KEYNOTE-042 rolls back programmed cell death ligand 1 threshold for non-small cell lung cancer pembrolizumab monotherapy without new insight into those deriving benefit

Amy Lauren Cummings, Edward B. Garon


The past two years have been exceptional for pembrolizumab in advanced non-small cell lung cancer (NSCLC). The publication of KEYNOTE-189 redefined first-line treatment with combination chemotherapy and pembrolizumab as a new standard-of-care in an unselected population, KEYNOTE-042 expanded the United States Food & Drug Administration (FDA)’s approval for first-line pembrolizumab monotherapy, and KEYNOTE-001 showed the most robust five-year overall survival (OS) results ever seen in advanced NSCLC, specifically among patients with high programmed cell death ligand 1 (PD-L1) expression (Table 1) (1-4).