Arrowhead Pharmaceuticals, Inc. (NASDAQ:ARWR) today announced that it has filed for regulatory clearance to initiate a Phase 1/2a clinical trial of ARO-INHBE, the company's investigational RNA interference (RNAi) therapeutic being developed as a potential treatment for obesity. Arrowhead also plans to file for regulatory clearance before the end of 2024 to initiate a clinical trial for its second obesity candidate, ARO-ALK7.

"Arrowhead's two investigational RNAi therapies for the treatment of obesity, ARO-INHBE and ARO-ALK7, are both designed to intervene in the same pathway that signals the body to store fat in adipose tissue. We have generated very promising preclinical data that suggests inhibition of these targets reduces body mass and fat mass but spares lean muscle mass resulting in improved body composition," said James Hamilton, M.D., Chief of Discovery and Translational Medicine at Arrowhead. "We have designed the initial Phase 1/2 study to evaluate single and multiple doses of ARO-INHBE monotherapy in Part 1 which will enroll patients with obesity, and to evaluate multiple doses of ARO-INHBE in combination with tirzepatide in Part 2 which will enroll diabetic and non-diabetic patients with obesity. We believe new therapeutic strategies with novel mechanisms of action, like ARO-INHBE and ARO-ALK7, have the potential to make a significant impact on the way obesity is treated and we are eager to initiate clinical studies of these important new programs."

ARO-INHBE is designed to reduce the hepatic expression of the INHBE gene and its secreted gene product, Activin E. INHBE is a promising genetically validated target in which loss-of-function INHBE variants in humans are associated with lower risk of obesity and metabolic diseases, such as type 2 diabetes. Activin E acts as a ligand in a pathway that regulates energy homeostasis in adipose tissue. Intervening in this pathway with investigational ARO-INHBE treatment has the potential to increase lipolysis, and reduce adipose hypertrophy and dysfunction, visceral adiposity, and insulin resistance.

An application for approval to initiate the clinical trial was submitted to the New Zealand Medicines and Medical Devices Safety Authority for review by the Standing Committee on Therapeutic Trials. Pending clearance, Arrowhead intends to proceed with AROINHBE-1001, A Phase 1/2a dose-escalating study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of ARO-INHBE in up to 78 adult volunteers with obesity. Part 1 of the study is designed to assess single and multiple doses of ARO-INHBE monotherapy, and Part 2 of the study is designed to assess ARO-INHBE in combination with tirzepatide, a subcutaneously administered GLP-1/GIP receptor co-agonist that has been approved in the United States and the European Union for management type 2 diabetes mellitus since 2022 and weight management since 2023/2024 respectively.