The advent of immune checkpoint inhibitors (ICIs) is underway to change the landscape of triple- negative breast cancer (TNBC) treatment. In this meta-analysis and position paper, we assess the role of atezolizumab and pembrolizumab in TNBC with the lens of precision medicine.
A systematic search of PubMed, Scopus, Web of Science and Google Scholar was conducted until July 15, 2022. Keywords were used as follows: triple-negative breast cancer, atezolizumab, pembrolizumab, biomarker, precision, chemotherapy.
A total of 3 clinical trials (i. IMpassion 130, ii. IMpassion 131 and iii. KN355) were included. The objective response rate (ORR) was higher in the treatment arm (atezolizumab/pembrolizumab) (ORR=1.35) as compared to placebo. Moreover, the progression free survival (PFS) in the treatment arm had a positive effect size (Cohen’s d=1.5). TNBC is a known aggressive and heterogenous subtype of breast cancer that is largely associated with high recurrence rate and metastasis. While the clinical outcomes of treatment are discussed, the use of precision medicine to target TNBC patients is a work in progress. TNBC developmental therapy depends on biomarker-based and precise clinical trials. IMpassion 130 could not ascertain that these findings would extend to other chemoimmunotherapy combinations, but supported the addition of checkpoint inhibitors to standard chemotherapy in first line care of TNBC. IMpassion 131 enrolled patients through immune cell expression ≥1%, VENTANA PD-L1 (SP142) assay. KN355 classified participants based on prior treatments and chemotherapy status.
In the era of precision medicine, ICIs are largely being used in novel clinical trials for TNBC. Only one of the three trials tested patients with the immunohistochemical assay and reported immune expression. Prospective studies are required to further optimize care for TNBC and find the best available treatment response biomarkers and modalities in guiding breast cancer decision-making. It is also imperative to identify the subgroup of patients who would derive the greatest benefit with ICI and precision-medicine guided therapy.
The authors.
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All authors have declared no conflicts of interest.