Merck's Keytruda makes the cut as a second-line monotherapy for certain esophageal cancer patients

Merck’s cornerstone checkpoint inhibitor Keytruda has added another jewel to its crown.

The US drugmaker on Wednesday disclosed that the PD-1 drug had won approval as a monotherapy for patients with recurrent locally advanced or metastatic squamous cell carcinoma of the esophagus, whose tumors express PD-L1, and whose disease has progressed despite one or more prior lines of systemic therapy.