Non-clinical immuno-toxicological evaluation of HER1 cancer vaccine in non-human primates: a 12-month study.

Human epidermal growth factor receptor (HER1) constitutes a tumor associated antigen. Its overexpression in many epithelial tumors has been associated with bad prognosis and poor survival. Cancer vaccine based on the extracellular domain (ECD) of HER1 and adjuvated in very small sized proteoliposomes (VSSP) and Montanide ISA 51-VG is a new and complementary approach for the treatment of epithelial tumors. The present study deals with the immunogenicity of this vaccine in Macaca fascicularis monkeys and evaluation of its toxicity during 12 months. Twelve monkeys were randomized into two groups of 3 animals per sex: control and vaccinated. Treated monkeys received 9 doses of vaccination and were daily inspected for clinical signs. Body weight, rectal temperature, cardiac and respiratory rates were measured during the study. Humoral immune response, clinical pathology parameters and delayed type hypensensitivity were analyzed. Skin biopsy was performed at the end of the study in all animals. Animal's survival in the study was 100% (n=12). Local reactions were observed at the administration site of four treated animals (n=6), with two showing slight inflammatory cutaneous damage. Clinical pathology parameters were not affected. HER1 vaccine induced high IgG antibodies titers in the treated animals even when DTH was not observed. The induced antibodies recognized HER1+ tumor cell lines, decreased HER1 phosphorylation and showed anti-proliferative and pro-apoptotic effects in H125 cells. In general the present study showed that HER1 vaccine induced specific immune response in M. fascicularis monkeys and was well tolerated, suggesting it could be safely used in clinical studies in epithelial cancer patients.