Arrowhead Pharmaceuticals (NASDAQ: ARWR) presented updated Phase 1/2a data on ARO-INHBE (an RNA interference therapeutic targeting Activin E) and ARO-ALK7 (RNAi targeting ALK7 receptor) at EASL 2026. Standalone data: ARO-INHBE monotherapy achieved mean visceral fat reduction of -9.9% at week 16 after a single dose and -15.6% placebo-adjusted after two doses at week 24, with a single dose increasing lean muscle tissue by 3.6%; ARO-ALK7 monotherapy achieved -14.1% placebo-adjusted visceral fat reduction at week 8 after a single dose. Combination data: ARO-INHBE plus low-dose tirzepatide (5 mg) enhanced reductions in visceral adipose tissue and liver fat content versus tirzepatide alone in participants with obesity with or without type 2 diabetes. Mean maximum Activin E reduction reached 85.3% at the 400 mg dose with persistent effect beyond 3 months. Additional 2026 readouts expected. The data extend the case for RNAi as a non-peptide, quarterly-dosed obesity add-on capable of shifting body composition rather than just body weight.
Arrowhead Pharmaceuticals presented Phase 1/2a interim clinical data on ARO-INHBE at EASL 2026 today (Rinki Murphy, MBChB, PhD presenting). ARO-INHBE is an RNAi therapeutic targeting the Activin E/ALK7 pathway — a genetically validated regulator of adipose fat storage. The data: a single 400 mg dose produced 85.3% mean maximum Activin E reduction with persistent effect beyond 3 months; ≥200 mg doses reduced liver fat 44%. In combination with low-dose tirzepatide 5 mg in obese patients with type 2 diabetes, ARO-INHBE doubled weight loss and tripled reductions in visceral fat, total fat, and liver fat versus tirzepatide alone. Effect persists through Week 24 supporting potential twice-yearly dosing. Arrowhead is engaging with regulatory authorities on Phase 2 designs in MASH and obesity. The combination data is the strongest evidence to date that adding a non-GLP-1 mechanism to incretin therapy can meaningfully amplify body-composition outcomes — a contrast to the GLP-1-alone monotherapy story that has dominated obesity-pharmacology since 2021.
EASL 2026 Day 1 in Barcelona delivered the most concentrated MASH-therapeutics data cycle of 2026. The peptide-mechanism cohort: Altimmune pemvidutide qFibrosis fibrosis regression (LBP-036), MetaVia DA-1726 48 mg Phase 1 noninvasive liver assessment, Novo Nordisk ESSENCE Japanese/menopausal subgroups. The non-peptide-mechanism cohort: Arrowhead ARO-INHBE RNAi (Activin E/ALK7 pathway), Galectin Therapeutics belapectin NAVIGATE (galectin-3 inhibitor), Sagimet Biosciences denifanstat + resmetirom combination (FASN inhibitor + Madrigal's Rezdiffra), Madrigal eight-poster Rezdiffra data drop on cardiovascular and portal hypertension markers. The combined cycle reframes MASH as a multi-mechanism battleground rather than a single-class indication — GLP-1/glucagon peptides compete against thyroid-hormone-receptor agonism, RNAi, galectin-3 inhibition, FASN inhibition, and emerging combinations. Thursday May 28 brings the Altimmune pemvidutide oral presentation at 17:00 CEST; Friday May 29 brings ASCO opening in Chicago to anchor the parallel peptide-oncology cycle.