Fig. 4.

Schematic illustration showing an enhancement of the viral spread in the presence of a porous extracellular matrix (ECM). An infected tumor cell (1) will eventually produce new infectious viral particles. The spread of a normal oncolytic adenovirus is hindered by a dense hyaluronic acid ECM (2). The VCN-01 adenovirus encodes the human hyaluronidase PH20, which is secreted by the infected cell and, in turn, the hyaluronidase degrades the hyaluronic acid, facilitating the spread of the viral progeny through the ECM to new tumor cells (3).