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Bending the Curve Trial by Trial
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IMPACT

Sipuleucel-T immunotherapy for castration-resistant prostate cancer

Phase 3N = 512NCT00065442

Population
Men with metastatic castration-resistant prostate cancer
Design
Double-blind, placebo-controlled, multicenter phase 3 trial; 2:1 randomization to sipuleucel-T (an autologous active cellular immunotherapy) or placebo, each given intravenously every 2 weeks for three infusions. Overall survival was analyzed with a stratified Cox model adjusted for baseline PSA and lactate dehydrogenase.
Primary endpoint
OS
Arms
  • Placebo (control, n = 171): Placebo, three intravenous infusions every 2 weeks
  • Sipuleucel-T (experimental, n = 341): Sipuleucel-T, three intravenous infusions every 2 weeks
People
Kantoff PW, IMPACT Study Investigators
OSHR 0.78 (95% CI 0.61–0.98)Δ median OS+4.1 monthsΔ 36-month OS+8.7 points
Show the numbers
Results reported for IMPACT
EndpointAnalysisSipuleucel-TPlaceboEffect
OSRandomized patients (analysis population not stated in the abstract)primaryKantoff 2010median 25.8 months; 31.7% at 3 ymedian 21.7 months; 23% at 3 yHR 0.78 (95% CI 0.61–0.98)P=0.03Hazard ratio from the stratified Cox model adjusted for baseline PSA and lactate dehydrogenase. The landmark values are 36-month survival probabilities. Time to objective disease progression was similar in the two groups.
Results reported for IMPACT
EndpointAnalysisSipuleucel-TPlaceboEffect
OSRandomized patients (analysis population not stated in the abstract)primaryKantoff 2010median 25.8 months; 31.7% at 3 ymedian 21.7 months; 23% at 3 yHR 0.78 (95% CI 0.61–0.98)P=0.03Hazard ratio from the stratified Cox model adjusted for baseline PSA and lactate dehydrogenase. The landmark values are 36-month survival probabilities. Time to objective disease progression was similar in the two groups.
Hazard ratio (95% CI) by endpoint. Values below 1 favour the experimental arm.
OS0.512◀ experimentalcontrol ▶
Data table
EndpointHR95% CI
OS0.780.61–0.98
Illustrative — modelled from reported values, not trial data. OS, primary.
0%25%50%75%100%0102030405060Months (modelled)
  • Placebo (control)
  • Sipuleucel-T (experimental)

Median-only curves assume a constant hazard (exponential) and fit plateaus, as seen with some immunotherapies, poorly.

Data table (modelled values)
MonthsPlaceboSipuleucel-T
0100.0%100.0%
1660.0%65.1%
3236.0%42.3%
4821.6%27.5%
6512.5%17.4%
Primary publication: Kantoff PW, Higano CS, Shore ND, Berger ER, Small EJ, Penson DF, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. N Engl J Med. 2010;363(5):411-22. PubMedDOI

Appears in

Sources

  1. Kantoff PW, Higano CS, Shore ND, Berger ER, Small EJ, Penson DF, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. N Engl J Med. 2010;363(5):411-22.

    PubMedDOI