Wild-type HSV-1 normally evades host cellular defenses. However, specific mutants of HSV-1 lack such function in the context of normal cells, but maintain their ability to evade host cell defenses in tumor cells. These strains are therefore selectively toxic to permissive tumor types and are useful as a viral therapy for cancer.
The HSV1716 therapy is currently being tested in a Phase I/IIa clinical trial in individuals with malignant pleural mesothelioma.