Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) presented interim clinical trial results for ARO-INHBE, an investigational RNA interference therapeutic for obesity and metabolic dysfunction-associated steatohepatitis, at the European Association for the Study of the Liver Congress.

The Phase 1/2a study showed that participants with obesity and baseline liver fat content greater than 8% who received 200mg or higher doses of ARO-INHBE monotherapy experienced a placebo-adjusted liver fat content reduction of 44%. The study included 10 participants with baseline liver fat content of 14.5±5.1%.

ARO-INHBE combined with low-dose tirzepatide (5 mg) resulted in enhanced reductions in visceral adipose tissue and liver fat content compared to tirzepatide alone in participants with obesity with or without Type 2 diabetes. Longer exposure to ARO-INHBE showed continued improvements in visceral fat and liver fat from week 12 to week 24.

The drug targets Activin E through RNA interference to reduce hepatic expression of the INHBE gene. A single administration of ARO-INHBE 400 mg achieved a mean maximum reduction of 85.3% in Activin E levels, with effects persisting beyond three months.

The company reported that ARO-INHBE has been generally well tolerated as monotherapy and in combination with tirzepatide. Most treatment-related adverse events were mild, with no events leading to study discontinuation. Injection site reactions were mild and self-limited.

The AROINHBE-1001 study is evaluating the safety, tolerability, and effectiveness of ARO-INHBE in up to 78 adult volunteers with obesity. Part 1 assesses single and multiple doses of ARO-INHBE monotherapy, while Part 2 evaluates the drug in combination with tirzepatide.

Arrowhead stated it is engaging with regulatory authorities on additional designs and endpoints for potential Phase 2 studies in MASH and obesity, according to the company's press release.