MCPyV-LT-encoding plasmid DNA vaccine ITI-3000

A cancer vaccine consisting of plasmid DNA encoding LTS220A, a truncated form of the large T antigen (LT) of Merkel cell polyomavirus (MCPyV; MCV) viral oncoprotein with a detoxifying serine to alanine mutation at position 220, and fused to the lysosome-associated membrane protein 1 (LAMP1), with potential immunostimulating and antineoplastic activities. Upon intramuscular administration, the MCPyV-LT-encoding plasmid DNA vaccine ITI-3000 expresses MCPyV-LT, which may elicit cytotoxic T-lymphocyte (CTL) and CD4+ T-cell responses against tumor cells that are expressing MCPyV, resulting in tumor cell lysis. The MCPyV viral oncoprotein is highly expressed in Merkel cell carcinoma (MCC) caused by MCPyV infection. Fusion of MCPyV-LT with LAMP1 allows for lysosomal targeting resulting in enhanced antigen presentation, thereby promoting CD4-positive T-cell responses and leading to a more balanced immune response.