Dupixent for Nasal Polyps Nears FDA Approval Amid Lymphoma Side Effect Lawsuits

Sanofi seeks ninth approval for the drug even as the FDA investigates whether users are being adequately warned about the risk of T-cell lymphoma from Dupixent.

The makers of the immunotherapy drug Dupixent say they will ask federal regulators for expanded approval to treat chronic sinus problems caused by fungal allergies, even as questions continue to be raised about a potential link between Dupixent and T-cell lymphoma, which has resulted in lawsuits now being pursued by former users over the failure to adequately disclose side effects associated with the treatment.

In a press release issued on November 7, Sanofi and Regeneron announced that Dupixent had performed positively in clinical trials to treat allergic fungal rhinosinusitis (AFRS). According to the company, Dupixent use reduced the size of nasal polyps, alleviating nasal congestion and sinus opacification caused by the fungal reactions.

Dupixent (dupilumab) was first approved in 2017 as an injectable immunotherapy drug for asthma and other inflammatory conditions affecting the skin and respiratory system. It has since expanded into multiple chronic disease areas, becoming one of Sanofi’s most profitable products worldwide.

Dupixent T-Cell Lymphoma Concerns

However, as the drug has racked up approvals by the U.S. Food and Drug Administration (FDA), there have been growing questions about whether Sanofi failed to adequately warn patients and the medical community about a potential link between Dupixent and T-cell lymphomas, following recent studies that found users may be more likely to develop cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL).

In April 2024 a study published in JAMA Dermatology concluded that Dupixent users were more than four times as likely to develop CTCL compared to non-users. The data pointed to a 350% increased risk of T-cell lymphoma among Dupixent users, while a European Respiratory Journal study in June 2025 linked Dupixent to a 4.5-fold higher risk of CTCL among asthma patients, with the risk climbing to 14-fold for those treated 16 weeks or longer. However, no information about the potential risk is included on the drug warning label.

As more users have linked Dupixent to CTCL and PTCL, Sanofi faces a growing potential for Dupixent cancer lawsuits being pursued by former users of the medication and their families, alleging that they may have avoided a CTCL diagnosis if earlier information and warnings had been provided for patients and the medical community.

Amid these concerns, Sanofi indicates it intends to ask the FDA to approve Dupixent for the treatment of AFRS. If the agency does so, it would be the immunotherapy drug’s ninth approval. Dupixent is currently approved for the treatment of atopic dermatitis, COPD, asthma, chronic rhinosinusitis, eosinophilic esophagitis, prurigo nodularis, chronic spontaneous urticaria and bullous pemphigoid.

Approval would mean that Sanofi could legally promote the drug as an AFRS treatment. Doctors could technically prescribe the drug for any treatment they deem necessary currently, but drug manufacturers are barred from advertising the drug as a treatment that the FDA has not yet specifically approved.

Sanofi is seeking approval even after the FDA confirmed earlier this year that it has opened a formal safety review into Dupixent’s potential cancer risks and is evaluating whether stronger warnings may be required. However, the company also says the FDA has made the request a priority review due to indications that the drug could lead to significant improvements in AFRS treatment.

Dupixent AFRS Study

The press release came as a result of a phase three clinical trial known as the LIBERTY-AFRS-AIMS study, which involved 62 adults and children aged 6 years or older, with 33 given Dupixent and 29 given a placebo.

According to Sanofi, the findings indicate Dupixent decreased nasal congestion due to AFRS by 50%, improved nasal obstruction by 66% and saw continued improvement after nearly a year of use, when compared to those given a placebo. Nasal polyp sizes also reduced by 60.8%, the researchers reported.

Patients taking the drug were 92% less likely to need corticosteroids or surgery.

Dupixent T-Cell Lymphoma Lawsuits

Even as Sanofi seeks further approvals, former Dupixent users are beginning to recognize that a prior CTCL diagnosis may have been caused or accelerated by the drug’s side effects. As regulators and independent researchers release more information, the size and scope of the litigation could grow significantly in the coming months and years.

Dupixent cancer lawyers are currently investigating claims by individuals who were prescribed the drug for any of its approved uses, and were later diagnosed with:

• Cutaneous T-cell lymphoma (CTCL)
• Mycosis fungoides
• Sézary syndrome
• Other T-cell lymphoma subtypes

To receive a free consultation to determine if you or a loved one may be eligible to file a lawsuit, submit information for review by a Dupixent lawyer.

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