TOGETHER-PsO: Combination Therapy Links Obesity Treatment to Psoriasis Clearance
Key Takeaways
Results from the TOGETHER-PsO trial indicate ixekizumab (Taltz) plus tirzepatide (Zepbound) was superior to ixekizumab alone for achieving PASI 100 and ≥10% weight loss at 36 weeks in adults with moderate-to-severe plaque psoriasis.
The combination therapy was associated with a 40% relative increase in PASI 100 rates compared to monotherapy.
The study population had a high disease burden, with a mean BMI >39 kg/m² and extensive skin involvement, reflecting a population often associated with reduced biologic response.
New data show that a combination therapy of ixekizumab (Taltz) plus tirzepatide (Zepbound) was superior to ixekizumab alone for achieving PASI 100 and ≥10% weight loss at 36 weeks in adults with moderate-to-severe plaque psoriasis.
The phase 3b TOGETHER-PsO trial evaluated concomitant ixekizumab (Taltz) and tirzepatide (Zepbound) in adults with moderate-to-severe plaque psoriasis and obesity or overweight with at least one weight-related comorbidity, according to a press release from the manufacturer (Lilly). At 36 weeks, the study met its primary endpoint, showing superiority of the combination therapy vs. ixekizumab monotherapy for achieving complete skin clearance (PASI 100) and at least 10% weight loss. Overall, 27.1% of patients receiving ixekizumab plus tirzepatide achieved both PASI 100 and ≥10% weight loss compared with 5.8% of those receiving ixekizumab alone (P < 0.001).
For one key secondary endpoint, 40.6% of patients treated with the combination achieved PASI 100 vs. 29.0% with monotherapy (a 40% relative increase [P < 0.05]). The enrolled population had a mean body mass index (BMI) greater than 39 kg/m² across study arms, which investigators noted was higher than populations studied in prior phase 3 psoriasis biologic trials. Approximately 25% body surface area involvement was reported at baseline, and 97% of participants had psoriasis affecting high-impact areas such as the scalp, face, or genitals.
Adverse events with concomitant therapy were generally mild to moderate and consistent with the known safety profiles of each agent.
"This study involved patients with particularly high BMI and difficult-to-treat psoriasis, making the PASI 100 results with Taltz plus Zepbound especially remarkable," said Mark Lebwohl, MD, Dean for Clinical Therapeutics, and Professor and Chairman Emeritus of the Department of Dermatology at the Icahn School of Medicine at Mount Sinai, and TOGETHER-PsO principal investigator, in the press release. "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."
Source: Lilly press release. February 18, 2026.