Abstract 2357: Therapeutic potential of the natural human IgG1k antibody pritumumab

Pritumumab is a natural human IgG1 kappa antibody derived from a regional draining lymph node of a patient with cervical carcinoma. The recognized antigen is an altered form of vimentin, called ecto-domain vimentin (EDV), that is expressed on the cell surface of epithelial tumor cells. A recombinant version of the mAb was made using the GPEx® system in CHO cells. In a series of comparable studies the CHO mAb was compared with the original hybridoma. Binding specificity with both flow cytometry and immunohistochemical analysis, Western blot analysis, and Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) activity confirms the comparability of the two versions. A concentration-dependent study of pritumumab-mediated ADCC suggests an EC50 of 39.6ng/ml. Further studies include establishing a xenograft model with both SCID and athymic nude mice in which pritumumab was effective in preventing tumor growth in nude mice but not in SCID mice. Analysis of a blood brain barrier model suggests pritumumab shows minimal distribution in normal brain tissues and significant binding in tumor areas of brain tissues indicating the mAb crosses the tumor brain barrier. Overall, these data together suggest pritumumab is suitable for development as an anti-tumor therapeutic. Citation Format: Ivan Babic, Rajesh Mukthavaram, Natsuko Nomura, Sandeep Pingle, Mark C. Glassy, Santosh Kesari. Therapeutic potential of the natural human IgG1k antibody pritumumab. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2357.