Can PD-L1 tumor proportion score be used as the key to unlocking the KEYNOTE studies of pembrolizumab in advanced lung cancer?

Despite substantial advancements in the management of advanced non-small cell lung cancer (NSCLC) made possible with application of molecularly targeted and immune-based strategies over the last two decades, significant challenges remain (1). On the basis of these advancements, the evidence-based initial management of advanced/metastatic NSCLC is now necessarily defined by tumor molecular and immune biomarkers so as to permit optimal pairing of patients with the most efficacious and least toxic therapies—and with previously unseen extension of survival in multiple large studies in these selected populations (2-5).