ESMO 2017: Docetaxel and abiraterone acetate plus prednisolone equally improved survival in patients with high-risk prostate cancer: first results from the STAMPEDE trial


  • Oncology Conference Roundups
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Takeaway

  • A subanalysis of the STAMPEDE trial found that docetaxel and abiraterone acetate plus prednisolone equally improved survival when added to long-term hormone therapy in patients with high-risk prostate cancer.
  • Either drug is acceptable and choice may depend on availability.

Why this matters

  • Early outcome measures of failure-free survival and progression-free survival treatment effect in STAMPEDE favoured abiraterone acetate plus prednisolone with HRs of 0.51 and 0.65, respectively.
  • Also, the estimates for late outcome measures of freedom from metastatic progression and freedom from symptomatic skeletal events favoured abiraterone acetate plus prednisolone but the differences were not statistically significant.
  • In order to clarify which combination is preferable, the analysis presented at ESMO used prospectively collected data to directly compare the 2 treatments while both arms of the trial were recruiting.

Study design

  • The analysis included 566 patients randomly assigned to receive docetaxel (n=189) and AAP (n=377), on top of standard hormonal therapy (and radiotherapy for some patients).
  • Groups were well balanced with 342 (60%) M1; 429 (76%) Gleason 8-10; 449 (79%) WHO PS 0; median age of 66 years; and prostate-specific antigen level of 56 ng/mL.
  • Median follow-up was 4 years.
  • Funding: Cancer Research UK, Medical Research Council, Janssen; Astellas, Clovis Oncology, Novartis, Pfizer, Sanofi-Aventis.

Key results

  • The estimate for the primary outcome of overall survival was a HR of 1.16.
  • The difference between the 2 treatments was not statistically significant, with confidence intervals giving estimates favouring both treatments.

Limitations

  • The study is underpowered, further analyses are needed and more data will come from the ongoing trials.

Expert comment

  • Professor Nicholas D. James (University of Birmingham), Chief Investigator of STAMPEDE said: “The individual STAMPEDE trials suggested that abiraterone may have a larger effect on survival than docetaxel, but this did not translate into a clear advantage in this analysis. Both drugs provide a survival advantage over standard of care. This study suggests that starting with either drug is acceptable and choice may depend on availability.”