Current and Emerging Biologic Therapies for the Treatment of Asthma: A Focus on Targeting Thymic Stromal Lymphopoietin (TSLP)

Chatfield Kacie¹ and Bill Tawil²*
¹Department of Biology, California State University, Channel Islands, Camarillo, USA
²Department of Bioengineering, University of California, Los Angeles (UCLA), USA
*Corresponding Author: Bill Tawil, Department of Bioengineering, UCLA School of Engineering, 420 Westwood Plaza, Room 5121, Engineering V. P.O. Box: 951600, Los Angeles, CA 90095-1600, USA.

Published: July 30, 2025

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Abstract  

Asthma is a chronic inflammatory airway disease that affects millions globally, contributing to substantial morbidity and mortality. A significant subset of patients remains uncontrolled despite conventional therapies. Biologic treatments that target type 2 inflammation, including monoclonal antibodies against IL-4, IL-5, IL-13, and IgE, have revolutionized asthma management; however, these therapies primarily address downstream inflammatory pathways. Thymic stromal lymphopoietin (TSLP), an epithelial-derived cytokine, has emerged as a pivotal upstream mediator in the pathophysiology of asthma, acting as a bridge between innate and adaptive immune responses. TSLP is critical in initiating and maintaining type 2 inflammation, positioning it as a promising therapeutic target. Tezepelumab (Tezspire), the first FDA-approved TSLP inhibitor, has demonstrated broad efficacy across various asthma phenotypes, effectively reducing exacerbation rates and improving lung function independent of eosinophil count or allergic status. Additionally, emerging TSLP-targeting biologics under development, such as the inhaled monoclonal antibody fragment ecleralimab (CSJ117), offer novel approaches to localized airway inflammation control. This review aims to explore the mechanisms, clinical efficacy, and economic implications of TSLP-targeting therapies, underscoring their potential to redefine the asthma biologics market and address the unmet therapeutic needs of patients with severe asthma.

Keywords: asthma; biologic; cytokine; ecleralimab (CSJ117); Tezspire (tezepelumab); thymic stromal lymphopoietin (TSLP)

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