Combination Therapy Improves Outcomes in Psoriatic Arthritis With Obesity

Key Takeaways

• Combination therapy with ixekizumab and tirzepatide significantly improved joint and weight outcomes in psoriatic arthritis compared with ixekizumab alone.
• Early separation in ACR50 responses suggests potential effects beyond weight loss alone.
• Safety was consistent with known profiles of both agents, with low discontinuation rates despite expected gastrointestinal events.

Combination therapy with ixekizumab and tirzepatide demonstrated superior disease control compared with ixekizumab alone in adults with psoriatic arthritis (PsA) and overweight or obesity, according to Phase 3b TOGETHER-PsA results presented by Joseph F. Merola, MD, MMSc, at the American Academy of Dermatology (AAD) 2026 Annual Meeting.

The 52-week randomized trial enrolled 271 patients with active PsA and elevated body mass index, a population known to have more severe disease and reduced treatment response.

“This is quite a difficult-to-treat psoriatic arthritis population,” Dr. Merola said, noting high rates of obesity, female sex, and prior advanced therapy exposure. 

Participants were randomized to ixekizumab plus tirzepatide or ixekizumab alone, with all patients receiving counseling on diet and exercise. The primary endpoint—simultaneous achievement of ACR50 and ≥10% weight reduction at Week 36—was met by 31.7% of patients receiving combination therapy versus 0.8% with ixekizumab alone (P < .001).

Combination therapy also improved joint outcomes. ACR50 responses were achieved in 33.5% of patients receiving ixekizumab plus tirzepatide compared with 20.4% receiving ixekizumab alone (P = .020), with separation observed as early as Week 4.

“As early as Week 4, we see separation and difference between the groups and ACR50, and that is really before there has been any meaningful weight change,” Dr. Merola noted, suggesting potential additive or independent anti-inflammatory effects. 

Additional benefits were observed across patient-reported outcomes, including physical function (HAQ-DI), fatigue (FACIT-F), and quality of life (SF-36), including improvements in mental health domains.

“It speaks a little bit to the holistic improvement that these patients are experiencing,” Dr. Merola said. 

Skin outcomes also favored combination therapy, with greater improvements in PASI responses and absolute psoriasis severity scores. Complementary findings from a parallel psoriasis study further supported enhanced skin clearance with combined therapy.

Safety findings were consistent with known profiles of both agents. Gastrointestinal adverse events were observed with tirzepatide, though discontinuation rates were low (2.9% vs 0.8% with ixekizumab alone). No new safety signals were identified.

“These data represent an important paradigm shift,” Dr. Merola said.