FDA Approves First Drug for Severe Allergic Fungal Sinusitis

TARRYTOWN, NY and PARIS – February 24, 2026 – By George Millen

Patients suffering from a severe and relentless form of sinus disease finally have a targeted treatment option, as the U.S. Food and Drug Administration (FDA) today approved Dupixent (dupilumab) for Allergic Fungal Rhinosinusitis (AFRS). The approval, granted to Regeneron Pharmaceuticals and Sanofi, marks the first and only medicine specifically indicated for this chronic condition in adults and children aged six and older.

AFRS is a debilitating type 2 inflammatory disease caused by an intense allergic reaction to environmental fungi. It traps patients in a frustrating cycle of nasal congestion, thick mucus, loss of smell, and invasive surgeries that often fail to provide lasting relief. For years, the standard of care has been surgical removal of fungal debris and polyps, followed by long courses of systemic steroids—a combination fraught with high recurrence rates and significant side effects. This approval signals a paradigm shift, moving from invasive procedures to targeted biologic therapy.

“As the first treatment specifically approved for AFRS, Dupixent offers the potential for relief to adults and children six years and older struggling with potentially debilitating symptoms,” said Kenneth Mendez, President and CEO of the Asthma and Allergy Foundation of America (AAFA), in a statement.

A New Standard for a Relentless Disease

For those living with AFRS, the disease is more than just a stuffy nose. It's a persistent condition that can dramatically impair quality of life. The disease is particularly prevalent in warm, humid climates and is characterized by the formation of thick, peanut butter-like mucus and nasal polyps that obstruct the sinuses. In severe cases, the inflammation can lead to the erosion of bone around the sinuses, causing facial deformities and, in rare instances, vision problems.

Until now, treatment has been a difficult balancing act. Surgery is necessary to clear the sinuses, but research shows that recurrence is common, with some studies indicating revision surgery is needed in over 50% of patients. This has left physicians and patients to rely on systemic corticosteroids to manage inflammation, a solution that comes with a well-known list of long-term health risks.

“We would perform the surgery, clear everything out, and tell the patient we’d see them again in a year or two for the same procedure. It was incredibly disheartening,” commented one otolaryngologist familiar with the challenges of treating AFRS. “We desperately needed something to break that cycle.”

Dupixent's approval, which was granted under the FDA's Priority Review designation, is based on the strength of the Phase 3 LIBERTY-AFRS-AIMS trial. The results were striking: patients treated with Dupixent saw a 92% reduction in the risk of needing either systemic corticosteroids or additional surgery over 52 weeks compared to placebo. Specifically, only 3% of Dupixent patients required steroids and none required surgery, compared to 31% and 7% in the placebo group, respectively. The drug also demonstrated significant improvements in sinus inflammation as seen on CT scans, a reduction in nasal polyp size, and a restoration of the patient's sense of smell.

The Science of Targeted Inflammation Control

Dupixent is not a new drug, but its application in AFRS represents a significant milestone. It is a fully human monoclonal antibody that works by inhibiting the signaling of interleukin-4 (IL-4) and interleukin-13 (IL-13), two key proteins that are central drivers of type 2 inflammation. This type of inflammation is the underlying cause of a host of allergic and inflammatory conditions, and AFRS is now officially on that list.

“With this approval, Dupixent once again demonstrates its value in advancing the treatment landscape for a chronic type 2 inflammatory disease with high unmet need,” said George D. Yancopoulos, M.D., Ph.D., President and Chief Scientific Officer at Regeneron. He noted that beyond symptom reduction, the trial showed fewer patients on Dupixent had bone erosion in their sinuses, underscoring the drug's potential to “establish a new standard of care.”

By precisely targeting the inflammatory pathway, Dupixent offers a stark contrast to the blunt-force approach of systemic steroids, which suppress the entire immune system. This targeted mechanism is what allows the drug to be effective across a seemingly disparate range of diseases.

An Expanding Empire for a Blockbuster Biologic

The AFRS approval is the ninth for Dupixent in the United States, cementing its status as a multi-billion-dollar blockbuster and a cornerstone of the Regeneron and Sanofi partnership. The drug is already approved for conditions including moderate-to-severe atopic dermatitis (eczema), certain types of asthma, eosinophilic esophagitis (EoE), and chronic rhinosinusitis with nasal polyps (CRSwNP).

This latest indication further validates the companies' long-term strategy of targeting the IL-4/IL-13 pathway. By proving the drug's efficacy across sino-nasal, skin, gut, and respiratory systems, Regeneron and Sanofi have built a formidable franchise. Each new approval expands the potential patient pool and solidifies Dupixent's dominance in the treatment of type 2 inflammatory diseases, making it one of the most successful and versatile biologics on the market.

With more than 1.4 million patients globally already being treated with the drug for its various indications, the addition of the AFRS population, while smaller than other groups, reinforces the drug's scientific and commercial momentum. The companies have indicated that submissions to other regulatory authorities around the world are planned.

The Path to the Patient: Navigating Access and Affordability

While the medical community and patient advocates celebrate the scientific breakthrough, the introduction of a high-cost biologic for a chronic condition immediately raises practical questions of access and affordability. The list price of specialty drugs like Dupixent can run into the tens of thousands of dollars per year, a cost that is prohibitive for nearly all patients without substantial insurance coverage.

In anticipation of these hurdles, the companies promote their DUPIXENT MyWay® program, which is designed to help patients navigate insurance complexities and provide financial assistance to those who are eligible. However, the long-term sustainability of such treatments within the broader healthcare system remains a subject of intense debate.

“An approval is a vital first step, but it’s not the last one. The real victory is when every patient who needs the medication can actually get it and afford it,” noted a patient advocate from a national health organization. “We will be watching closely to see how insurers respond and whether co-pay and deductible burdens create a new barrier for the very people this drug is meant to help.”

The approval for use in children as young as six also adds a layer of complexity, as it commits families to a potentially lifelong, expensive therapy. As Dupixent moves from a revolutionary treatment to a new standard of care for AFRS, the focus will inevitably shift from the clinical trial results to the real-world challenges of ensuring equitable access to this life-changing medicine.