Efficacy and safety evaluation of neoadjuvant immunotherapy plus chemotherapy for resectable non–small cell lung cancer in real world

Objectives The combination of immunotherapy and chemotherapy has shown great efficacy in stage IV non–small cell lung cancer (NSCLC) and is now widely used in clinical treatment strategy. This study retrospectively analyzed the efficacy and safety of neoadjuvant immunotherapy plus chemotherapy for resectable NSCLC in real world. Methods We retrospectively analyzed patients with NSCLC who received neoadjuvant immunotherapy plus chemotherapy and underwent complete tumor resection in Zhejiang Cancer Hospital between January 2019 and January 2021. Tumor staging was based on the eighth TNM classification system of the American Joint Committee on Cancer staging criteria. The safety and toxicity (including operative and postoperative complications) and the efficacy [including objective response rate (ORR), disease control rate (DCR), tumor major pathological remission (MPR), and pathological complete response (pCR)] were evaluated. Results In total, 368 patients with NSCLC were administered with neoadjuvant immunotherapy. Of them, 211 patients were included in this retrospective study. Most patients had stage II–III disease, with 75 (35.5%) and 88 (41.7%) patients diagnosed with clinical stages IIB and IIIA, respectively. A total of 206 patients (97.6%) received at least two doses of neoadjuvant immunotherapy plus chemotherapy. In addition, 121 patients (57.3%) have achieved MPR, and 80 patients (37.9%) have achieved pCR, with ORR at 69.2% and DCR at 97.7%. Treatment-related adverse events occurred in 46.4% of patients, and the incidence rate of grade 3 or 4 treatment-related adverse events was 13.3% (13/98). Moreover, adverse events of any grade of surgical complication occurred in 15.6% of patients. One-year disease-free survival was 80.6% (170/211). Conclusions Neoadjuvant immunotherapy plus chemotherapy has significant efficacy with a high pCR and tolerable adverse effects for patients with resectable stage II–III NSCLC in real world.


Introduction
Lung cancer is one of the leading causes of cancer-related deaths worldwide, and non-small cell lung cancer (NSCLC) accounts for 80%-85% of new cancer cases (1). Despite the combination of multimodal therapy treatment strategy including surgery, chemotherapy, and radiotherapy for patients with resectable NSCLC, 25%-70% of patients at different stages will relapse in 5 years (2). In the past decades, although many efforts have been made to develop the perioperative management of resectable NSCLC (3,4), patients still have to face a high risk of recurrence and death. Therefore, it is still of urgent need to develop new treatment methods.
In past 5 years, immune checkpoint inhibitors (ICIs), especially programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1) inhibitors, have significantly changed the treatment paradigm for patients with advanced NSCLC and provided long-term survival hope for patients with metastatic lung cancer. Now, PD-1 and PD-L1 inhibitors combined with chemotherapy have become the standard first-line treatment methods for advanced NSCLC (5)(6)(7). Given the profound impact of PD-1 and PD-L1 inhibitors on advanced NSCLC, many experts have paid great attention to investigating the potential role of ICIs in resectable NSCLC, and several undergoing clinical trials have reported promising results (8)(9)(10)(11). The Checkmate 159 trial was the first study to use PD-1 inhibitor as neoadjuvant regimen for resectable NSCLC, and it showed that, after two doses of nivolumab preoperatively, 45% of resected tumors (9/20) had a major pathological remission (MPR), and 10% of patients (2/20) even achieved a pathological complete response (pCR) (12). The NADIM trial (NCT 03081689) applied three preoperative cylces of PD-1 inhibitor with chemotherapy on individuals with stage IIIA disease. The results showed that 41 patients had underwent tumor resection, 34 (83%) had achieved MPR, 26 (63%) had achieved pCR. Moreover, 37 patients (90%) achieved pathlogical downstaging, and 35 patients (85%) are alive and free of recurrence with a median follow-up of 24 months (9).
Recently, the phase 3 Checkmate 816 trial showed that neoadjuvant with nivolumab and chemotherapy significantly improved the pCR (24.0%) compared with traditional chemotherapy (2.2%) for resectable NSCLC with a tolerable safety (13). All these data revealed that the neoadjuvant immunotherapy combined with chemotherapy may provide a new treatment strategy for resectable NSCLC.
In this study, we retrospectively collected data from 211 patients with resectable stage IB-IIIB NSCLC, who have received neoadjuvant immunotherapy plus chemotherapy and underwent complete tumor resection in our center to evaluate the efficacy and safety.

Patients and data collection
Patients with NSCLC who received neoadjuvant immunotherapy plus chemotherapy and underwent radical resection between January 2019 to January 2021 in Zhejiang Cancer Hospital were reviewed. A total of 211 patients with NSCLC identified from a screened population of 368 patients were enrolled in this study. The main inclusion criteria were as follows (1): histologically confirmed NSCLC (2), clinically stages I-III (3), no metastatic cervical lymph nodes or prior cancer therapy (4), negative driver mutation (5), received at least one dose of neoadjuvant immunotherapy plus chemotherapy, and (6) underwent radical surgery with curative intent. Tumor staging was based on the eighth TNM classification system of the American Joint Committee on Cancer staging criteria. All patients underwent routine baseline tumor diagnosis and staging, including chest computed tomography (CT), brain magnetic resonance imaging, and positron emission tomography-CT (PET-CT). The neoadjuvant regimen was PD-1 inhibitors combined with platinum-based chemotherapy, which was administered intravenously every 21 days. The PD-1 inhibitors include nivolumab, pembrolizumab, camrelizumab, toripalimab, sintilimab, and tislelizumab. Preoperative chest CT scan was necessary to evaluate the efficacy of neoadjuvant regimen. Follow-up information was obtained through inpatient medical records and telephone inquiries. The last follow-up date was 1 March 2022. This retrospective study was approved by the Institutional Ethics Board of Cancer Hospital of the University of Chinese Academy (No. IRB-2022-48).

Study end points and assessment method
Radiological response of the tumor including objective response rate (ORR) and disease control rate (DCR) was assessed after neoadjuvant immunotherapy plus chemotherapy and before the operation according to the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1). Disease-free survival (DFS) was defined as the time from diagnosis to disease progression, relapse, or death, whichever came first.
Postoperative pathological remission including MPR and pCR was assessed by specilaized pathologist after neoadjuvant immunotherapy plus chemotherapy. MPR is defined as neoadjuvant therapy-induced tumor regression with less than 10% vital tumor tissue, and pCR is defined as neoadjuvant therapy-induced complete tumor regression without vital tumor tissue (14).
Neoadjuvant therapy adverse events were evaluated on the basis of the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. From the beginning of neoadjuvant immunotherapy to the end of the treatment within 1 month, any adverse events that occurred, regardless of whether there is a relationship with the neoadjuvant immunotherapy, were judged as an adverse event. Time to surgery is defined as the time from the end of neoadjuvant therapy to the surgical operation. Postoperative complications occurred within 30 days after surgery were documented, including pain, anemia, subcutaneous emphysema, prolonged air leak, pneumonia, pleural effusion, and atrial fibrillation.

Statistical analysis
Patients were characterized by clinicopathological variables such as age, sex, histology, and stage. Categorical variables were presented as absolute and relative frequency, and numerical variables were presented as mean (SD) or median. The median length of follow-up was calculated using the Kaplan-Meier method. The Kaplan-Meier method was also used to calculate the DFS. All the statistical tests were two-sided with a significance level at p<0.05. Statistical analyses were performed with the SPSS 25.0.

Patients and treatments
From January 2019 to January 2021, 211 patients who were diagnosed with primary NSCLC underwent radical R0 resection after neoadjuvant immunotherapy plus chemotherapy in our center. The major clinicopathological characteristics of 211 patients were shown in Table 1
In addition, compared with the evaluation results of CT and postoperative pathology, the RECIST v1.1 evaluation based on preoperative CT imaging could not fully reflect the patient's final pathological remission status. In addition, 1 patient who has been evaluated PD by radiologic assessment was confirmed to have no disease progression after surgery. Among 80 patients who achieved pCR, only four patients showed CR according to the RECIST v1.1, whereas 63 patients showed PR and 10 patients showed SD. The conformity between radiologic assessment and pathological assessment was 48.3% (102/211). The difference between the preoperative CT imaging and pathological evaluation results of a representative patient was shown in Figure 3.
At a median follow-up of 17.0 months, 1-year DFS was 80.6% (170/211). Twenty-eight patients have relapsed, and the specific progression patterns were shown in Table 2. In addition, 14 patients died during postoperative follow-up. Among them, six patients were related with tumor progression, three patients were dead within 30 days after surgery, three patients died with immune-related adverse events during the postoperative adjuvant immunotherapy, and another two patients died with unknown cause.

Safety and surgical complications
No previously unreported toxicities were observed in relation to the neoadjuvant immunotherapy plus chemotherapy. Overall, the incidence of treatment-related adverse events (TRAEs) was low, and most were grade 1 or 2. TRAE occurred in 46.4% of patients, and the incidence rate of grade 3 or 4 TRAE was 13.3% (13/98). The most common grade 3 or 4 TRAE was neutropenia (1.9%), immune-related hepatitis (1.4%), immune-related pneumonia (0.5%), thrombocytopenia (0.9%), and rash (0.9%) ( Table 3). Among all these patients, 31 of them occurred more than two adverse events and six patients terminated the neoadjuvant immunotherapy due to the toxic effects.
Adverse events in any grade of surgical complication occurred in 15.6% of patients. The most common adverse events were prolonged air leak (7, 21.2%) and pleural effusion (7, 21.2%) ( Table 4). In addition, one patient experienced reoperation due to postoperative bleeding, and two patients experienced pulmonary embolism.

Discussion
Neoadjuvant immunotherapy plus chemotherapy for resectable NSCLC is promising and attractive. This study is a retrospective real-world assessment of neoadjuvant PD-1 A B FIGURE 1 Surgical approach (A) and type of surgery (B) of patients by baseline stages of disease.   (9) and CheckMate 816 trials were of three doses, and NCT02716038 trial (10) was of four doses. In addition, a meta-analysis showed that three doses of neoadjuvant chemotherapy could reduce the risk of death (15). In our study, more than two-thirds of patients received two doses of neoadjuvant of immunotherapy plus chemotherapy. In addition, 54.7% (81/148) of patients achieved MPR and 35.8% (53/148) achieved pCR. In the three or more doses subgroup, the percentage of MPR and pCR was 65.5% (38/58) and 44.8% (26/58), respectively. The results demonstrated that the increase of the neoadjuvant dose may have the trend to improve the pCR and MPR rate. In addition, preclinical studies suggested that there is a window between neoadjuvant immunotherapy and surgery, and shortening or delaying the interval between surgery and neoadjuvant immunotherapy could lead T cells to become inactivated or return to dysfunctional state, which will significantly affect survival (22). It is really challenging to determine the timing of surgery after neoadjuvant immunotherapy to ensure the strongest activity of T cells. In the NADIM trial, it is suggested to take operation 3 to 7 weeks after the end of neoadjuvant immunotherapy. In addition, the A B FIGURE 3 Radiological and pathological response of neoadjuvant immunotherapy plus chemotherapy. (A) The CT imaging and pathological diagnosis at baseline. (B) The CT imaging after two doses of neoadjuvant immunotherapy plus chemotherapy, and the pathological results after surgery. This was a 70-year-old male patient with smoking history, who was diagnosed as cT3N1M0 (stage IIIA) squamous cell carcinoma at baseline. After two doses of neoadjuvant immunotherapy plus chemotherapy, the patient achieved SD according to RECIST v1.1 with CT imaging assessment of 24% shrinkage of tumor. This patient underwent R0 resection with sleeve lobectomy and the pathological results with pCR. The regression bed is characterized by dense immune infiltrates with features of activation (tertiary lymphoid structure and dense tumor infiltrating lymphocytes infiltrates), along with features of cell death. Checkmate 816 trial suggested to take operation within 6 weeks. An expert consensus for 2020 recommended to take operation 4 to 6 weeks after the last neoadjuvant immunotherapy (23). In this study, the median time between the end of neoadjuvant immunotherapy and surgery was 4.1 weeks. All patients underwent R0 resection, 73.7% of patients underwent minimally invasive surgery, and less than 10% patients received the conversion to thoracotomy. Moreover the addition of PD-1 inhibitors to neoadjuvant chemotherapy did not increase the incidence of surgery complications or impede the feasibility of surgery, as well as the length of hospitalization. These results indicated that the surgery timing in 4 to 6 weeks after the last neoadjuvant immunotherapy is practicable.
Notably, although studies have proposed MPR as a surrogate end point in neoadjuvant trials for resectable NSCLC (24)(25)(26)(27), the relation between pCR and survival is still under debate in the setting of neoadjuvant immunotherapy. In the NADIM trial, the radiologic response according to CT scans and pCR was not significantly associated with survival (28). Unlike conventional chemotherapy, the response pattern of patients treated with  immunotherapy may be different, with some patients developing pseudo-progression or hyperprogression (29). As in our study, the CT evaluation could not accurately reflect the efficacy of neoadjuvant immunotherapy, and recent studies showed that FDG PET-CT could better play the role in assessment of response to immunotherapy (30,31). In addition, a recent study from the International Neoadjuvant Melanoma Consortium supports the role of pCR as an early surrogate end point for recurrence-free survival and overall survival (27).
In our study, although we do not have the long-term survival data due to the short follow up, among the 28 patients who have progressed after surgery during follow up, only four patients were pCR, which may indicate that pCR may be related with better DFS. Thus, in this regard, it still need more trials and long follow-up to illustrate whether pCR is an appropriate surrogate end point. In addition, in the NADIM trial, PD-L1 expression could not predict survival (28), which was similar with the studies in metastatic NSCLC (5, 32). The SAKK 16/14 trial  also demonstrated that there was no association between MPR and pretreatment PD-L1 expression (33). Thus, the PD-L1 expression was not mandatory in this study. Overall, the preliminary results in this study showed the excellent efficacy of the neoadjuvant immunotherapy plus chemotherapy in resectable NSCLC. In addition, the addition of neoadjuvant of immunotherapy did not increase the difficulty of surgical procedure and surgery-related adverse events. However, there are some limitations in our study. It is a retrospective study from a single cancer center with short-term follow up, and there may be omissions in the records of immune-related and surgery-related adverse events. In addition, the PD-L1 expression status of patients at baseline and the patient reported outcomes were not recorded. This study only included patients who had undergone R0 resection after neoadjuvant immunotherapy, and the adjuvant therapy was not well controlled. Numerous questions still need to be investigated, such as the dose of neoadjuvant immunotherapy, the maintenance immunotherapy treatment after surgery, and the appropriate end point and biomarkers.
In conclusion, this study presented a promising efficacy of neoadjuvant PD-1 inhibitors plus chemotherapy for patients with resectable stage I-III NSCLC and tolerable toxicities. However, these findings still need prospective clinical trials to confirm.

Data availability statement
The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethics statement
The studies involving human participants were reviewed and approved by the Institutional Ethics Board of Cancer Hospital of the University of Chinese Academy (No. IRB-2022-48). Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements. Written informed consent was not obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.