Background Abiraterone is an oral antiandrogen therapy approved in September 2011 by the European Medicines Agency (EMA) for metastatic castration resistant prostate cancer (mCRPC) in men whose disease had progressed on a docetaxel based chemotherapy, and was included in our hospital´s formulary in 2012.
Purpose To assess the effectiveness of abiraterone in patients with mCRPC in our hospital in real life conditions, and to analyse previous ketoconazole therapy and patient performance status as prognostic factors of response to treatment with abiraterone.
Material and methods A retrospective longitudinal study was carried out from January 2012 to October 2014. We included all patients that had started treatment with abiraterone for mCRPC after chemotherapy progression in our hospital, excluding those from clinical trials. Patients’ medical records were reviewed and the following data were collected: demographics (date of birth), pharmacotherapeutic (dosing, treatment duration, previous treatments) and clinical variables (performance status (Eastern Cooperative Oncology Group scale – ECOG), progression date). The main outcome was progression free survival (PFS), assessed by Kaplan-Meier plots. Analyses with log rank test stratified by prior ketoconazole therapy and performance status were also performed.
Results 36 patients (mean age 78 years old (range 65–87)) were included in the study. They had predominantly an ECOG score >1 (83.3%) and no previous ketoconazole therapy (63.9%). Median duration of treatment with abiraterone was 7.1 months (range 3.0–23.7) and dose reductions were not required. A median PFS of 7.5 months (95% CI 5.14 to 9.85) was determined. Patients with no previous ketoconazole therapy had a median time to progression of 9.5 months (95% CI 5.7 to 11.4) compared with 6.9 months (95% CI 4.3 to 9.8) in the previous ketoconazole therapy group (95% CI 4.4 to 6.1) (p = 0.5). Performance status subgroup analysis results were: median PFS 7.5 months (95% CI 5.4 to 9.5) in patients with ECOG ≤1 vs. 6.3 months (95% CI 2.5 to 10.1) in the ECOG >1 group (p = 0.6).
Conclusion The effectiveness of abiraterone in the treatment of mCRPC under real life conditions is consistent with clinical trials. Patients without previous ketoconazole treatment and a good performance status had better progression free survival outcomes, although the results were not statistically significant.
References and/or Acknowledgements COU-AA-301 study.
No conflict of interest.
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