Indianapolis, USA | March 28, 2026
Phase 3b Study Demonstrates Superior Clinical Outcomes
Eli Lilly and Company has announced breakthrough results from its Phase 3b TOGETHER-PsA clinical trial, demonstrating that the combination of Taltz (ixekizumab) and Zepbound (tirzepatide) delivers superior efficacy compared to Taltz monotherapy in adults with psoriatic arthritis (PsA) and obesity. Presented at the 2026 American Academy of Dermatology (AAD) Annual Meeting, the study met its primary and all key secondary endpoints, showing statistically significant improvements across multiple disease parameters.
At 36 weeks, 31.7% of patients receiving the combination therapy achieved both ACR50 response and ≥10% weight reduction, compared to just 0.8% in the monotherapy arm. Notably, improvements in PsA disease activity were observed as early as Week 4, even before meaningful weight loss occurred, indicating a rapid therapeutic effect driven by the combined mechanism of action.
Comprehensive Benefits Across Disease and Metabolic Health
Beyond joint symptom relief, the combination therapy delivered broad, clinically meaningful improvements in both inflammatory and metabolic parameters, addressing the complex interplay between PsA and obesity. Patients treated with Taltz and Zepbound experienced higher rates of Minimal Disease Activity (MDA), improved fatigue scores, physical function, and mental health-related quality of life, and significant reductions in systemic inflammation markers such as hsCRP.
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Additionally, the therapy showed notable cardiometabolic benefits, including reductions in body weight, BMI, blood pressure, glucose levels, HbA1c, triglycerides, and cholesterol, highlighting its potential as a holistic treatment strategy. Given that approximately 65% of PsA patients also suffer from obesity or related comorbidities, this dual-target approach represents a major advancement in addressing multi-dimensional disease burden that traditional therapies often fail to fully manage.
Transforming Treatment Paradigms for Complex Patients
The TOGETHER-PsA trial underscores a growing shift toward integrated therapeutic strategies that simultaneously target immune-mediated inflammation and metabolic dysfunction. Taltz, an IL-17A monoclonal antibody, works by inhibiting pro-inflammatory cytokine signaling, while Zepbound, a dual GIP and GLP-1 receptor agonist, promotes weight loss and metabolic regulation. The combination was generally well tolerated, with adverse events consistent with the known safety profiles of each therapy, primarily including mild-to-moderate gastrointestinal and injection site reactions.
Experts emphasize that this approach could redefine standard-of-care for patients with PsA and obesity, offering a more personalized and effective treatment pathway. With ongoing regulatory discussions and increasing clinical validation, Lilly continues to strengthen its leadership in immunology and metabolic disease innovation, advancing therapies that deliver both clinical efficacy and improved patient quality of life.
Source: Eli Lilly press release
