DAB(389)IL-2 (denileukin diftitox, ONTAK): a new fusion protein technology.

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Foss FM

DAB(389)IL-2 (denileukin diftitox, ONTAK): a new fusion protein technology.

Clin Lymphoma. 2000 Nov;1 Suppl 1:S27-31.

PubMed ID

11707860 [ View in PubMed

]

Abstract

Genetic engineering has led to the development of fusion protein toxins, which are targeted effector molecules that combine a targeting ligand such as a growth factor with a cytocidal moiety such as a plant or bacterial toxin. The first genetically constructed family of fusion proteins used diphtheria toxin as the toxophore for receptor-binding domain substitution. Diphtheria toxin consists of three domains: an enzymatically active adenosine diphosphate (ADP) ribosyltransferase domain, a hydrophobic transmembrane domain, and a C-terminal receptor-binding domain. Introduction of the enzymatically active domain into the cytosol via receptor-mediated endocytosis results in inhibition of protein synthesis by ADP ribosylation of elongation-factor 2. DAB(486)IL-2, in which the native receptor-binding domain of diphtheria toxin was replaced with the full-length interleukin-2 (IL-2) gene, was capable of intoxicating high-affinity IL-2 receptor-bearing cells in vitro with an IC(50) of 10(-10) M; whereas, cells lacking the full component of the high-affinity IL-2 receptor (p55, p75, p64) were relatively resistant (IC(50) of 10(-8) M). Because of a short in vivo half-life of DAB(486)IL-2, efforts to reengineer the molecule were undertaken, leading to the DAB(389)IL-2 construct, which had a twofold to threefold higher Kd than DAB(486)IL-2 and a longer half-life, resulting in a tenfold increase in potency. Thus far, the clinical activity of both IL-2 chimeric fusion toxins has been similar, with the DAB(389)IL-2 molecule displaying more favorable pharmacokinetics.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Denileukin diftitox	Cytokine receptor common subunit gamma	Protein	Humans	Unknown	Not Available	Details