Daniel E. Tracey

AVX-470: a novel oral anti-TNF antibody with therapeutic potential in inflammatory bowel disease.

Background:Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which is currently treated with injected monoclonal antibodies specific for tumor necrosis factor (TNF). We developed and characterized AVX-470, a novel polyclonal antibody specific for human TNF. We evaluated the oral activity of AVX-470m, a surrogate antibody specific for murine TNF, in several well-accepted mouse models of IBD. Methods:AVX-470 and AVX-470m were isolated from the colostrum of dairy cows that had been immunized with TNF. The potency, specificity, and affinity of both AVX-470 and AVX-470m were evaluated in vitro and compared with infliximab. AVX-470m was orally administered to mice either before or after induction of colitis, and activity was measured by endoscopy, histopathology, immunohistochemistry, and quantitative measurement of messenger RNA levels. Colitis was induced using either 2,4,6-trinitrobenzene sulfonate or dextran sodium sulfate. Results:AVX-470 and AVX-470m were shown to be functionally comparable in vitro. Moreover, the specificity, neutralizing potency, and affinity of AVX-470 were comparable with infliximab. Orally administered AVX-470m effectively reduced disease severity in several mouse models of IBD. Activity was comparable with that of oral prednisolone or parenteral etanercept. The antibody penetrated the colonic mucosa and inhibited TNF-driven mucosal inflammation with minimal systemic exposure. Conclusions:AVX-470 is a novel polyclonal anti-TNF antibody with an in vitro activity profile comparable to that of infliximab. Oral administration of a surrogate antibody specific for mouse TNF is effective in treating mouse models of IBD, delivering the anti-TNF to the site of inflammation with minimal systemic exposure.

Effects of AVX-470, an Oral, Locally Acting Anti-Tumour Necrosis Factor Antibody, on Tissue Biomarkers in Patients with Active Ulcerative Colitis

BACKGROUND AND AIMS AVX-470 is an orally administered, bovine-derived, anti-tumour necrosis factor (TNF) antibody with local activity in the gastrointestinal tract. In the first-in-human clinical trial of AVX-470 in active ulcerative colitis, we evaluated inflammatory biomarkers in colon tissue as measures of disease activity and early response to treatment. METHODS Thirty-six patients received active drug (AVX-470 at 0.2, 1.6 or 3.5g/day) or placebo over 4 weeks. Colon biopsy samples were collected from 5 regions of colon at baseline and week 4. Tissue inflammatory biomarkers were evaluated by immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR), epithelial cell apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) and bovine immunoglobulin by immunohistochemistry and mass spectrometry. Endoscopic activity (Ulcerative Colitis Endoscopic Index of Severity [UCEIS]) at colonoscopy was assessed in each colonic region by a central reader. RESULTS Bovine immunoglobulin was observed in mucosal tissue before and after dosing in lamina propria and submucosal layers of biopsy tissue. Baseline levels of TNF, myeloperoxidase (MPO), CD68 and interleukin (IL)-1β and, to a lesser extent, IL-6 mRNA were 2- to 3-fold higher in distal vs proximal colon tissue, corresponding to the 2- to 3-fold differences in baseline severities of endoscopic scores. Reductions of >10-fold in TNF and, to lesser extents, in MPO and epithelial cell apoptosis were observed in proximal and distal colon biopsies after 4 weeks of AVX-470 3.5g/day treatment. Reductions in TNF scores were correlated with changes in MPO and CD3 immunohistochemistry scores. CONCLUSIONS These results are consistent with anti-TNF activity of orally administered AVX-470 in colon mucosal tissue in ulcerative colitis patients and demonstrate the utility of tissue biomarkers in assessing disease and treatment response in early clinical studies. CLINICAL TRIAL REGISTRATION NUMBER This trial was registered with Clinicaltrials.gov as study NCT01759056 and with EudraCT as study 2012-004859-27.

Serum and colostral antibody production in cows immunized with recombinant human tumor necrosis factor

The use of hyper-immune bovine colostrum as a human therapeutic platform is an emerging technology with potential to deliver the efficacy of antibody therapeutics with the convenience and safety of oral or topical application. It is necessary to understand how the bovine immune system responds to immunization with foreign proteins, both in terms of the serum antibody response and the transfer of antigen-specific antibodies into the colostrum to enable efficient large-scale production of therapeutic antibodies. We have immunized 25 cows with recombinant human tumor necrosis factor (rhTNF) and measured the levels of rhTNF-specific antibodies in the serum and colostrum of these animals. We observed a decline of 84±9% in serum IgG1 concentrations in the final weeks of pregnancy that presumably reflects rapid transport of IgG1 into colostrum. The serum IgG2 levels remained constant, such that the serum IgG1 to IgG2 ratio was 1:20 at parturition. We observed substantial animal-to-animal variability in the levels of anti-rhTNF antibodies in both serum and colostrum samples. In particular, a subset of 4 cows had extraordinarily high colostral anti-rhTNF antibody production. Only a weak correlation was found between the peak serum anti-rhTNF activity and the colostral anti-rhTNF activity in these animals. The 4 cows with high colostral anti-rhTNF activities trended toward higher serum IgG1 loss relative to average colostral anti-rhTNF producers, but this difference was not statistically significant in this small sample. The high-anti-rhTNF-producing cows also exhibited a greater proportion of rhTNF-specific antibodies that bound to bovine IgG1- and IgG2-specific detection antibodies relative to the total anti-rhTNF immunoglobulin population. This finding suggests that the isotype distribution of the anti-rhTNF response is varied between individuals and genetic or environmental factors may increase the yield of antigen-specific colostral antibodies.

Sa2004 Effects of AVX-470m, an Oral Polyclonal Anti-TNF Antibody, on Survival and Biomarkers in a Murine Model of Gastrointestinal Acute Radiation Syndrome

Intestinal mucositis is a common side-effect in patients undergoing radiotherapy and poses a severe dose-limiting factor in treatment1. Identification of compounds that prevent radiationinduced mucositis and improve intestinal restitution may offer new therapeutic strategies for maintaining intestinalmucosal integrity in patients undergoing radiotherapy. Pathogenesis of mucositis involves production of pro-inflammatory cytokines and reactive oxygen metabolites2,3 and increased apoptosis in intestinal epithelium, leading to loss of intestinal structure and function4. STW 5 is an herbal multi-component preparation having potent anti-oxidant and anti-inflammatory properties in intestinal inflammatory disorders,5,6, making it an attractive candidate to study its potential usefulness in mucositis. Intestinal mucositis was induced experimentally in rats by exposing them to whole body irradiation from a Caesium 137 source at a radiation dose of 6 Gray. Three days later, rats developed intestinal mucositis, judged by histological examination of the small intestine and measurement of associated parameters in intestinal homogenates and serum. STW5 was given orally for 5 days to rats in graded doses of 2 10 ml/kg before exposing them to radiation and continued for 3 days after exposure. Animals were sacrificed 24h later. Pretreatment with STW 5 led to dosedependent reduction in histological changes. A dose of 5 ml/kg was chosen to study in detail the protective effects of the preparation on relevant associated parameters. Histologically, irradiation caused shortening and fusion of villi, activation of mucus secreting glands, inflammatory cell infiltration of lamina propria and mucosal atrophy. Inflammation markers: tumor necrosis factor and myeloperoxidase activity in homogenates were also raised. The changes were associated with a rise in thiobarbituric acid reactive substances, reduction in glutathione and in protein content of intestinal homogenates. Biomarkers of intestinal tissue injury: plasma diamineoxidase was raised while citrulline7 was significantly reduced. Apoptosis was evidenced by a rise in cytosolic calcium, depletion of mitochondrial cytochrome c and B-cell lymphoma 2. Most histological changes and associated derangement in the parameters tested were largely prevented by STW 5. The findings pave the way to a new therapeutic approach in management of radiation induced mucositis. 1Costa G and Donaldson SS (1979) N Engl J Med 300, 1471-1474, 2MacNaughton WK (2000) Aliment Pharmacol Ther. 14, 523-528, 3Linard C et al (2003) Am J Physiol Gastrointest Liver Physiol. 285, 556-565, 4Wong TC et al (2006) J Pain Symptom Manage. 32, 27-37, 5Khayyal MT et al (2006) Phytomedicine. 13 Suppl 5, 56-66, 6Schempp H et al (2006) Phytomedicine. 2006;13 Suppl 5, 36-44 7Lutgens L and Lambin P (2007) World J. Gastroenterol., 13, 3033 3042

In Vitro Pharmacology of AVX-470, an Oral Anti-TNF Polyclonal Antibody for the Treatment of IBD: P-203

(human homologue is IL-8) in Tg-villin-MMP9 compared to WT mice. Organ culture ELISA showed significantly increased expression of Kc protein levels among Tg-villin-MMP9 mice (2.6160.18) compared to WT mice (1.2860.25). This result was also supported by in vitro model. Stably transfected HCT116 colonic epithelium cell line over-expressing MMP9 exhibited a significant increase in IL-8 protein levels (3.360.56) compared to vector (1.4660.14). Tg-villin-MMP9 mice exposed to DSSand S.T.-induced colitis exhibited a significant loss of body weight and higher mortality. Tg-villin-MMP9 mice exposed to DSSinduced colitis exhibited significantly higher clinical score (9.560.5) compared to WT littermates (6.560.6). Tg-villin-MMP9 mice undergoing DSSand S.T.-induced colitis showed significantly higher histological scores (7.260.5 and 7.860.6 respectively) and increased MPO activity (1.960.7 MPO U/mg protein and 2.460.4) compared to WT animals (3.660.8 and 3.260.5; and 0.760.2 MPO U/mg protein and 0.660.4 respectively). Further, the level of mRNA encoding Kc was also significantly higher (9.0610.5fold) in Tg-villin-MMP9 mice undergoing DSS-induced colitis, and also in mice undergoing S.T.-induced colitis (7.869.6-fold), compared to the levels in WT littermates. CONCLUSION(S): Together, the data show that constitutive expression of MMP9 in colonic epithelium causes spontaneous inflammation associated with permeability defect and an increase in the levels of pro-inflammatory chemokine Kc. Results acquired from the study may help in modifying the therapeutic strategy as the treatment of acute colitis.