eculizumab

Eculizumab is a humanized monoclonal antibody that inhibits the terminal complement cascade by binding to complement component C5, preventing its cleavage to C5a and C5b and thereby blocking formation of the membrane attack complex. By reducing complement-mediated destruction of red blood cells and endothelial injury, it can lessen disease activity in certain conditions.

Clinical use includes paroxysmal nocturnal hemoglobinuria (PNH), aHUS, and, in some settings, other complement-mediated diseases such as generalized myasthenia gravis (gMG) and neuromyelitis optica spectrum disorder (NMOSD). Indications and approved patient populations vary by country and regulatory agency.

Administration is by intravenous infusion, with dosing regimens that differ by indication; typically an induction phase followed by maintenance infusions every two weeks. All patients are advised to receive vaccination against Neisseria meningitidis prior to starting therapy due to an increased risk of meningococcal infections; some cases warrant ongoing antimicrobial prophylaxis and vigilant infection monitoring.

Safety considerations include risk of meningococcal infection, infusion reactions, headache, and hypertension. The drug has been developed by Alexion Pharmaceuticals and is marketed as Soliris. Alexion was acquired by AstraZeneca, which continues development and distribution in many regions.