Checkpoint inhibitors after chemoradiation: is it ready for prime time?

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death in the United States (1). About a third of the patients diagnosed with NSCLC are diagnosed at a locally advanced stage (stage III). Despite concurrent chemoradiation, the outcome for patients diagnosed with locally advanced NSCLC is very poor with a 5-year survival of <20% (2-4). Recently a new class of drugs blocking the immune checkpoint pathways have revolutionized the treatment paradigm for many solid tumors (5). Immune checkpoint pathways serve a critical role in maintaining immune-homeostasis and inducing immune tolerance to self. Immune checkpoint pathways, particularly the programmed death-1 (PD-1) axis is often co-opted by cancer cells to evade the anti-tumor immune response (6-8). Several such drugs targeting the PD-1 axis are approved by the United States Food and Drug Administration (US-FDA) for treating patients with metastatic NSCLC.