A particular toxin that has been used in targeted toxins is Pseudomonas exotoxin A (PE). The effectiveness of PE-containing targeted toxins has been demonstrated against various forms of cancer, including hairy cell leukemia (HCL) and pediatric acute lymphocytic leukemia (pALL). Although early variations these targeted toxins have demonstrated efficacy upon first administration, the continued administration of a targeted toxin often leads to a reduced patient response. The primary cause of the reduced response is the formation of neutralizing antibodies against PE by the patient.
Several variations of PE have been created to reduce the immunogenicity of PE as a means of increasing the therapeutic effectiveness of targeted toxins through multiple rounds of drug administration. This technology involves the identification of two important B-cell epitopes on PE, and the elimination of those epitopes by mutation. These new PE variants retain a sufficient cell killing activity while increasing their therapeutic effectiveness toward patients that receive multiple administrations. By further combining these new mutations with previously identified modifications that also improve the efficacy of PE-based targeted toxins, it may be possible to treat any disease characterized by cells that express a particular cell surface receptor when in a disease state. CRADA Opportunity: The National Cancer Institute, Molecular Biology Section, is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize this technology. Please contact John Hewes, Ph.D. at 301-435-3121 or hewesj@mail.nih.gov for more information. Click here to view the NCI collaborative opportunity announcement.
Source: http://www.ott.nih.gov/Technologies/abstractDetails.aspx?RefNo=2273
