Unconventional immunotherapy with an unconventional target.

Pritumumab, a natural human IgG1 kappa antibody was obtained from a regional draining lymph node of a patient with cervical carcinoma through traditional hybridoma technology. Specificity analysis of the target antigen, an altered form of vimentin called, ecto-domain vimentin (EDV), shows it to be limited to cell surface expression on cancer cells. Clinically, 249 brain cancer patients were treated with a low dose pritumumab regimen, either at 1 mg once a week or 1 mg twice a week, and of those evaluated overall response rates of between 25-30% were seen with several complete and partial responses. A clinical trial assessing higher doses of pritumumab as a therapeutic for brain cancer is expected to begin this year. Overall, these data together suggest pritumumab is suitable for further development as an anti-tumor therapeutic.