Eli Lilly's Combination Therapy Shows Promise in Treating Psoriasis and Obesity

2026-10-09 companies

Indianapolis, Friday, 9 October 2026.
Eli Lilly’s trial combining Taltz and Zepbound significantly reduced inflammatory biomarkers in patients with both psoriasis and obesity, highlighting an integrated approach to immunometabolic health.

Clinical Trial Findings and Biomarker Analysis

On October 8, 2026, Eli Lilly (NYSE: LLY) presented exploratory data from the Phase 3b TOGETHER-PsO clinical trial at the Fall Clinical Dermatology Conference in Las Vegas [1][2]. The study evaluated the concomitant use of Taltz (ixekizumab) and Zepbound (tirzepatide) against Taltz monotherapy in adults with moderate-to-severe plaque psoriasis and obesity [3]. By Week 36, the combination therapy resulted in 482 differentially expressed proteins compared to 140 for Taltz alone, representing a substantial increase in biomarker activity [2][3]. This difference in protein expression can be calculated as 244.286 percent higher in the combination arm, indicating a broader biological response [3]. Additionally, the combination group showed 467 differentially expressed genes versus 16 for monotherapy, with biomarker responses observed as early as Week 12 [1][7].

Immunometabolic Connections

The analysis indicates that reductions in inflammatory immune activity, specifically regarding neutrophil-associated markers, mediated a portion of the additional Psoriasis Area and Severity Index response observed in the combination treatment arm [2]. Mark Genovese, M.D., senior vice president of Lilly Immunology development, stated that patients with psoriasis and obesity face a complex burden that is often addressed in silos [4]. He noted that the broader biomarker changes observed may point to a meaningful relationship between immune and metabolic biology [1]. James G. Krueger, M.D., Ph.D., Professor and Laboratory Head at The Rockefeller University, added that the findings identified differences in inflammatory pathways when patients received concomitant treatment [3]. Approximately 61% of psoriasis patients in the United States also suffer from obesity, highlighting the immunometabolic link Lilly aims to address [4][6].

Market Reaction and Valuation

Following the announcement, BofA Securities adjusted its Eli Lilly price target to $1,341 from $1,344 while maintaining a Buy rating [4]. This adjustment represents a change of -0.223 percent in the analyst’s target price [4]. As of October 9, 2026, Eli Lilly shares were priced at USD 1,164.15 on Pluang, with a market cap of $1.04 trillion [6]. The company trades at 24.4x forward earnings, exceeding the 18.3x average for healthcare stocks [5]. Competitor Novo Nordisk is currently rated as a Buy over Eli Lilly by some analysts, citing a 26% valuation discount relative to big pharma peers [6]. Cantor Fitzgerald maintained an Overweight rating for Eli Lilly while increasing price targets, alongside similar actions for AbbVie, Merck, and Pfizer [6].

Safety and Regulatory Context

Taltz carries safety warnings including risks of tuberculosis reactivation, serious allergic reactions, and inflammatory bowel disease [2][3]. Zepbound carries significant safety warnings, including a risk of thyroid C-cell tumors, acute pancreatitis, and gallbladder problems [2]. Patients are advised that oral birth control pills may have reduced efficacy when using Zepbound, requiring alternative contraception for 4 weeks after initiation and dose increases [3]. Eli Lilly maintains that its forward-looking statements reflect current beliefs and expectations, subject to substantial risks and uncertainties inherent in pharmaceutical research [2]. The company explicitly stated that there is no guarantee that future study results will align with findings to date [2].

Sources

Eli Lilly Zepbound