NEW YORK – The European Commission on Monday approved Merck's immune checkpoint inhibitor Keytruda (pembrolizumab) plus chemotherapy for newly diagnosed gastric or gastroesophageal cancer patients whose tumors are HER2-negative and express PD-L1 with a combined positive score of at least one.
The approval comes several months after the European Medicine Agency's Committee for Medicinal Products for Human Use (CHMP) recommended approval of this indication based on results from the Phase III KEYNOTE-859 clinical trial. In the overall study population, those on the Keytruda-containing regimen lived longer than those who got just chemo, regardless of their PD-L1 expression status. However, CHMP recommended approval for Keytruda-chemo for PD-L1-expressing gastric cancer based on the fact that 80 percent of patients in the study were PD-L1-positive.
Adding Keytruda to chemo in KEYNOTE-859 reduced the risk of death by 22 percent versus chemo alone in the overall population, but the regimen reduced the risk of death by 26 percent in the PD-L1-expressing population. Given there was more benefit seen with Keytruda-chemo compared to just chemo regardless of PD-L1 status, the US Food and Drug Administration last month approved the first-line combination as a treatment for HER2-negative gastric cancer patients for the broader PD-L1-agnostic population.
The EC on Monday also announced its approval of Keytruda-chemo as a first-line treatment for biliary tract cancer patients.