TABLE 3

Outcomes in small cell lung cancer (extensive stage) studies with immune checkpoint inhibitors, according to PD-L1 status

Trial	IMpower133 [4, 83]		KEYNOTE-604 [82]		Pembrolizumab maintenance [86]		KEYNOTE-158 [90]
Study phase	III		III		II		II
Setting	First-line		First-line		Maintenance		≥2nd line
Treatment	Carboplatin+etoposide ± atezolizumab		Platinum salt+etoposide ± pembrolizumab		Pembrolizumab		Pembrolizumab
Total patients	403		453		45		107
PD-L1 evaluated patients	137		360		20		65
PD-L1 IHC	SP263		22C3		22C3		22C3
PD-L1 status	TC or IC		CPS		Stromal interface		CPS
	<1%	≥1%	<1%	≥1%	Negative	Positive	<1%	≥1%
	65	72	175	185	12	8	50	15
PFS data according to PD-L1 status	HR		HR		mPFS (months)		mPFS (months)
	0.51 (0.30–0.89)	0.87 (0.5–1.49)	0.80 (0.58–1.11)	0.84 (0.60–1.18)	1.3 (0.6–2.5)	6.5 (1.1–12.8)	1.9 (1.6–2.0)	2.1 (2.0–8.1)
							6-month PFS
							14.3%	38.9%
							12-month PFS
							8.2%	28.5%
OS data according to PD-L1 status	NA	NA	0.73 (0.54–1.01)	0.68 (0.49–0.94)	mOS (months)		mOS (months)
					7.6 (2.0–12.7)	12.8 (1.1–17.6)	5.9 (3.3–10.1)	14.9 (5.6–NR)
							6-months OS
							48.3%	66%
							12-months OS
							30.7%	53.1%

Data between parenthesis indicate 95% confidence intervals. IHC: immunohistochemistry; mPFS: median progression-free survival; mOS: median overall survival; OS: overall survival; TC: tumour cells; IC: immune cells; HR: hazard ratio; NA: not available; CPS: combined positive score.