Abstract
Background:
Neoadjuvant chemoimmunotherapy demonstrates favorable survival outcomes and high pathological complete response (pCR) rates, but its efficacy in resectable N1/N2 nonsmall cell lung cancer (NSCLC) remains unproven. Additionally, predictive biomarkers for treatment efficacy and the relationship between lymph node status postneoadjuvant therapy and survival are unclear. This prospective study evaluates the efficacy and safety of combining penpulimab with chemotherapy for resectable N1/N2 NSCLC.
Materials and Methods:
This prospective cohort study enrolled patients aged ≥18 years with resectable N1/N2 NSCLC. Patients received penpulimab, carboplatin, and paclitaxel (for squamous cell carcinoma) or pemetrexed (for adenocarcinoma) every 21 days for three cycles, followed by surgery within 6 weeks. Primary endpoint: major pathological response (MPR). Secondary endpoints: pCR, objective response rate (ORR), R0 resection rate, disease-free survival (DFS), overall survival (OS), and treatment- and surgery-related adverse events. The study was Ethics Committee-approved.
Results:
From August 2022 to August 2023, 32 patients were enrolled. The preoperative ORR was 75.0%. R0 resection was achieved in 96.9%. MPR and pCR were achieved in 51.6% and 22.6% of patients, respectively. Significant associations between pCR and Response Evaluation Criteria in Solid Tumors response categories (P < 0.001), downstaging of nodal status (P = 0.007), and tumor mutational burden (TMB) (P = 0.037) were observed in our analysis. Multivariate regression analysis showed that no clinical factor other than TMB was predictive of the pCR. One-year DFS was 84.4%, and OS was 96.9%, with a median follow-up of 18 months. DFS was 100% in the MPR group versus 66.7% in the non-MPR group (P < 0.001) and higher in the pCR group (P = 0.0074). Nodal downstaging was observed in 50.0%, with superior survival in this group. Adverse events occurred in 93.8%, primarily fatigue, nausea, vomiting, and rashes.
Conclusion:
This is the first report of neoadjuvant penpulimab in N1/N2 NSCLC, demonstrating efficacy, feasibility, and survival benefits, especially in patients with high tumor mutational burden.
Keywords: N1/N2, neoadjuvant therapy, nonsmall cell lung cancer, PD-1 inhibitor, penpulimab
Introduction
Lung cancer is a common cancer with a high incidence and mortality rate worldwide, with 85% of cases being nonsmall cell lung cancer (NSCLC)[1]. Surgical resection is the main treatment option for early-stage NSCLC, with a high survival rate. However, even with complete tumor resection, the prognosis of patients with stage II-III locally advanced NSCLC with N1/N2 lymph node metastasis remains poor, with a 5-year overall survival (OS) rate of 20–40%[2]. Even with a combination of chemotherapy and surgery, only a 5–6% improvement in the 5-year survival rate is achieved[3]. Therefore, effective systemic treatments are needed for resectable N1/N2 NSCLC.
HIGHLIGHTS
This study is the first published trial utilizing penpulimab in combination with chemotherapy for neoadjuvant treatment of N1/N2 nonsmall cell lung cancer to investigate its efficacy and safety.
Significant associations between pathological complete response, objective response rate, and downstaging of nodal status or tumor mutational burden were observed in our analysis.
The disease-free survival was higher in the major pathological response group than in the nonmajor pathological response group.
Neoadjuvant therapy, especially neoadjuvant immunotherapy, targets the PD-1/PD-L1 axis with immune checkpoint inhibitors to activate the immune system, enabling T cell-mediated responses to identify and eliminate cancer cells and ultimately prolong patient survival[4]. According to recent clinical trials, the pathological complete response (pCR) rate of neoadjuvant chemoimmunotherapy is 24–63%, and the major pathological response (MPR) rate is 36–83%[5-7]. Therefore, chemoimmunotherapy has been widely proposed as a therapeutic modality for neoadjuvant therapy. Although some patients benefit from the procedure, potential safety issues, efficacy predictions, and surgical difficulties have raised concerns. Currently, established immune therapy biomarkers, including PD-L1 tumor proportion score (TPS), tumor mutation burden (TMB), and pathological response, are still uncertain for predicting long-term survival[8].
For locally advanced NSCLC with N1/N2 lymph node metastasis, several studies have shown that lymph node clearance is closely related to the survival benefits after neoadjuvant chemoradiotherapy[9,10]. However, the benefits of lymph node clearance with chemoimmunotherapy remain unproven. Therefore, it is crucial to collect data on neoadjuvant chemoimmunotherapy, including survival outcomes, comparisons between squamous cell carcinoma and adenocarcinoma, detailed information on the lymph node and primary lesion pathological remission, and survival benefits. Penpulimab, as a novel PD-1 monoclonal antibody with an optimized molecular structure, has been reported in studies to prolong the survival of patients with advanced NSCLC[11,12]. However, its efficacy and safety as neoadjuvant therapy remain unverified. Therefore, we conducted a prospective clinical trial to assess the efficacy and safety of combining penpulimab with chemotherapy in patients with N1/N2-positive NSCLC. Additionally, we aimed to determine predictive factors for pathological responses and the relationship between lymph node clearance and survival benefits.
Materials and methods
Participants
This investigator-initiated, single-center, prospective cohort study of neoadjuvant penpulimab plus chemotherapy in resectable NSCLC was conducted at Xinqiao Hospital, Army Medical University, Chongqing, China. The study protocol was reviewed and approved by the Ethics Committee of the Xinqiao Hospital, Army Medical University (Approve Number: 2022-228-03), and informed consent was obtained from each patient. The ethical review process included a thorough examination of the study design, informed consent forms, and patient information sheets to ensure adherence to ethical standards and protection of patient rights. Patient rights were safeguarded through several measures, including the use of a standardized informed consent process, the presence of a witness during the consent process, and the provision of a copy of the signed consent form to each participant.
Patients were eligible for enrolment if they were at least 18 years of age, had been diagnosed with stage II-IIIA NSCLC in accordance with the criteria set forth by the American Joint Committee on Cancer (AJCC 8th edition), and had been deemed operable by a thoracic surgeon. In line with the Response Evaluation Criteria in Solid Tumors (RECIST) (version 1.1), all participants exhibited an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, measurable disease, demonstrated adequate organ function, and possessed adequate lung function. Patients were excluded from enrolment if they had known EGFR mutations or ALK/ROS1 translocations. Genomic variations were identified via comprehensive next-generation sequencing panel testing, with results confirmed within 14 days of sample collection. PD-L1 testing was performed using the FDA-cleared Dako 22C3 pharmDx kit (Agilent Technologies, Santa Clara, CA) on the Dako Autostainer Link 48 platform. TPS was assessed by two independent pathologists blinded to clinical outcomes, with discordant cases resolved through a multihead microscope review.
Trial design
Participants received intravenous penpulimab (200 mg), carboplatin (400 mg/m2), and pemetrexed (500 mg/m2) for nonsquamous carcinoma or paclitaxel (175 mg/m2) for squamous carcinoma on day 1 of each 21-day cycle for three cycles before undergoing surgical resection. Adverse events were recorded using the Common Terminology Criteria for Adverse Events (version 5.0) at each follow-up on the first day of each cycle, recorded from the initial administration of drugs until at least 28 days after treatment termination, and followed up until the adverse event resolved or stabilized. The safety was monitored continuously. Participants were entitled to withdraw from the investigation at any point without providing a reason. Similarly, the investigational team reserves the right to discontinue participation due to unacceptable toxicity, protocol noncompliance, or other reasons.
A chest computed tomography (CT) scan was conducted after the completion of the initial two treatment cycles. In the event of disease progression, patients were immediately subjected to surgical intervention according to the RECIST criteria. The surgical procedures were conducted by a single team, which facilitated the harmonization of surgical techniques and optimized the management of surgical complications. All enrolled patients completed 1-3 cycles of postoperative adjuvant therapy, maintaining identical pharmacological agents and dosing schedules to their preoperative treatment protocols, with no subsequent maintenance immunotherapy administered following completion of the combined chemoimmunotherapy regimen. Patients underwent clinical and pathological examinations within 2 weeks postoperatively to assess MPR and pCR, followed by chest CT scans every 6 months for 2 years and annually thereafter. Assessment of MPR was conducted by pathologists who quantified the percentage of residual viable tumors in the resected primary tumors. This was achieved using previously reported methods. Tumor tissue samples were prepared for analysis by sectioning, and the percentage of viable tumor tissue was quantified for each tumor slide.
Outcomes
The primary endpoint was the proportion of patients achieving MPR (≤10% viable tumor tissue at surgery).
Secondary endpoints included pCR, objective response rate (ORR), R0 resection rate, 1-year disease-free survival (1-y DFS%) rate, OS, and disease-free survival (DFS), and treatment- and surgery-related adverse events. The period of observation began on the date of surgery and continued until either disease recurrence or death. This prospective cohort work was reported in line with the STROCSS criteria[13].
Statistical analysis
The results for the primary endpoint were expressed as frequencies and percentages, and a two-sided 95% confidence interval (CI) was calculated using the Clopper-Pearson method. The relationships between clinical parameters and pathological responses were assessed using either the chi-square test or Fisher’s exact test. Survival probabilities were estimated using the Kaplan–Meier method. Median event-free times were calculated and compared between groups using log-rank tests. Safety data were expressed as frequencies and percentages of affected patients.
Univariate and multivariate logistic analysis was used to explore the potential factors for achieving pCR and MPR in patients who underwent surgery, with odds ratios and 95% CIs calculated. All statistical analyses were performed using SPSS Statistics 27 and R software version 3.4.1, with a P-value <0.05 considered a statistically significant difference.
Results
Between August 2022 and August 2023, 36 patients were evaluated to determine their eligibility, and 32 patients who met the inclusion criteria were enrolled in the study (Fig. 1). Of these, 12 (40.6%) had adenocarcinoma and 19 (59.4%) had squamous cell carcinoma. Tumor PD-L1 expression at baseline was 1% or lower in 15 (46.9%) patients and 1% or higher in 17 (53.1%) patients. The preoperative nodal stage was recorded in 21 (65.6%) patients for N1 and 11 (34.4%) for N2. The baseline patient characteristics are shown in Table 1.
Figure 1.
Flow chart of participants.
Table 1.
Patients characteristics
| Patients (n = 32) | |
|---|---|
| Age | |
| ≥65 | 10(31.3%) |
| <65 | 22(68.7%) |
| Sex | |
| Male | 24(75%) |
| Female | 8(25%) |
| Smoking status | |
| Current or former smoker | 16(50%) |
| Never smoked | 16(50%) |
| Preoperative nodal stage | |
| N1 | 21(65.6%) |
| N2 | 11(34.4%) |
| Stage at presentation* | |
| IIA | 12(37.5%) |
| IIB | 9(28.1%) |
| IIIA | 11(34.4%) |
| Cancer type | |
| Adenocarcinoma | 13(40.6%) |
| Squamous cell carcinoma | 19(59.4%) |
| PD-L1 expressiona | |
| >1% | 17(53.1%) |
| ≤1% | 15(46.9%) |
| ECOG Physical Score | |
| 0 | 18(56.3%) |
| 1 | 14(43.7%) |
| TMB (Tumor mutational burden) | |
| >5.7 | 16(50%) |
| ≤5.7 | 16(50%) |
Data are median (IQR) or n (%).
Classified on the basis of the American Joint Committee on Cancer 8th edition staging system.
Measured by use of the 22C3 pharmDx kit.
Surgery was performed on 32 patients, with complete resection achieved in 31 cases (96.9%), as shown in Table 2. Of the 32 patients, 29 (90.6%) underwent video-assisted thoracoscopic surgery, and three (9.4%) underwent open thoracotomy. No treatment-related delays or surgery-related complications attributable to neoadjuvant therapy were observed (Table 2).
Table 2.
Surgical outcomes
| Patients (n = 32) | |
|---|---|
| Had successful surgical resection with curative intent | 31/32(96.9%) * |
| Location, cases | |
| LU | 6/32(18.75%) |
| LL | 6/32(18.75%) |
| RU | 9/32(28.1%) |
| RM | 3/32(9.4%) |
| RL | 8/32(25%) |
| Operative time(min) | 117.5(70-250) |
| Postoperative drainage(ml) | 530(250-1450) |
| Intraoperative bleeding(ml) | 85(20-500) |
| Type of surgery | |
| Video-assisted thoracoscopic surgery | 29(90.6%) |
| Thoracotomy | 3(9.4%) |
| Surgical resection | |
| Lobectomy | 28(87.5%) |
| Bilobectomy | 2(6.25%) |
| Sleeve resection | 2(6.25%) |
| Margins | |
| Negative | 31/32(96.9%) |
| Positive | 1/32(3.1%) |
| Surgical complications | |
| Total incidence rates | 12/32(37.5%) |
| Pian | 7/32(21.9%) |
| Pulmonary infection | 3/32(9.4%) |
| Postoperative bleeding | 1/32(3.1%) |
| Air leak | 2/32(6.3%) |
| Urinary tract infection | 1/32(3.1%) |
| Postoperative arrhythmia | 2/32(6.3%) |
| Hoarseness | 1/32(3.1%) |
| Postoperative hospital stays (days) | 4.5(3-9.5) |
Data are n/N (%) or median (IQR).
A patient failed to achieve R0 resection during surgery
Sixteen of the 31 patients (51.6%) exhibited an MPR (Table 3). Seven patients demonstrated a pCR, three of whom had Stage IIIA disease at the initial presentation. Notably, there was a significant difference in MPR between the preoperative nodal stages N1 and N2 (P = 0.046), as well as the stages at presentation IIA or IIB and IIIA (P = 0.046). Similarly, we assessed the pathological response in patients grouped according to tumor histology in a separate analysis. Among the patients who achieved MPR, 10 had squamous cell carcinoma, and six had adenocarcinoma. Moreover, among patients who achieved pCR, five had squamous cell carcinoma, and two exhibited adenocarcinoma. Significant associations were observed between pCR and RECIST criteria response categories (P < 0.001), downstaging of nodal status (P = 0.007), and TMB (P = 0.037) (Table 4). Nevertheless, a significant association was observed between MPR and RECIST response categories (P < 0.001), with no significant difference between the MPR and other baseline patient characteristics (Table 5). Univariate and multivariate regression analysis demonstrated that none of the clinical factors, including age, sex, smoking status, tumor stage, ECOG Physical Score, N2 lymph node metastasis, downstaging of nodal status, PD-L1 expression, and ORR, were significantly associated with the achievement of pCR (Table 6) or MPR (Table 7). Notably, patients exhibiting a high TMB were found to have an increased likelihood of attaining pCR.
Table 3.
Pathological response rates
| Major pathological response | Pathological complete response | |
|---|---|---|
| Intention-to-treat population | 16/31(51.6%) | 7/31(22.6%) |
| Cancer type* | ||
| Adenocarcinoma | 6(37.5%) | 2(28.6%) |
| Squamous cell carcinoma | 10(62.5%) | 5(71.4%) |
| P value | 0.317 | 0.257 |
| Preoperative nodal stage | ||
| N1 | 12(75%) | 4(57.1%) |
| N2 | 4(25%) | 3(42.9%) |
| P value | 0.046 | 0.705 |
| Stage at presentation | ||
| IIA or IIB | 12(75%) | 4(57.1%) |
| IIIA | 4(25%) | 3(42.9%) |
| P value | 0.046 | 0.705 |
Data are n/N (%) unless otherwise indicated.
Only includes patients who underwent successful R0 surgical resection.
Table 4.
Characteristics classified by pathological complete response
| Pathological complete response | P-value | ||
|---|---|---|---|
| No (<100%) | Yes (100%) | ||
| n = 24 | n = 7 | ||
| RECIST | |||
| CR | 0(0%) | 7(100%) | P<0.001 |
| PR | 16(66.7%) | 0(0%) | |
| SD | 8(33.3%) | 0(0%) | |
| PD | 0(%) | 0(0%) | |
| Age | |||
| ≥65 | 8(33.3%) | 1(14.3%) | 0.639 |
| <65 | 16(66.7%) | 6(85.7%) | |
| Sex | |||
| Male | 18(75%) | 5(71.4%) | 1 |
| Female | 6(25%) | 2(28.6%) | |
| Smoking status | |||
| Current or former smoker | 14(58.3%) | 2(28.6%) | 0.22 |
| Never smoked | 10(41.7%) | 5(71.4%) | |
| ECOG Physical Score | |||
| 0 | 15(62.5%) | 3(42.9%) | 0.413 |
| 1 | 9(37.5%) | 4(57.1%) | |
| Preoperative nodal stage | |||
| N1 | 17(70.8%) | 4(57.1%) | 0.652 |
| N2 | 7(29.2%) | 3(42.9%) | |
| Downstaging of nodal status in patients with N2 or N1 at baseline | |||
| N2 to N2 or N1 to N1 | 15(62.5%) | 0(0%) | 0.007 |
| N2 to N1/N0 or N1 to N0 | 9(37.5%) | 7(100%) | |
| Stage at presentation | |||
| IIA | 10(41.6%) | 2(28.6%) | 0.757 |
| IIB | 7(29.2%) | 2(28.6%) | |
| IIIA | 7(29.2%) | 3(42.8%) | |
| PD-L1 expression | |||
| >1% | 10(41.6%) | 6(85.8%) | 0.083 |
| ≤1% | 14(58.4%) | 1(14.2%) | |
| TMB (Tumor mutational burden) | |||
| >5.7 | 9(37.5%) | 6(85.8%) | 0.037 |
| ≤5.7 | 15(62.5%) | 1(14.2%) | |
Table 5.
Characteristics classified by major pathological response
| Major pathological response | P-value | ||
|---|---|---|---|
| No (<90%) | Yes (≥90%) | ||
| n = 15 | n = 16 | ||
| RECIST | |||
| CR | 0(0%) | 7(43.8%) | P<0.001 |
| PR | 7(46.7%) | 9(56.2%) | |
| SD | 8(53.3%) | 0(0%) | |
| PD | 0(0%) | 0(0%) | |
| Age | |||
| ≥65 | 6(40%) | 3(18.7%) | 0.252 |
| <65 | 9(60%) | 13(81.3%) | |
| Sex | |||
| Male | 12(80%) | 11(31.2%) | 0.685 |
| Female | 3(20%) | 5(68.8%) | |
| Smoking status | |||
| Current or former smoker | 8(53.3%) | 8(50%) | 1 |
| Never smoked | 7(46.7%) | 8(50%) | |
| ECOG Physical Score | |||
| 0 | 9(60%) | 9(56.2%) | 1 |
| 1 | 6(40%) | 7(43.8%) | |
| Preoperative nodal stage | |||
| N1 | 9(60%) | 12(75%) | 0.458 |
| N2 | 6(40%) | 4(25%) | |
| Downstaging of nodal status in patients with N2 nor N1 at baseline | |||
| N2 to N2 or N1 to N1 | 8(53.3%) | 7(43.8%) | 0.724 |
| N2 to N1/N0 or N1 to N0 | 7(46.7%) | 9(56.2%) | |
| Stage at presentation | |||
| IIA | 5(33.3%) | 7(43.7%) | 0.666 |
| IIB | 4(26.7%) | 5(31.3%) | |
| IIIA | 6(40%) | 4(25%) | |
| PD-L1 expression | |||
| >1% | 6(40%) | 10(62.5%) | 0.289 |
| ≤1% | 9(60%) | 6(37.5%) | |
| TMB (Tumor mutational burden) | |||
| >5.7 | 5(33.3%) | 10(62.5%) | 0.156 |
| ≤5.7 | 10(66.7%) | 6(37.5%) | |
Table 6.
Univariate and multivariate logistic analysis of predictive factors for achieving pCR
| Variables | Univariate analysis | Multivariate analysis | ||||
|---|---|---|---|---|---|---|
| OR | 95%CI | P | OR | 95%CI | P | |
| Objective response rate | 0.696 | 0.531-0.912 | 0.999 | |||
| Age (≥65 years) | 0.333 | 0.034-3.261 | 0.345 | 3.156 | 0.280-35.543 | 0.352 |
| Sex (Male) | 0.133 | 0.020-0.876 | 0.849 | |||
| Smoking status (Current or former smoker) | 0.286 | 0.046-1.780 | 0.180 | |||
| ECOG Physical Score (0) | 2.222 | 0.402-12.285 | 0.360 | |||
| Preoperative nodal stage(N2) | 1.821 | 0.321-10.342 | 0.499 | |||
| Downstaging of nodal status in patients with N2 or N1 at baseline (N2 to N2 or N1 to N1) | 0.563 | 0.365-0.867 | 0.998 | |||
| Stage at presentation (IIB and IIIA) | 1.465 | 0.530-4.049 | 0.462 | |||
| PD-L1 expression (≤1%) | 0.119 | 0.012-1.149 | 0.066 | |||
| TMB (Tumor mutational burden) (≤5.7) | 0.100 | 0.010-0.970 | 0.047 | 10.210 | 1.025-101.726 | 0.048 |
Table 7.
Univariate and multivariate logistic analysis of predictive factors for achieving MPR
| Variables | Univariate analysis | Multivariate analysis | ||||
|---|---|---|---|---|---|---|
| OR | 95%CI | P | OR | 95%CI | P | |
| Objective response rate | 0.304 | 0.164-0.565 | 0.999 | |||
| Age (≥65 years) | 0.346 | 0.068-1.759 | 0.346 | |||
| Sex (Male) | 0.550 | 0.106-2.860 | 0.477 | |||
| Smoking status (Current or former smoker) | 0.875 | 0.214-3.586 | 0.853 | |||
| ECOG Physical Score (0) | 1.167 | 0.279-4.871 | 0.833 | |||
| Preoperative nodal stage(N2) | 0.500 | 0.108-2.314 | 0.375 | |||
| Downstaging of nodal status in patients with N2 or N1 at baseline (N2 to N2 or N1 to N1) | 0.681 | 0.165-2.804 | 0.594 | |||
| Stage at presentation (IIB and IIIA) | 0.695 | 0.296-1.629 | 0.402 | |||
| PD-L1 expression (≤1%) | 0.400 | 0.094-1.699 | 0.214 | |||
| TMB (Tumor mutational burden) (≤5.7) | 0.300 | 0.069-1.312 | 0.110 | |||
All 32 patients completed at least three cycles of treatment. The most common treatment-related adverse events were fatigue (13/32, 40.6%), nausea/vomiting (12/32, 37.5%), rash (11/32, 34.4%), neutropenia (12/32, 37.5%), constipation (7/32, 21.9%), and diarrhea (6/32, 18.8%). Severe grade 3–4 events included rash (1/32, 3.1%) and neutropenia (1/32, 3.1%). One patient (3.1%) developed grade 3 febrile neutropenia. Immune-related adverse events included diarrhea, arthralgia, myalgia, liver dysfunction, and hypothyroidism (Table 8). Two patients required a dose reduction due to rashes and neutropenia. There were no treatment-related deaths.
Table 8.
Treatment-related adverse events
| Grade 1–2 | Grade 3-4 | |
|---|---|---|
| Fatigue | 13(40.6%) | |
| Nausea or Vomiting | 12(37.5%) | |
| Rash | 11(34.4%) | 1(3.1%) |
| Neutropenia | 9(28.1%) | 1(3.1%) |
| Constipation | 7(21.9%) | |
| Diarrhoea* | 6(18.8%) | |
| Arthralgia or myalgia* | 5(15.6%) | |
| Hepatic dysfunction* | 4(12.5%) | |
| Anaemia | 4(12.5%) | |
| Hypothyroidism* | 4(12.5%) | |
| Thrombocytopenia | 3(9.4%) | |
| Anorexia | 3(9.4%) |
Data are n (%). Shown are the treatment-related adverse events of any grade that occurred in more than 10% of patients, or any treatment-related adverse events of grade 3 and above. No grade 5 treatment-related adverse events were reported.
Possible immune-mediated adverse events.
At a median follow-up of 18 months (interquartile range, 17–19 months) from the first day of treatment, 24 (77.4%) of the 31 patients who underwent successful R0 surgical resection were alive at the time of reporting, and 21 patients had no evidence of recurrence. Of the 10 patients with disease recurrence, two experienced brain recurrence, and seven died. Although the median DFS was not reached in the overall patient cohort, the median OS was 24 months (95% CI, 20 to not reached) (Fig. 2), indicating the potential efficacy of the treatment. The 1-y DFS% were 84.4% (95% CI, 71.1–97.7%) for DFS and 96.9% (95% CI, 90.5–100%) for OS across the entire patient cohort.
Figure 2.
Kaplan–Meier survival curves.
(A) Disease-free survival. (B) Overall survival. Shaded areas represent 95% CIs.
In the DFS analysis, the median DFS for patients without an MPR was 17 months (95% CI, 11–not reached), whereas for those with an MPR, it was not reached (Fig. 3A). The 1-y DFS in the MPR group was 100% compared to 66.7% in the non-MPR group (P < 0.001). The median DFS for patients with or without pCR was not reached. While the two curves in Figure 3 were not significantly different from each other (P = 0.054), the overall DFS was higher in the pCR group than in the non-pCR group (Fig. 3B). A comparable phenomenon was observed in patients with a downstaged nodal status (Fig. 4). The N2 or N1 downstaging group exhibited superior outcomes compared to the nondownstaging group.
Figure 3.
Kaplan–Meier survival curves according to the pathological response.
(A) Disease-free survival comparisons: MPR vs. non-MPR. (B) Disease-free survival comparisons: pCR vs. non-pCR.
Figure 4.
Kaplan–Meier survival curves according to the downstaged nodal status.
Discussion
To the best of the authors’ knowledge, there is a limited number of studies on the surgical-related safety and efficacy of neoadjuvant chemoimmunotherapy in patients with N1/N2 NSCLC[14,15]. This trial is the first to explore the combination of penpulimab with chemotherapy for the neoadjuvant treatment of N1/N2 NSCLC, utilizing a 1-year DFS endpoint. This combined strategy has shown promising efficacy and safety in advanced lung cancer[11], prompting us to investigate its effectiveness in a neoadjuvant setting.
This study met its primary endpoint with MPR achieved in 51.6% of patients and pCR in 22.6%, consistent with published neoadjuvant chemoimmunotherapy pCR rates (25-48%)[5,6]. Furthermore, the 1-year DFS rate achieved was 84.4% (with a median follow-up of 18 months), which is closely aligned with the results of other neoadjuvant chemoimmunotherapy trials, such as NADIM (1-year event-free survival [EFS] of 95.7%)[6] and Checkmate 816 (1-year EFS of 76.1%)[5]. Notably, the median follow-up duration of 18 months in our study is a limitation, as it may not fully capture the long-term outcomes of the treatment. The median OS of 24 months suggests a potential benefit of the neoadjuvant regimen; however, the median DFS has not yet been reached, which limits our ability to draw definitive conclusions regarding the durability of the treatment effects. We plan to continue follow-up and report long-term outcomes, including 5-year survival rates, in a future update of this study. Additionally, in previous studies, patients who achieved MPR or pCR demonstrated improved DFS[16,17]. MPR strongly correlated with 1-year DFS (100% vs. 66.7%, P < 0.001), whereas pCR demonstrated nonsignificant DFS trends, potentially influenced by cohort size constraints and biological response heterogeneity. Therefore, the association between the pathological response and survival benefit warrants further evaluation in future clinical trials of neoadjuvant treatment for NSCLC. Meanwhile, we observed that a subset of patients experienced lymph node downstaging following neoadjuvant chemoimmunotherapy, whereas others showed no change. It is well-established that advanced stages of lung cancer are associated with poorer survival outcomes. Therefore, it is of interest to determine whether patients who experience tumor downstaging following neoadjuvant therapy may achieve improved survival. We analyzed survival associations: nodal downstaging demonstrated a nonsignificant trend toward improved PFS, contrasting with Du et al’s findings[18] where complete nodal clearance predicted superior DFS/OS. Our focus on nodal downstaging rather than clearance (ypN0) may explain this discrepancy – subgroup analysis restricted to ypN0 patients could yield concordant results.
This investigation evaluated determinants of neoadjuvant chemoimmunotherapy efficacy, focusing on clinicopathological variables and molecular biomarkers. Our analysis revealed significant correlations between pathological responses (MPR/pCR) and radiological tumor regression, with lymph node downstaging demonstrating selective association with pCR (P = 0.032) but not MPR. Although prior studies implicate histological subtype[15,19] (squamous vs. nonsquamous) and nodal metastasis burden[20] (N1 vs. N2) in therapeutic response modulation, our cohort failed to substantiate these relationships. Multivariate regression confirmed TMB as an independent pCR predictor, contrasting with PD-L1 expression’s nonsignificant predictive value – consistent with previously reported chemoimmunotherapy trials[21] demonstrating attenuated PD-L1 utility compared to immunotherapy monotherapy paradigms. Divergent reports linking PD-L1 TPS to survival outcomes[5,22] likely reflect spatial heterogeneity between biopsy specimens and surgical resection materials. The mechanistic basis for TMB’s predictive superiority may reside in its quantification of tumor neo-antigenic load, thereby enhancing immune system recognition and therapeutic targeting. Current biomarker limitations necessitate multimodal prediction frameworks integrating TMB, PD-L1 spatial distribution, and immunophenotypic profiling. Future directions should prioritize multiomics approaches[23] evaluating tumor microenvironment dynamics, including stromal-immune interactions and treatment-induced clonal selection patterns.
In addition to exploring the efficacy of penpulimab in combination with chemotherapy for the neoadjuvant treatment of N1/N2 NSCLC, we observed the adverse reactions caused by the combined treatment. We found that the most common adverse reaction was fatigue, with an incidence rate of 40.6%, which is similar to that of other studies, demonstrating an incidence of 50% in NADIM[6] and 40% in NCT04326153[17]. The results showed that although the overall incidence of adverse reactions to neoadjuvant chemoimmunotherapy was 93.75%, the occurrence of grade 3-4 adverse reactions was relatively low at 6.2% (one case of neutropenia and one case of rash). Furthermore, the incidence of grade 3-4 treatment-related adverse events was 33.5% for the nivolumab-chemotherapy combination[5] and 44.9% for the pembrolizumab-chemotherapy combination[24]. The incidence of high-grade adverse reactions was lower than that reported in these similar studies. The reason for this was that penpulimab, a new PD-1 monoclonal antibody using the IgG1 subtype, has been optimized for the Fab and Fc regions, characterized by high specificity, good stability, and strong affinity, enhancing efficacy while reducing the risk of immune-related adverse events[25]. In the AK105-302 study[11], penpulimab demonstrated good safety in the treatment of advanced squamous cell carcinoma. The most common drug-related adverse reactions observed in this study were fatigue, nausea, vomiting, and rash, which may have been related to chemotherapy. The incidence of immune-related adverse reactions (mainly myalgia, hypothyroidism, and liver function defects) was low.
For surgical physicians, in addition to focusing on the efficacy and adverse reactions of drugs, the surgical difficulties and risks associated with neoadjuvant treatment were also of concern. In this study, we found that the average surgical time for patients who underwent neoadjuvant chemoimmunotherapy was 200 min, which was similar to the reported surgical time for lung cancer surgery without neoadjuvant treatment[26], indicating that neoadjuvant chemotherapy did not significantly increase the surgical time. Additionally, we found that although all patients in the study were assessed to have lymph node metastasis before treatment, only two of them underwent open thoracic surgery, and the average intraoperative bleeding was only 200 mL, comparable to the reported bleeding volume of thoracoscopic surgery without neoadjuvant treatment. Moreover, this finding indicated that neoadjuvant chemoimmunotherapy did not significantly increase surgical difficulty or affect patient safety. Postoperative complications were also observed in these patients, such as pain, with an incidence of 21.9%, which may be related to the placement of drainage tubes. Notably, the average postoperative hospital stay was 4.5 days, with an overall postoperative complication rate of 37.5%. These results are comparable to those previously reported in patients who did not undergo neoadjuvant therapy[27]. These findings are sufficient to demonstrate that neoadjuvant chemoimmunotherapy does not adversely affect patients’ postoperative recovery.
Regarding the selection of postoperative adjuvant treatment strategies, we chose to continue the neoadjuvant treatment plan for one to three cycles. In contrast to the NADIM[6] and SAKK 16/14 trials[28], in which patients were administered adjuvant immunotherapy for a duration of 1 year following surgery, other neoadjuvant trials deviated from this approach. Furthermore, clarity regarding the duration and necessity of adjuvant immunotherapy within the context of neoadjuvant chemoimmunotherapy trials for NSCLC remains to be elucidated.
This study had some limitations. First, although it is the first to use penpulimab as a neoadjuvant treatment for N1/N2 NSCLC, it was a single-arm prospective cohort study and did not directly compare its efficacy and safety with those of other neoadjuvant treatment options. Potential confounders include evolving standard-of-care practices or selection bias toward healthier patients. Second, although this study focused on patients with N1/N2 NSCLC, it only included samples from a single center with a small sample size, which may limit the generalizability of the findings. The treatment approach and patient population may be specific to the center where the study was conducted, and the results may not be representative of other centers or patient populations. Sample size constraints also hinder the comprehensive capture of patient population diversity, including factors such as biological tumor variability and comorbidities, which may lead to an overestimation or underestimation of the therapy’s broader applicability. However, the study’s findings provide valuable preliminary data on the efficacy and safety of the penpulimab-chemotherapy combination and highlight the need for further research in this area. Lastly, in the exploration of efficacy biomarkers, we used traditional TMB and PD-L1. Future studies will integrate complementary biomarkers, such as tumor-infiltrating lymphocyte density, peripheral immune profiling, and emerging checkpoints (e.g., LAG-3), to better stratify patients. To further elucidate the mechanisms underlying the observed responses and identify potential biomarkers of sensitivity or resistance, we plan to conduct comprehensive biomarker analyses by pre- and post-treatment biopsies in an ongoing phase II trial (ChiCTR2300072183 ). This trial is also targeting patients with locally advanced NSCLC, which began enrollment in 2024 and has already enrolled 15 participants. Tissues and blood samples from all patients were collected to facilitate multiomics analysis.Despite these limitations, the results of this study are consistent with those of other studies that have examined the efficacy and safety of PD-1 inhibitors in the treatment of NSCLC. Although our single-center design allowed for meticulous quality control, we recognize the need for external validation. Hence, we have established a multi-institutional registry (n =9 hospitals) to collect real-world data on the efficacy and safety of combining penpulimab with chemotherapy for resectable N1/N2 NSCLC.
Conclusion
In summary, this prospective cohort study presents the first report of the efficacy and survival outcomes of patients with N1/N2 NSCLC treated with the novel PD-1 inhibitor (penpulimab) as neoadjuvant therapy. The findings of this study suggest that the neoadjuvant combination of penpulimab with chemotherapy may be a promising treatment approach for resectable N1/N2 NSCLC, especially for patients with high TMB. These findings provide new insights into the application of chemoimmunotherapy as a neoadjuvant treatment for resectable N1/N2 NSCLC.
Footnotes
Dong Zhou and Jia-Ming He contributed equally to this work.
Sponsorships or competing interests that may be relevant to the content are disclosed at the end of this article.
Published online 12 June 2025
Contributor Information
Dong Zhou, Email: zhoudong@tmmu.edu.cn.
Liang Chen, Email: wanganhui1995@163.com.
Zhi Zhenge, Email: zhengzhi0830@163.com.
Xu-Feng Deng, Email: 674965568@qq.com.
Jiao Zhang, Email: swuzhangjiao@163.com.
Hong Zheng, Email: ziecoe@tmmu.edu.cn.
Ji-Gang Dai, Email: daijigang@tmmu.edu.cn.
Ethical approval
This study was approved by the Ethics Committee of Xinqiao Hospital, Third Military Medical University (Army Medical University) (approval number: 2022-228-03).
Consent
Informed consent was obtained from each patient.
Sources of funding
This work was supported by grants from the Noncommunicable Chronic Diseases-National Science and Technology Major Project (2024ZD0529400), the Key Projects of the National Natural Science Fund for Regional Innovation Development Joint Fund (U24A20715), National Natural Science Foundation of China (82404694), Science and Technology Commission, and the Chongqing Health Commission Joint Medical Research Program of Chongqing (2024MSXM090), Natural Science Foundation of Chongqing (CSTB2024NSCQ-MSX1164, CSTB2024NSCQ-KJFZZDX0009), and the Key Projects of Talent Incubation Plan of Xinqiao Hospital (2022YQB012, 2024YQB093).
Author contributions
D.Z.: Methodology (lead); writing–original draft (lead). J.-M.H.: writing – the original draft (lead). J.-C.Y.: Data curation (lead); resources (lead). Y.-Q.L.: Data curation (lead); resources (lead). L.C.: Conceptualization (equal); data curation (equal). X.-F.D.: Data curation (both authors). Z.Z.: Data curation (and) formal analysis (equal). J.Z.: Data curation (both) and formal analysis (both). X.L.: Conceptualization (equal); formal analysis (equal). H.Z.: Conceptualization (lead), writing, review, and editing (lead). J.-G.D.: Project administration (lead); writing, review, and editing (equal).
Conflicts of interest disclosure
The authors declare that they have no conflicts of interest.
Research registration unique identifying number (UIN)
The study was registered at Chictr.org.cn (identifier: ChiCTR2200064928).
Guarantor
Corresponding author Ji-Gang Dai, MD, PhD, is fully responsible for this study.
Provenance and peer review
Not commissioned, externally peer-reviewed.
Data availability statement
All data generated and analyzed in this study are included in this published article. The corresponding author may request the data presented herein.
Acknowledgements
None.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All data generated and analyzed in this study are included in this published article. The corresponding author may request the data presented herein.