Murine and humanized constructs of monoclonal antibody M195 (anti‐CD33) for the therapy of acute myelogenous leukemia Conference Paper


Authors: Caron, P. C.; Schwartz, M. A.; Co, M. S.; Queen, C.; Finn, R. D.; Graham, M. C.; Divgi, C. R.; Larson, S. M.; Scheinberg, D. A.
Title: Murine and humanized constructs of monoclonal antibody M195 (anti‐CD33) for the therapy of acute myelogenous leukemia
Conference Title: 4th Conference on Radioimmunodetection and Radioimmunotherapy of Cancer
Abstract: Long‐term survival rates of patients with acute myelogenous leukemia treated with intensive chemotherapy are 15–20%, despite efforts to develop new treatment strategies. Murine M195 (131I‐M195), an anti‐CD33, immunoglobulin (Ig) G2a monoclonal antibody has reactivity restricted to early myeloid cells and myeloid leukemic blasts but not hematopoietic progenitors. Previous trials in patients with relapsed or refractory myeloid leukemia showed that 131I‐M195 rapidly targeted to the bone marrow and internalized into target cells. This article describes a therapeutic dose escalation study in which 24 patients received from 50 mCi/m2 to 210 mCi/m2 of 131I‐M195 in divided doses. Cytoreduction of peripheral cell counts and bone marrow blasts occurred without nonhematopoietic toxicity. Doses of 131I‐M195 greater than 135 mCi/m2 were associated with marrow cytoreduction sufficient to necessitate bone marrow transplant. However, 37% of the patients developed human anti‐mouse antibody, preventing retreatment. To decrease immunogenicity and improve effector function, chimeric IgG1 and IgG3, and complementarity‐determining region‐grafted, humanized IgG1 and IgG3 versions of mouse M195 were developed by genetic engineering techniques. The new versions maintained specificity and biologic function, and they were superior to the mouse M195 in their ability to perform antibody‐dependent cellular cytotoxicity against leukemia cells. Humanized M195, but not chimeric M195, showed a 4–8.6 times higher avidity than its mouse counterpart. Because effector function of IgG depends to a large extent on Fc clustering, a homodimeric HuG1 also was developed. Homodimeric HuG1 showed an ability to cause additional dramatic improvements in effector functions, as well as an ability to internalize and retain radioisotope in target leukemia cells. Monomeric and dimeric forms of humanized M195 may be advantageous in the therapy of acute myelogenous leukemia. Cancer 1994; 73:1049–56. Copyright © 1994 American Cancer Society
Keywords: adult; clinical article; acute granulocytic leukemia; human cell; conference paper; cancer radiotherapy; animal; mice; cancer immunotherapy; blood toxicity; antineoplastic activity; monoclonal antibody; antibodies, monoclonal; drug uptake; iodine radioisotopes; antigens, cd; immunoglobulin g2a; radioimmunotherapy; internalization; bone marrow toxicity; antibody dependent cellular cytotoxicity; antigens, differentiation, myelomonocytic; acute myelogenous leukemia; raji cell; m195; monoclonal antibody m 195; cell strain hl 60; leukemia, myelocytic, acute; antibody-dependent cell cytotoxicity; human; priority journal; support, non-u.s. gov't; support, u.s. gov't, p.h.s.; monoclonal antibody i 131; chimeric proteins; antibody‐dependent cellular cytotoxicity; anti‐cd33; chimeric and humanized antibodies
Journal Title Cancer
Volume: 73
Issue: 3 Suppl.
Conference Dates: 1992 Sep 17-19
Conference Location: Princeton, NJ
ISBN: 0008-543X
Publisher: Wiley Blackwell  
Date Published: 1994-02-01
Start Page: 1049
End Page: 1056
Language: English
DOI: 10.1002/1097-0142(19940201)73:3+<1049::Aid-cncr2820731344>3.0.Co;2-1
PROVIDER: scopus
PUBMED: 8306247
DOI/URL:
Notes: Export Date: 14 January 2019 -- Article -- Source: Scopus
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MSK Authors
  1. Chaitanya Divgi
    163 Divgi
  2. Ronald D Finn
    279 Finn
  3. Steven M Larson
    958 Larson
  4. Philip C Caron
    90 Caron
  5. Martin C Graham
    53 Graham