Patient cohort
Overall, 153 patients (125 men [81.7%]; average age, 47.6 years [SD, 9.8 years]) participated in the phase 2 clinical trial of KL-A167 (anti-PD-L1 monotherapy) for R/M-NPC (Table 1). The median OS is 456 days. Table 2 showed patients’ baseline peripheral blood lymphocyte subsets.
Table 1. Characteristics of Patients
Characteristic
|
Patients, No. (%)
(N=153)
|
Age (mean (SD))
|
47.6 (9.8)
|
Gender
|
|
male
|
125 (81.7)
|
female
|
28 (18.3)
|
ECOG PS
|
|
0
|
59 (38.6)
|
1
|
94 (61.4)
|
T Stage
|
|
T0-2
|
103 (67.3)
|
T3-4
|
50 (32.7)
|
N Stage
|
|
N0-2
|
127 (83.0)
|
N3
|
26 (17.0)
|
Liver Metastasis
|
|
Yes
|
59 (38.6)
|
No
|
94 (61.4)
|
Smoke
|
|
Yes
|
98 (64.1)
|
No
|
55 (35.9)
|
Alcohol
|
|
Yes
|
111 (72.5)
|
No
|
42 (27.5)
|
Lactate Dehydrogenase U/L
(median [IQR])
|
232.0 [176.0, 403.0]
|
EBV DNA Copies/mL
(median [IQR])
|
1865.0 [421.5, 12275.0]
|
Body Mass Index
(median [IQR])
|
21.6 [19.1, 23.5]
|
Abbreviations: ECOG PS, Eastern Cooperative
Oncology Group Performance Status.
Table 2. Baseline Lymphocyte Subsets Percentage of Patients
Baseline Lymphocyte Subsets Percentage
|
Patients, No. (%)
(N=153)
|
NK cells (mean (SD))
|
28.4 (12.1)
|
NK cells group
|
|
≤25.57%
|
42 (47.7)
|
>25.57%
|
46 (52.3)
|
CD4/CD8 ratio (mean (SD))
|
3.0 (10.9)
|
CD4/CD8 ratio group
|
|
≤0.43%
|
16 (17.6)
|
>0.43%
|
75 (82.4)
|
Total T cells (mean (SD))
|
58.0 (13.3)
|
Total T cells group
|
|
≤65.08%
|
68 (68.0)
|
>65.08%
|
32 (32.0)
|
Helper T cells (mean (SD))
|
23.6 (7.8)
|
Helper T cells group
|
|
≤22.1%
|
49 (51.6)
|
>22.1%
|
46 (48.4)
|
Suppressor cytotoxic T cells (mean (SD))
|
30.7 (11.7)
|
Suppressor cytotoxic T cells group
|
|
≤38.47%
|
69 (72.6)
|
>38.47%
|
26 (27.4)
|
B cells (mean (SD))
|
9.4 (5.5)
|
B cells group
|
|
≤15.1%
|
76 (88.4)
|
>15.1%
|
10 (11.6)
|
Cutoff value of baseline lymphocyte subsets percentage is calculated by the Maximally Selected Log-rank Statistic method.
Association Between Lymphocyte Subsets Percentage and OS, PFS
We conducted the analysis of the association continuous lymphocyte subsets percentage and groups of high and low lymphocyte subsets percentage and OS and PFS. We found that OS and PFS were not significantly different in the two groups of CD4/CD8 ratio in both univariate analysis and multivariate analysis (Table 3). The differences in OS and PFS between two groups of Total T cells were not significant in univariate and multivariate analysis (Table 3). In multivariate analysis of Helper T cells, patients in low Helper T cells percentage group had longer OS than those in high Helper T cells percentage group [HR, 2.08(95%CI, 1.11-3.89); p=0.022] (Table 3). In multivariate analysis of Suppressor Cytotoxic T cells, patients in high Suppressor Cytotoxic T cells percentage group had longer OS than those in low Suppressor Cytotoxic T cells percentage group [HR, 0.51(95%CI, 0.28-0.93); p=0.029] (Table 3). Patients in the high baseline NK cells percentage group had significantly shorter median OS than those in the low baseline NK cells percentage group (12.1 months vs 26.3 months, p<0.001) (Figure 1). In the analysis of NK cells, patients in high NK cells percentage group had an increased risk of death compared with patients in low NK cells percentage group [HR, 2.49(95%CI, 1.39-4.47); p=0.002] (Table 3). The results were consistent in the multivariate analysis of OS [HR, 3.14(95%CI, 1.47-6.75); p=0.003] (Table 3). Patients in low NK cells percentage group also had longer PFS than those in high NK cells percentage group (5.5 months vs 3.7 months, p<0.001) (Figure 1). Patients in low NK cells percentage group had lower risk of progression than those in high NK cells percentage group in univariate [HR, 1.62(95%CI, 1.02-2.57); p=0.041] (Table 3) and multivariate [HR, 2.04(95%CI, 1.16-3.59); p=0.013] (Table 3) analysis of PFS. It was found that higher continuous NK cells percentage is significantly associated with higher risk of death [HR, 1.04(95%CI, 1.01-1.08); p=0.019] and progression [HR, 1.03(95%CI, 1.01-1.05); p=0.010] (Table 3). Higher continuous B cells was associated longer OS [HR, 0.93(95%CI, 0.86-0.99); p=0.032] (Table 3). However, in
Table 3 Cox Analysis for Association Between Lymphocyte Subsets Percentage and Survival Outcomes for Patients with R/M-NPC Receiving Anti-PD-L1 Monotherapy
|
|
OS
|
|
PFS
|
|
|
Univariate analysis
|
|
Multivariate analysis
|
|
Univariate analysis
|
|
Multivariate analysis
|
|
|
HR (95%CI)
|
p value
|
|
HR (95%CI)
|
p value
|
|
HR (95%CI)
|
p value
|
|
HR (95%CI)
|
p value
|
CD4/CD8 ratio
|
continuous
|
0.99(0.96-1.03)
|
0.742
|
|
0.99(0.96-1.02)
|
0.616
|
|
1.02(1.00-1.04)
|
0.035
|
|
1.02(1.00-1.04)
|
0.047
|
low vs high
|
2.50(0.92-4.53)
|
0.078
|
|
1.48(0.63-3.51)
|
0.368
|
|
1.17(0.65-2.08)
|
0.605
|
|
1.07(0.65-2.00)
|
0.832
|
Total T Cells
|
continuous
|
1.00(0.98-1.02)
|
0.823
|
|
0.99(0.97-1.02)
|
0.648
|
|
1.00(0.66-1.01)
|
0.662
|
|
0.99(0.97-1.01)
|
0.305
|
low vs high
|
0.69(0.38-1.20)
|
0.187
|
|
0.86(0.44-1.65)
|
0.644
|
|
0.76(0.48-1.21)
|
0.246
|
|
0.71(0.43-1.20)
|
0.200
|
Helper T Cells
|
continuous
|
1.01(0.97-1.04)
|
0.645
|
|
1.02(0.97-1.06)
|
0.448
|
|
1.00(0.97-1.03)
|
0.816
|
|
1.02(0.98-1.04)
|
0.519
|
low vs high
|
1.62(0.96-2.73)
|
0.072
|
|
2.08(1.11-3.89)
|
0.022
|
|
1.24(0.80-1.92)
|
0.329
|
|
1.51(0.92-2.48)
|
0.099
|
Suppressor Cytotoxic T Cells
|
continuous
|
1.00(0.98-1.02)
|
0.782
|
|
1.00(0.98-1.02)
|
0.912
|
|
0.97(0.94-1.00)
|
0.008
|
|
0.98(0.96-1.00)
|
0.103
|
low vs high
|
0.67(0.37-1.23)
|
0.198
|
|
1.33(0.84-2.10)
|
0.222
|
|
0.41(0.18-0.93)
|
0.032
|
|
0.51(0.28-0.93)
|
0.029
|
NK Cells
|
continuous
|
1.01(0.98-1.03)
|
0.518
|
|
1.04(1.01-1.08)
|
0.019
|
|
1.01(0.99-1.03)
|
0.241
|
|
1.03(1.01-1.05)
|
0.010
|
low vs high
|
2.49(1.39-4.47)
|
0.002
|
|
3.14(1.47-6.75)
|
0.003
|
|
1.62(1.02-2.57)
|
0.041
|
|
2.04(1.16-3.59)
|
0.013
|
B Cells
|
continuous
|
0.97(0.92-1.02)
|
0.249
|
|
0.93(0.86-0.99)
|
0.032
|
|
0.98(0.94-1.03)
|
0.419
|
|
1.00(0.94-1.05)
|
0.875
|
low vs high
|
0.37(0.11-1.19)
|
0.096
|
|
0.45(0.12-1.62)
|
0.220
|
|
0.85(0.41-1.77)
|
0.659
|
|
1.03(0.44-2.42)
|
0.944
|
In multivariate analysis, we adjusted for age, gender, ECOG PS, T stage, N stage, liver metastasis, serum LDH multivariate analysis, no significant differences in OS and PFS were demonstrated between high and low B cells groups.
Association Between Lymphocyte Percentage and ORR, DCR
We performed logistics regression analysis to explore the relationship between lymphocyte subsets and ORR, DCR. However, we found no significant difference in other analysis of lymphocyte percentage and ORR, DCR between low and high two groups (eFigure 1). The results were consistent in the analysis of continuous lymphocyte subsets percentage (eFigure 1).
Characteristics of Patients grouped by NK cells and Correlation of NK cells and other lymphocyte
Given the good prognostic predictive ability of NK cells percentage, we additionally analyzed the characteristics of patients in high and low NK cell percentage groups (Table 4). We also explored the correlation of NK cells percentage and other lymphocyte subsets percentage. There is a negative linear correlation between NK cells percentage and B cells percentage (r=-0.179; p<0.001) (eFigure 1). NK cells percentage also had a negative linear correlation with Total T cells percentage (r=-0.795; p<0.001) (eFigure 1), Helper T cells percentage (r=-0.397; p<0.001) (), Suppressor Cytotoxic T cells percentage (r=-0.555; p<0.001) (eFigure 1). However, we did not see a linear correlation between NK cells and CD4/CD8 percentage (r=0.258; p>0.05) (eFigure 1).
Table 4. Characteristics of Patients grouped by NK cells
|
NK cells≤25.57%,No. (%) (N=42)
|
NK cells>25.57%,
No. (%) (N=46)
|
p-value
|
Age (mean (SD))
|
47.1 (9.7)
|
48.9 (9.4)
|
0.383
|
Gender
|
|
|
0.167
|
male
|
33 (78.6)
|
42 (91.3)
|
|
female
|
9 (21.4)
|
4 (8.7)
|
|
ECOG PS
|
|
|
0.012
|
0
|
24 (57.1)
|
13 (28.3)
|
|
1
|
25 (46.3)
|
69 (69.7)
|
|
T Stage
|
|
|
0.610
|
T0-2
|
28 (66.7)
|
34 (73.9)
|
|
T3-4
|
14 (33.3)
|
12 (26.1)
|
|
N Stage
|
|
|
1.000
|
N0-2
|
36 (85.7)
|
39 (84.8)
|
|
N3
|
6 (14.3)
|
7 (15.2)
|
|
Liver Metastasis
|
|
|
0.012
|
Yes
|
24 (57.1)
|
13 (28.3)
|
|
No
|
18 (42.9)
|
33 (71.7)
|
|
Smoke
|
|
|
0.929
|
Yes
|
26 (61.9)
|
27 (58.7)
|
|
No
|
16 (38.1)
|
19 (41.3)
|
|
Alcohol
|
|
|
0.622
|
Yes
|
30 (71.4)
|
36 (78.3)
|
|
No
|
12 (28.6)
|
10 (21.7)
|
|
LDH U/L
(median [IQR])
|
205.2
[166.5, 341.2]
|
232.5
[181.5, 403.0]
|
0.3759
|
EBV DNA Copies/mL
(median [IQR])
|
882.0
[400.0, 5980.0]
|
3035.0
[431.8, 14725.0]
|
0.255
|
BMI
(median [IQR])
|
22.8
[20.0, 24.2]
|
21.2
[19.3, 22.8]
|
0.088
|
Abbreviations: ECOG, Eastern Cooperative Oncology Group.