Preclinical work is under way to assess whether Vaxfectin can optimize prime-boost DNA vaccine.
Karolinska Institute entered a research collaboration to evaluate Vical’s Vaxfectin® adjuvant with Bioject Medical Technologies’ Biojector® 2000 needle-free injection system with a multivalent DNA vaccine against HIV.
The Institute is currently conducting nonclinical safety studies to support a planned Phase I trial of a Vaxfectin-formulated HIV DNA vaccine as part of a prime-boost regimen. This regimen consists of three doses of unadjuvanted DNA vaccines followed by a single dose of a viral vector vaccine. The Vaxfectin adjuvant is intended to optimize the priming of immune responses and increase the performance of or potentially even eliminate the need for the viral vector vaccine boost.
“The results from our initial Phase I trial were quite good, with over 90 percent of subjects achieving detectable immune responses against HIV after the prime-boost vaccination,” says Eric Sandstrom, M.D., Ph.D., professor at the Karolinska Institute. “We hope to improve the breadth and magnitude of immune responses in the next clinical trial by using the Vaxfectin adjuvant with our DNA-priming vaccine.”
Karolinska Institute’s vaccine contains synthetic versions of genes encoding internal and surface proteins from different HIV subtypes. The combination is designed to provide protection against the most prevalent HIV strains circulating in Europe, Africa, and The Americas.
The prime-boost approach uses two vaccine components given at different times. The two vaccine components differ in how the genes are packaged. The DNA prime vaccine component contains only the specific gene sequences in a plasmid DNA ring and cannot reconstitute into an infectious virus. The HIV DNA vaccine was developed by Swedish Institute for Infectious Disease Control and the Karolinska Institute in Sweden.
The viral vector boost vaccine component uses a modified vaccinia ankara virus to shuttle the same noninfectious gene sequences into the body. The boost vaccine component was developed by the NIH and Walter Reed Army Institute of Research and does not use an adjuvant.