THE "NEW" PROSTATE CANCER INFOLINK

This afternoon, James et al. will report the full details from the most recently completed component of the STAMPEDE trial (see NCT00268476). However, data from the abstract are already available.

In this component of the STAMPEDE trial, James and his colleagues randomized men with high-risk, locally advanced prostate cancer or metastatic prostate cancer to either

• Standard of care (SOC) , with androgen deprivation therapy (ADT) for 2 or more years and appropriate radiation therapy (which was mandated for men with N0M0 disease and encouraged for men with N+M0 disease) or
• SOC + abiraterone acetate (1000 mg/day) + prednisolone (5 mg/day)

Between November 2011 and January 2014, the research team randomized 1,917 patients to one or other of these arms of the trial. Here are the core results:

• The patients were well balanced between the two arms of the trial.
  • Average (median) patient age was 67 years.
  • 52 percent of the patients had metastatic (M1) disease.
  • 20 percent of the patients had N+M0 or NxM0 disease.
  • 28 percent of the patients had N0M0 disease.
  • 95 percent of the patients were newly diagnosed.
  • Average (median) patient PSA level was 53 ng/ml.
  • Average (median) follow-up was 40 months.
• 262 patients died in the SOC alone arm of the trial (and 82 percent of these men died of prostate cancer).
• 184 patients died in the SOC + abiraterone + predisolone arm of the trial.
• The adjusted hazard ratio (aHR) for overall survival for the SOC + abiraterone + predisolone arm of the trial compared to the SOC alone arm was 0.63 (p = 0.115 × 10^-7).
• The overall survival rate at 3 years improved from 76 percent for the SOC alone arm to 83 percent for the  SOC + abiraterone acetate + prednisilone arm.
• In terms of other outcomes, there were
  • 535 failure-free survival events in the SOC + abiraterone + prednisolone arm
  • 248 failure-free survival events in the SOC alone arm
  • This difference was also highly statistically significant (aHR = 0.29; p = 0.377 × 10^-63)
• Grade 3 adverse events were seen in
  • 29 percent of patients on SOC
  • 41 percent of patients on SOC + abiraterone + prednisolone
• Grade 4 adverse events were seen in
  • 3 percent of patients on SOC
  • 5 percent of patients on SOC + abiraterone + prednisolone
• Grade 5 adverse events (i.e., adverse events causing patient deaths) were seen in
  • 3 patients on SOC alone (of which 1 was treatment-related)
  • 9 patients on SOC + abiraterone + prednisolone (of which 2 were treatment-related).

James and his colleagues conclude that the results of this large trial

show a clinically and statistically significant effect on overall survival and failure-free survival from adding abiraterone at start of ADT with a manageable increase in toxicity. ADT [± radiation therapy as appropriate] + abiraterone is a new standard of care for this group.

The “New” Prostate Cancer InfoLink would note that the potential risk for increased side effects is not negligible, and so clinicians will need to apply this new standard form of care with some caution.

The unanswered question is whether we now need to compare ADT + abiraterone + predisolone to ADT + docetaxel chemotherapy + prednisone or prednisolone in this group of patients. James and his colleagues seem to be suggesting that the improvement in outcomes offered by ADT + abiraterone + prednisolone renders that trial unnecessary.

Filed under: Diagnosis, Living with Prostate Cancer, Management, Risk, Treatment |