In recent years, CIK cells (cytokine-induced killer cells), an immunotherapeutic approach with broad anti-tumor activity, have demonstrated extensive application prospects in the field of oncology. CIK cell therapy has evolved from an experimental technique to clinical maturity, achieving breakthroughs in areas such as post-hepatocellular carcinoma recurrence prevention, adjuvant chemotherapy for lung cancer, synergistic therapy for breast cancer, and reversal of PD-1 resistance. These advancements have offered hope to countless patients with refractory diseases.
CIK Cell Therapy and Its Mechanism of Action
CIK cells are a heterogeneous population obtained by co-culturing human peripheral blood mononuclear cells (PBMCs) with multiple cytokines in vitroover a period of time. These cells express both CD3 and CD56 membrane proteins, hence their alternative name "NK-like T lymphocytes." They combine the potent anti-tumor activity of T lymphocytes with the MHC-unrestricted tumor-killing advantage of natural killer (NK) cells, characterized by strong proliferation capacity, high anti-tumor activity, and broad tumor-killing spectrum. Regarded as a leading candidate for next-generation adoptive cell immunotherapy against cancer, CIK cells have garnered significant attention.
Mechanistically, CIK cells exert anti-tumor effects through multiple pathways: On one hand, they directly lyse tumor cells by releasing cytotoxic substances such as perforin and granzyme; on the other hand, they secrete large amounts of cytokines including interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) to modulate the tumor microenvironment and activate the body’s endogenous anti-tumor immune response. Critically, CIK cell killing is independent of major histocompatibility complex (MHC) recognition, endowing them with broad anti-tumor activity and enabling them to effectively overcome tumor immune evasion via MHC downregulation.
Latest Clinical Research Progress of CIK Cell Therapy
In recent years, CIK cell therapy has achieved multiple breakthroughs in cancer immunotherapy, particularly demonstrating significant clinical value in the comprehensive treatment of solid tumors. A wealth of clinical data confirms that CIK cell therapy can significantly extend disease-free survival (DFS) and overall survival (OS) in patients with various cancers, and exhibits synergistic effects when combined with existing treatment modalities.
Breakthroughs in Lung Cancer Treatment
Studies on non-small cell lung cancer (NSCLC) have shown that adjuvant CIK cell therapy combined with chemotherapy post-surgery increases 5-year OS to 67.8% in patients, significantly higher than the 52.2% observed in the chemotherapy-only group. This development has provided new survival hope for advanced lung cancer patients.
Major Advances in Post-Hepatectomy Recurrence Prevention
China’s first CIK cell therapy product, "EAL® (Aikelongzai Injection)," has submitted a marketing application targeting high-risk patients following radical hepatectomy for hepatocellular carcinoma. Clinical data reveal that this therapy reduces mortality risk by 42.7% and significantly extends OS. In the 2022 CSCO Guidelines for the Diagnosis and Treatment of Primary Liver Cancer, CIK cell therapy was included in the adjuvant treatment recommendations post-hepatectomy (evidence level: Class 2A).
Significant Synergy in Breast Cancer Combination Therapy
CIK cell therapy combined with conventional treatments extends DFS in breast cancer patients. A retrospective analysis of 294 triple-negative breast cancer patients showed that the 5-year DFS rate reached 77.9% in the CIK-chemotherapy group, markedly higher than the 69.8% in the chemotherapy-only group.
Validation of Long-Term Survival Benefits in Colorectal Cancer
In colorectal cancer treatment, a 10-year follow-up of 98 patients demonstrated that the median OS in the CIK combination group was 78.3 months, with a 5-year survival rate of 66%—significantly superior to the conventional treatment group (57.3 months, 39.6%).
Despite its promising clinical applications, the technical complexity of CIK cell preparation and challenges in quality control remain major bottlenecks limiting widespread adoption. From PBMC collection to the final application of CIK cell products, the entire manufacturing process involves multiple critical steps, each posing unique technical challenges that directly impact product quality and therapeutic efficacy.
Obtaining a sufficient number of highly active CIK cells is a fundamental clinical requirement. Research indicates that CIK cells with optimal anti-tumor activity are the CD3⁺CD56⁺ double-positive subset, and the proportion of these cells (positive rate) in the total population directly influences treatment outcomes. Additionally, CIK therapy demands high cell counts—for example, adjuvant treatment for NSCLC typically requires approximately 8.0×10⁹ to 1.3×10¹⁰ CIK cells per session.
Current large-scale CIK cell preparation methods remain immature, lacking standardized culture systems. This results in high heterogeneity of cell products, making cross-comparison and efficacy evaluation difficult. Moreover, suboptimal culture outcomes (low positive rates and insufficient cell counts) often fail to meet clinical needs, necessitating improvements in induction and expansion methods to generate more effective cells.
Against this backdrop, Yocon Biotech has addressed industry pain points through targeted innovation, upgrading its original CIK cell culture system. The upcoming YOCON serum-free CIK cell culture kit features higher cell yields, improved positive rates, and more stable culture results, making it better suited for large-scale CIK production. This advancement provides a reliable tool to standardize and scale CIK cell therapy.
As an emerging treatment modality, CIK cell therapy is gradually transforming the landscape of cancer care. With its unique advantages and robust clinical efficacy, CIK cells have brought new hope to numerous cancer patients. As research deepens and technologies advance, we are confident that CIK cell therapy will play an increasingly pivotal role in future oncology, delivering greater benefits to patients worldwide.
