New Phase 3b findings on Lilly’s Taltz paired with Zepbound show durable, strengthened results at one year in adults living with psoriatic disease and obesity

By week 52, patients on Taltz and Zepbound held onto or built further on the gains in psoriasis or psoriatic arthritis activity seen at week 36, the point at which the TOGETHER PsO and TOGETHER PsA trials first showed statistically superior results compared with Taltz alone.

Markers of systemic inflammation and metabolic health kept improving or held steady at the one year mark for patients on Taltz plus Zepbound relative to those on Taltz alone, based on pre-specified, exploratory endpoints.

Findings from these first of their kind studies add to the growing body of knowledge around immunometabolic health.

Eli Lilly and Company announced 52 week results from TOGETHER PsO and TOGETHER PsA, two novel open label Phase 3b trials that evaluated the combined use of Taltz (ixekizumab) and Zepbound (tirzepatide) against Taltz alone in adults with either moderate to severe plaque psoriasis or active psoriatic arthritis who also had obesity or were overweight with at least one additional weight related health condition. At the week 36 primary endpoint reported previously, the Taltz and Zepbound combination produced statistically superior improvements in both disease activity and metabolic measures compared with Taltz alone across both trials. The newly released data show these gains held steady or continued to improve through week 52, with no new safety issues identified.

Mark Genovese, M.D., senior vice president of Lilly Immunology development, said the initial results from these unprecedented studies were already striking, demonstrating that combining Taltz and Zepbound improved outcomes for patients dealing with both psoriatic disease and obesity. He said what makes the latest findings especially notable is seeing those improvements deepen further or hold steady across a full year, spanning disease activity, inflammation, and metabolic health. He noted that people carrying the combined burden of psoriatic disease and obesity are frequently managed through separate, uncoordinated treatment approaches, and said this durable, multi-measure evidence supports a more integrated strategy that could address immunometabolic health for patients living with these chronic conditions.

Psoriasis and psoriatic arthritis are immune mediated conditions frequently associated with metabolic dysfunction, including obesity. In the United States, roughly 61 percent of people with psoriasis and 65 percent of people with psoriatic arthritis also have obesity or are overweight with at least one weight related comorbidity, a combination often linked to weaker treatment outcomes. Participants entered the trials with an average body mass index of 39.2 in TOGETHER PsO and 37.6 in TOGETHER PsA.

Joseph F. Merola, M.D., MMSc, a dermatologist and rheumatologist who serves as president of the Psoriasis and Psoriatic Arthritis Clinics Multicenter Advancement Network, co-president of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis, and president of the Rheumatology-Dermatology Society, said psoriatic disease is frequently accompanied by obesity or being overweight, which can make it harder to reach treatment goals for both skin and joints. He said that in psoriatic arthritis, the stronger improvements in disease activity seen with Taltz and Zepbound within the first month, before any clinically meaningful weight loss had occurred, persisted through the full year. He said that in psoriasis, sustaining complete skin clearance at one year reflects real, lasting benefit for patients, and that combined with ongoing metabolic gains, the findings illustrate what becomes possible when psoriatic disease and obesity are treated together.

At week 52, the following results were observed (note: week 52 analyses reflect pre-specified, exploratory objectives without multiplicity control, and comparisons between timepoints are descriptive rather than statistically tested):

Primary outcome: The primary multi-component outcome continued improving through week 52 in both trials. In TOGETHER PsO, the primary outcome combined a PASI 100 response with at least 10 percent weight loss, reached by 30.6 percent of patients on Taltz plus Zepbound at week 52 compared with 4.4 percent on Taltz alone. In TOGETHER PsA, the primary outcome combined at least a 50 percent reduction in disease activity per ACR50 criteria with at least 10 percent weight loss, achieved by 39.2 percent of patients on the combination at week 52 versus 1.7 percent on monotherapy.

PsO disease activity, key secondary outcome: In TOGETHER PsO, the share of patients on Taltz and Zepbound reaching complete skin clearance, the highest possible bar via PASI 100, held steady at 40.5 percent at week 52, compared with 29.1 percent for Taltz alone.

PsA disease activity, key secondary outcome: In TOGETHER PsA, the proportion of patients achieving ACR50 with the combination therapy climbed further to 43.7 percent at week 52, compared with 15.7 percent for Taltz monotherapy, building on ACR50 gains that had already appeared by week 4, well before clinically meaningful weight loss occurred.

Systemic inflammation: Patients on Taltz and Zepbound also showed deepening improvements in systemic inflammation over time in both trials, as measured through high sensitivity C-reactive protein.

Metabolic outcomes: Gains in body mass index, blood pressure, glucose, HbA1c, triglycerides, and total cholesterol among patients on the combination versus Taltz alone were either sustained or continued to improve.

Adverse events among participants receiving Taltz and Zepbound together were generally mild to moderate in severity, and the nature of these events aligned with the established safety profile of each medicine individually. Within the combination treatment group across both trials, adverse events reported by 5 percent or more of participants included nausea, diarrhea, constipation, injection site reactions, vomiting, dizziness, and headache.

Taltz is a monoclonal antibody that selectively binds to the interleukin 17A cytokine, blocking its interaction with the IL-17 receptor. It stands as the only biologic with data supporting a potentially comprehensive treatment strategy alongside an incretin therapy for people with psoriasis or psoriatic arthritis who also live with obesity or being overweight. Zepbound remains the only FDA approved medication that acts as a dual GIP and GLP-1 receptor agonist for weight management.

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Related Topics and Keywords

Lilly's Taltz, Lilly's Taltz (ixekizumab), obesity, psoriatic disease, Zepbound® (tirzepatide), Zepbound™