct treatments: docetaxel, enzalutamide, or abiraterone. Patients were excluded if the diagnosis age was < 40 years or had documented other malignancies.
Exposures: Two NHAs: abiraterone and enzalutamide. Chemotherapy: docetaxel.
Main outcome measures: The primary endpoint was overall survival. Secondary outcomes were PSA-PFS and annualised HRU during the follow-up period.
Statistical analysis: We employed propensity score matching in comparative analysis, based on 54 confounding factors. We implemented flexible parametric survival models based on preliminary analysis that indicated non-linearity in the hazard function to model overall and PSA progress-free survival. Further, we conducted inverse probability of treatment weighting and inverse probability of censor weighting for sensitivity analysis.

Results: After PS matching, the cohort consisted of 1,250 patients evenly split between NHAs and docetaxel treatment arms (n=625 each). Survival analysis revealed no significant difference in overall survival for cohorts treated with both or either NHAs versus docetaxel (NHA: hazard ratio [HR] 0.99, 95% confidence interval [CI] 0.89 to 1.09, abiraterone: HR 0.96, [95% CI 0.86 to 1.08], enzalutamide: HR 0.91, [95% CI 0.78 to 1.05]) in line with sensitivity analysis.
NHAs associated with better PSA-PFS (HR 0.86, [95% CI 0.77 to 0.96]). In HRU analysis, NHA treatments presented significantly lower health resource usage, evaluated by the median annual inpatient admissions numbered (NHA 1.37 [IQR: 0.00 to 5.14] vs docetaxel 9.04 [IQR: 4.98 to 13.28]), outpatient visits (NHA 17.73 [IQR: 12.75 to 24.90] vs docetaxel 25.70 [IQR: 17.74 to 38.21]), annual inpatient length of stay (NHA 2.44 days [IQR: 0.00 to 16.04] vs docetaxel 12.70 days [IQR: 6.33 to 25.41]).

Conclusions: Our findings showed a comparable overall survival between adjunct treatments but a superior PSA progression-free survival and HRU profile for NHAs.