From January 2019 to May 2020, 35 patients with resectable stage IIIA and IIIB non-NSCLC were treated with neoadjuvant chemoimmunotherapy at TJMUCH. The median age of the cohort was 62.17 ± 5.99 (43–72) years, 82.86% were men, 71.43% had squamous carcinoma, 88.57% were stage IIIA, and 48.57% were PD-L1 positive(≥ 50%). For the clinical TNM stage, 12 patients are T1N2M0; 8 are T2N2M0;10 are T3N1M0; 5 is T3N2M0 and 1 are T4N1M0. All the patients underwent baseline tumor staging, including pretreatment biopsy, pathological evaluation of mediastinal lymph nodes (if indicated) by bronchoscopy or mediastinoscopy, positron-emission tomography-computed tomography (PET-CT), and contrast-enhanced CT or magnetic resonance imaging of the brain and chest. Patients with squamous carcinoma received 2 courses of Pembrolizumab 2 mg/kg IV q3w added to cisplatin 75 mg/m2 IV q3w plus paclitaxel liposome 135 mg/m2 q3w; and patients with non-squamous carcinoma received Pemetrexed 500 mg/m2 IV q3w instead of paclitaxel liposome. (Table 1).
Table 1
Characteristics of the patients at baseline according to the pathological response
|
|
All patients
|
pCR
|
no PCR
|
|
P value
|
Age
|
|
|
|
|
|
>=65
|
12
|
6
|
6
|
0.903
|
< 65
|
23
|
12
|
11
|
|
Sex
|
|
|
|
|
|
|
Male
|
29
|
16
|
13
|
0.33
|
|
Female
|
6
|
2
|
4
|
|
cTNM
|
|
|
|
|
0.33
|
|
IIIA
|
29
|
16
|
13
|
|
|
IIIB
|
6
|
2
|
4
|
|
Smoking status
|
|
|
|
|
0.186
|
|
Never
|
8
|
2
|
6
|
|
|
Former
|
4
|
3
|
1
|
|
|
Current
|
33
|
13
|
10
|
|
Histology
|
|
|
|
|
0.275
|
|
Adenocarcinoma
|
7
|
2
|
5
|
|
|
Squamous carcinoma
|
26
|
15
|
11
|
|
|
Large cell carcinoma
|
1
|
0
|
1
|
|
|
Sarcomatoid carcinoma
|
1
|
1
|
0
|
|
PD-L1
|
|
|
|
|
0.625
|
|
≥ 50%
|
20
|
11
|
9
|
|
|
< 50%
|
15
|
7
|
8
|
|
Invasion status of the bronchus
|
|
|
|
|
0.004
|
|
Yes
|
17
|
13
|
4
|
|
|
No
|
18
|
5
|
13
|
|
RECIST status
|
|
|
|
|
0.404
|
|
PR
|
|
11
|
8
|
|
|
SD
|
|
7
|
9
|
|
Surgical approach
|
|
|
|
|
0.296
|
|
Open
|
34
|
18
|
16
|
|
|
Completed VATS§
|
1
|
0
|
1
|
|
Type of resection
|
|
|
|
|
0.846
|
|
Single Lobectomy #
|
9
|
5
|
4
|
|
|
Pneumonectomy
|
3
|
1
|
2
|
|
|
Bilobectomy$
|
9
|
4
|
5
|
|
|
Complex Lobectomy*
|
14
|
8
|
6
|
|
§Video-assisted thoracoscopic surgery |
# Does not include pneumonectomy, bilobectomy, or complex lobectomy |
$ Does not include pneumonectomy |
*Complex lobectomy includes sleeve resection and sleeve or partial resection of the pulmonary artery or surgery for pancoast tumors |
Safety and feasibility
Neoadjuvant Pembrolizumab plus paclitaxel liposome or pemetrexed combined with cisplatin was not associated with any previously unreported toxic effects. Pre-surgical grade 3 toxicity, i.e. rash, occurred in 1/35 patients. All the 35 eligible patients (100%) underwent complete tumor resection and the median interval between the administration of the second dose of NCIO and surgery was 33.4 (range, 28–35) days, and. No treatment-related surgical delays occurred as defined in the protocol. 18/35 (51.43%) patients achieved pCR, and 26/35 (74.29%) exhibited MPR. And there are 1 patients had no residual tumor in the primary tumor but had a residual tumor in hilar lymph nodes, which we considered as 0% pathological regression . According to the pathological responses, all patients were dived into pCR group and non-pCR group. In the pCR group, the median age was 61.5±6.88 years, 88.89% were men, 83.33% had squamous carcinoma, 88.89% were stage IIIA, and 61.10% were PD-L1 TPS >50%, while in the non-pCR group, the median age was 62.88±5.01 years, 76.47% were men, 64.71% had squamous carcinoma, 76.47% were stage IIIA, and 52.94 % were PD-L1 TPS >50%. (Table 1, Figure 1).
At a median of 13.29 (range, 3–24) months of postoperative follow-up, 33/35 (94.29%) patients who had undergone surgical resection were alive and recurrence-free. One patient died 3 months after the surgery because of cerebral ischemic stroke (patient 3), and the other died after 10 months post-surgery due to mass N2 lymph nodes metastasis (patient 1). One patient was diagnosed with brain metastasis (patient 25) 12 months after the surgery. The median duration of recurrence-free survival had not been reached at the time of data analysis. Hence, based on the available data, no significant differences were detected in the progression-free survival (PFS) and overall survival (OS) between the pCR and non-pCR groups (Figure 2).
Pathological findings after neoadjuvant PD-1 blockade
Representative radiological and pathological responses after two preoperative NCIO are shown in Figure 3. MPR occurred in 26/35 (74.29%) patients; 18 patients (51.43%) had pCR in the primary tumor. Despite apparent tumor enlargement on preoperative CT (possibly because of the infiltration of immune cells into the tumor), one patient exhibited pCR, that is pseudoprogression . In primary tumors with MPR, we observed a large number of infiltrating lymphocytes and macrophages. This finding was compatible with an immunological mechanism of response along with the phenomenon that necrotic tumor was associated with fibrotic tissue repair (Figure 3).
Invasion status of the bronchus with pathological response
We also analyzed the invasion status of the bronchus (ISB )by bronchoscope based on CT or PET-CT for all the patients. If the tumor invades the bronchus, a neoplasm is seen in the bronchus by the bronchoscope. If the tumor has not invaded the bronchus, we can only observe the red color and narrowing near the opening of the bronchus due to the pressure from the tumor (Figure 4a). Interestingly, 17/35 (48.57%) patients were evaluated as Invade and 18/35 (51.43%) as no-Invade. Of these, 13 (76.47%) patients in the Invade group presented pCR response, and all the 17(100%) patients showed the MPR response. On the other hand, only 5 (27.78%) patients in the no-Invade group showed pCR response, and 9 (50.00%) patients did not demonstrate MPR . The Pearson’s rho is 0.7280 and there is significant difference between the two groups (P=0.0009; Figure 4b).
Expression of PD-L1 with pathological response
The expression of PD-L1 could be evaluated in pretreatment biopsy samples in all patients (Figure 5A). A pCR or MPR response occurred in both PD-L1-positive and PD-L1-negative tumors. The correlation between the TPS scores of pretreatment biopsy samples and pathological regression was analyzed. Figures 5B shows that there is no association between PD-L1 expression before the treatment and the pathological response to NCIO (Pearson’s r=-0.071; P=0.685).
Immune proofing of T cells to NCIO
To further explore the T-cell proofing of these patients, flow cytometry analysis was performed. CD4+ and CD8+ T cells and Treg cells were evaluated in the post-surgery samples in 17 available patients (Figure 7). The ratio of the CD4+, CD8+ T cells, and Treg cells to T cells and all cells of the sample were analyzed in the pCR and MPR groups. As shown in Figure 7b, the proportion of CD 4+ T cells to T cells was 36.93±12.34 and 43.67±14.61 in the pCR group and non-PCR group, respectively (P>0.05), while the percentage of CD 4+ T cells to all cells in the sample was 7.42±4.94 and 10.39±11.90 in the pCR and non-PCR groups, respectively (P>0.05). Moreover, the percentage of CD8+ T cells to T cells was 50.74±12.78 and 43.90±19.70 in the pCR and non-PCR groups, respectively (P>0.05). Furthermore, the percentage of CD 8+ T cells to all cells in the sample was respectively 10.43±7.97 and 9.71±6.97 in the pCR and non-PCR groups, respectively (P>0.05). The percentage of Treg cells to T cells was 1.55±1.25 and 3.57±2.69 in the pCR and non-PCR groups, respectively (P>0.05), while that of Treg cells to all cells in the sample was 0.41±0.57 and 1.04±1.27 in the pCR and non-PCR groups, respectively (P>0.05).