New York, Jan 6, 2026, 11:34 AM EST — Regular session
- Arrowhead shares jump after interim data on two obesity candidates
- Company flags bigger weight loss and deeper fat cuts when paired with Lilly’s tirzepatide
- Focus turns to durability, safety and the next clinical updates
Arrowhead Pharmaceuticals shares rose about 16% on Tuesday after early clinical data showed its experimental gene-silencing obesity drug boosted weight loss when used alongside Eli Lilly’s tirzepatide, sold as Zepbound. The stock was up 16% at $74.13 in midday trading, after swinging between $62.17 and $76.32. 1
The update lands amid a scramble for new obesity treatments that can add to GLP-1 drugs — a fast-growing market where investors now weigh not just pounds lost, but what kind of weight comes off. Many patients and doctors want therapies that tilt results toward fat loss while limiting side effects and loss of lean tissue.
Pasadena, California-based Arrowhead said ARO-INHBE plus tirzepatide drove 9.4% weight loss at week 16 in obese patients with type 2 diabetes, versus 4.8% for tirzepatide alone, with MRI scans showing larger reductions in visceral fat and liver fat. Visceral fat is deep belly fat wrapped around organs and is linked to metabolic disease; outside expert Carel le Roux said the interim results showed “dramatic and rapid reductions in visceral fat.” Arrowhead also reported early signs for a second obesity candidate, ARO-ALK7, and said it is holding a virtual webinar at 11:30 a.m. EST on Tuesday to discuss the data. 2
H.C. Wainwright said the early readout offered “a significant validation” of Arrowhead’s TRiM RNA interference platform and reiterated its buy rating on the shares. 3
The obesity update follows another Arrowhead catalyst this week: Health Canada issued a Notice of Compliance for REDEMPLO (plozasiran) to reduce triglycerides in adults with familial chylomicronemia syndrome, a rare condition tied to a high risk of pancreatitis. CEO Christopher Anzalone said the company was “thrilled to start the new year” with the approval, noting the drug can be self-injected at home once every three months. 4
But the obesity results are interim and drawn from small early-stage cohorts, and investors will want to see whether the effects hold up in larger studies with longer follow-up. The add-on approach also raises practical questions — including how payers will view combination use on top of already-expensive GLP-1 therapy and how regulators set the bar for approval. 5
For traders, the next test is whether Arrowhead can keep the gains as investors dig into the safety profile and how durable the fat-loss effect looks over time. Any clarity on dosing cadence and how the drugs perform without a GLP-1 partner will shape expectations.
