The FDA granted accelerated approval to Merck’s Keytruda (pembrolizumab) in gastric cancer tumors that express the PD-L1 protein, as determined by an agency-approved test.
Patients must have had disease progression on or after two or more prior systemic therapies, including fluoropyrimidine- and platinum-containing chemotherapy and, if appropriate, HER2/neu-targeted therapy.
The approval, for recurrent locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma, was based on the results of an open-label, non-comparative trial that enrolled 259 patients. PD-L1 expression was evaluated by the IHC 22C3 pharmDx in vitro diagnostic test developed by Dako, which also received FDA approval. For the 143 patients with tumors expressing PD-L1, the objective response rate was 13.3 percent.