Phase II Study of Neoadjuvant Concurrent Chemo-immuno-radiation Therapy Followed by Surgery and Adjuvant Immunotherapy for Resectable Stage IIIA-B (Discrete N2) Non–small-cell Lung Cancer: SQUAT trial (WJOG 12119L)

Introduction: We describe our ongoing multicenter, prospective, single-arm, phase II trial of neoadjuvant concurrent chemo-immuno-radiation therapy followed by surgical resection and adjuvant immunotherapy for resectable stage IIIA-B (discrete N2) non–small-cell lung cancer (NSCLC) (registered at the Japan Pharmaceutical Information Center, Clinical Trials Information-195069). Patients and Methods: Key inclusion criteria include (1) clinical T1-3/T4 (tumor size) N2 stage IIIA-B NSCLC, and (2) pathologically confirmed N2 without extranodal invasion (based on diagnostic imaging). Patients will receive concurrent chemoradiotherapy (carboplatin [area under the curve = 2] and paclitaxel [40 mg/m²] on days 1, 8, 15, 22, and 29, with involved-field radiation therapy [RT] [dose 50 Gy] on days 1-25) and neoadjuvant immunotherapy (durvalumab [1500 mg] on days 1 and 29). Surgical resection with mediastinal lymph node dissection is performed within 2 to 6 weeks after RT. Consolidation therapy with durvalumab is administered for up to 1 year after surgery. The primary endpoint is major pathologic response (MPR) (≤10% residual viable tumor) according to the central pathological assessment. Secondary endpoints are progression-free survival, overall survival, and safety. The sample size is planned to be 31 patients based on the exact binomial distribution with a 1-sided significance level of 5% and a power of 80%, and assuming a threshold MPR rate of 40% and an expected MPR rate of 65%. Conclusion: This trial will help establish a novel treatment strategy for resectable N2-positive NSCLC.