Lilly reports Phase IIIb psoriasis trial met dual skin clearance and weight-loss endpoint
Lilly said a Phase IIIb trial of ixekizumab plus tirzepatide in psoriasis and obesity or overweight beat ixekizumab alone on complete skin clearance plus at least 10% weight loss at 36 weeks.
Eli Lilly and Company said its Phase IIIb trial evaluating concomitant treatment with ixekizumab and tirzepatide in adults with moderate-to-severe psoriasis and obesity or overweight demonstrated superior efficacy compared with ixekizumab monotherapy. At 36 weeks, patients receiving concomitant ixekizumab and tirzepatide achieved the study’s primary endpoint, demonstrating superiority over ixekizumab monotherapy in reaching both complete skin clearance (PASI 100) and at least 10% weight reduction.
A total of 27.1% of patients receiving combination therapy met this dual endpoint compared with 5.8% receiving biologic treatment alone (p<0.001). In a key secondary endpoint, combination therapy produced a 40% relative increase in PASI 100 achievement versus monotherapy (40.6% vs. 29.0%, p<0.05).
The enrolled population represented one of the highest BMI cohorts studied in psoriasis biologic trials, with mean BMI exceeding 39 kg/m², which is approximately 9–10 kg/m² higher than populations evaluated in prior Phase III registrational studies using psoriasis biologic therapies. Psoriasis and obesity frequently coexist, with approximately 61% of patients living with psoriasis also affected by overweight or obesity alongside related comorbidities. Increasing body mass index has been associated with reduced response rates to biologic therapies.
Ixekizumab selectively inhibits interleukin-17A, a cytokine central to inflammatory signaling in psoriatic disease. Tirzepatide, a dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist, reduces body weight through metabolic regulation and appetite suppression. Safety findings were consistent with established profiles for both agents, with adverse events generally mild to moderate. The most commonly reported events included gastrointestinal symptoms and injection-site reactions.
The data were announced in February 2026. Detailed Phase IIIb study results are expected to be published in a peer-reviewed journal and discussed with regulatory authorities, according to the company.