Association of claudin 18.2 expression with outcomes of ramucirumab plus paclitaxel as second-line therapy in advanced gastric cancer

Table 1 Baseline clinicopathologic characteristics according to claudin 18.2 status, n (%)

Variable	Level	Overall (n = 103)	Negative (n = 61)	Positive (n = 42)	P value
Age [mean (SD)]		60.57 (11.55)	61.05 (10.56)	59.88 (12.96)	0.616
Sex	Female	52 (50.5)	32 (52.5)	20 (47.6)	0.778
	Male	51 (49.5)	29 (47.5)	22 (52.4)
Eastern Cooperative Oncology Group	0-1	99 (96.1)	60 (98.4)	39 (92.9)	0.367
	≥ 2	4 (3.9)	1 (1.6)	3 (7.1)
Human epidermal growth factor receptor 2	0	62 (60.2)	38 (62.3)	24 (57.1)	0.476
	1+	30 (29.1)	17 (27.9)	13 (31.0)
	2+, SISH-	5 (4.9)	3 (4.9)	2 (4.8)
	2+, SISH+	2 (1.9)	2 (3.3)	0 (0.0)
	3+	4 (3.9)	1 (1.6)	3 (7.1)
Epstein-Barr virus	0	84 (81.6)	52 (85.2)	32 (76.2)	0.180
	1	2 (1.9)	0 (0.0)	2 (4.8)
	NE	17 (16.5)	9 (14.8)	8 (19.0)
MutL homolog 1	0	87 (84.5)	52 (85.2)	35 (83.3)	0.633
	1	1 (1.0)	1 (1.6)	0 (0.0)
	NE	15 (14.6)	8 (13.1)	7 (16.7)
Tumor mutational burden	High	11 (10.7)	6 (9.8)	5 (11.9)	0.653
	Low	73 (70.9)	42 (68.9)	31 (73.8)
	NE	19 (18.4)	13 (21.3)	6 (14.3)
Microsatellite instability status	MSS	0 (0.0)	0 (0.0)	0 (0.0)	Not available
	non-MSS	103 (100.0)	61 (100.0)	42 (100.0)
Metastasis	No	4 (3.9)	2 (3.3)	2 (4.8)	1.000
	Yes	99 (96.1)	59 (96.7)	40 (95.2)
Liver	No	81 (78.6)	49 (80.3)	32 (76.2)	0.796
	Yes	22 (21.4)	12 (19.7)	10 (23.8)
Peritoneal	No	43 (41.7)	27 (44.3)	16 (38.1)	0.674
	Yes	60 (58.3)	34 (55.7)	26 (61.9)
Bone	No	99 (96.1)	60 (98.4)	39 (92.9)	0.367
	Yes	4 (3.9)	1 (1.6)	3 (7.1)

Baseline demographic, clinical, and molecular characteristics of the 103 patients treated with ramucirumab plus paclitaxel, stratified by claudin 18.2 (CLDN18.2) expression status. CLDN18.2 positivity was defined as immunohistochemical staining in ≥ 75% of tumor cells. Variables include age, sex, Eastern Cooperative Oncology Group performance status, molecular features (human epidermal growth factor receptor 2 status, Epstein-Barr virus status, MutL homolog 1 expression, and tumor mutational burden category), microsatellite status, and patterns of metastatic disease. There were no statistically significant differences between the CLDN18.2-positive and CLDN18.2-negative groups, indicating well-balanced baseline characteristics. MSS: Microsatellite stable; NE: Nuclear envelope; SISH: Silver-enhanced in situ hybridization.