Metastatic colorectal cancer cells from patients previously treated with chemotherapy are sensitive to T-cell killing mediated by CEA/CD3-bispecific T-cell-engaging BiTE antibody

Abstract

Background: Novel technologies to redirect T-cell killing against cancer cells are emerging. We hypothesised that metastatic human colorectal cancer (CRC) previously treated with conventional chemotherapy would be sensitive to T-cell killing mediated by carcinoembryonic antigen (CEA)/CD3-bispecific T-cell-engaging BiTE antibody (MEDI-565).Methods: We analysed proliferation and lysis of CEA-positive (CEA) CRC specimens that had survived previous systemic chemotherapy and biologic therapy to determine whether they could be killed by patient T cells engaged by MEDI-565 in vitro.Results: At low concentrations (0.1-1 ng ml-1), MEDI-565 T cells caused reduced proliferation and enhanced apoptosis of CEA human CRC specimens. High levels of soluble CEA did not impair killing by redirected T cells and there was no increase in resistance to T-cell killing despite multiple rounds of exposure.Conclusions: This study shows for the first time that metastatic CRC specimens derived from patients previously treated with conventional chemotherapy can be lysed by patient T cells. Clinical testing of cancer immunotherapies, such as MEDI-565 that result in exposure of tumours to large numbers of T cells, is warranted. © 2010 Cancer Research UK All rights reserved.