Table 1.

Immune checkpoint inhibitors in metastatic breast cancer

Study	Phase	Checkpoint inhibitor	Combination	Population	Number of patients	PD-L1 selection	ORR (RECIST 1.1)
KEYNOTE-01227	1b	Pembrolizumab	Nil	TNBC ; pre-treated	32	PD-L1 positive (expression in stroma or ≥1% tumour cells)	18.5%
KEYNOTE-08629, 30	2	Pembrolizumab	Nil	TNBC ; Cohort A, pre-treated; Cohort B, first line	Cohort A: 170 Cohort B: 52	Cohort A, unselected; Cohort B, PD-L1 positive (combined positive score ≥1%)	Cohort A: 5% Cohort B: 23%
Emens et al.31	1a	Atezolizumab	Nil	TNBC ; majority pre-treated	21	PD-L1 positive (≥5% of infiltrating immune cells)	24%
Schmid et al.25	1a	Atezolizumab	Nil	TNBC ; first line or pre-treated	115	Unselected	10%
Tolaney et al.32	1b/2	Pembrolizumab	Eribulin	TNBC ; first line or pre-treated	39	Unselected	33.3%
Adams et al.34	1b	Atezolizumab	Nab-paclitaxel	TNBC ; first line or pre-treated	32	Unselected	42%
KEYNOTE-02836	1b	Pembrolizumab	Nil	ER+/HER2-; pre-treated	25	PD-L1 positive (expression in stroma or ≥1% tumour cells)	12%
JAVELIN39	1b	Avelumab	Nil	Unselected ; pre-treated	168	Unselected	5.4%

Summary of recently presented studies of anti-PD1/PD-L1 therapy in metastatic breast cancer.

ORR objective response rate, TNBC triple-negative breast cancer