The use of eculizumab in renal transplantation.

The complement system plays a vital role in mediating disease processes within renal allografts. Eculizumab is a humanized monoclonal antibody that targets complement protein C5, inhibiting cleavage into C5a and C5b, and therefore preventing formation of the membrane attack complex (MAC). It has been used primarily within renal transplantation to treat atypical hemolytic-uremic syndrome (aHUS) and antibody-mediated rejection (AMR) post-transplant, and also as prophylaxis in transplants at high risk for these conditions. Eculizumab appears to be effective in protecting renal allografts when post-transplant aHUS or AMR occur, although the published cases report relatively short follow-up. It is unclear how long treatment should continue (a particularly important issue given the expense of the drug), or whether eculizumab contributes to the development of accommodation in humans. When used for prophylaxis, eculizumab also appears to be effective. Some highly sensitized patients have developed either acute AMR or features of chronic AMR despite administration of the drug - this suggests that complement activation is not the only mechanism responsible for AMR. All patients should receive vaccination against Neisseria meningitidis prior to receiving eculizumab. Clinical trials, predominantly in antibody-incompatible renal transplantation, are ongoing to determine the optimal use of C5 inhibition.