Prostate Cancer – Two »equally” good new treatments for patients with high risk prostate cancer
Patients with high risk prostate cancer starting long-term hormone therapy may benefit from two new treatments, according to late-breaking results from the STAMPEDE trial presented at the ESMO 2017 Congress in Madrid.
Long-term hormone therapy alone has been the standard of care for patients with high risk locally advanced or metastatic prostate cancer. STAMPEDE is a platform protocol using a multi-arm, multi-stage design to efficiently investigate a number of new treatments versus standard of care in patients with high risk prostate cancer. The trial previously found that docetaxel improved survival compared to standard of care (hazard ratio [HR], 0.78), and that abiraterone acetate with prednisolone also improved survival compared to the same standard of care (HR, 0.63).
First author Matthew Sydes, statistician, MRC Clinical Trials Unit, University College London, UK, said: »The analysis presented today uses prospectively collected data from the STAMPEDE trial to directly compare patients randomised to the docetaxel and abiraterone acetate plus prednisolone (AAP) research arms while both arms of the trial were recruiting. This comparison included 566 patients.
The estimate for the primary outcome of overall survival was a HR of 1.16, and the difference between the two treatments was not statistically significant, with confidence intervals capturing estimates favouring both AAP and docetaxel.
For the early outcome measures of failure-free survival and progression-free survival, estimates of treatment effect clearly favoured AAP with HRs of 0.51 and 0.65, respectively. The estimates of treatment effect for late outcome measures of freedom from metastatic progression and freedom from symptomatic skeletal events favoured AAP but the differences between treatment groups were not statistically significant.
Professor Nicholas D. James, Chief Investigator of STAMPEDE and Consultant Oncologist at University of Birmingham and Queen Elizabeth Hospital, Birmingham, UK, said: »The individual trials suggested that abiraterone may have a larger effect on survival than docetaxel, but this did not translate into a clear advantage in this study. This study suggests that starting with either drug is acceptable and choice may depend on availability.”
Commenting for ESMO, professor Cora N.Sternberg, Chief, Department of Medical Oncology, San Camillo Forlanini Hospital, Rome, Italy, pointed out that the toxicity profiles were quite different in the two trials. The AAP results are consistent with the LATITUDE trial, which also favoured AAP over standard of care in high risk patients.
She said: »Both STAMPEDE randomised trials support starting hormonal therapy plus either AAP or six cycles of docetaxel. At one and two years, the percentage of patients with grade 3 or 4 (severe) toxicities was low and similar among the two groups. Toxicities associated with chemotherapy for six cycles will dominate decisions about upfront docetaxel. Toxicities associated with AAP are also likely to influence decisions”.
Regarding the need for further studies, Sternberg said: »Cardiovascular follow-up will be important in patients taking AAP. In the future, we will get data on whether patients could start with both docetaxel and novel hormonal therapy such as AAP. Ongoing randomised trials in metastatic hormone sensitive prostate cancer will evaluate the combination of novel hormonal therapy and chemotherapy upfront (ARASENS; NCT02799602) as will data from the PEACE 1 trial (NCT01957436) in which two-thirds of patients will receive AAP plus docetaxel chemotherapy for hormone sensitive high risk prostate cancer.”
# LBA31_PR Sydes MR et al: Adding abiraterone acetate plus prednisolone (AAP) or docetaxel for patients (pts) with high-risk prostate cancer (PCa) starting long-term androgen deprivation therapy (ADT): directly randomised data from STAMPEDE (NCT00268476)
# 783O Chi K et al: Benefits of Abiraterone Acetate Plus Prednisone (AA+P) When Added to Androgen Deprivation Therapy (ADT) in LATITUDE on Patient (Pt) Reported Outcomes (PRO)
# LBA33 Vale CL et al: What are the optimal systemic treatments for men with metastatic, hormone-sensitive prostate cancer? A STOPCaP systematic review and network meta-analysis
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