Immunotherapy Alone or in Combination with Chemotherapy as First-Line Treatment of Non-Small Cell Lung Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized the management of metastatic and selected cases of unresectable advanced non-small cell lung cancer (NSCLC). Importantly for patients, this implies that in the absence of a targetable oncogenic driver [especially epidermal growth factor receptor (EGFR) gene mutations and anaplastic lymphoma kinase (ALK) gene rearrangements] and in the presence of high programmed death-ligand 1 (PD-L1) expression (≥ 50%), they are eligible for mono-therapy with pembrolizumab thereby avoiding chemotherapy as the first line of treatment. This mono-immunotherapy approach for high PD-L1 metastatic NSCLC is associated with improved overall survival (OS) and radiological responses (RR) with lesser toxicity as compared with conventional platinum doublet chemotherapy for both non-squamous and squamous histological types. However, majority of NSCLC patients either have no or low expression of PD-L1 (