Lilly’s TOGETHER-PsA Trial Shows Dual Therapy Can Improve Psoriatic Arthritis and Weight Outcomes

Lilly’s TOGETHER-PsA Trial Shows Dual Therapy Can Improve Psoriatic Arthritis and Weight Outcomes

By, Admin 9 January 2026

Eli Lilly has reported positive topline results from the Phase 3b TOGETHER-PsA trial, marking a first-of-its-kind integrated treatment approach for psoriatic arthritis (PsA).

The study evaluated Taltz (ixekizumab) used alongside Zepbound (tirzepatide) versus Taltz alone in adults with active PsA and obesity or overweight.

A First for PsA: Treating Inflammation and Obesity Together

Psoriatic arthritis and obesity often coexist.

  • Around 65% of adults with PsA in the US also have obesity or overweight with related comorbidities.
  • Despite guideline recommendations, these conditions are usually treated separately.
  • TOGETHER-PsA is the first controlled study to test an incretin therapy with a PsA biologic.

The results suggest this separation may no longer make sense.

Primary Endpoint Met at 36 Weeks

The trial met its primary endpoint with strong statistical significance.

At Week 36:

  • 31.7% of patients on Taltz + Zepbound achieved:
    - ACR50 (50% improvement in PsA activity)
    - ≥10% weight reduction
  • Only 0.8% of patients on Taltz alone achieved both outcomes
  • p < 0.001

This confirms superiority over biologic monotherapy.

Key Secondary Endpoint: Better PsA Control

The combination therapy also delivered clear disease activity benefits.

  • 33.5% of patients on Taltz + Zepbound achieved ACR50
  • 20.4% of patients on Taltz alone achieved ACR50
  • This represents a 64% relative increase
  • p < 0.05

Treating obesity meaningfully reduced the burden of PsA.

A Difficult-to-Treat Patient Population

This was not a low-risk cohort.

Key baseline characteristics:

  • Average BMI: 37.6 kg/m²
  • High PsA disease activity and functional impairment
  • Over 60% had prior exposure to advanced therapies

Despite this, combination therapy delivered superior outcomes.

Safety Profile Remained Consistent

Adverse events were generally mild to moderate. Most common events:

  • Combination arm: nausea, diarrhea, constipation, injection site reactions
  • Taltz alone: injection site reactions, upper respiratory infections

No new safety signals were identified beyond known profiles.

Why This Matters Clinically?

According to investigators, these results may redefine PsA care.

  • Obesity appears to directly influence PsA disease activity
  • Addressing metabolic drivers improves inflammatory outcomes
  • PsA may be partly an obesity-related condition for many patients

This opens the door to more holistic treatment strategies.

What Makes This Approach Different?

Taltz

  • IL-17A monoclonal antibody
  • Rapid-acting, durable PsA biologic

Zepbound

  • Dual GIP/GLP-1 receptor agonist
  • FDA-approved for obesity management
  • Addresses appetite, caloric intake, and metabolic inflammation

Together, they target both immune and metabolic pathways.

What’s Next for the TOGETHER Program?

  • Detailed 36-week data will be presented at an upcoming medical meeting
  • Results will be discussed with regulators
  • TOGETHER-PsO, studying plaque psoriasis with obesity, is ongoing
  • Topline PsO data are expected in H1 2026

The Big Picture

Taltz is now the first biologic in PsA with data supporting use alongside an incretin therapy.

The TOGETHER-PsA trial shows that:

  • Treating obesity improves arthritis outcomes
  • Integrated therapy can outperform biologic monotherapy
  • A paradigm shift in PsA management may be underway

For patients living with both PsA and obesity, this could change the standard of care.

Optimize Your trial insights with Clival Database.

Are you exhausted from the uncertainty of trial insights pricing? Clival Database ensures the clarity in the midst of the global scenario for clinical trials to you.

Clival Database is one of the best databases that offers an outstanding number of clinical trial data in terms of 50,000+ molecules and from primary regulatory markets as well as new entrants like Indian and Chinese markets.

With Clival, you get accurate positioning of historical sales data, patent database, company profiling, safety & efficacy, and prediction of launch of new innovative molecules helping you to align your research and driving down the cost.

To add value, we further break down our analytics for you so that improving your operational effectiveness; optimizing your clinical trials; and offering you accurate and high-quality data at lowest possible prices becomes possible.

Elevate your trial success rate with the cutting-edge insights from Clival database.

Check it out today and make more informed sourcing decisions! Learn More!