Predictive Biomarker in Metastatic Triple-Negative Breast Cancer
Posted: Friday, January 18, 2019
There may be consistency between local and central estrogen receptor/progesterone receptor/HER2 testing, and PD-L1 appears to be the most predictive biomarker for choosing untreated patients with treatment-naive, locally advanced or metastatic triple-negative breast cancer who benefit from the combination therapy of atezolizumb and nab-paclitaxel, according to the IMpassion130 study. Leisha A. Emens, MD, PhD, of Johns Hopkins University, Baltimore, and colleagues presented these study results at the 2018 San Antonio Breast Cancer Symposium (SABCS; Abstract GS1-04).
IMpassion130is a global, randomized, double-blind, placebo-controlled, phase III study that evaluated the efficacy of the PD-L1 inhibitor atezolizumab plus nab-paclitaxel versus placebo plusnab-paclitaxel inpatients with metastatic triple-negative breast cancer. Patients were randomly assigned (1:1) to receive nab-paclitaxel at100 mg/m2 intravenously (days 1, 8, and 15 of a 28-day cycle) plus atezolizumab at 840 mg intravenously every 2 weeks or placebo. The treatment continued until disease progression or toxicity. The researchers also analyzed several biomarkers: PD-L1 on tumor cells, intratumoral CD8, stromal tumor-infiltrating lymphocytes, BRCA1/2 mutational status, and estrogen receptor/progesterone receptor/HER2 status.
PD-L1 was predictive of efficacy of atezolizumab plus nab-paclitaxel, and a high proportion of PD-L1 tumor cell–positive tumors were PD-L1 immune cell–positive. “Intratumoral CD8, but not [stromal tumor-infiltrating lymphocytes], were correlated with PD-L1 [immune cell]. Consequently, CD8 was predictive of the efficacy of atezolizumab plus nab-paclitaxel for progression-free and overall survival, whereas the stromal tumor-infiltrating lymphocytes were predictive of progression-free survival alone,” according to the investigators.
Disclosure: The study authors’ disclosures can be found at SABCS.org.
