Moxetumomab pasudotox

MxP is a CD22-directed cytotoxin. It is stated as an immunotoxin which is defined as the class of agents that combine the selectivity of antibodies towards the target and the potency of toxins to perform the pharmacological anticancer function. CD22 is a B-lymphocyte restricted transmembrane protein with a high density in HCL cells when compared with normal B cells. After binding to CD22, MxP is internalized and processed, which allows the release of the modified toxin. This toxin inhibits protein translation which induces an apoptotic state of the high CD22-expressed cancer cell.

The toxin included in MxP is the Pseudomonas exotoxin A which, after internalization, undergoes conformational changes and in the cytosol, the ribosylation activity of the domain III of the toxin inactivates the eukaryotic translation elongation factor (eEF-2) by transferring ADP (adenosine di-phosphate-ribose) from NAD to a modified histidine at position 715 in eEF-2. This action produces the inactivation of eEF-2 which leads to protein synthesis inhibition and programmed cell death.