Kolon Life Science will publicly unveil for the first time the preclinical study results of its anticancer gene therapy candidate 'KLS-3021' targeting head and neck squamous cell carcinoma (HNSCC). The company announced Wednesday that it will present the research findings in a poster presentation at the American Association for Cancer Research (AACR 2026) Annual Meeting to be held in San Diego from April 17 to 22 (local time). HNSCC is considered a cancer type with high recurrence rates where demand for new treatments remains significant.
KLS-3021 is a next-generation anticancer gene therapy candidate that loads therapeutic genes PH-20, IL-12, and sPD1-Fc onto a recombinant vaccinia virus engineered for enhanced cancer cell selectivity. The compound is designed to decompose intratumoral stroma and induce anticancer immune responses in addition to the virus's direct oncolytic mechanism.
According to Kolon Life Science, KLS-3021 demonstrated excellent anti-tumor effects in HNSCC preclinical studies regardless of PD-L1 (a protein expressed on cancer cell surfaces) expression levels. In high PD-L1 expression models, a single intratumoral injection showed superior tumor suppression compared to 'anti-PD-1,' a standard immunotherapy drug. In low expression models, it also exhibited higher tumor regression than 'cisplatin,' a first-generation chemotherapy agent. The company interpreted these results as evidence that KLS-3021 can enable stable tumor treatment regardless of PD-L1 expression levels, potentially expanding the scope of treatment. In animal models implanted with human head and neck cancer, a single dose significantly reduced tumor burden, and all subjects in the treatment group achieved long-term survival.
A mechanism converting the tumor microenvironment was also confirmed. KLS-3021 goes beyond directly attacking tumors to transform the tumor microenvironment in favor of anticancer immunity. After KLS-3021 administration, signals attracting immune cells, inflammatory responses, and T-cell infiltration and activation all increased, while immunosuppressive macrophage markers decreased.
Kolon Life Science plans to continuously strengthen its HNSCC research on KLS-3021. Using the AACR presentation as a milestone, the company also intends to demonstrate the therapeutic development potential and scalability as a next-generation oncolytic virus platform to global researchers. The company is currently conducting parallel studies on KLS-3021 for prostate cancer and triple-negative breast cancer. "We will continue to refine our development strategy focusing on cancer types with significant unmet needs and actively pursue global research and development collaborations," said Lee Han-kook, CEO of Kolon Life Science.