Taltz and Zepbound combination maintains improved psoriatic arthritis outcomes at one year

Eli Lilly has reported detailed 52-week results from the Phase IIIb TOGETHER-PsA study showing sustained improvements in disease activity, patient-reported outcomes and metabolic measures with Taltz and Zepbound used together in adults with psoriatic arthritis and obesity or overweight.

The open-label study compared concomitant treatment with Taltz, also known as ixekizumab, and Zepbound, or tirzepatide, against Taltz alone.

At one year, 43.7% of patients receiving the combination achieved ACR50, representing at least a 50% improvement in psoriatic arthritis disease activity.

This compared with 15.7% of patients receiving Taltz alone.

The proportion achieving ACR50 with the combination was almost three times higher than with Taltz monotherapy at Week 52.

Lilly said a greater proportion of patients in the combination group achieved ACR50 as early as Week 4, before clinically meaningful weight loss had occurred.

The combination also continued to produce substantial weight reduction.

At Week 52, 85.7% of patients receiving Taltz and Zepbound achieved at least a 10% reduction in body weight compared with 6.7% of patients receiving Taltz alone.

The combined primary outcome of ACR50 together with at least 10% weight reduction was achieved by 39.2% of patients in the combination group at one year compared with 1.7% in the Taltz-only group.

Patients receiving both treatments also showed improvements across additional disease activity measures.

Minimal Disease Activity was achieved by 28.2% of patients in the combination group compared with 13.6% with Taltz alone.

The Disease Activity Index for Psoriatic Arthritis decreased by 32.2 points from baseline with the combination compared with a 20.3-point reduction with Taltz.

High-sensitivity C-reactive protein levels also declined more with combined treatment, with a 2.2 mg/L reduction from baseline compared with 0.4 mg/L with Taltz alone.

Patient-reported outcomes were maintained or further improved between Weeks 36 and 52.

Physical function, measured using the Health Assessment Questionnaire-Disability Index, improved by 0.6 points with Taltz and Zepbound compared with 0.3 points with Taltz alone.

Fatigue scores improved by 9.7 points with combined treatment compared with 4.8 points with Taltz monotherapy.

The combination also produced improvements in metabolic measures including body mass index, body weight, systolic blood pressure, glucose, HbA1c, triglycerides and total cholesterol.

Lilly had previously reported that the study met its primary and key secondary endpoints at Week 36, demonstrating statistically significant superiority for Taltz plus Zepbound over Taltz alone.

The Week 52 analyses were prespecified exploratory objectives and were not controlled for multiplicity, meaning comparisons at this timepoint should be interpreted as supportive rather than confirmatory.

Mark Genovese, MD, Senior Vice President of Lilly Immunology Development, said the results demonstrate durable improvements across disease control, physical function, fatigue and metabolic outcomes when psoriatic arthritis and obesity are treated together.

Adverse events with the combination were generally mild to moderate and were consistent with the known safety profiles of the individual medicines.

The most common adverse events in the combination group included nausea, diarrhoea, constipation, injection-site reactions, vomiting, urinary tract infections, sinusitis, dizziness and headache.

The findings were presented at ACR Convergence 2026 and simultaneously published in Arthritis & Rheumatology.

---

---

Related Topics and Keywords

ACR Convergence 2026, ACR50, Biopharma, clinical trials, DAPSA, Eli Lilly, immunometabolic health, ixekizumab, metabolic health, Minimal Disease Activity, obesity, overweight, patient-reported outcomes, pharma news, Phase IIIb, psoriatic arthritis, rheumatology, Taltz, tirzepatide, TOGETHER-PsA, weight loss, Zepbound™