Eli Lilly and Co. (NYSE: LLY) on Wednesday presented new clinical data showing the lasting benefits of a dual-drug approach for active psoriatic arthritis. The headline: when you pair an immunology drug with a weight-loss drug, the results don't just hold up over a year. They get better.

The detailed 52-week results indicate sustained and enhanced efficacy when combining two specific therapies, offering a positive outlook for patients managing multiple health conditions at once.

Inside the TOGETHER-PsA Trial

The data comes from the TOGETHER-PsA Phase 3b open-label clinical trial. Researchers assessed the concomitant administration of Taltz (ixekizumab) and Zepbound, or tirzepatide, and compared that combined regimen directly against Taltz on its own.

The Numbers That Matter

The composite outcome of psoriatic arthritis disease activity (ACR50) plus at least 10% weight reduction was achieved at Week 52 by 39.2% of the combination arm and 1.7% of the Taltz-alone arm. Compare that with 31.7% and 0.8%, respectively, at Week 36. In other words, the gap widened as the trial went on.

On the weight side alone, 85.7% of combination patients and 6.7% of monotherapy patients achieved at least 10% weight reduction at one year.

One detail worth flagging: Lilly reported that ACR50 responses began separating between the arms as early as Week 4, before clinically meaningful weight loss was observed. That suggests the joint benefits aren't merely a downstream effect of dropping pounds.

Participants taking Taltz and Zepbound together maintained their initial health gains. In many cases, patients showed further improved outcomes as they progressed through Week 52 of the trial. The combination therapy delivered these sustained improvements across several critical health metrics, with the clinical team observing continued progress in overall disease activity and crucial metabolic measures. The trial also recorded ongoing advancements in various patient-reported outcomes over the course of the year.

Building on Earlier Milestones

These comprehensive 52-week findings build heavily upon the trial's earlier achievements. As previously reported by the company, the Taltz and Zepbound combination already met the primary endpoint of the study at 36 weeks, and the dual therapy achieved all key secondary endpoints at that threshold. During that earlier phase, the combination treatment demonstrated statistically significant superiority when compared directly to the Taltz-only regimen.

Minimal disease activity was achieved at Week 52 by 28.2% of the combination arm and 13.6% of the monotherapy arm.

LLY Price Action: Eli Lilly shares were down 0.45% at $1425.79 at the time of publication on Wednesday. The stock is trading near its 52-week high of $1453.00, according to market data.