In PD-1 rivalry, Merck's Keytruda catches up with Opdivo in rare lung cancer type

Merck & Co. refuses to give Bristol Myers Squibb the comfort of an immunotherapy monopoly in a rare type of lung cancer.

Merck’s Keytruda, used in combination with chemotherapy, significantly improved survival of patients with unresectable malignant pleural mesothelioma in a phase 2/3 trial, the company said Friday.