On January 6, 2026, Arrowhead Pharmaceuticals, Inc. (ARWR) announced preliminary results for the company's two obesity programs: ARO-INHBE and ARO-ALK7. In combination with tirzepatide, ARO-INHBE doubled weight loss and tripled reductions in visceral fat, total fat, and liver fat compared to tirzepatide alone. ARO-INHBE was well tolerated both as a monotherapy and in combination with tirzepatide. Most treatment emergent adverse events (TEAEs) were mild in severity and there were no discontinuations from the study or study drug due to TEAEs. A single dose of ARO-ALK7 resulted in rapid dose dependent reductions in mean visceral fat with a -14.1% reduction, adjusted for placebo, at Week 8. The company is planning to expand the Phase 1/2a trials for both compounds as well as launch Phase 2b studies in 2026.
