Lilly's Zepbound–Taltz combo wins again in obesity, psoriasis study

Eli Lilly is positioning its popular obesity drug Zepbound for a potential push into the immunology space. Phase 3 findings show that combining Lilly's GLP-1 dual agonist with Lilly's autoimmune drug Taltz produced positive outcomes in patients with psoriasis who also have obesity or overweight.

Results from the late-stage trial, dubbed Together-PsO, indicate that Zepbound taken with Taltz, an IL-17A antagonist, delivered significantly stronger patient outcomes than Taltz alone.

The Taltz–Zepbound combo hit its primary endpoint and all key secondaries in the 274-patient psoriasis trial, the company said. Notably, 27% of participants saw their skin completely clear up and lost at least 10% of their body weight by week 36, compared to the 6% of patients who reached those benchmarks on Taltz alone.

According to a key secondary endpoint, patients taking Lilly's two drugs were also 40% more likely to experience full skin clearance (PASI 100) than those who only took Taltz.

"For people living at the intersection of these chronic inflammatory diseases, these PASI 100 results represent far more than a clinical milestone -- they demonstrated what becomes possible when we address both simultaneously,” Adrienne Brown, Lilly’s immunology chief, said in the press release.

Around 6 out of 10 people in the United States with psoriasis struggle with obesity or excess weight along with at least one weight-related comorbidity, underlining the need for therapies that tackle the full scope of disease burden, the company said.

The Together-PsO study included patients with a particularly high disease burden, which is a population often linked to less favorable treatment outcomes. Research shows that people with a higher body mass index (BMI) are less likely to achieve complete skin clearance (PASI 100).

Patients in the trial had an average BMI of more than 39 across both treatment groups, Lilly said.

"This study involved patients with particularly high BMI and difficult-to-treat psoriasis, making the PASI 100 results with Taltz plus Zepbound especially remarkable," Mark Lebwohl, M.D., Dean for Clinical Therapeutics, and Professor and Chairman Emeritus of the Department of Dermatology at the Icahn School of Medicine at Mount Sinai, and the study's principal investigator, added.

"The findings show that treating psoriasis and obesity or overweight at the same time significantly improved outcomes, reinforcing psoriasis as an obesity-related condition and supporting a potential comprehensive approach to care."

The full details from the 36-week study will be submitted for publication in a peer-reviewed journal and shared with regulators, the company said in its release. However, no timeline was provided.

While a potential label expansion would hinge upon regulatory review, these phase 3 results build on the findings from another late-stage study announced last month that involved patients with psoriatic arthritis.

In that trial, 32% of patients who took Zepbound–Taltz achieved a 50% improvement in disease activity while also losing at least 10% of their body weight. Comparatively, just 1% of patients taking Taltz alone met both benchmarks.

These first-of-its-kind study results could pave the way for broader treatment strategies that address both chronic inflammatory and metabolic conditions.

Alivia Kaylor is a scientist and the senior site editor of Pharma Life Sciences.