Induction Chemoimmunotherapy in Combination With Chemoradiotherapy and Consolidation Immunotherapy in Unresectable Locally Advanced Non-Small Cell Lung Cancer

Concurrent chemoradiotherapy followed by consolidation immunotherapy has become the standard treatment approach for unresectable locally advanced NSCLC based on the PACIFIC study. However, disease recurrence remains common, and long-term progression-free survival remains unsatisfactory. Strategies to further improve outcomes and optimize the integration of systemic therapy and radiotherapy are still needed. Induction chemoimmunotherapy has demonstrated significant tumor regression and downstaging effects in locally advanced NSCLC. Tumor burden reduction achieved during induction treatment may improve radiotherapy feasibility, enhance target conformity, reduce radiation exposure to surrounding normal tissues, and potentially improve the therapeutic effectiveness of subsequent radiotherapy.We also hypothesize that induction chemoimmunotherapy can achieve early immune activation, thereby enhancing the synergy between subsequent chemoradiotherapy and immunotherapy and potentially improving the survival outcomes of the current PACIFIC treatment paradigm. This multicenter phase I/II study consists of two sequential parts. The phase I portion is designed as a single-arm safety lead-in study evaluating induction chemoimmunotherapy followed by concurrent chemoradiotherapy and consolidation immunotherapy. If predefined safety criteria are met, the study proceeds to a phase II randomized, open-label, parallel-group trial in which eligible participants are randomized in a 1:1 ratio to receive either induction chemoimmunotherapy followed by concurrent chemoradiotherapy and consolidation immunotherapy or the standard PACIFIC regimen consisting of concurrent chemoradiotherapy followed by consolidation immunotherapy. Randomization is stratified by disease stage (IIIA vs. IIIB/IIIC) and PD-L1 tumor cell expression (\<1% vs. ≥1%). The objective of this study is to determine whether the addition of induction chemoimmunotherapy to the standard PACIFIC treatment strategy improves progression-free survival while maintaining an acceptable safety profile. For the phase I safety lead-in study, the co-primary endpoints are treatment safety, assessed by the incidence of grade 3 or higher treatment-related adverse events, and progression-free survival (PFS). For the phase II randomized study, the primary endpoint is progression-free survival (PFS). Secondary endpoints include overall survival (OS), objective response rate (ORR), treatment completion rate, local control rate, and treatment-related adverse events. Exploratory analyses include evaluation of minimal residual disease (MRD) to determine whether baseline and dynamic changes in MRD status are associated with treatment response, progression-free survival, and overall survival in participants receiving combined radiotherapy and immunotherapy.