P79.09 Neoadjuvant Combination Sintilimab plus Chemotherapy in Patients with Resectable Stage IIIA Non-Small Cell Lung Cancer.

Introduction: Patients with stage IIIA non-small cell lung cancers (NSCLC) are potentially curable, however 5-year survival rate remains disappointing of 40%. The median overall survival (OS) of stage III resectable NSCLC was only 31months, and 22 months for N2. At present, the standard treatment of neoadjuvant therapy is still platinum dual-drug chemotherapy. Antibodies that block programmed death 1 (PD-1) protein combined with chemotherapy improves survival in patients with advanced NSCLC. Sintilimab, a highly selective, fully human monoclonal antibody (mAb), blocks the interaction of PD-1 and its ligands and has demonstrated clinical benefit in various clinical studies. Therefore, it is still a question to be explored whether immunochemotherapy combined with chemotherapy can improve the pathological response rate, the disease-free survival (DFS) and OS. This study assessed the effects of the addition of Sintilimab to traditionnal neoadjuvant chemotherapy in resecrable NSCLC, aims to observe whether Sintilimab in combination with chemotherapy can be a new choice for treatment of resectable NSCLC. Methods: This is a prospective, single-center, single-arm Phase II clinical trial (NCT04326153). In this pilot study, patients with resectable stage III A NSCLC received 2 cycles of neoadjuvant treatment (Sintilimab+Nab-paclitaxel+carboplatin) prior to surgery. Surgery must be done within the 3rd-4th week. Patients that are R0 confirmed by surgical pathology evaluation will receive 2 cycles of adjuvant treatment (Sintilimab+Nab-paclitaxel+carboplatin), and treatment of Sintilimab for six months. The primary endpoint is the rate of 24-month DFS. Secondary endpoints included major pathological response (mPR), the pathological complete response (pCR), OS, and adverse events (AEs). Results: The ongoing trial has not reached pre-specified endpoints for analysis. At present, there are 2 patients who meet the standard have completed the operation after neoadjuvant. Patient A was diagnosed as large cell lung cancer with clinical stage III A (T4N1M0). The evaluation of CT was partial response (PR)(Fig.1(a)(b)(c)(d)). The pathological response rate was 60%. Pathological stage reduced to stage I B (pT2aN0M0). Treat-related AE was increase of aspartate transaminase and alanine aminotransferase (grade II CTCAE5.0). Patient B was diagnosed as adenocarcimoma with clinical stage III A (T1bN2M0). The evaluation of CT was stable disease (SD)(Fig.1(e)(f)(g)(h)). The pathological response rate was 30%. Pathological stage reduced to stage II B (pT1cN1M0). Treat-related AE was leukopenia (grade II CTCAE5.0). All adverse reactions can be returned to normal after symptomatic treatment. [Formula presented] Conclusion: Neoadjuvant Sintilimab plus chemotherapy showed a bright efficacy with no intolerable adverses. It may improve the downstage rate and pathologic remission rate of patients with NSCLC. Whether it can improve the DFS and OS of patients remains to be further observed with experimental data. Keywords: non-small cell lung cancer, Immunotherapy, neoaduvant