Opportunity for T Cell Vaccines

In recent years there has been a resurgence of scientific and commercial interest in vaccines. Underlying this interest are advances in understanding the immune response, renewed recognition of vaccines' public health and healthcare cost benefits, concern about pandemic threats, and the emergence for the first time of blockbuster products. The current market, driven by new infectious disease vaccines, has grown to $13 billion.

The vaccines successfully developed to date are primarily aimed at the humoral (B cell) arm of the immune system to generate antibody responses. The other, cellular arm of the immune system has not been harnessed successfully for vaccine development for either prevention or therapy. The cellular immune response is generated by specific types of T cells that recognize and eliminate diseased cells and produce cytokines to mobilize immune defenses. T cells are believed to play central roles in approximately 40 major diseases, representing an enormous opportunity for Genocea to develop vaccines that modulate cellular immunity in treatment as well as prevention for new markets estimated to reach $34 billion in 2017.

New Targets for Intracellular Pathogens, Cancer, and Autoimmune Diseases

For example it is believed that for many intracellular pathogens such as herpes, chlamydia, and malaria, the humoral immune response is insufficient to generate protective immunity and a robust cellular immune response is necessary. The health and economic impact of intracellular pathogens and the need for vaccines is substantial. Chlamydia is the most frequently reported sexually transmitted disease of bacterial origin in the U.S. Herpes simplex type 2, which causes painful genital sores, affects an estimated 50-60 million people in the U.S. and as many as ten times that number worldwide.

In addition, recently researchers discovered a new cellular immune pathway called Th17 that is activated against pathogens that colonize mucosal tissue. The discovery of this pathway provides the basis for a new T cell vaccine approach to preventing such diseases S. pneumoniae, H. pylori and C. difficile.

Beyond infectious disease, autoimmune disorders and cancers represent additional opportunities for altering the immune response with T cell vaccines. Autoimmune disorders, in which the cellular immune response is directed against a patient's own tissue, result from a failure of the immune recognition process to distinguish normal from foreign (e.g. diseased tissue). In the case of cancer, tumor cells escape immune recognition.