Dendreon Corporation made headlines in 2006 and 2007 for it's struggle to get FDA approval for the ACIs Neuvenge and Provenge. What is ACI and why might it be an effective treatment for various cancers?
Active Cellular Immunotherapies (ACIs), or Active Specific Immunotherapies, such as those developed by Dendreon Corporation, are a new approach to treating cancer. ACI works by enhancing or encouraging immune response to cancerous cells.
In contrast to Passive Cellular Immunotherapy, where effector cells are infused into the patient but not induced or expanded within the patient, ACI involves inducing an effective response to tumor cells within patients whose immune systems have failed to do so on their own. These methods generally involve introducing tumor antigens to the host effector cells.
Dendreon's technology utilizes the human immune system's own T cells, which they believe may be the most effective defense against cancer. T cells are activated against specific antigens and might serve to target tumor cells based on cell-specific antigens. However, cancerous cells have their own defenses against T cells, which include inhibiting their activation. ACI approaches include exposing T cells to tumor-specific antigens, reducing down-regulation of T cell activation and overcoming other mechansims by which cancerous cells suppress the immune system.
The Merck Manuals Online Medical Library: Immunotherapy