[Skip to Navigation]
Sign In
June 24, 2021

Atezolizumab in Metastatic Triple-Negative Breast Cancer—No Contradiction in the Eyes of a Dispassionate Observer

Author Affiliations
  • 1Department of Oncology, ZNA, Antwerp, Belgium
  • 2Departments of Oncology and Public Health Sciences, Queen's University, Kingston, Ontario, Canada
  • 3Division of Cancer Care and Epidemiology, Queen's University, Kingston, Ontario, Canada
JAMA Oncol. 2021;7(9):1285-1286. doi:10.1001/jamaoncol.2021.1966

The results of the IMpassion131 trial that were presented at the 2020 Congress of the European Society for Medical Oncology1 started important discussions in the oncology community about the role of atezolizumab, a programmed death–ligand 1 (PD-L1) inhibitor, in treating metastatic triple-negative breast cancer (mTNBC), especially surrounding the discrepancy in the overall survival (OS) results of the IMpassion131 trial compared with those of previously published IMpassion130.2 These trials tested the benefit of adding atezolizumab to taxane in first-line treatment of mTNBC. IMpassion130 demonstrated a progression-free survival (PFS) benefit with the addition of atezolizumab to nab-paclitaxel in the intention-to-treat (ITT) analysis and PD-L1–positive subgroup and seemingly an OS benefit only in the PD-L1–positive subgroup, whereas in IMpassion131, atezolizumab plus paclitaxel did not improve PFS nor OS in the ITT or PD-L1–positive group vs paclitaxel alone. Several explanations have been proposed for these discrepant results.3,4 We believe these discussions miss a simpler and parsimonious explanation, that atezolizumab does not improve OS in mTNBC. In this Viewpoint, we offer some reasons why this may be the best explanation for the observed differences between IMpassion130 and IMpassion131.

Add or change institution
Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Not all submitted comments are published. Please see our commenting policy for details.

Limit 140 characters
Limit 3600 characters or approximately 600 words
    1 Comment for this article
    What about the PD-L1 Diagnostic Test?
    David Rimm, MD-PhD | Yale University School of Medcine
    The possible explanations are all feasible but a key possibility is missed. The assay to define PD-L1 positivity (SP142 with IC>1) has been shown by multiple studies to be non-reproducible. Thus it is possible the assay picked the right group in IMpassion 130 by chance, but the assay failed to pick the right group in IMpassion 131.
    CONFLICT OF INTEREST: Advisory Board Member for Roche