Vical Presents Promising Preclinical Data on IL-2 Electroporation Program

Researchers at Vical has presented preclinical (mouse) data, supporting the company's decision to advance into Phase I human testing with an investigational method of delivering interleukin-2 (IL-2) for patients with recurrent metastatic melanoma.

IL-2 protein is a potent immune system stimulant delivered intravenously as a treatment for metastatic melanoma. With this systemic delivery method, high circulating levels of protein are required to get sufficient immune activity at the site of melanoma tumors, but these high serum levels frequently cause severe systemic toxicities.

The novel approach being developed by Vical involves direct injection into a tumor lesion of plasmid DNA (pDNA) encoding IL-2, followed by electroporation, the local application of an electrical charge designed to enhance the uptake of the pDNA into tumor cells. The pDNA is designed to cause cells within the tumor to produce high levels of IL-2 protein locally and stimulate the immune system to attack the tumor without the associated systemic toxicities.

Results of the preclinical testing indicated that mice receiving IL-2 pDNA injections followed by electroporation, compared with mice receiving IL-2 pDNA injections without electroporation, had two- to three-fold higher levels of IL-2 in the injected tumor, significantly reduced tumor growth and a three-fold advantage in tumor-free status after 60 days.