Immune Checkpoint Inhibitors - A Narrative Review on PD-1/PD-L1 Blockade Mechanism, Efficacy, and Safety Profile in Treating Malignancy

Sep 21, 2026

Uploaded by Eliana

Checkpoint inhibitors have been implicated in the treatment of several cancers due to their ability to exploit the immune system's regulatory pathways. The review emphasizes PD-1 and PD-L1–targeted immunotherapeutic agents, describing their mechanisms, efficacies, and safety profiles. It synthesizes peer-reviewed systematic reviews and outcomes from clinical trials across malignancies including lung, breast, and skin. The analysis highlights advances in oncologic immunotherapy and the growing need for effective cancer interventions.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Introduction And Background

Checkpoint Inhibitors and PD-1/PD-L1 Mechanism

Agents Targeting PD-1 and PD-L1

Review Methodology

Efficacy of anti-PD-1/PD-L1 Agents

Durvalumab and Its Results Within Clinical Trials

Open Access Review Article DOI: 10.7759/cureus.58138 Review began 03/26/2024 Review ended 04/09/2024 Published 04/12/2024 © Copyright 2024 Benelli et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. Immune Checkpoint Inhibitors: A Narrative Review on PD-1/PD-L1 Blockade Mechanism, Efficacy, and Safety Profile in Treating Malignancy Nicolas D. Benelli 1, Ian Brandon 2, Karina E. Hew 3 1. Internal Medicine, St. George 's University School of Medicine, St. George 's, GRD 2. Family Medicine, Baptist Health South Florida, Miami, USA 3. Gynecologic Oncology, University of Florida College of Medicine-Jacksonville, Jacksonville, USA Corresponding author: Nicolas D. Benelli, [nbenelli@sgu.edu](nbenelli@sgu.edu) Abstract Checkpoint inhibitors have been implicated in the treatment of several cancers due to their ability to exploit the immune system 's regulatory pathways. This article serves to emphasize the importance of these immunotherapeutic agents and provide further insight into their mechanisms, efficacies, and safety profiles. The main agents in question include programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) . Several literature sources were found to assess the use of these inhibitors in cancers involving the lung, breast, and skin. Several peer-reviewed systematic reviews and the outcomes of clinical trials are combined within this article to support the use and further investigation of these agents in treating neoplasms. Further research into these forms of therapy underscores the revolutionary advancement of oncological interventions, which is important given the rising incidence of neoplasms within populations. Categories: Allergy/Immunology, Oncology, Therapeutics Keywords: pd-l1, pd-1 inhibitor, immune checkpoint inhibitors, cancer, cancer immunotherapy Introduction And Background The American Cancer Society reports millions of new cancer cases being diagnosed annually, making neoplasm a leading cause of patient mortality [1] . Cancer carries a complex etiology that involves a plethora of risk factors including metabolic abnormalities, social behaviors such as smoking or drinking, genetic predisposition, and infectious agents. The pathogenesis of cancer involves a series of events resulting in uncontrolled cell growth leading to the formation of a tumor. The progression of cancer involves a tumor metastasizing to different sites and altering the natural chemistry or physiology within the body to avoid immune detection and enhance oncogenesis. One of the ways in which malignant cells may avoid immune detection is by binding to a particular receptor on T-cells: the programmed cell death protein 1 (PD-1) receptor. Programmed death ligand 1 (PD-L1) is a protein that is expressed in various malignant cells. When a tumor cell binds to a T-cell via PD-L1, T-cell activity is suppressed and unable to properly kill the cancer cell [2] . This mechanism can be seen in Figure 1. How to cite this article Benelli N D , Brandon I, Hew K E (April 12 , 2024) Immune Checkpoint Inhibitors: A Narrative Review on PD-1/PD-L1 Blockade Mechanism , Efficacy , and Safety Profile in Treating Malignancy. Cureus 16(4): e58138. DOI 10.7759/cureus.58138 FIGURE 1 : PD-1 and PD-L1 binding Image credit: Nicolas Benelli PD-1: programmed cell death protein 1 , PD-L1: programmed death ligand 1 , TCR: T-cell receptor, MHC: major histocompatibility complex Inhibitors of this interaction between T-cells and cancer cells have been developed, and these inhibitors can specifically target PD-1 on T-cells or PD-L1 on tumor cells. These inhibitors may be used as monotherapy or can be combined with traditional chemotherapy to treat a specific cancer. This therapy helps reactivate the immune res

FAQs

What is the PD-1/PD-L1 blockade mechanism described in the review?

PD-1 is a receptor on T-cells, while PD-L1 is expressed on various malignant cells. When a tumor cell binds PD-L1 to T-cells, T-cell activity is suppressed, reducing the ability to kill cancer cells.

Which cancers and literature sources are used to support the review’s conclusions?

The review combines peer-reviewed systematic reviews and clinical trial outcomes, focusing on cancers involving lung, breast, and skin. It also discusses mechanisms tied to malignancies treated in clinical trials.

How was the literature for this narrative review selected?

The review uses peer-reviewed literature indexed on platforms such as PubMed, Medline, and Embase. Search terms included immune checkpoint inhibitors, PD-1 inhibitors, PD-L1 inhibitors, and immunotherapy, with filters applied to include studies after 2010.

Sep 21, 2026

Uploaded by Eliana