The anticancer drug pembrolizumab (Keytruda), when used in combination with platinum- and fluoropyrimidine-based chemotherapy, is now approved to treat metastatic or locally advanced esophageal or gastroesophageal junction cancers. It is to be used in patients whose cancers are not suitable for surgical resection or definitive chemoradiation.
Pembrolizumab is a programmed death receptor-1 (PD-1)-blocking monoclonal antibody that can inhibit the immune response and decrease tumor growth. Previously, pembrolizumab was approved for treating a variety of other cancers, including melanoma, small cell lung cancer, non-small cell lung cancer, cervical cancer, and renal cell carcinoma, among others.
The drug's efficacy in treating metastatic or locally advanced esophageal or gastroesophageal junction cancer was determined in a multicenter, randomized, placebo-controlled trial of 749 patients. Those who received pembrolizumab with chemotherapy had a statistically significant improvement in overall survival and progression-free survival compared with those receiving placebo with chemotherapy. Overall survival was 12.4 months for patients receiving pembrolizumab versus 9.8 months for those receiving placebo.
The most common adverse effects of pembrolizumab during the clinical trial were nausea, constipation, diarrhea, vomiting, stomatitis, fatigue/asthenia, decreased appetite, and weight loss. These are similar to the adverse effects of pembrolizumab when used to treat other types of cancer. Pembrolizumab's label also carries warnings and precautions that the drug can produce severe or fatal immune-mediated reactions in any organ system or tissue, infusion-related reactions (which can be severe or life-threatening), complications of allogeneic hematopoietic stem cell transplantation before or after treatment with pembrolizumab or another PD-1/PD ligand 1-blocking antibody, and embryo-fetal toxicity.
Nurses should carefully monitor patients for signs of immune-mediated adverse reactions and evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. If immune-mediated adverse reactions are suspected, the drug may need to be withheld or permanently discontinued. If infusion-related reactions occur, the rate of infusion should be slowed or stopped permanently. Women of childbearing age should use effective contraception owing to the risk of embryo-fetal toxicity.
For complete prescribing information for pembrolizumab, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2021/125514s096lbl.pdf.