Recently, recurrent copy number gains (CNG) in chromosome 9p involving PD-L1 were detected in many cancer types including lung cancer, melanoma, bladder cancer, head and neck cancer, cervical cancer, soft tissue sarcoma, prostate cancer, gastric cancer, ovarian cancer, and triple-negative breast cancer.
This open-label, single-arm, phase 2 study enrolled 55 eligible patients with advanced or metastatic TNBC irrespective of BRCA mutation status or programmed death-ligand 1 (PD-L1) expression at 34 US sites.
In this review, we discuss the current evidence for PD-1/PD-L1 blockade in metastatic triple-negative breast cancer (TNBC), HER2+ breast cancer and ER+ disease, as well as the emerging evidence for use in the early-stage (neoadjuvant) setting.
In IMpassion130, combining atezolizumab with first-line nab-paclitaxel for metastatic TNBC significantly improved progression-free survival and showed a clinically meaningful effect on overall survival in patients with PD-L1-positive tumors.
These data suggest that a minimal system comprised of cGAMP-NP alone is sufficient to modulate the tumor microenvironment to effectively control PD-L1-insensitive TNBC.
Several ongoing clinical trials are investigating the use of immuno-targeting therapy with programmed cell death protein-1 and programmed death-ligand 1 (PD-L1) inhibitors for triple-negative breast cancer.
There are also significant advancements in triple-negative breast cancer: By combining chemotherapy and immunotherapy, an advantage for overall survival was able to be demonstrated in a subgroup (immune cells PD-L1-positive).
Based on IMpassion130 clinical trial (NCT02425891), the Food and Drug Administration (FDA) has recently granted an accelerated approval for atezolizumab (TECENTRIQ®), a monoclonal antibody drug targeting PD-L1, plus chemotherapy (Abraxane; nab®-Paclitaxel) for the treatment of adults with PD-L1-positive, unresectable, locally advanced or metastatic TNBC.
In silico analysis of The Cancer Genome Atlas (TCGA) data shows that expression of histone lysine-specific demethylase 1 (LSD1) is inversely associated with the levels of cytotoxic T cell-attracting chemokines (C-C motif chemokine ligand 5 (CCL5), C-X-C motif chemokine ligand 9 and 10 (CXCL9, CXCL10)) and programmed death-ligand 1 (PD-L1) in clinical TNBC specimens.
In the randomised Phase 3 IMpassion130 trial, atezolizumab combined with nab-paclitaxel (atezo + nab-P) in 902 patients with triple-negative breast cancer (TNBC) showed prolonged progression-free survival (PFS) in both the intention-to-treat (ITT) population and programmed death-ligand 1 (PD-L1)-positive subgroup compared with placebo plus nab-P (plac + nab-P).
Programmed Death Ligand 1 (PD-L1) Tumor Expression Is Associated with a Better Prognosis and Diabetic Disease in Triple Negative Breast Cancer Patients.
Furthermore, we found that targeting both MHC-I and II restricted tumor epitopes was necessary to decrease the growth of the poorly immunogenic TNBC model 4T1 and that combination with PD-L1 blockade increased the number of responders to checkpoint inhibition.
The anti-PD-L1 drug atezolizumab produced durable responses among 10% of patients with triple-negative breast cancer in a large phase I trial presented at the American Association for Cancer Research Annual Meeting 2017.
Our findings suggest that PD-L1-positive/TILs-low tumors are associated with a poor prognosis in patients with TNBC, and that it is important to focus on the combination of PD-L1 expression on tumor cells and TILs present in the tumor microenvironment.
A trend toward a higher ORR was seen in patients with PD-L1+ versus PD-L1- tumor-associated immune cells in the overall population (16.7% vs. 1.6%) and in the TNBC subgroup (22.2% vs. 2.6%).
These drugs were selected based on the following: PTX is approved for TNBC; nintedanib combined with docetaxel has shown phase III clinical trial success, albeit in NSCLC; VEGF can act as local immunosuppressive factor; and PD-L1 antibody plus taxane therapy was recently reported to have encouraging phase III trial benefit in TNBC.
The induction of PD‑L1 by the combined use of stilbenoids was most pronounced in the Cal51 triple-negative breast cancer (TNBC) and SW620 colon cancer cells.
Recently, we have seen 3 newly approved targeted therapies for TNBC, including the PARP inhibitors olaparib and talazoparib for germline BRCA mutation associated breast cancer (gBRCAm-BC) and most recently the checkpoint inhibitor, atezolizumab in combination with nab-paclitaxel for programmed death-ligand 1 (PD-L1+) advanced TNBC.
We investigated TILs and PD-L1 status in TNBCs before or after preoperative systemic therapy (PST) to elucidate the clinical significance of PD-L1 expression.