Metformin Plus Tyrosine Kinase Inhibitors for Treatment of Patients With Non-small Cell Lung Cancer With EGFR Mutations

Lung cancer is the most common neoplastic disease globally, with over 2 million new cases annually, accounting for 11.6% of all cancer diagnoses. It remains the leading cause of cancer-related deaths. Non-small cell lung cancer (NSCLC) makes up 80-85% of lung cancer cases, with most patients diagnosed at an advanced stage. Five-year survival rates are low, ranging from 8-18% worldwide. Advances in molecular biology have led to the identification of therapeutic targets in NSCLC. One of the most studied is the epidermal growth factor receptor (EGFR), a key regulator of tumor cell functions and a focus of targeted therapy development. EGFR mutations occur in about 15% of NSCLC cases globally but reach up to 34% in Mexico. Patients with these mutations are treated with tyrosine kinase inhibitors (TKIs), which improve response rates and progression-free survival (PFS) over chemotherapy. However, resistance to TKIs typically develops, prompting the need for strategies to overcome this challenge and extend PFS. Up to 30% of NSCLC patients have somatic mutations in the liver kinase B1 (LKB1) gene, a tumor suppressor that inhibits mTOR. In one study, 24 patients with LKB1 expression treated with metformin plus TKIs showed significantly improved overall survival. LKB1 activates AMP-activated protein kinase (AMPK), which regulates cell cycle and survival in NSCLC. Loss of LKB1 reduces AMPK activation and increases tumor necrosis following bevacizumab treatment. A study of 99 NSCLC samples linked high AMPK expression to poorer survival, though its role in metformin response is unclear. Metformin, a biguanide used for type 2 diabetes, has shown anticancer properties. Studies suggest metformin reduces cancer incidence and mortality. In vitro, it induces G0/G1 cell cycle arrest and counters TKI resistance due to epithelial-mesenchymal transition (EMT). Retrospective studies support its benefit in NSCLC, and prospective trials of metformin plus TKIs have yielded mixed results. This phase 3 randomized study aims to evaluate PFS in NSCLC patients with EGFR mutations treated with TKIs plus placebo versus TKIs plus metformin.