Efficacy and safety of envafolimab plus platinum-based chemotherapy as neoadjuvant therapy in resectable stage IIb-IIIb NSCLC: A single-arm, prospective, exploratory study.

e20510 Background: Multiple clinical trials have reported the striking benefit for PD-1/PD-L1 monoclonal antibody combined with chemotherapy neoadjuvant therapy for non-small cell lung cancer (NSCLC), while the efficacy of subcutaneous injection of anti-PD-L1 Envafolimab combined with chemotherapy neoadjuvant therapy for NSCLC patients has not been demonstrated yet. Envafolimab is a novel recombinant protein of a humanized camel-derived single-domain anti-PD-L1 antibody fused with a human IgG1 Fc fragment designed for subcutaneous injection, making it easy to administer and improving patient compliance. This study aims to investigate the efficacy and safety of Envafolimab plus platinum-based chemotherapy as neoadjuvant therapy in resectable stage IIB-IIIB NSCLC. Methods: In this prospective, open-label, single-arm study aims to enroll histologically confirmed, potentially resectable stage IIB-IIIB NSCLC patients. Eligible patients will receive concurrent 300 mg Envafolimab and chemotherapy (cisplatin 50~100mg/m 2 or carboplatin AUC = 4~6 plus pemetrexed 500mg/m 2 or docetaxel 60-75mg/m 2 ) on day 1 for three 21-day cycles. Radical surgery was scheduled within 4-6 weeks after the last dose of neoadjuvant therapy, followed by optional adjuvant therapy. Follow up will last for three years unless the subject withdraws. The primary endpoint was major pathological response (MPR) rate. The secondary endpoints included R0 resection rate, pathological complete response (pCR) rate, and safety. Results: Between May 2024 and October 2025, 15 patients were enrolled, and included for efficacy and safety analysis. Neoadjuvant treatment was started in 15 patients. Surgery was done in 5 patients. MPR was achieved in 2 patients. R0 resection was achieved in 2 patients. pCR was achieved in 1 patients. No unacceptable toxicity or treatment-related deaths occurred. Conclusions: As of the data reporting date, Envafolimab in combination with platinum-based chemotherapy demonstrated a robust preliminary MPR in Neoadjuvant Therapy of NSCLC patients with manageable safety profile. In consist with the results from intravenous anti-PD-1 antibody plus chemotherapy in NSCLC patients, subcutaneous injection of envafolimab with chemotherapy provided a more convenient dose regimen in this population. Clinical trial information: 2400079595 .