One ACI Approach

One approach to active cellular immunotherapy (ACI)

Dendreon Corporation is investigating an ACI platform that entails ex vivo activation of antigen presenting cells (APCs) with tumor-associated antigens. Dendreon's approach is characterized by three key factors:

• Use of autologous APCs. This strategy makes the ACI a precise match for the patient's own immune system. This specificity should produce a more focused and potent immune response than would be expected with treatments not similarly "customized".⁹
• Ex vivo activation of APCs. Among tumors' immunoevasive mechanisms is the ability to down-modulate antigen processing. In this ACI model, the antigen is introduced to APCs in an ex vivo environment, away from tumors' inhibitory influence. Each patient's APCs are isolated in large numbers; the antigen and APCs are combined, allowing APCs to capture and process the antigen in a stimulatory environment; and the now-activated, antigen-loaded APCs are infused into the patient, where they can potentially stimulate a T cell response against cancer cells.^3-8
• Choice of target antigen. Tissue-specific differentiation antigens are potential targets in tumors of dispensable tissues, such as melanoma and prostate cancer.⁶ Dendreon looks to utilize tissue-specific or tumor-associated antigens, and to re-engineer the recombinant target antigens enhance their immunogenicity.

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