Kolon Life Science announced Thursday that Europe has granted a patent titled “recombinant vaccinia virus and pharmaceutical composition comprising same,” related to KLS-3021, a gene therapy candidate for the treatment of solid tumors.

This European patent marks the ninth registration, following approvals in Korea, Japan, Canada, Singapore, and China. The patent is currently under review in the U.S. and Brazil.

KLS-3021 is an oncolytic virus pipeline being developed to treat solid tumors. Kolon Life Science has engineered a technology that incorporates the PH-20, sPD1-Fc, and IL-12 genes into a vaccinia virus-based oncolytic virus. Through genetic recombination, the virus achieves high selectivity for cancer cells, enhancing its therapeutic effects. The technology is designed to maximize both the virus’s direct tumor-killing ability and its capacity to activate immune cells to boost anti-cancer effects.

The PH-20 gene encodes an enzyme that breaks down hyaluronic acid, a key component of the extracellular matrix that hinders drug delivery. The sPD1-Fc gene blocks the immune evasion mechanism of cancer cells (PD-L1/2), helping sustain immune cell activity. The patent also includes the IL-12 gene, which activates immune cells such as T cells and NK cells to attack cancer.

“KLS-3021 is a next-generation oncolytic virus therapy being developed for the treatment of solid tumors, and we are currently accelerating its clinical entry,” said Kim Sun-jin, CEO of Kolon Life Science. “We expect to further strengthen our technological competitiveness in the global market through this European patent registration.”

Kolon Life Science also holds other patents related to KLS-3021, including “poxvirus-derived promoter, and vector comprising same” and “recombinant vaccinia virus and use thereof.”