Phase 3b TOGETHER-PsO: adding tirzepatide to ixekizumab shifted more immune and metabolic biomarkers in psoriasis with obesity

Eli Lilly and Company announced on October 9, 2026 new exploratory data from the TOGETHER-PsO Phase 3b clinical trial evaluating the concomitant use of Taltz (ixekizumab) and Zepbound (tirzepatide) compared with Taltz alone in adults with moderate-to-severe plaque psoriasis and obesity or overweight with at least one additional weight-related comorbid condition. The prespecified analysis was presented at the 2026 Fall Clinical Dermatology Conference in Las Vegas.

The analysis found that when Taltz and Zepbound were used together, changes were observed in more psoriasis disease-associated and metabolic biomarkers compared with Taltz monotherapy. By Week 36 this included 482 versus 140 differentially expressed proteins and 467 versus 16 differentially expressed genes, with broader biomarker responses visible as early as Week 12. Lilly said the data suggest an immunometabolic relationship between psoriasis and obesity; in the U.S., approximately 61% of people with psoriasis also have obesity or overweight with at least one weight-related comorbidity.

Lilly previously reported that the combination met the trial's Week 36 primary endpoint, showing superior skin clearance and clinically meaningful weight reduction compared with Taltz alone, with improvements maintained or further improved through Week 52 and safety consistent with the known profiles of both medicines.

Context and limits: this is a prespecified exploratory biomarker analysis from a company-funded trial, announced in a company news release; full conference presentation data have not been independently reviewed here, and biomarker shifts do not by themselves establish clinical benefit. This brief reports study findings dated October 9, 2026 and is not a treatment recommendation.