Eli Lilly Study Finds Zepbound Dual Treatment Improves Arthritis, Helps Patients Lose Weight

On Thursday, Eli Lilly and Co. (NYSE:LLY) revealed topline results from the novel TOGETHER-PsA open-label Phase 3b trial evaluating the concomitant use of Taltz (ixekizumab) and Zepbound (tirzepatide) compared to Taltz alone for active psoriatic arthritis (PsA) and obesity or overweight with at least one weight-related condition. Psoriatic arthritis is linked to psoriasis (a condition that affects skin and nails). It causes joint pain, stiffness, and a skin rash. At 36 weeks, treatment with concomitant Taltz and Zepbound met the primary and all key secondary endpoints for superiority to Taltz monotherapy. The company on Thursday said that TOGETHER-PsA is the first controlled study to evaluate an incretin therapy used with a PsA biologic. Study Data In the study, 31.7% of patients in the Taltz plus Zepbound treatment arm achieved a 50% improvement in PsA activity and a weight reduction of at least 10%, compared to 0.8% of patients on Taltz monotherapy, meeting the primary endpoint. In a key secondary endpoint, Taltz plus Zepbound delivered a 64% relative increase over Taltz monotherapy in the proportion of patients who achieved ACR50 (33.5% of patients vs. 20.4%, respectively), demonstrating that treatment of obesity or overweight with Zepbound reduced the burden of PsA. ACR50 means that a patient has at least a 50% reduction in tender/swollen joints and other core symptoms. Adverse events in participants treated with concomitant administration of Taltz and Zepbound were generally mild to moderate, and the types of adverse events were consistent with the known safety profile of each medicine. The most common adverse events were nausea, diarrhea, constipation, and injection site reactions in the concomitant treatment arm, and injection site reactions and upper respiratory tract infections in the Taltz monotherapy arm. Taltz is a monoclonal antibody that selectively binds with interleukin 17A (IL-17A) cytokine and inhibits its interaction with the IL-17 receptor. Zepbound is the only FDA-approved dual GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist obesity management medication. Topline results from the ongoing TOGETHER-PsO trial of concomitant Taltz and Zepbound compared to Taltz monotherapy in moderate-to-severe plaque psoriasis and obesity or overweight are also expected in the first half of 2026. LLY Price Action: Eli Lilly and Co shares were up 0.72% at $1093.00 during premarket trading on Friday. The stock is approaching its 52-week high of $1133.95, according to Benzinga Pro data. Photo via Shutterstock