We have developed new agents for the treatment of cancer by geneticall
y modifying Pseudomonas exotoxin. We have deleted the cell-binding reg
ion of Pseudomonas exotoxin and replaced it with various growth factor
s or the combining regions of antibodies in a single chain form. These
new recombinant molecules are called recombinant toxins. Several diff
erent types of recombinant toxins have been produced. B3(Fv)-PE38KDEL
is a recombinant toxin that kills many different adenocarcinomas and e
pidermoid carcinomas. The molecule is now undergoing preclinical devel
opment.