SURVIVAL OUTCOMES OF ABIRATERONE AND ENZALUTAMIDE IN THE TREATMENT OF METASTATIC CASTRATION-RESISTANT PROSTATE CANCER: A SINGLE-CENTER RETROSPECTIVE ANALYSIS
Author(s)
Guilherme Baleiras, MSc1, João Soares, MSc2, Diogo Mendes, PhD1, Ana Paula Roque, MSc3, Maria do Carmo Gonçalves, MSc3, Carlos Alves, PhD1, Sandra Queimado, MSc3.
1Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal, 2Clevidence, Oeiras, Portugal, 3Local Health Unit of Castelo Branco (ULSCB), Castelo Branco, Portugal.
1Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal, 2Clevidence, Oeiras, Portugal, 3Local Health Unit of Castelo Branco (ULSCB), Castelo Branco, Portugal.
OBJECTIVES: Abiraterone and enzalutamide are two novel androgen receptor-targeted therapies approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC). However, real-world evidence comparing these treatments in Portugal remains limited. This study assessed the survival outcomes of patients with mCRPC treated in routine clinical practice.
METHODS: This retrospective cohort study retrieved data from clinical records of patients with mCRPC treated with abiraterone or enzalutamide at a Portuguese local health unit between June 2015 and March 2026. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and compared between the two treatment groups. Cox proportional hazards models were used to assess treatment effects while adjusting for age, Gleason score, baseline prostate-specific antigen (PSA), prior chemotherapy, and prior androgen deprivation therapy (ADT). Missing Gleason score and PSA were handled using multiple imputation by chained equations.
RESULTS: Fifty-nine patients were included, 35 treated with abiraterone and 24 with enzalutamide. The median age was 76 years, 37% had a Gleason score ≥8, the median baseline PSA was 37 ng/mL, and 19% and 92% had received prior chemotherapy and ADT regimens, respectively. Median OS and PFS were 12.9 months each with abiraterone and 21.1 months and 14.7 months with enzalutamide, respectively, with no significant differences between treatments (log-rank p>0.96 for both). In multivariable Cox analysis, no statistically significant differences between treatments were observed for OS (HR=1.19; 95% CI: 0.50-2.82; p=0.69) or PFS (HR=1.05; 95% CI: 0.45-2.45; p=0.91). Patients with higher baseline PSA were significantly more likely to experience disease progression (HR=1.35; 95% CI: 1.02-1.78; p=0.04). No other covariates were significantly associated with OS or PFS.
CONCLUSIONS: Abiraterone and enzalutamide showed similar survival outcomes in patients with mCRPC. Baseline PSA was associated with disease progression. These findings contribute to the limited real-world evidence on treatment outcomes for mCRPC in Portugal.
METHODS: This retrospective cohort study retrieved data from clinical records of patients with mCRPC treated with abiraterone or enzalutamide at a Portuguese local health unit between June 2015 and March 2026. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method and compared between the two treatment groups. Cox proportional hazards models were used to assess treatment effects while adjusting for age, Gleason score, baseline prostate-specific antigen (PSA), prior chemotherapy, and prior androgen deprivation therapy (ADT). Missing Gleason score and PSA were handled using multiple imputation by chained equations.
RESULTS: Fifty-nine patients were included, 35 treated with abiraterone and 24 with enzalutamide. The median age was 76 years, 37% had a Gleason score ≥8, the median baseline PSA was 37 ng/mL, and 19% and 92% had received prior chemotherapy and ADT regimens, respectively. Median OS and PFS were 12.9 months each with abiraterone and 21.1 months and 14.7 months with enzalutamide, respectively, with no significant differences between treatments (log-rank p>0.96 for both). In multivariable Cox analysis, no statistically significant differences between treatments were observed for OS (HR=1.19; 95% CI: 0.50-2.82; p=0.69) or PFS (HR=1.05; 95% CI: 0.45-2.45; p=0.91). Patients with higher baseline PSA were significantly more likely to experience disease progression (HR=1.35; 95% CI: 1.02-1.78; p=0.04). No other covariates were significantly associated with OS or PFS.
CONCLUSIONS: Abiraterone and enzalutamide showed similar survival outcomes in patients with mCRPC. Baseline PSA was associated with disease progression. These findings contribute to the limited real-world evidence on treatment outcomes for mCRPC in Portugal.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
CO64
Topic
Clinical Outcomes, Health Technology Assessment, Patient-Centered Research
Topic Subcategory
Comparative Effectiveness or Efficacy, Relating Intermediate to Long-term Outcomes
Disease
Oncology