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Opinion Article - Immunology Case Reports (2023) Volume 6, Issue 4

Immune checkpoint inhibitors (ICIs) in cancer immunotherapy

Abdul Reza*

Department of Immunology, Iran University of Medical Sciences, Iran

*Corresponding Author:
Abdul Reza
Department of Immunology
Iran University of Medical Sciences
Iran
E-mail:rabdul@iums.ac.ir

Received:30-July-2023, Manuscript No. AAICR-23-109013; Editor assigned:04-Aug-2023, PreQC No. AAICR-23-109013(PQ); Reviewed:18-Aug-2023, QC No. AAICR-23-109013; Revised:24-Aug-2023, Manuscript No. AAICR-23-109013(R); Published:31-Aug-2023, DOI:10.35841/aaicr-6.4.161

Citation: Reza A. Immune checkpoint inhibitors (ICIs) in cancer immunotherapy. Immunol Case Rep. 2023;6(4):161

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Introduction

Cancer remains one of the most formidable challenges in the field of medicine, affecting millions of lives worldwide. Despite significant advancements in conventional treatments such as surgery, chemotherapy, and radiation therapy, a considerable number of cancer patients face limited treatment options and poor prognosis. In recent years, the emergence of cancer immunotherapy, particularly immune checkpoint inhibitors (ICIs), has revolutionized the oncology landscape by harnessing the body's immune system to fight cancer. This article explores the concept of ICIs, their mechanisms of action, and their significant impact on cancer treatment [1].

Role of immune checkpoints in cancer

The immune system is a complex network of cells and molecules that work together to recognize and eliminate abnormal cells, including cancer cells. However, cancer cells have evolved various mechanisms to evade the immune system's surveillance and attack, allowing them to grow and spread uncontrollably. One such mechanism involves the activation of immune checkpoints. Immune checkpoints are pathways in the immune system that help regulate the immune response and maintain self-tolerance to avoid attacking healthy tissues. These checkpoints, such as programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), play a crucial role in preventing excessive immune responses that could lead to autoimmunity. Cancer cells often exploit these checkpoints by upregulating certain proteins like PD-L1, which binds to PD-1 on T cells, inhibiting their function and preventing them from attacking the tumor cells. As a result, the immune system becomes less effective in recognizing and destroying cancer cells, leading to tumor growth and disease progression [2].

Birth of immune checkpoint inhibitors

ICIs are a class of drugs that aim to reverse the immune evasion mechanisms employed by cancer cells. They work by blocking the interactions between immune checkpoints and their ligands, effectively reactivating the immune system's ability to recognize and attack cancer cells. Monoclonal antibodies are the most common form of immune checkpoint inhibitors. The first FDA-approved ICI was ipilimumab, a CTLA-4 inhibitor, which received approval in 2011 for the treatment of metastatic melanoma. Since then, several other ICIs have been developed and approved for various types of cancer, providing new hope for patients with previously limited treatment options. ICIs primarily target three key immune checkpoint pathways are PD-1/PD-L1, CTLA-4, and others like LAG-3, TIM-3, and IDO. By blocking these pathways, ICIs unleash the immune system's potential, enhancing the anti-tumor immune response. Drugs such as pembrolizumab and nivolumab target the PD-1 receptor or its ligand, PD-L1. By blocking PD-1/PD-L1 interactions, these drugs prevent the cancer cells from deactivating T cells, allowing them to recognize and attack the tumor. Ipilimumab is the first-in-class CTLA-4 inhibitor that disrupts the interaction between CTLA-4 and its ligands on antigen-presenting cells, enhancing the activation and proliferation of T cells. Emerging therapies target additional immune checkpoints like LAG-3, TIM-3, and IDO to further improve the immune response against cancer cells [3].

Clinical applications and successes

ICIs have demonstrated remarkable efficacy across various cancer types, leading to durable responses and long-term survival in some patients. These agents have been particularly successful in treating melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, and Hodgkin's lymphoma. In addition to standalone use, researchers are exploring combination therapies, using ICIs in conjunction with other immunotherapies or traditional treatments, to further enhance their effectiveness. Combinations of ICIs with chemotherapy, targeted therapies, and radiation therapy are being investigated in ongoing clinical trials [4].

Despite the tremendous success of ICIs, challenges remain. Not all patients respond to these therapies, and resistance to ICIs can develop over time. Identifying biomarkers that can predict treatment response and resistance is a crucial area of research. Moreover, ICIs can lead to immune-related adverse events (irAEs) due to the uncontrolled activation of the immune system. These irAEs can affect various organs and require careful management and monitoring. In the future, ongoing research will focus on expanding the use of ICIs to other cancer types, identifying novel targets for combination therapies, and developing personalized approaches to maximize treatment efficacy while minimizing adverse effects [5].

Conclusion

Despite the tremendous success of ICIs, challenges remain. Not all patients respond to these therapies, and resistance to ICIs can develop over time. Identifying biomarkers that can predict treatment response and resistance is a crucial area of research. Moreover, ICIs can lead to immune-related adverse events (irAEs) due to the uncontrolled activation of the immune system. These irAEs can affect various organs and require careful management and monitoring. In the future, ongoing research will focus on expanding the use of ICIs to other cancer types, identifying novel targets for combination therapies, and developing personalized approaches to maximize treatment efficacy while minimizing adverse effects.

References

  1. Naidoo J, Page DB, Li BT, et al. Toxicities of the anti-PD-1 and anti-PD-L1 immune checkpoint antibodies. Ann Oncol. 2015;26(12):2375-91.

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  2. Nicolas-Boluda A, Vaquero J, Vimeux L, et al. Tumor stiffening reversion through collagen crosslinking inhibition improves T cell migration and anti-PD-1 treatment. Elife. 2021;10:e58688.

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