Zhang Z, Zhang M, Ravetch JV, Goldman C, Waldmann TA. Effective therapy for a murine model of adult T-cell leukemia with the humanized anti-CD2 monoclonal antibody, MEDI-507.
Blood 2003;
102:284-8. [PMID:
12649132 DOI:
10.1182/blood-2002-11-3601]
[Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adult T-cell leukemia (ATL) develops in a small proportion of individuals infected with the retrovirus human T-cell leukemia virus (HTLV-1). We evaluated the efficacy of MEDI-507 (a humanized monoclonal antibody directed against CD2) alone and in combination with humanized anti-Tac (HAT) directed toward CD25, the interleukin-2 receptor alpha (IL-2Ralpha) using a human adult T-cell leukemia xenograft model. Weekly treatments (4) with HAT significantly prolonged the survival of the ATL-bearing mice when compared with phosphate-buffered saline (PBS)-treated controls (P <.0001). Mice treated with MEDI-507 (100 microg/wk for 4 weeks) survived longer than those treated with HAT (P <.0025). Furthermore, prolonged treatment (6 months) of ATL with MEDI-507 significantly improved the outcome when compared with a short course (4 weeks) of therapy (P <.0036). Such treatment with weekly MEDI-507 for 6 months led to a prolonged survival of the ATL-bearing mice that was comparable with the survival observed in the control group of mice that did not receive a tumor or therapeutic agent. We also found that the expression of Fcgamma receptors (FcRgamma) on polymorphonuclear leukocytes and monocytes was required for MEDI-507-mediated tumor killing in vivo. Thus, the tumor-killing mechanism with MEDI-507 in vivo required the expression of the receptor FcRgammaIII on polymorphonuclear leukocytes and monocytes, suggesting that it is mediated by a form of antibody-dependent cellular cytotoxicity. These results demonstrate that MEDI-507 has therapeutic efficacy on ATL in vivo and provides support for a clinical trial involving this monoclonal antibody in the treatment of patients with CD2-expressing leukemias and lymphomas.
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