C5 and atypical hemolytic-uremic syndrome: Eculizumab (trade name Soliris), a recombinant humanized monoclonal antibody that inhibits C5 cleavage by the C5 convertase via binding to C5 was recently approved for atypical hemolytic-uremic syndrome (aHUS), a disease that causes abnormal blood clots to form in the kidneys (2011).