Arrowhead Pharmaceuticals said Tuesday that its gene-silencing candidates helped people with obesity lose fat, very early results that could intensify the competition among biotechs to develop longer-lasting weight loss drugs.

In an ongoing Phase 1/2 study, a cohort of patients took two doses of a candidate called ARO-INHBE, spaced one month apart, in combination with Eli Lilly’s Zepbound. They lost 9.4% of their weight after 16 weeks, while those on Zepbound alone lost 4.8%. These data were from patients with obesity and diabetes, who typically don’t lose as much weight on treatments as those who don’t have diabetes.

Shares of Arrowhead jumped 14.7% in premarket trading.