Neoadjuvant QL1706 plus chemotherapy in patients with stage II-IIIB squamous non-small cell lung cancer: study protocol for a prospective, single-arm, multicentre phase II trial.

INTRODUCTION: Lung squamous cell carcinoma is a subtype of non-small cell lung cancer (NSCLC) and its biological characteristics or treatment responses might differ from non-squamous NSCLC. Although neoadjuvant immunotherapy combined with chemotherapy has become the guideline-recommended treatment for resectable NSCLC, clinical benefits remain suboptimal as a substantial proportion of patients fail to achieve pathological complete response (pCR). Hence, we conduct a clinical study on QL1706 combined with chemotherapy for the neoadjuvant treatment of squamous NSCLC. METHODS: This is a phase II, multicentre, single-arm, prospective clinical trial. The study includes patients with stage II-IIIB squamous NSCLC who are eligible or potentially eligible for surgical resection. Enrolled patients receive the neoadjuvant treatment regimen consisting of three cycles of QL1706 (5 mg/kg, d1, Q3W) combined with platinum-doublet chemotherapy. The primary endpoint is the pCR rate. The secondary endpoints are major pathological response, clinical response rate, R0 resection rate, event-free survival, overall survival, safety and tolerability, feasibility of surgery and incidence rate of complications during the perioperative period or within 90 days after the surgery. ETHICS AND DISSEMINATION: The study was approved by the ethics committee of Zhejiang Cancer Hospital on 29 May 2025 (IRB-2025-667). The current study protocol version is V.5.0. Patient enrollment has been ongoing since October 2025. The results of this study will be presented to peer-reviewed journals and scientific conferences. TRIAL REGISTRATION NUMBER: ChiCTR2500104283.