Limertinib Plus Carboplatin and Etoposide for EGFR-mutant NSCLC With SCLC Transformation After EGFR-TKI Progression

This is a single-center, prospective interventional Phase II study designed to assess the efficacy, safety and mechanism of resistance to limertinib combined with carboplatin and etoposide in EGFR-mutant NSCLC patients who have histologically confirmed small-cell transformation after progression on EGFR-TKI therapy. Thirty patients will receive Limertinib orally once daily (80 mg) plus carboplatin (AUC 5-6, day 1) and etoposide (100 mg/m², days 1-3) every 21 days until disease progression or unacceptable toxicity. Radiographic tumor evaluation will be conducted every 6 weeks per RECIST v1.1. Tumor tissue and blood specimens will be collected at baseline and upon disease progression for next-generation sequencing to elucidate the molecular mechanisms underlying histological transformation.