CyaA vectors were developed through the modification of the reguatory enzyme adenylate cyclase from the bacterium Bordetella pertussis, and - according to the Institut Pasteur which engineered the vector - are the only delivery system that naturally targets specific antigens directly to Antigen Presenting Cells (APC).
Parisian biotech Genticel – which holds the exclusive license to the platform – is using the technology to developing its own therapeutic vaccines, which, unlike preventative vaccines, induce cell-mediated immunity in patients already suffering from a disease.
This US patent covers the use of a "CyaA-based vector comprising a tumor antigen associated with an adjuvant, and the usage of the same CyaA-based vector comprising a tumor antigen associated with an adjuvant in combination therapy with a chemotherapeutic agent,” Genticel CEO Martin Koch told this publication.
APCs, or sentinel cells, play a key role in the initiation of an immune response against pathogens. CyaA vectors anchor themselves to APCs where they deliver the antigen to trigger the activation of two different classes of immune cells, Koch continued.
The first class “will kill the cells carrying the same antigen that was carried by the vector,” he told us, while the second class “will help the production of specific “killer cells” and the generation of a memory immune response.”
“After vaccination with the vector carrying the antigen, the overall effect is a specific cellular immune response eradicating the cells expressing that same antigen.”
Genticel’s lead product is its therapeutic human papillomavirus (HPV) vaccine ProCervix, currently in Phase I trials, and Koch said the firm would consider interest from other pharma firms in both the tech and vaccine candidates.
“We have had and still have interest from parties which are both mid and large pharmaceutical companies engaged either in immunotherapies, in vaccines or in women health,” he said.
“Of course Genticel will consider the opportunity to license the therapeutic vaccine candidates to a third party, which could pursue the clinical development beyond the ongoing phase 2 trial and up to commercialization.”