Eli Lilly’s Psoriasis and Obesity Drugs Deliver Superior Results in Clinical Trial
Eli Lilly and Company (NYSE: LLY) has reported encouraging results from its Phase 3b clinical trial evaluating a combination of Taltz and Zepbound. Notably, the study showed that pairing the psoriasis treatment with the company’s obesity medication produced stronger outcomes than Taltz alone in adults with moderate-to-severe plaque psoriasis who are also overweight or obese.
Combination Therapy Demonstrates Superior Outcomes
At 36 weeks, the TOGETHER-PsO trial met its primary endpoint. Specifically, 27.1% of participants receiving both Taltz and Zepbound achieved complete skin clearance (PASI 100) along with at least 10% weight loss. By comparison, only 5.8% of patients treated with Taltz alone reached the same benchmark.
Moreover, the combination therapy significantly improved skin clearance rates overall. In fact, the study showed a 40% relative increase in patients achieving PASI 100 compared to Taltz monotherapy (40.6% versus 29.0%). Taken together, these findings suggest that addressing both inflammation and weight simultaneously may enhance overall treatment effectiveness.
Study Population Reflects Higher Disease Burden
Importantly, the study enrolled 274 participants with an average body mass index (BMI) above 39 kg/m², which is substantially higher than patient populations included in earlier Phase 3 psoriasis biologic trials. In other words, the trial evaluated a group with more severe obesity than typically studied.
Additionally, participants had extensive psoriasis involvement. On average, about 25% of their body surface area was affected. Furthermore, nearly all patients experienced psoriasis in high-impact areas such as the face, scalp, or genitals—areas that can significantly affect quality of life.
Safety Profile Remains Consistent
Meanwhile, safety findings aligned with expectations. Lilly reported that adverse events in the combination group were generally mild to moderate and consistent with the known safety profiles of both medications.
The most common side effects included nausea, diarrhea, constipation, injection site reactions, dosing errors, vomiting, and dizziness. Overall, the tolerability profile did not reveal unexpected safety concerns.
Addressing Overlapping Conditions
Taltz works by targeting the interleukin-17A (IL-17A) cytokine and is already approved for moderate-to-severe plaque psoriasis and other inflammatory conditions. Zepbound, on the other hand, acts as a dual GIP and GLP-1 receptor agonist and is approved for obesity management.
Importantly, these two therapies address a substantial overlap in patient populations. According to Lilly, approximately 61% of people with psoriasis in the United States also have obesity or are overweight with at least one weight-related comorbidity. Therefore, combining treatments may offer a more comprehensive approach for this large group of patients.
Next Steps
Looking ahead, Eli Lilly plans to publish the detailed 36-week data in a peer-reviewed journal and engage with regulatory authorities to discuss the findings. Ultimately, the company believes these results reinforce the potential of combination therapy to improve outcomes in patients managing both psoriasis and obesity.
In summary, the TOGETHER-PsO trial highlights how integrated treatment strategies may help address complex, overlapping health conditions more effectively.
