Nuris Ledón

Systemic and Skin Toxicity in Cercopithecus aethiops sabaeus Monkeys Treated During 26 Weeks with a High Intravenous Dose of the Anti- Epidermal Growth Factor Receptor Monoclonal Antibody Nimotuzumab

Nimotuzumab (h-R3) is a humanized anti-epidermal growth factor receptor monoclonal antibody (mAb) registered for treating head and neck tumours. The present study was designed to evaluate the systemic and skin toxicity of chronic intravenous administration of the h-R3 in a relevant species demonstrated by comparing the h-R3 binding affinity constants (Kd) in microsomal placental fractions from Homo sapiens and Cercopithecus aethiops monkeys using an EGF-Receptor radioligand competition assay. The Kd obtained for Nimotuzumab were 9.1x10-8 M for monkeys and 4.5x10-8 M for humans. Monkeys (n=18) were distributed into 3 groups with 3 animals of each sex in each group. Group I received saline; group II received 2.85 mg/kg of h-R3; and group III received 28.57 mg/kg of the h-R3, which represent 1 and 10 times the human dose, and they were weekly intravenously treated during 26 weeks. During the study there were no deaths. Electroneurophysiological, sanguine chemistry and haematological results did not evidence alterations. Areas of haematomas, probably related with the administration procedure, were observed at the administration zones of all animals. The electrocardiography study showed at the end of the study a slight increase in the cardiac frequency of 4 treated animals without others signs. Unexpectedly, skin biopsies and a detailed clinical inspection of the animals did not detect the presence of cutaneous rash or any other skin toxicity sign reported for the majority of the anti-EGF-R monoclonal antibodies. It is concluded that doses up to 28.5 mg/kg of h-R3, intravenously administered during 26 weeks to Cercopithecus aethiops monkeys, do not produce considerable toxic effects.

Repeated dose intramuscular injection of the CIMAvax-EGF vaccine in Sprague Dawley rats induces local and systemic toxicity

CIMAvax-EGF consists of a human recombinant epidermal growth factor (EGF), coupled to P64k, a recombinant carrier protein from N. meningitis, and Montanide ISA 51 as adjuvant. The vaccine immunization induces a specific antibody production, inhibiting the EGF/EGF-R interaction through EGF deprivation. The objective of this study was to assess the CIMAvax-EGF toxicity in Sprague Dawley rats after intramuscular administration of repeated doses (6 months) and at the same time to determine if rat is a relevant species for studying CIMAvax-EGF vaccine. Rats were randomly distributed into four groups: control, Montanide ISA 51, treated with 1× and 15× of human total dose of the antigen. Animals were immunized weekly during 9 weeks, plus 9 immunizations every 14 days. Rats were inspected daily for clinical signs. Body weight, food consumption, and rectal temperature were measured during the administration of doses. Blood samples were collected for hematological, serum biochemical determinations and EGF titles at the beginning, three months and at the end of experimentation. Gross necropsy and histological examination of tissues were performed on animals at the end of the assay. Vaccine provoked the apparition of antibodies against EGF in the rats, demonstrating rat species relevance in these studies. Body weight gain, food and water consumption were not affected. CIMAvax-EGF and Montanide ISA 51 produced local damage at the administration site, showing multiple cysts and granulomas. Both vaccine-treated groups showed neutrophil elevation, besides an AST increase probably related to the damage at the administration site. Rectal temperature was found to be significantly higher in 15× treated group after immunizations, probably induced by the inflammatory process at the injection site. In summary, the clinical pathology findings together with the body temperature results, appear to be caused by the inflammatory reaction at the administration site of the vaccine, mainly mediated by the oil-based adjuvant Montanide ISA 51, probably enhanced by the immunological properties of the antigen. This study showed evidences that intramuscular administration during 26 weeks of CIMAvax-EGF at doses up to 15× human total dose is well tolerated in rats and it has a clinical importance since this long lasting study in relevant species allows to treat cancer patients with tumors during long periods with relative weight safety margin.

Hematological, biochemical, respiratory, cardiovascular and electroneurophysiological parameters in African green monkeys (Cercopithecus aethiops sabaeus). Its use in non-clinical toxicological studies.

Background  The purpose of this study is to better characterize the hematological, biochemical, respiratory, cardiovascular and electroneurophysiological parameters in young adult Cercopithecus aethiops sabaeus of both sexes. The rhesus and cynomolgus monkeys are widely used as experimental primate models. However, only few articles have been published testing toxicological effects of pharmaceuticals on African green monkey.

Effects of an epidermal growth factor receptor-based cancer vaccine on wound healing and inflammation processes in murine experimental models.

Anti‐epidermal growth factor receptor (EGFR) therapies have been proven clinically effective for a variety of epithelial tumours. Vaccination of mice with the extracellular domain (ECD) of autologous EGFR overcomes the tolerance to self‐EGFR and has antimetastatic effect on EGFR+ tumour. Because EGF/EGFR‐signalling plays an important role in the inflammation stage of wound healing, the main objective of this study was to explore the possible role of murine (m) EGFR‐ECD vaccine in the croton‐oil‐induced ear oedema and wound healing process in mice as autologous experimental models, mimicking the possible post‐surgical wound complication in patients treated with human EGFR‐ECD/VSSP vaccine. Mice were intramuscularly immunised four times; biweekly with the mEGFR‐ECD/VSSP/Mont. Seven days later, an 8 mm diameter, full‐thickness skin wound was created on the back of each animal. Immunisation induced a strong specific humoral response against the mEGFR‐ECD protein and a DTH dose–response curve but interestingly, animals treated with mEGFR‐ECD/VSSP/Mont had similar inflammatory and healing speed responses compared to control ones. These data suggest that application of mEGFR‐ECD/VSSP vaccine as a therapeutic approach in cancer patients could not elicit a poor healing process after surgery.