Clinicians are struggling to make sense of conflicting regulations from the Food and Drug Administration and the European Medicines Agency on whether measuring programmed death–ligand 1 (PD-L1) is essential before prescribing checkpoint inhibitors for gastroesophageal cancer.
"In the last couple of years, the incorporation of PD-1 antibodies is really changing our standard of care and international guidelines in this disease," said Ian Chau, MD, a consultant medical oncologist at the Royal Marsden Hospital, London.
He moderated a debate at the 2022 Gastrointestinal Cancers Symposium on the importance of measuring PD-L1 expression levels before administering immune checkpoint inhibitor therapy.
Tumor cells can use PD-1 signaling to deactivate the response of T cells that would otherwise destroy them, and several new drugs are designed to block that signaling.
Multiple randomized controlled trials have shown the benefit of adding such checkpoint inhibitors to chemotherapy for gastroesophageal cancer and currently, chemotherapy plus a checkpoint inhibitor is standard care, Chau said.
PD-1–blocking antibodies include pembrolizumab (Keytruda, Merck) for colorectal cancer, gastric cancer, esophageal cancer, hepatocellular carcinoma, and renal cell carcinoma, among other cancers. And, nivolumab(Opdivo, Bristol-Myers Squibb) approved for renal cell carcinoma, colorectal cancer, hepatocellular carcinoma, and esophageal squamous cell carcinoma, among other cancers.
