Sunday June 30, 2019 from 07:30 to 09:00
Abiraterone vs. docetaxel for metastatic hormone-sensitive prostate cancer: A Markov microsimulation model
Amanda Hird1, Douglas C. Cheung2, Diana E. Magee2, Rano Matta1, Robert K. Nam1, Girish S. Kulkarni2.
1Urology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada; 2Urology, Toronto General Hospital, University of Toronto, Toronto, ON, Canada
Introduction: In the setting of metastatic castrate-sensitive prostate cancer (mCSPC), androgen-deprivation therapy (ADT) has traditionally been the standard of care; however, the introduction of early docetaxel chemotherapy (DC) and anti-androgen agents (abiraterone with prednisone [AA]) have resulted in significant improvements in overall survival (OS).1-3 While these two alternative regimens have shown to be efficacious, they have not been compared head-to-head and it remains unclear which regimen should be offered as the initial treatment regimen. Our aim was to determine whether ADT with AA or ADT with DC resulted in improved quality adjusted life months (QALMs) among men with de novo mCSPC.
Methods: A Markov microsimulation model was constructed employing two-dimensional Monte Carlo simulation. A lifetime horizon was used. Our primary outcome was QALMs. Secondary outcomes included rates of second- and third-line therapy, OS, and adverse events. A systematic literature review was used to generate probabilities and utilities to populate the model. The base case was a 65-year-old patient with de novo mCSPC.
Results: A total of 100 000 microsimulations were generated. AA resulted in a longer QALM of 36.8 months compared to 36.0 months with DC. Mean crude OS was 55.9 months with AA and 54.2 months with DC. A total of 44.9% and 45.6% of patients received second-line therapy and 8.6% and 8.2% of patients received third-line therapy in the AA and DC groups, respectively. Grade 3/4 adverse events were experienced in 56.4% of patients receiving initial AA and 26.4% of patients receiving initial DC.
Conclusions: This study suggests that AA results in a higher QALM and crude OS compared to DC. Until robust randomized trials can be completed, the results of this study may help to guide treatment. However, the ultimate choice should be based on patient and tumour factors.
 Sweeney CJ, Chen YH, Carducci M, et al. Chemohormonal therapy in metastatic hormone-sensitive prostate cancer. N Engl J Med 2015;373:737-46. https://doi.org/10.1056/NEJMoa1503747
 Fizazi K, Tran N, Fein L, et al. Abiraterone plus prednisone in metastatic castration-sensitive prostate cancer. N Engl J Med 2017;377:352-60. https://doi.org/10.1056/NEJMoa1704174
 James ND, Sydes MR, Clarke NW, et al. Addition of docetaxel, zoledronic acid, or both to first-line long-term hormone therapy in prostate cancer (STAMPEDE): Survival results from an adaptive, multiarm, multistage, platform randomized controlled trial. Lancet 2016;387:1163-77. https://doi.org/10.1016/S0140-6736(15)01037-5