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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3 Suppl
pubmed:dateCreated
1994-3-14
pubmed:abstractText
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.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0008-543X
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1049-56
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Murine and humanized constructs of monoclonal antibody M195 (anti-CD33) for the therapy of acute myelogenous leukemia.
pubmed:affiliation
Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
pubmed:publicationType
Journal Article, Clinical Trial, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't