Dupixent T-Cell Lymphoma Lawsuits May Follow Recent Studies Linking Drug to Cancer Risks

FDA has received nearly 300 reports of T-cell lymphoma diagnoses among users, raising concerns about the link between Dupixent and cancer.

Following the publication of several recent studies and case reports that linked side effects of Dupixent to cutaneous T-cell lymphoma (CTCL), a number of former users are now seeking legal representation and planning to file lawsuits against Sanofi and Regeneron, alleging that the drug makers withheld critical warnings about the risk that Dupixent may cause this rare but serious blood cancer.

Dupixent (dupilumab) is a monoclonal antibody that was first introduced by Sanofi and Regeneron in 2017, when it received FDA approval for the treatment of moderate-to-severe atopic dermatitis in adults who did not respond to topical therapies. It was the first biologic therapy of its kind for eczema, quickly becoming a blockbuster drug due to its effectiveness in reducing inflammation and itching.

Since then, the FDA has expanded Dupixent’s approvals to cover multiple inflammatory and immune-related diseases, and it is now widely prescribed to both children and adults with atopic dermatitis, eosinophilic asthma, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, prurigo nodularis, and more recently, COPD with an eosinophilic phenotype, chronic spontaneous urticaria and bullous pemphigoid.

The drug works by targeting the IL-4 receptor alpha, a key component in the IL-4 and IL-13 signaling pathways that drive type-2 inflammation. By blocking these pathways, Dupixent reduces overactive immune responses responsible for conditions like eczema, asthma and nasal polyps.

However, after more than 1 million people have already been treated with Dupixent worldwide, independent researchers are now cautioning that side effects the drug has on the immune system may also reduce the body’s ability to detect and control abnormal T-cell growth, which could allow malignant cells to expand.

These warnings, alongside a growing number of T-cell lymphoma side effects being reported by Dupixent users to the FDA, have led to a number of lawyers beginning to investigate Dupixent T-cell lymphoma lawsuits, and it is widely expected that Sanofi and Regeneron could face a surge in claims as more former users discover that they may have avoided the cancer risks if the drug makers had provided warnings to users and the medical community.

Research Linking Dupixent to Cutaneous T-Cell Lymphoma

Over the last several years, a series of peer-reviewed studies and published case reports have raised concerns that Dupixent may be associated with an increased risk of cutaneous T-cell lymphoma (CTCL).

Early warnings began with individual patient case studies in 2019, which documented rapidly worsening CTCL symptoms after treatment with dupilumab. Since then, larger cohort analyses have reinforced the link, suggesting that patients receiving the drug may face significantly higher odds of developing T-cell lymphoma compared to those who did not.

Dupixent Linked to 300% Higher Risk of CTCL

In a study published in JAMA Dermatology on April 6, 2024, researchers examined whether patients with atopic dermatitis (AD) who were treated with Dupixent had a higher risk of developing cutaneous T-cell lymphoma compared to those who were not treated with the biologic.

The investigators used large health records data to compare outcomes and controlled for factors such as age, sex and race, while also excluding patients with prior use of immune-suppressing medications to avoid bias.

Researchers found that patients who used Dupixent had a 300% higher risk of developing CTCL than those who did not (odds ratio 4.10). Even after adjustments for demographics and medication history, the increased risk remained statistically significant, at more than two times higher (OR 3.20).

These findings highlighted a concerning association between Dupixent and lymphoma that could not be explained solely by underlying eczema severity.

T-Cell Lymphoma Side Effects From Dupixent Reinforced

In August 2024, another study using the TriNetX database was published, building on the earlier findings and further investigating the potential risks tied to Dupixent. Researchers designed the study to focus exclusively on atopic dermatitis patients and excluded those with other inflammatory diseases or who had previously received biologic therapies that might also carry a lymphoma risk. By carefully matching patients by age, sex and race, they sought to isolate the effect of Dupixent on lymphoma outcomes.

The analysis revealed that individuals with atopic dermatitis treated with Dupixent faced a 350% higher risk of developing CTCL compared to matched controls (relative risk 4.59).

These results reinforced the conclusions of the April 2024 JAMA study, providing another layer of evidence that Dupixent exposure may significantly elevate the likelihood of developing cutaneous T-cell lymphoma.

Dupixent Asthma Study Published in June 2025

In June 2025, a study published in The European Respiratory Journal, led by Sheng-Kai Ma expanded the scope beyond eczema by examining whether Dupixent increased lymphoma risk among asthma patients. Using data from the TriNetX network, the study compared individuals starting Dupixent with those prescribed a common asthma regimen of inhaled corticosteroids combined with a long-acting beta agonist (ICS/LABA).

The findings revealed that asthma patients treated with Dupixent had a 4.5-fold increased risk of CTCL compared to those on ICS/LABA therapy.

Among patients who continued treatment for at least 16 weeks, the risks climbed even higher, with a 14-fold increase in mature T- and NK-cell lymphomas, a category that includes CTCL. This suggested that not only does Dupixent appear tied to lymphoma in eczema patients, but the risk may also extend to other disease populations using the drug.

Case Reports Show Dupixent May “Unmask” or Accelerate Hidden Lymphomas

Concerns about Dupixent and lymphoma risks began even earlier, with a series of case reports published in the Journal of the American Academy of Dermatology (JAAD) in 2019.

These reports described patients with severe eczema who were later found to have CTCL after beginning treatment with Dupixent. In several cases, dermatologists noted that Dupixent appeared to “unmask” the cancer, allowing it to progress more rapidly than expected.

Physicians cautioned that Dupixent’s mechanism of suppressing IL-4 and IL-13 inflammation may mask lymphoma symptoms that initially resemble eczema, delaying a proper diagnosis until the cancer is more advanced. These early reports provided the first warning signs of the potential risk, which have since been echoed and validated by larger studies.

FDA Reports of T-Cell Lymphoma Linked to Dupixent

In addition to published studies, the FDA’s Adverse Event Reporting System (FAERS) contains hundreds of reports submitted by patients and healthcare providers linking Dupixent (dupilumab) to various forms of T-cell lymphoma. While FAERS data does not prove causation, it is a critical safety signal that regulators and researchers use to identify potential drug risks requiring further investigation.

As of the most recent update, the FAERS dashboard shows nearly 300 reports of T-cell lymphoma cases among Dupixent users, including both confirmed cutaneous T-cell lymphoma (CTCL) and other related subtypes. These adverse event reports add to concerns raised in the medical literature, reinforcing calls for closer monitoring of patients prescribed the drug.

Types of T-Cell Lymphoma Reported to FAERS

According to FDA FAERS data, the following cases have been associated with Dupixent use:

• Cutaneous T-Cell Lymphoma: 138 cases
• Lymphoma (unspecified): 104 cases
• T-Cell Lymphoma (general): 41 cases
• CTCL, Stage IV: 6 cases
• Anaplastic Large Cell Lymphoma (T- and null-cell types): 5 cases
• CTCL, Stage III: 3 cases
• Angioimmunoblastic T-Cell Lymphoma: 2 cases
• CTCL, Stage I: 2 cases
• Recurrent T-Cell Lymphoma: 2 cases
• Adult T-Cell Lymphoma/Leukemia: 1 case
• Unclassifiable T-Cell Lymphoma: 1 case

In total, 298 cases of lymphoma or related T-cell malignancies have been reported to FAERS in connection with Dupixent. While not every adverse event report can be independently verified, the volume and specificity of these cases provide further evidence that Dupixent may be contributing to serious cancer risks in some patients.

Dupixent T-Cell Lymphoma Lawsuits Under Investigation

Law firms are now investigating cases for individuals who were prescribed Dupixent for any of its approved uses and later diagnosed with cutaneous T-cell lymphoma (CTCL) or another T-cell lymphoma subtype.

Dupixent lawyers indicate that even though litigation is still in the investigation stage, the growing body of medical research and FDA adverse event data may support claims that patients were exposed to unnecessary risk without proper disclosure.

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