Lawrence Fong, MD, associate professor, Department of Medicine (Hematology/Oncology), University of California, San Francisco, discusses the systemic antitumor effect and clinical response in a phase II trial of intratumoral electroporation of plasmid interleukin-12 (IL-12) in patients with advanced melanoma.
Fong says rather than trying to use an vaccine to induce an immune response, researchers attempted to utilize the patient’s own tumor as a vaccine. In this study, a DNA plasmid was injected into the tumor site and then electrodes were placed into the tumor site to introduce the injected DNA into the tumor microenvironment.
The injected plasmid expresses IL-12, Fong says, which is one of the critical cytokines that help teach T cells to recognize antigens. The study found that when this cytokine was introduced to tumors in patients with metastatic melanoma, responses are seen not only in the site of injection, but also at distant tumor sites. Fong says this is consistent with the idea that an immune response is being activated that can circulate and impact cancer at other sites.
This trial is now being expanded based upon these results, Fong says. Researchers hope to further understand the mechanics of this interaction.
<<< View more from the 2014 ASCO Annual Meeting