FDA Approves Dupixent as First New Targeted CSU Therapy in Over a Decade
Chronic spontaneous urticaria, sometimes referred to as chronic idiopathic urticaria, is a condition characterized by the spontaneous appearance of hives (wheals), swelling (angioedema), or both, for six weeks or longer without an identifiable external trigger. The disease is marked by intense itchiness, skin inflammation, and recurrent, unpredictable flares that can severely impact a person’s quality of life. For many, CSU is more than just a skin disorder—it’s a chronic condition that disrupts sleep, causes psychological distress, and impairs daily activities including work and social interactions.
Despite the use of second-generation antihistamines, which are considered the standard first-line treatment, a significant proportion of CSU patients continue to experience uncontrolled symptoms. According to recent estimates, more than 300,000 people in the United States alone have CSU that remains inadequately controlled by H1 antihistamines. These patients are often left in a state of uncertainty, dealing with the physical discomfort and emotional burden of an unpredictable and often stigmatizing condition.
Kenneth Mendez, President and Chief Executive Officer of the Asthma and Allergy Foundation of America, emphasized the personal toll CSU can take on patients, stating:
“People with chronic spontaneous urticaria experience sudden, unpredictable hives and severe itch that cause a significant, and often overwhelming, burden on their everyday lives. The approval of this treatment offers patients more options and the chance to control their disease.”
Dupixent’s Mechanism of Action and the Role of Type 2 Inflammation
Dupixent (dupilumab) is a fully human monoclonal antibody that inhibits the signaling of the interleukin-4 (IL-4) and interleukin-13 (IL-13) pathways, which are central drivers of type 2 inflammation. This inflammatory pathway is implicated in a number of atopic and allergic diseases, including atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyposis, eosinophilic esophagitis, and prurigo nodularis.
The newly approved indication for CSU marks the seventh condition for which Dupixent has received FDA approval, further expanding its role as a foundational biologic treatment across a wide range of type 2 inflammatory diseases. Notably, several of these conditions—including atopic dermatitis and asthma—commonly co-occur with CSU, creating a complex web of inflammatory diseases that often share underlying immune dysregulation.
Dr. George D. Yancopoulos, M.D., Ph.D., Board co-Chair, President, and Chief Scientific Officer at Regeneron, and one of the principal inventors of Dupixent, reflected on the significance of this regulatory approval:
“Dupixent is the first new targeted treatment for chronic spontaneous urticaria, or CSU, in over ten years, with pivotal trials demonstrating its ability to help patients significantly reduce the hallmark symptoms of intense itch and unpredictable hives associated with this disease.
With this FDA decision, Dupixent is now approved for seven chronic, debilitating atopic conditions driven in part by underlying type 2 inflammation… providing patients with one treatment that might help multiple atopy conditions.”
Clinical Trials Demonstrate Robust Efficacy and Consistent Safety
The FDA’s approval was supported by compelling data from a robust clinical development program that included three Phase 3 trials: Study A, Study B, and Study C. These trials were specifically designed to evaluate the efficacy and safety of Dupixent as an add-on therapy for patients with CSU who were inadequately controlled on standard H1 antihistamines.
- Study A involved 136 biologic-naïve patients aged 12 years and older.
- Study C enrolled 148 similar patients.
- Study B, a supplemental study with 108 participants, focused on patients who were either inadequate responders or intolerant to anti-IgE therapy (such as omalizumab) and remained symptomatic despite antihistamine use.
In both Study A and Study C, Dupixent met its primary and key secondary endpoints. Patients receiving Dupixent experienced significant reductions in itch severity and urticaria activity—a composite score of itch and hives—at 24 weeks, compared to placebo. Moreover, Dupixent was associated with a higher likelihood of achieving well-controlled disease or even complete symptom resolution. This highlights the potential of Dupixent not only to mitigate symptoms but to improve overall disease control for those with limited treatment options.
Safety data from all three studies were consistent with Dupixent’s established safety profile across its other indications. The most common treatment-emergent adverse event, observed in ≥2% of patients, was injection site reactions, which occurred more frequently in the Dupixent group than in the placebo group.
Dr. Alyssa Johnsen, M.D., Ph.D., Global Therapeutic Area Head, Immunology and Oncology Development at Sanofi, emphasized the transformative potential of this new indication:
“CSU patients with uncontrolled disease experience highly burdensome itch and hives that can significantly disrupt daily living.
This FDA approval provides a new treatment option to help address the underlying drivers of these severe and recurring signs and symptoms. Dupixent has the potential to improve outcomes for CSU patients who previously had limited treatment options.”
Global Expansion and Future Outlook
The U.S. approval of Dupixent for CSU follows earlier regulatory successes in other major markets. The treatment has already been approved for the same indication in Japan, the United Arab Emirates (UAE), and Brazil. Regulatory submissions are currently under review in several other regions, including the European Union, as Sanofi and Regeneron pursue a coordinated global expansion strategy.
As the medical community continues to recognize the burden of chronic inflammatory conditions like CSU, the need for innovative, targeted therapies becomes increasingly apparent. Dupixent’s broad range of indications and its ability to address overlapping disease pathways position it as a critical tool in the treatment arsenal for allergic and inflammatory disorders.
The FDA’s approval of Dupixent for the treatment of chronic spontaneous urticaria represents a much-needed advancement for patients who have struggled for years with limited options and inadequate symptom control. With compelling clinical trial results, a consistent safety profile, and the ability to treat coexisting atopic conditions, Dupixent offers new hope for patients and marks a new era in the management of CSU.
By expanding its reach to yet another chronic type 2 inflammatory disease, Dupixent continues to solidify its role as a transformative therapy in modern immunology—ushering in a more personalized, effective approach to treating burdensome, overlapping atopic diseases.
