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Lilly: 43.7 percent reached ACR50 at week 52 on Taltz plus Zepbound vs 15.7 percent on Taltz alone

Eli Lilly and Company said 43.7 percent of adults with psoriatic arthritis and obesity or overweight reached ACR50 at 52 weeks on Taltz and Zepbound together, against 15.7 percent on Taltz alone. The company gave the figures at ACR Convergence 2026 for the TOGETHER-PsA trial.

By The Priority Review desk

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Eli Lilly and Company said that at 52 weeks, 43.7 percent of adults with psoriatic arthritis (PsA) and obesity or overweight who took Taltz (ixekizumab) and Zepbound (tirzepatide) together reached ACR50, against 15.7 percent who took Taltz alone, according to its release. The figures come from the TOGETHER-PsA trial, and the company said they were presented as an oral presentation at ACR Convergence 2026 and published in Arthritis & Rheumatology on November 11, 2026. The 52-week comparison of the two arms comes from a trial that the registry lists as completed.

ACR50 by arm and timepoint Taltz alone against Taltz plus Zepbound, week 36 and week 52 0% 10% 20% 30% 40% 50% Percent of participants reaching ACR50 Taltz alone week 36 20.4% Taltz plus Zepbound week 36 33.5% Taltz alone week 52 15.7% Taltz plus Zepbound week 52 43.7% 271 participants were randomized 1:1 to Taltz alone or Taltz given concomitantly with Zepbound. The week 52 analyses are pre-specified, exploratory objectives without multiplicity control. From Lilly's release of November 11, 2026, and the trial registry record NCT06588296. The Priority Review.
ACR50 by arm and timepoint Taltz alone against Taltz plus Zepbound, week 36 and week 52 0% 10% 20% 30% 40% 50% Percent of participants reaching ACR50 Taltz alone week 36 20.4% Taltz plus Zepbound week 36 33.5% Taltz alone week 52 15.7% Taltz plus Zepbound week 52 43.7% 271 participants were randomized 1:1 to Taltz alone or Taltz given concomitantly with Zepbound. The week 52 analyses are pre-specified, exploratory objectives without multiplicity control. From Lilly's release of November 11, 2026, and the trial registry record NCT06588296. The Priority Review.

Why it matters

The registry record lists Eli Lilly and Company as the sponsor of a randomized, open-label Phase 3 study of ixekizumab given alone or together with tirzepatide in adults with active psoriatic arthritis and obesity or overweight. Lilly said Taltz is approved for adults with active psoriatic arthritis, and that Zepbound is indicated for adults with obesity, or some adults who are overweight and also have at least one weight-related medical problem. In the release, the company said that about 65% of people with PsA in the U.S. also have obesity or overweight with at least one weight-related comorbidity, and that patients in TOGETHER-PsA had a mean BMI of 37.6 at baseline.

Results at 36 and 52 weeks

Lilly said Taltz and Zepbound met the primary outcome and all key secondary outcomes for superiority to Taltz alone at 36 weeks. The company's release lists these percentages, Taltz alone against Taltz plus Zepbound:

  • ACR50 plus at least 10% weight reduction (primary outcome): 0.8 percent against 31.7 percent at week 36, and 1.7 percent against 39.2 percent at week 52.
  • ACR50: 20.4 percent against 33.5 percent at week 36, and 15.7 percent against 43.7 percent at week 52.
  • At least 10% weight reduction: 4.5 percent against 84.5 percent at week 36, and 6.7 percent against 85.7 percent at week 52.
  • Minimal Disease Activity: 15.3 percent against 26.3 percent at week 36, and 13.6 percent against 28.2 percent at week 52.

The release also lists changes from baseline at week 52, Taltz alone against Taltz plus Zepbound: DAPSA change -20.3 against -32.2, hsCRP change -0.4 mg/L against -2.2, HAQ-DI change -0.3 against -0.6, FACIT-Fatigue change 4.8 against 9.7, and SF-36 mental component score change 0.2 against 3.4. Lilly said a greater share of patients reached ACR50 on the combination as early as Week 4, before clinically meaningful weight loss was observed. The company also said the combination was associated with improvements in BMI, body weight, systolic blood pressure, glucose, HbA1c, triglycerides and total cholesterol compared with Taltz alone.

Trial design

Lilly describes TOGETHER-PsA (NCT06588296) as a 52-week Phase 3b, randomized, multicenter, assessor-blinded, open-label study. The company said 271 participants were randomized 1:1 to Taltz alone or Taltz given concomitantly with Zepbound, both by subcutaneous injection, and that both arms received counseling on a reduced-calorie diet and increased physical activity. The registry record lists enrollment of 279 participants (actual) and lists the study as completed, with study start on September 24, 2024 and primary completion on November 18, 2025.

The company said eligible participants had active PsA and a BMI of at least 30 kg/m², or at least 27 to less than 30 kg/m², with at least one additional weight-related comorbid condition.

Safety

Lilly said adverse events in participants who took the two medicines together were generally mild to moderate, and consistent with the known safety profile of each medicine. The company listed the most common adverse events, in at least 5% of participants, in the combination arm as nausea, diarrhea, constipation, injection site reactions, vomiting, urinary tract infections, sinusitis, dizziness and headache. In the Taltz arm they were injection site reactions, upper respiratory tract infections, arthralgia and diarrhea.

What remains uncertain

Lilly's release states that the week 52 analyses are pre-specified, exploratory objectives without multiplicity control, and that comparisons between timepoints are descriptive and not tested or controlled for multiplicity (Lilly release).

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