International Journal of Clinical Case Reports 2024, Vol.14, No.5, 230-241 http://medscipublisher.com/index.php/ijccr 230 Review Article Open Access Efficacy of Cancer Vaccines in Clinical Trials: A Systematic Review Jianmin Liu Sinovac Biotech Co., Ltd., Haiding, 100193, Beijing, China Corresponding email: Jianminliu@sinovac.com International Journal of Clinical Case Reports 2024, Vol.14, No.5 doi: 10.5376/ijccr.2024.14.0024 Received: 03 Jul., 2024 Accepted: 10 Aug., 2024 Published: 06 Sep., 2024 Copyright © 2024 Liu, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Liu J.M., 2024, Efficacy of cancer vaccines in clinical trials: a systematic review, International Journal of Clinical Case Reports, 14(5): 230-241 (doi: 10.5376/ijccr.2024.14.0024) Abstract This study evaluates the efficacy of cancer vaccines in clinical trials, focusing on their impact on overall survival (OS), progression-free survival (PFS), and tumor response rates. The study synthesizes data from various studies, including vaccines for different cancer types such as non-small cell lung cancer, melanoma, and breast cancer. Results indicate that while cancer vaccines can generate immune responses, their ability to consistently improve clinical outcomes varies depending on factors like patient characteristics, tumor type, and combination with other therapies such as immune checkpoint inhibitors. In many trials, combination therapies demonstrated superior efficacy compared to vaccines alone, suggesting that vaccines may be most effective when used as part of a multimodal approach. The study also highlights challenges such as limited response rates in some cancers, the need for better biomarkers, and optimization of vaccine delivery systems. Overall, cancer vaccines offer promise, but further research is necessary to enhance their clinical impact. Keywords Cancer vaccines; Immunotherapy; Clinical trials; Tumor response; Combination therapies 1 Introduction Cancer vaccines play a crucial role in immunotherapy by activating the immune system to specifically recognize and eliminate cancer cells. Compared to traditional cancer treatments, cancer vaccines offer higher specificity and fewer side effects. However, the clinical application of cancer vaccines faces challenges, as tumor cells can evade immune attacks by downregulating antigen expression or creating an immunosuppressive microenvironment. While early clinical trials demonstrated strong immune responses, they showed limited improvements in clinical outcomes, such as survival rates or tumor reduction (Murahashi et al., 2016).With advancements in tumor immunology, the development of personalized cancer vaccines, particularly through the identification of neoantigens, has been overcoming these challenges. Personalized cancer vaccines are designed using the unique mutations in a patient's tumor, significantly enhancing immune recognition while minimizing damage to healthy tissues (Şahin and Türeci, 2018). Cancer vaccines are categorized into preventive and therapeutic types. Preventive vaccines, such as the HPV vaccine, aim to stop virus-induced cancers and effectively reduce the incidence of cervical and other related cancers. Therapeutic cancer vaccines target patients with existing cancers, stimulating the immune system to recognize tumor antigens and destroy cancer cells. Common types of therapeutic vaccines include peptide vaccines, dendritic cell vaccines, and personalized cancer vaccines (Murahashi et al., 2016). Personalized cancer vaccines, developed based on unique mutations in a patient's tumor, use neoantigens to enhance the specificity of immune responses. These vaccines have shown great potential in preclinical and early-phase trials, especially when combined with immune checkpoint inhibitors, to further boost efficacy (Şahin and Türeci, 2018). The motivation of this study is to address the growing need for a comprehensive evaluation of cancer vaccine trials in recent years, with a focus on their immunogenicity, efficacy, and safety across various cancer types. This study will analyze key clinical indicators, including overall survival, progression-free survival, and tumor response rates, to gain a clearer understanding of vaccine performance. The study will also investigate the impact of combining cancer vaccines with other immunotherapies, particularly PD-1 and CTLA-4 inhibitors. By examining factors that influence vaccine efficacy, such as antigen selection, patient characteristics, and vaccine design, the goal of this
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