Breakthrough Trial Shows Dual-Drug Therapy Transforms Psoriasis and Obesity Treatment

A new Phase 3b trial has shown promising results for patients battling both severe psoriasis and obesity. The study, called TOGETHER-PsO, tested a combination of two drugs—Taltz and Zepbound—against Taltz alone. Following the announcement, shares in Eli Lilly and Company dropped by 1.65%, closing at $1,018.92 on Tuesday.

The trial involved 274 adults with moderate-to-severe plaque psoriasis who also had overweight or obesity, along with at least one weight-related health issue. Participants had an average BMI of over 39 kg/m², with most suffering from extensive skin involvement in high-impact areas.

After 36 weeks, 27.1% of patients on the combined therapy achieved complete skin clearance (PASI 100) and lost at least 10% of their body weight. This compared to just 5.8% of those taking Taltz alone. Overall, 40.6% of the combination group reached full skin clearance, a 40% relative improvement over the 29% seen with Taltz monotherapy.

The study also met its primary endpoint, proving the combination therapy's superiority in both skin and weight outcomes. Secondary measures reinforced these benefits, showing meaningful gains in managing psoriasis symptoms and reducing weight. Side effects remained mostly mild to moderate, aligning with the drugs' established safety records.

Psoriasis affects millions worldwide, with around 61% of U.S. patients also struggling with overweight or obesity. Researchers now stress the importance of integrated treatments that address both skin and metabolic health together.

The TOGETHER-PsO findings suggest that combining Taltz and Zepbound could offer a more effective approach for patients with severe psoriasis and obesity. The results highlight the potential for dual-targeted therapies to improve both skin clearance and weight management. Eli Lilly's stock decline reflects investor reaction to the trial's implications for future treatment strategies.