Pembrolizumab as an immune checkpoint inhibitor in cancer therapy

Cancer is characterized by uncontrolled proliferation of abnormal cells and the ability of malignant cells to evade immune surveillance. Immune checkpoint pathways, particularly the programmed cell death protein-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway, play an important role in tumor immune evasion. Pembrolizumab is a humanized IgG4 monoclonal antibody that binds to PD-1 and prevents its interaction with PD-L1 and PD-L2, resulting in restoration of T-cell antitumor activity. This review highlights the pathophysiology of cancer with emphasis on immune evasion and discusses the mechanism of action, pharmacokinetics, pharmacodynamics, clinical applications, dosage and administration, contraindications and precautions, and safety profile of pembrolizumab. Clinical evidence has identified pembrolizumab as an important treatment option for several cancers, although immune-related adverse events are an important limitation. Appropriate patient selection and management of immune-related adverse events are critical to achieving optimal therapeutic outcomes. Pembrolizumab is an important step in cancer immunotherapy and continues to play a significant role in the treatment of selected malignancies.