Skip to content
Bending the Curve Trial by Trial
?

IMpassion131

First-line paclitaxel with or without atezolizumab for unresectable locally advanced or metastatic triple-negative breast cancer

Phase 3N = 651NCT03125902

Population
Untreated unresectable locally advanced or metastatic triple-negative breast cancer (no prior systemic therapy, or at least 12 months since neoadjuvant or adjuvant chemotherapy); 45% PD-L1-positive
Design
Double-blind, placebo-controlled phase 3 trial randomised 2:1 to atezolizumab 840 mg (days 1 and 15) or placebo with paclitaxel 90 mg per square metre (days 1, 8, 15) every 28 days. Primary endpoint investigator-assessed PFS, tested first in the PD-L1-positive population (SP142, immune cell expression at least 1%), then ITT.
Primary endpoint
PFS
Arms
  • Atezolizumab plus paclitaxel (experimental): Atezolizumab 840 mg plus paclitaxel 90 mg/m2
  • Placebo plus paclitaxel (control): Placebo plus paclitaxel 90 mg/m2
People
Miles D, IMpassion131 investigators
PFSHR 0.82 (95% CI 0.60–1.12)Δ median PFS+0.3 monthsOSHR 1.11 (95% CI 0.76–1.64)Δ median OS−6.2 months
Show the numbers
Results reported for IMpassion131
EndpointAnalysisAtezolizumab plus paclitaxelPlacebo plus paclitaxelEffect
PFSPD-L1-positive populationInvestigator-assessedprimaryMiles 2021median 6 monthsmedian 5.7 monthsHR 0.82 (95% CI 0.60–1.12)P=0.20
OSPD-L1-positive populationfinalMiles 2021median 22.1 monthsmedian 28.3 monthsHR 1.11 (95% CI 0.76–1.64)Final OS results; the abstract reports no difference between arms. Results in the ITT population were described as consistent (no values in the abstract).
Results reported for IMpassion131
EndpointAnalysisAtezolizumab plus paclitaxelPlacebo plus paclitaxelEffect
PFSPD-L1-positive populationInvestigator-assessedprimaryMiles 2021median 6 monthsmedian 5.7 monthsHR 0.82 (95% CI 0.60–1.12)P=0.20
OSPD-L1-positive populationfinalMiles 2021median 22.1 monthsmedian 28.3 monthsHR 1.11 (95% CI 0.76–1.64)Final OS results; the abstract reports no difference between arms. Results in the ITT population were described as consistent (no values in the abstract).
Hazard ratio (95% CI) by endpoint. Values below 1 favour the experimental arm.
PFSOS0.512◀ experimentalcontrol ▶
Data table
EndpointHR95% CI
PFS0.820.6–1.12
OS1.110.76–1.64
Illustrative — modelled from reported values, not trial data. PFS, primary.
0%25%50%75%100%02468101214Months (modelled)
  • Atezolizumab plus paclitaxel (experimental)
  • Placebo plus paclitaxel (control)

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

Data table (modelled values)
MonthsAtezolizumab plus paclitaxelPlacebo plus paclitaxel
0100.0%100.0%
463.0%61.5%
839.7%37.8%
1128.1%26.2%
1517.7%16.1%
Illustrative — modelled from reported values, not trial data. OS, final.
0%25%50%75%100%0204060Months (modelled)
  • Atezolizumab plus paclitaxel (experimental)
  • Placebo plus paclitaxel (control)

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

Data table (modelled values)
MonthsAtezolizumab plus paclitaxelPlacebo plus paclitaxel
0100.0%100.0%
1856.9%64.3%
3533.4%42.4%
5319.0%27.3%
7110.8%17.6%
Primary publication: Miles D, Gligorov J, André F, Cameron D, Schneeweiss A, Barrios C, et al. Primary results from IMpassion131, a double-blind, placebo-controlled, randomised phase III trial of first-line paclitaxel with or without atezolizumab for unresectable locally advanced/metastatic triple-negative breast cancer. Ann Oncol. 2021;32(8):994-1004. PubMedDOI

Appears in

Sources

  1. Miles D, Gligorov J, André F, Cameron D, Schneeweiss A, Barrios C, et al. Primary results from IMpassion131, a double-blind, placebo-controlled, randomised phase III trial of first-line paclitaxel with or without atezolizumab for unresectable locally advanced/metastatic triple-negative breast cancer. Ann Oncol. 2021;32(8):994-1004.

    PubMedDOI