Immunotherapy in triple-negative breast cancer: A literature review and new advances

Table 2 Common commercially monoclonal programmed death ligand 1 antibodies for immunohistochemical analysis to assess the expression of programmed death ligand 1 (considering Food and Drug Administration approvals)

PD-L1 antibody	Immunotherapy	IHC assay	Cut-off	Line
22C3	Pembrolizumab	DAKO	TPS ≥ 1%	1L
			TC ≥ 1%	2L
28-8	Nivolumab	DAKO	TC ≥ 1%	2L
SP142	Atezolizumab	Ventana	TC ≥ 50% and/or IC ≥ 10%	1L
			TC ≥ 1% and/or IC ≥ 1%	2L
SP263	Durvalumab	Ventana	TC ≥ 1%	1L maintenance, in unresectable stage III after chemoradiation therapy
	Nivolumab		TC ≥ 1%	2L
	Pembrolizumab		TC ≥ 50%	1L
73-10	Avelumab	DAKO	TC ≥ 1%	2L (not approved)

Notes: (1) Atezolizumab in combination with nab-paclitaxel is approved as 1L of treatment for patients with unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC) whose tumors express programmed death ligand 1 (PD-L1) immune cells (IC) (PD-L1 stained tumor-infiltrating IC of any intensity covering ≥ 1% of the tumor area), as determined by a Food and Drug Administration (FDA) approved test (Ventana SP142); and (2) Pembrolizumab with chemotherapy is approved as 1L of treatment for patients with locally recurrent unresectable or mTNBC whose tumors express PD-L1 CPS ≥ 10, as determined by an FDA approved test (PD-L1 IHC 22C3 PharmDx). CPS: Combined positive score; IC: Immune cell; IHC: Immunohistochemistry; TC: Tumor cell; TPS: Tumor proportion score; 1L: First-line; 2L: Second-line; PD-L1: Programmed death ligand 1.