Arrowhead Pharmaceuticals, Inc. announced topline results from Part 2 of a Phase 1/2 clinical study of ARO-C3, the company's investigational RNA interference (RNAi) therapeutic designed to reduce liver production of complement component 3 (C3) as a potential therapy for various complement mediated diseases. Select Phase 1/2 Study Results: Patients with IgA nephropathy (IgAN) (n=14) received subcutaneous doses of ARO-C3 (400 mg) on Days 1, 29, and 113 and were followed through Day 169; Pharmacodynamic effects; Maximum mean reduction in C3 of 89% and mean sustained reduction of greater than 87% from baseline through week 24; Maximum mean reduction in serum AH50 (alternative pathway hemolytic assay) of 85% and mean sustained reduction greater than 76% from baseline through week 24. Maximum mean reduction in Wieslab AP (alternative pathway) of 100% and mean sustained reduction greater from baseline through week 24; Duration of effect supportive of once every three month or less frequent subcutaneous dosing in later stage studies; Effects on proteinuria; Mean reduction in spot UPCR of 41% and maximum individual reduction of 89% from baseline by week 24; Safety and Tolerability; ARO-C3 was generally well-tolerated in patients with IgAN; No serious or severe treatment emergent adverse events (TEAE) and no TEAEs that led to study or study drug discontinuation; The only TEAEs reported in more than 1 subject were headache, cough, and nasopharyngitis; No infections with encapsulated organisms.