An abstract summarising results from the STAMPEDE trial has been published online by the American Society for Clinical Oncology (ASCO), ahead of their 2015 annual meeting in Chicago, USA, later this month. The abstract reports the first results of three of the original questions from the STAMPEDE trial. The results show that adding the chemotherapy drug docetaxel to standard hormone therapy improves survival for men with advanced, hormone-naive prostate cancer.
At ASCO’s Annual Meeting, the research team will be reporting results from 2,962 men who were assigned to four of STAMPEDE’s nine treatment arms:
- The standard treatment arm (at least three years of hormone therapy, with or without radiotherapy)
- Standard treatment plus docetaxel for six 3-week cycles
- Standard treatment plus zoledronic acid for two years
- Standard treatment plus both docetaxel and zoledronic acid.
These men were followed up for an average of 3.5 years. Six in 10 of these men had cancer that had distant spread beyond their prostate when joining the trial, and the rest had high-risk, locally advanced prostate cancer.
Men in the group allocated the standard treatment plus docetaxel lived on average for 10 months longer than men who had the standard treatment alone.
Men in the group allocated the standard treatment plus zoledronic acid did not live longer than men who had the standard treatment alone.
Men in the group allocated the standard treatment plus docetaxel plus zoledronic acid as well as the standard treatment lived longer on average than those who had the standard treatment alone. However, adding zoledronic acid to docetaxel did not seem to add any benefits beyond just docetaxel and the standard treatment.
While docetaxel was associated with some additional side effects compared to the standard treatment alone, as expected, the side effects were manageable. Very few patients discontinued docetaxel due to side effects. Results of a cost-effectiveness analysis will be reported at a later time.
Matt Sydes, senior trial statistician at MRC CTU at UCL said “We are delighted that data from the STAMPEDE trial will be presented at ASCO 2015 by Chief Investigator, Professor Nick James. The data clearly show that docetaxel has a positive impact for men with high-risk hormone-naïve prostate cancer. We expect docetaxel will become part of a new standard-of-care for suitable men.”
STAMPEDE (Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy), is the largest randomised clinical trial of treatment for men with prostate cancer ever conducted, with nearly 7,000 patients enrolled since 2005. The trial, which continues to recruit new men, has an innovative multi-stage, multi-arm design, which was developed with and run from the MRC Clinical Trials Unit at UCL. The multi-arm multi-stage or “MAMS” design, which was developed by MRC CTU, allows several treatments to be assessed against a single control arm. Recruitment can be stopped early to treatments that are not sufficiently promising after interim analyses. New treatments that become available after the trial has started can also be added. Matt Sydes said “We have shown in STAMPEDE that we can put this innovative design into practice.”
ASCO President, Peter Paul Yu, said: “This is the biggest trial of its kind and strongly suggests that adding chemotherapy to standard hormone therapy can extend the lives of men with advanced prostate cancer. Its innovative design is exciting, and one that we may begin to see in other areas of oncology.”
These results will be published in full in a peer-reviewed journal later this year. Sites will continue to follow-up these men to look at longer-term outcomes. The STAMPEDE trial is also looking at a number of other approaches to treating men with prostate cancer.
This study received funding and support from Cancer Research UK, UK Medical Research Council, the UK National Cancer Research Institute, the UK Department of Health, Sanofi-Aventis, Novartis, Pfizer, Janssen, and Astellas, with the Chief Investigator supported by University of Birmingham and University of Warwick.