Dr. Mittendorf on FDA Approval of Frontline Atezolizumab/Nab-Paclitaxel in PD-L1+ TNBC

Elizabeth A. Mittendorf, MD, PhD, director of the Breast Immuno-Oncology Program at Dana-Farber/Brigham and Women's Cancer Center, discusses the frontline approval of atezolizumab (Tecentriq) in combination with nab-paclitaxel (Abraxane) in patients with locally advanced or metastatic PD-L1-positive triple-negative breast cancer.

This anticipated approval is based on findings from the phase III IMpassion130 trial, in which the addition of atezolizumab to nab-paclitaxel led to a 40% reduction in the risk of progression or death compared with nab-paclitaxel alone in this patient population. The coprimary endpoints were progression-free and overall survival (OS).

When the data were presented and published, Mittendorf notes that there was a statistically significant improvement in PFS, which was most pronounced in patients who were PD-L1 positive. Additionally, an interim analysis of OS showed that, in the intent-to-treat population, although that there was a benefit with the combination, it was not found to be statistically significant. However, the OS benefit increased to 25 months in the PD-L1-positive population, which Mittendorf said garnered enthusiasm among physicians and patients.

Although this marks a tremendous advance in TNBC treatment, she adds that it now needs to be determined which patients will not respond to this regimen, or which patients initially respond and then progress on treatment. This approval will continue the enthusiasm for immunotherapy research in other breast cancer subtypes, she concludes.

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