From discovery to approval: A brief history of the compstatin family of complement C3 inhibitors.

The FDA approval of pegcetacoplan (Empaveli), a PEGylated compstatin-based C3 therapeutic, as a new treatment for paroxysmal nocturnal hemoglobinuria (PNH) marks a milestone in the history of complement drug discovery. Almost 15 years after the approval of the first complement-specific drug for PNH, the anti-C5 antibody eculizumab, a novel class of complement inhibitors with a distinct mechanism of action finally enters the clinic. This landmark decision broadens the spectrum of available complement therapeutics, offering patients with unmet clinical needs or insufficient responses to anti-C5 therapy an alternative treatment option with a broad activity profile. Here we present a brief historical account of this newly approved complement drug, consolidating its approval within the long research record of the compstatin family of peptidic C3 inhibitors.