Apellis Pharmaceuticals, Inc. is a biopharmaceutical company focused on the development of novel therapeutic compounds to treat disease through the inhibition of the complement system, which is an integral component of the immune system, at the level of C3, the central protein in the complement cascade. The company's lead product candidate is pegcetacoplan (APL-2), an investigational drug that is being developed for the treatment of several diseases, including paroxysmal nocturnal hemoglobinuria (PNH), geographic atrophy (GA), and complement-dependent nephropathies. The company was founded in 2009 and is headquartered in Waltham, Massachusetts.