eculizumabi

Ecullizumabi, commonly written as eculizumab, is a humanized monoclonal antibody that binds to complement component 5 (C5). By inhibiting the cleavage of C5 to C5a and C5b, it prevents formation of the membrane attack complex and blocks terminal complement–mediated cell lysis. This mechanism makes it effective in diseases driven by uncontrolled complement activation.

Indications and use vary by country, but eculizumab is approved for conditions such as paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS). In some regions it has also received approvals for generalized myasthenia gravis and for neuromyelitis optica spectrum disorder. Dosing consists of an induction (loading) phase followed by maintenance dosing, with regimens tailored to the indication. Treatments are delivered by intravenous infusion, typically on a biweekly schedule after the initial loading doses.

Development and brand history: eculizumab was developed by Alexion Pharmaceuticals and marketed under the brand name Soliris. Alexion was acquired by AstraZeneca in 2021, continuing the distribution and expansion of the therapy in various regions.

Safety and monitoring: a principal safety concern is the increased risk of meningococcal infections due to inhibition of terminal complement. Patients should be vaccinated against meningococcus at least two weeks before starting therapy, if feasible; if urgent treatment is needed, vaccination should be given with appropriate antibiotic prophylaxis. Other infections and immune-related effects can occur, and monitoring for adverse events is advised. The therapy is expensive and access considerations are often discussed in clinical and policy contexts.