CLG561

CLG561 is a fully human antibody Fab fragment that acts as a properdin inhibitor. Properdin is a positive regulator of the alternative pathway of the complement system; by neutralizing properdin, CLG561 inhibits both early (C3a and C3b/iC3b) and late (C5a and C5b, membrane attack complex) activation products in the complement cascade[1][3]. The drug was developed for intravitreal injection to treat eye disorders such as geographic atrophy secondary to dry age-related macular degeneration (AMD). It was investigated as monotherapy and in combination with LFG316 (tesidolumab), another complement inhibitor. Development reached Phase 2 clinical trials but was discontinued after failing to show efficacy in reducing lesion growth in geographic atrophy[4][8]. The original developer was Alcon; later development involved MorphoSys and Novartis following corporate changes.