Pozelimab: First Approval.

Pozelimab (pozelimab-bbfg; VEOPOZ™) is a fully human immunoglobulin (Ig) G4 (i.e. IgG4 with a proline substitution to promote stabilization of the disulfide bonds between the two heavy chains) monoclonal antibody developed by Regeneron Pharmaceuticals Inc., to block the activity of complement factor 5 (C5) and prevent diseases mediated by the complement pathway. In August 2023, pozelimab received its first approval for the treatment of adults, and paediatric patients aged ≥ 1 year with CD55-deficient protein-losing enteropathy (PLE), also known as CHAPLE disease, in the USA. It is the first US FDA-approved treatment for this disease. In the USA, pozelimab has been granted orphan drug designations for the treatment of paroxysmal nocturnal haemoglobinuria (PNH) [both as a monotherapy and in combination with cemdisiran] and for the treatment of myasthenia gravis (in combination with cemdisiran). Pozelimab is also undergoing clinical development in several other countries worldwide for the treatment of CD55-deficient PLE, PNH and myasthenia gravis. This article summarizes the milestones in the development of pozelimab leading to this first approval for the treatment of adults, and paediatric patients aged ≥ 1 year with CD55-deficient PLE, also known as CHAPLE disease, in the USA.