Lilly’s Taltz plus Zepbound shows efficacy in psoriatic arthritis trial

INDIANAPOLIS - Eli Lilly and Company (NYSE:LLY) announced results from a Phase 3b clinical trial evaluating the combined use of Taltz (ixekizumab) and Zepbound (tirzepatide) compared to Taltz alone in adults with active psoriatic arthritis and obesity or overweight with at least one weight-related comorbid condition. The pharmaceutical giant, with a market capitalization of $786 billion, continues to demonstrate its position as a prominent player in the industry, according to InvestingPro analysis.

The TOGETHER-PsA trial results were presented today at the 2026 American Academy of Dermatology Annual Meeting and published in Arthritis & Rheumatology, according to a press release statement.

At the primary endpoint of 36 weeks, the combination treatment met the primary and all key secondary endpoints. The primary endpoint showed 31.7% of patients achieved ACR50 response plus at least 10% weight reduction with the combination therapy, compared to 0.8% with Taltz alone. ACR50 requires at least 50% improvement in tender and swollen joints plus improvement in three of five other core disease activity measures.

The trial enrolled 271 participants randomized 1:1 to receive either Taltz alone or combined with Zepbound, both administered subcutaneously. Participants had an average body mass index of 37.6 kg/m² across both treatment arms. More than 60% had prior experience with one or more advanced therapies.

Key secondary endpoints showed 33.5% of patients on combination therapy achieved ACR50 compared to 20.4% on Taltz alone. Additionally, 84.5% of combination therapy patients achieved at least 10% weight reduction versus 4.5% on monotherapy.

The combination treatment also showed 26.3% of patients achieving Minimal Disease Activity compared to 15.3% with Taltz alone. Improvements were observed in fatigue scores, physical function, and mental health-related quality of life measures.The positive trial results come as Eli Lilly maintains strong financial momentum, with revenue growth of 45% over the last twelve months and a P/E ratio of 38.5. InvestingPro data indicates the stock is currently undervalued relative to its Fair Value, placing it among companies on the Most Undervalued list. The company has earned a "GREAT" financial health score and maintains an impressive Piotroski Score of 9, reflecting strong fundamentals. For investors seeking deeper insights, a comprehensive Pro Research Report is available, offering expert analysis on LLY alongside 1,400+ other US equities.

Adverse events were generally mild to moderate and consistent with the known safety profiles of each medicine. The most common adverse events in the combination arm included nausea, diarrhea, constipation and injection site reactions.

Approximately 65% of adults with psoriatic arthritis in the U.S. also have obesity or overweight with at least one weight-related comorbidity.

In other recent news, Eli Lilly has been the focus of several notable developments. Morgan Stanley reiterated its Overweight rating on Eli Lilly, maintaining a price target of $1,313, as prescription data for Mounjaro and Zepbound showed stable numbers. Jefferies also reaffirmed a Buy rating with a $1,300 price target, highlighting the prescription data for oral Wegovy, which recorded significant numbers in its early launch weeks. Eli Lilly’s Ebglyss demonstrated promising long-term efficacy in a Phase 3b study for eczema, with 94% of patients achieving a 75% reduction in eczema severity. Additionally, 75% of participants saw a 90% improvement, and a majority reported significant itch relief. In related pharmaceutical industry news, India’s Eris Lifesciences launched a generic version of semaglutide, priced at $13.8 per month, under the brand name Sundae. This development introduces a cost-effective alternative for diabetes treatment in India.

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