October 12, 2017, by NCI Staff
An FDG-PET scan of a patient with gastroesophageal junction cancer.
Credit: Li M, Oxford Medical Case Reports Sept. 2014. doi: 10.1093/omcr/omu041.
The Food & Drug Administration (FDA) has granted accelerated approval to the immunotherapy drug pembrolizumab (Keytruda®) for use in some patients with advanced gastric (stomach) cancer.
The approval, announced on September 22, covers the use of pembrolizumab in patients with advanced gastric cancer or gastroesophageal junction cancer that has progressed despite two or more prior lines of treatment with standard therapies. The gastroesophageal junction is a narrow space where the esophagus meets the stomach.
To receive the drug, patients’ tumors also must express the protein PD-L1. In conjunction with the pembrolizumab approval, FDA also cleared the Dako PD-L1 IHC 22C3 pharmDx assay to measure PD-L1 expression in patients with gastric cancer.
As is often the case with accelerated approvals, FDA based its decision on promising results from an early- or mid-stage clinical trial. In this case, the approval was based on findings from a stage 2 clinical trial, called Keynote-059, in which all patients, regardless of PD-L1 status, received pembrolizumab.
In the trial, which enrolled 259 patients with advanced gastric or gastroesophageal junction cancer, approximately 12% of patients experienced at least partial tumor shrinkage following treatment. However, patients in the trial whose tumors expressed PD-L1 (I’m.e., were PD-L1 positive) were more likely to respond.
According to the most recent data from the trial, presented last month at the European Society for Medical Oncology (ESMO) annual meeting, 16% of PD-L1-positive patients achieved at…