Recent Clinical Applications of Novel Immune Checkpoint Inhibitors in Tumor Treatment

Abstract

Surgery, radiotherapy, and chemotherapy remain the primary first-line treatments for malignant tumors, yet these diseases still exhibit high morbidity and mortality. The introduction of immune checkpoint inhibitors (ICIs) has fundamentally reshaped the therapeutic paradigm in oncology. ICIs target CTLA-4, PD-L1, PD-1, blocking the immunosuppressive pathways that tumors initiate against immune cells, which demonstrates efficacy in various types of cancer. In non-small cell lung cancer (NSCLC), ICIs used as monotherapy and in combination of ICIs and chemotherapy can significantly improve clinical survival rates and have become a standard and effective treatment regimen for advanced NSCLC patients. In hepatocellular carcinoma (HCC), the combination use of ICIs and anti-angiogenic drugs have become first-line standards, and dual-blockade strategies also show therapeutic effects. The pan-cancer treatment targeting the MSI-H/dMMR molecular subtype breaks the traditional model and exhibits significant therapeutic potential for various solid tumors, e.g., pancreatic cancer, melanoma, and renal cell carcinoma (RCC). Future efforts need to explore novel checkpoint molecules, identify predictive biomarkers, develop optimized combination regimens, and clarify the differences in ICIs efficacy among HCC patients with different etiologies. This article reviews the mechanism of action of ICIs, their therapeutic applications in NSCLC, HCC, pancreatic cancer, and other cancers, as well as current achievements and future directions.