Arrowhead Pharmaceuticals, Inc. is a biopharmaceutical company, which engages in the development of medicines that treat intractable diseases by silencing the genes that cause them. The firms preclinical stage drug candidates include ARO-ANG3, ARO-AAT, ARO-APOC3, ARO-HIF2, ARO-HSD, ARO-Lung2, ARO-COV, and ARO-ENaC. The company was founded by Robert Bruce Stewart in 1989 and is headquartered in Pasadena, CA.