Systemic Treatments for Chronic Spontaneous Urticaria: Anti-IgE and Beyond

Chronic urticaria, which is divided into chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), affects a significant percentage of the global population and carries a high burden of unmet medical need. Current standard of care includes nonsedating H1-antihistamines and omalizumab, which targets peripheral blood IgE and downregulates mast cell and basophil IgE receptors. However, omalizumab provides complete hive resolution in approximately 45% of patients and does not produce lasting remission. This review examines the clinical data for newly approved and emerging systemic therapies spanning IgE-based and non-IgE-based targeting strategies. The therapeutic landscape has expanded rapidly, and multiple mechanisms are under investigation. IgE-targeted approaches include omalizumab biosimilars, with CT-P39 having received Food and Drug Administration (FDA) approval. Dupilumab received FDA approval for H1-antihistamine-refractory CSU, supporting targeting type 2 cytokines, IL-4 and IL-13. Most recently, a Bruton's tyrosine kinase inhibitor (BTKi), remibrutinib, demonstrated significant reductions in Urticaria Activity Score over 7 days in phase 3 trials, leading to FDA approval. Newer c-Kit (cKit or KIT) inhibitors have also shown efficacy in CSU and CIndU, with barzolvolimab showing sustained efficacy post-treatment. Finally, other BTKi, Janus kinase (JAK) inhibitors, tyrosine kinase 2/JAK inhibitors, MRGPRX2 antagonists, and other novel mechanisms are advancing through clinical trials. Some drugs have been halted in development because of safety concerns, such as fenebrutinib (BTKi), THB001 (Larvol; c-Kit inhibitor), and EP262 (MRGPRX2 antagonist), whereas others, targeting the alarmin thymic stromal lymphopoietin (tezepelumab), the Th2 cytokine IL-5 (mepolizumab) and its receptor IL-5R (benralizumab), as well as lirentelimab (sialic acid-binding immunoglobulin-like lectin 8 [Siglec-8]) and AK006 (Siglec-6), were halted because of lack of efficacy. However, these failed trials have provided informed insights into the relevant pathways for CSU pathogenesis and treatment. In summary, systemic therapies for CSU are maturing with multiple phase 3 programs targeting the IgE pathway and Th2 cytokines leading to recent approvals. This review will provide an overview of these recently completed and ongoing clinical studies investigating emerging IgE and non-IgE therapeutic options for CSU.