Eculizumab an anti-C5 monoclonal antibody is used in the treatment of:

A major advance in the management of PNH has been the development of a humanized monoclonal antibody, eculizumab, directed against the complement component C5. By blocking the complement cascade downstream of C5, eculizumab abrogates complement-dependent intravascular hemolysis in all PNH patients. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Pages 884-86