mSJ-612

mSJ-612 is a genetically engineered oncolytic vaccinia virus (Wyeth strain) developed by SillaJen in collaboration with Seoul National University. It features deletions in the thymidine kinase (TK) and K2L genes to enhance tumor selectivity, and expresses murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) to stimulate anti-tumor immunity. Unlike the related candidate mSJ-650, mSJ-612 does not express the human complement regulatory protein CD55. Consequently, it is highly susceptible to complement-mediated destruction and antibody neutralization in circulation, and is primarily utilized as a control virus in preclinical studies evaluating systemic intravenous administration of oncolytic therapies.