BLUE BELL, Pa., Jan. 23, 2014 /PRNewswire/ -- Inovio Pharmaceuticals, Inc. (INO) today unveiled that the company has developed a new DNA-based cytokine immune activator, interleukin -33 (IL-33), that in combination with optimized DNA vaccines delivered by electroporation increased the potency and efficacy of the therapeutic response to the DNA vaccines in a preclinical study. The findings of this study reveal that IL-33 could be an effective immune booster when used with Inovio's products to generate therapeutic immune responses against cancers and chronic viral infections in humans. Inovio has developed a portfolio of patent-protected IL-33 and other immune activators to form combination therapies with its DNA vaccines and immunotherapies with the goal of achieving the greatest possible efficacy against targeted diseases.
A therapeutic vaccine study treating HPV-16 based cancer-bearing mice demonstrated rapid and complete tumor regression after treatment with Inovio's HPV16 (human papillomavirus type 16) vaccine in combination with DNA-based IL-33. Both were delivered using Inovio's CELLECTRA® electroporation device. Previous studies have shown that the HPV 16 DNA vaccine alone was able to prevent tumor growth in mice and delay progression or cure mice of tumors. Addition of the IL-33 immune activator resulted in a more rapid and complete regression of established tumors in the mouse model.
The adjuvant/vaccine combination induced potent CD4 and CD8 T cells. Notably, inclusion of the DNA-based IL-33 immune activator significantly increased the magnitude of vaccine-specific CD8 T cell responses. Prior research has demonstrated that CD4 and CD8 T cells are both important in cellular immune responses; however, CD8 T-cells, or killer T cells, are considered especially integral to fighting cancers and chronic infectious diseases.
The peak vaccine-induced expansion of CD8 T cells at 14 days after vaccination correlated with complete tumor regression. This desirable outcome points to the important role IL-33 and other immune activators may play in combination with Inovio's cancer treatments in development.
The results of this study, conducted by Inovio scientists and collaborators, are detailed in a paper entitled: "Alarmin IL-33 acts as potent immunoadjuvant enhancing antigen-specific cell-mediated immunity and inducing potent anti-tumor immunity," published in Cancer Research .
Dr. J. Joseph Kim, Inovio's President and CEO, said: "To create the most effective arsenal of therapeutic products against cancer and infectious diseases, we are researching combination therapies using our DNA immunotherapies with checkpoint inhibitors and immune activators to optimize their therapeutic effects. While we have already reported best-in-class T cell responses from two DNA vaccines in human trials, this published study shows for the first time how DNA-based IL-33 can boost antigen-specific immune responses generated by our DNA immunotherapies and vaccines.
"We are developing multiple DNA plasmid based cytokine and chemokine genes as immune activators and I am proud to say that Inovio has more of these immune activators in its pipeline than anyone else in the world. We have initiated human studies using other DNA-based cytokines and look forward to moving IL-33 into clinical trials in combination with our DNA vaccines," Dr. Kim added.