The study showed that DepoVax platform promotes antigen specific immune responses, however, unlike the control vaccine, the DepoVax formulation does not induce problematic immune regulatory responses.
DPX-0907 is an oil-depot vaccine formulation that is currently being tested in a Phase 1 clinical trial for the therapy of breast, ovarian or prostate cancer patients. DPX-0907 uses lyophilized (freeze-dried) liposomes, containing seven antigens and an adjuvant, and an oil delivery. The seven peptide antigens were identified from the surface of breast and ovarian tumor cell lines, but were not found on normal cells.
The antigens were selected on the basis of their association with pathways essential for tumor growth and survival. Given DPX-0907’s favorable safety profile, its ability to differentially promote type-1 versus Treg-type immunity, and its lyophilized format for enhanced shelf-life and stability, the DepoVax technology appears to be a promising platform for the development of the next generation of therapeutic/prophylactic vaccines for cancer and infectious diseases.
Immunovaccine said that the paper entitled, ‘A Novel Breast or Ovarian Cancer Peptide Vaccine Platform That Promotes Specific Type-1 but not Treg or Tr1-type Responses’ is published in the April 2010 issue of the Journal of Immunology, Volume 33, Number 3.
Transgenic mice vaccinated with DPX-0907 exhibited more than double the number of peptide-specific (CD8+IFN-g+), T-cells when compared with the control oil emulsion-based vaccine. In fact, mice that received follow-up booster immunizations of DPX-0907 maintained the high levels of interferon gamma (a cytokine indicative of vaccine-induced T cell immunity), whereas the mice immunized with the control vaccine displayed significantly lower levels of the T cell activation cytokine.
The study suggested that the novel DepoVax delivery platform may provide better sustained antigen-specific immune responses compared to other peptide vaccine delivery methods. Interestingly, DPX-0907 formulation also provided a safer vaccine alternative to the control emulsion vaccine.
Marc Mansour, vice president of R&D at Immunovaccine, said: “The results of this study, indicate that our DepoVax vaccine platform may be able to improve the delivery and performance of cancer vaccines, by tipping the scales in favor of an active and uninhibited immune response following vaccination. If successful, such a platform may help potentiate other cancer immunotherapies.”