The investigational medicinal product (IMP) DCVAC/PCa (investigational treatment) is made from the cells of the immune system. In order to make the DCVAC/PCa, a type of white blood cell called a monocyte is used.

Monocytes are a normal component of human blood. During a standard immune response, monocytes mature into a different cell type – dendritic cells. Dendritic cells then work together with other immune system cells in the body so that they are able to activate an immune response to foreign substances.

In the manufacturing of DCVAC/PCa, monocytes are harvested from a trial subject’s blood in a process called leukapheresis (see the section entitled Leukapheresis). Prepared dendritic cells are then exposed to prostate cancer cells killed by a special method. Under laboratory conditions, the subject’s own dendritic cells engulf killed tumor cells and expose tumor cell parts on their surface. When other immune system cells are encountered, an immune response to the tumor cells is initiated.

The purpose of the VIABLE clinical study is, among other things, a way of verifying whether the investigational treatment, DCVAC/PCa, is capable of initiating both a short‐term and long‐term immune response to cancer cells when injected back into the subject’s body.