Lilly reports Phase 3b TOGETHER-PsA results showing Taltz plus Zepbound significantly outperforms Taltz alone, achieving superior disease control and weight reduction in psoriatic arthritis patients with obesity.
Written By: Nikita Jha, BPharm
Reviewed By: Pharmacally Editorial Team
Eli Lilly and Company reported detailed results from the Phase 3b TOGETHER-PsA trial showing that the combination of Taltz (ixekizumab) and Zepbound (tirzepatide) significantly outperformed Taltz alone in adults with active psoriatic arthritis (PsA) and obesity or overweight. The findings were presented at the American Academy of Dermatology (AAD) Annual Meeting 2026 and published in Arthritis & Rheumatology.
At Week 36, the study met its primary endpoint, with 31.7% of patients receiving Taltz plus Zepbound achieving both ACR50 response and at least 10% weight reduction, compared to 0.8% with Taltz alone, demonstrating clear superiority of the combination approach. Improvements in joint symptoms were observed as early as Week 4 in the combination arm, even before clinically meaningful weight loss was seen.
Beyond the primary outcome, the combination therapy showed consistent, broad benefits across psoriatic arthritis disease activity and patient-reported outcomes. Patients receiving Taltz and Zepbound experienced greater improvements in disease control, physical function, fatigue, and mental health-related quality of life compared to Taltz monotherapy.
The combination was also associated with meaningful reductions in systemic inflammation and improvements in cardiometabolic parameters, including body weight, blood pressure, and glycemic measures, supporting its dual impact on inflammatory and metabolic disease pathways.
Adrienne Brown, Executive Vice President and President, Lilly Immunology, said the combination led to meaningful improvements in symptoms, fatigue, and daily functioning, highlighting the potential of a comprehensive treatment approach for patients living with both conditions.
Philip Mease, M.D., Director of Rheumatology Research at Swedish Medical Center and Clinical Professor at the University of Washington, said that treating psoriatic arthritis and obesity together resulted in broad improvements in disease activity and quality of life, supporting a shift toward more integrated treatment strategies for this complex patient population.
Psoriatic arthritis and obesity frequently coexist, with a substantial proportion of patients experiencing increased disease burden and poorer clinical outcomes. The TOGETHER-PsA population reflected this challenge, enrolling patients with high baseline disease activity, impaired physical function, and an average body mass index of 37.6 kg/m². More than 60% of participants had prior exposure to advanced therapies, underscoring the unmet need in this population. These findings support an integrated treatment approach that targets both inflammatory disease and metabolic dysfunction.
Notably, this approach builds on earlier findings from the TOGETHER-PsO trial in plaque psoriasis, where the combination of Taltz and Zepbound also demonstrated significant improvements in skin clearance and weight reduction, supporting the broader applicability of this dual-target strategy across psoriatic disease.
The safety profile of the combination was consistent with the known profiles of each therapy, with adverse events generally mild to moderate. The most common events in the combination arm included gastrointestinal symptoms such as nausea, diarrhea, and constipation, along with injection site reactions, while Taltz monotherapy was primarily associated with injection site reactions and upper respiratory tract infections.
Taltz is an IL-17A inhibitor that reduces inflammation by blocking pro-inflammatory cytokine signaling, while Zepbound is a dual GIP and GLP-1 receptor agonist that promotes weight loss by reducing appetite and caloric intake. TOGETHER-PsA (NCT06588296) is a 52-week, randomized, open-label Phase 3b study evaluating this combination strategy in 271 patients.
Lilly plans to discuss these findings with regulators, with the data positioning Taltz as the first biologic supported by clinical evidence for a combined immunologic and metabolic treatment strategy in patients with psoriatic arthritis and obesity.
References
Phase 3b data presented at AAD Annual Meeting show Lilly’s Taltz (ixekizumab) plus Zepbound (tirzepatide) delivered superior efficacy for adults with psoriatic arthritis and obesity, 28 March 2026, Phase 3b data presented at AAD Annual Meeting show Lilly’s Taltz (ixekizumab) plus Zepbound (tirzepatide) delivered superior efficacy for adults with psoriatic arthritis and obesity | Eli Lilly and Company
Ixekizumab Concomitantly Administered with Tirzepatide in Adults with Psoriatic Arthritis and Obesity or Overweight (TOGETHER-PsA), ClinicalTrials.gov ID NCT06588296, https://clinicaltrials.gov/study/NCT06588296
About the Writer
Nikita Jha BPharm is a pharmacy graduate with expertise in clinical research, pharmacovigilance, and medical writing. In her words, she is passionate about translating complex scientific data into clear, accurate healthcare communications that advance drug safety and patient care.