Immuno-toxicological evaluation of her1 cancer vaccine in non-human primates: a 6-month subcutaneous study

<b>Purpose:</b> A vaccine composition based on the extracellular domain of the human epidermal growth factor receptor 1 (HER1-ECD) and the combination of VSSP (very small size proteoliposomes) and Montanide ISA 51 adjuvants when used by intramuscular route, demonstrated promising results in preclinical studies. However, in order to avoid potential adverse events due to the use of Montanide, it is proposed to modify the vaccine formulation by using VSSP (very small size proteoliposomes) adjuvant alone, and to evaluate the quality of subcutaneously induced immune response. This study aimed to assess the immunotoxicological effects of HER1 vaccine in <i>Cercopithecus aethiops</i>. <b>Materials and methods:</b> Fifteen monkeys were randomized into four groups: Negative Control (Tris/NaCl, s.c.), Positive Control (200 µg HER1-ECD/VSSP/Montanide ISA-51 VG, i.m), Low Dose (200 µg HER1-ECD/VSSP/Tris NaCl, s.c.) and High Dose (800 µg HER1-ECD/VSSP/Tris NaCl, s.c). All monkeys received 7 doses and were daily inspected for clinical signs. Body weight, rectal temperature, cardiac and respiratory rates were measured during the study, and electrocardiographical and ophthalmological studies were performed. Humoral and cellular immune response and clinical pathology parameters were analyzed. <b>Results:</b> Animal’s survival in the study was 100% (<i>n</i> = 15). Administration site reactions were observed in the Positive Control animals (<i>n</i> = 4). HER1 vaccine administered subcutaneously (High Dose Group) achieved good IgG antibody titers although lower than the Positive Control group, but with higher ability to inhibit HER1 phosphorylation. <b>Conclusions: </b>This suggests that the alternative of eliminating the use of Montanide in the HER1 vaccine preparation and the using subcutaneous route is feasible.