Review of Survival Data From STAMPEDE Study

Chicago—The randomized, controlled STAMPEDE trial was presented during a session at the ASCO 2015 Annual Meeting by Nicholas David James and colleagues [J Clin Oncol. 2015;33; abstract 5001]. The study recruited men with high-risk locally advanced or metastatic prostate cancer (PC) who were starting long-term hormone therapy for the first time.

The study initially assessed adding a variety of treatment approaches to standard PC care, including hormone therapy for three or more years. The results presented included the primary survival rates for three research comparisons recruited through an intermediate analysis:

  • Docetaxel (D)
  • Zoledronic acid (ZA)
  • Combination D + ZA

Patients included in the study were randomized 2:1:1:1 to receive standard of care (control group), standard of care plus D, standard of care plus ZA, and standard of care plus D plus ZA.

ZA 4 mg was given for six 3-week cycles, then 4-week cycles until 2 years. D 75 mg/m2 was given for six 3-week cycles with prednisone 10 mg daily.

The study’s primary end point was survival from time of randomization to death from any cause.

Between October 2005 and March 2013, 2962 patients were enrolled in the study. The groups were well balanced, according to the researchers, and the patients’ median age was 65 years. Sixty-one percent of patients had metastatic disease, and 93% were diagnosed within 6 months of randomization. The median prostate-specific antigen was 65 ng/mL. Median patient follow-up was 42 months.

Grade 3 through 5 treatment-related toxicities were reported in 31% of the standard of care group, 50% of standard of care + D group, 32% of standard of care plus ZA group, and 52% of standard of care plus D plus ZA group.

A total of 405 deaths occurred in the control group, of which 84% were attributed to PC. The hazard ratio (HR) was 0.76 for the standard of care plus D group (95% confidence interval [CI], 0.63-0.92; P=.003) compared with standard of care alone. In addition, the HR was 0.83 for the standard of care plus ZA group (95% CI, 0.79-1.11; P=.437) compared with standard of care alone. And the HR was 0.81 for the standard of care plus D plus ZA group (95% CI, 0.68-0.97; P=.02) compared with standard of care alone.

The median survival was increased by 10 months from 67 months with standard of care to 77 months for those receiving standard of care plus D.

The researchers concluded, “Survival data from STAMPEDE show a clinically and statistically significant improvement in survival from adding [D] but not from adding [ZA] in men starting long-term hormone therapy for the first time.”

Source: James ND, Sydes MR, Mason MD, et al. Docetaxel and/or zoledronic acid for hormone-naïve prostate cancer: First overall survival results from STAMPEDE (NCT00268476). Abstract of presentation at the American Society of Clinical Oncology 2015 Annual Meeting, Chicago, Illinois, May 31, 2015.