What Is Dupixent?
Dupixent (dupilumab), developed by Sanofi-Aventis and Regeneron Pharmaceuticals, is a biologic therapy approved by the U.S. Food and Drug Administration (FDA) to treat several inflammatory and immune-mediated conditions. It works by blocking specific immune pathways that are overly active in people with severe atopic dermatitis, asthma, nasal polyps, eosinophilic esophagitis, and other type-2 inflammatory diseases. By reducing this immune activity, Dupixent can help relieve symptoms like itching, skin rashes, difficulty breathing, and nasal polyps. Patients or their caregivers administer Dupixent themselves through subcutaneous injections every 2, or 4 weeks, depending on the patient’s age, weight, and treatment needs.
Dupixent is commonly prescribed to treat:
- Atopic Dermatitis (Eczema)
- Moderate-to-Severe Asthma
- Chronic Rhinosinusitis with Nasal Polyps
- Eosinophilic Esophagitis (EoE)
- Prurigo Nodularis
- Chronic Spontaneous Urticaria
- Bullous Pemphigoid
Sanofi and Regeneron have promoted Dupixent as a safer long-term alternative to systemic steroids or immunosuppressants. Although Dupixent is effective in reducing symptoms by mitigating inflammation, some concerns have emerged regarding its potential effects on the immune system, particularly in relation to identifying abnormal white blood cell growth, such as skin T-cell lymphomas and other non-Hodgkin lymphomas. Clinical reports indicate that certain patients using Dupixent subsequently developed Cutaneous T-Cell Lymphoma (CTCL) or were diagnosed with previously undetected lymphomas, potentially due to early symptoms resembling eczema.
Signs and Symptoms of CTCL
As part of the immune system, skin plays a major role in the lymphatic system. Certain cancers of the lymph system are known as Lymphomas. Cutaneous T-cell Lymphoma is a type of cancer that originates in the skin. It is one of the non-Hodgkins Lymphoma group of cancers that affects a certain type of white blood cell known as T-cells. CTCL may include subtypes of Cutaneous T-cell Lymphoma including Sézary Syndrome, Mycosis Fungoides, and other T-cell Lymphoma subtypes.
Common Symptoms of CTCL may include:
- Persistent rash or eczema-like skin lesions
- Scaly patches on the skin
- Thickened or raised skin plaques
- Severe itching
- Swollen or enlarged lymph nodes
- Hair loss
- Skin discoloration or ulceration
- Tumor-like growths on the skin surface
In some cases, early CTCL may be misdiagnosed as severe atopic dermatitis—resulting in prolonged Dupixent use prior to a lymphoma diagnosis. If you experience persistent or worsening skin symptoms while using Dupixent, consult your healthcare provider immediately. A skin biopsy or blood test may be necessary to rule out CTCL. Without close monitoring, there is a risk of a delayed diagnosis, which can allow the cancer to spread and become more aggressive.
Emerging Evidence Linking Dupixent to CTCL
Multiple recent studies and clinical reports have investigated a potential association between Dupixent and lymphoma, with a particular focus on Cutaneous T-Cell Lymphoma (CTCL). Observational database analyses have indicated an increased incidence of CTCL diagnoses among patients receiving Dupixent compared to those who were not exposed to the medication.
Multiple cohort studies have found that patients treated with dupilumab for atopic dermatitis had a significantly increased relative risk of developing cutaneous T-cell lymphoma compared to patients who did not receive the drug, with some analyses suggesting roughly a four-fold higher risk.
A 2025 population-based cohort study of asthma patients reported that dupilumab-treated individuals had an increased risk of lymphoma, especially T-cell and natural killer (NK)-cell lymphomas.
Published reports describe patients who developed CTCL, Mycosis fungoides (MF), Sézary syndrome, anaplastic large cell lymphoma, and other hematologic malignancies after starting Dupixent therapy.
Some researchers believe Dupixent may unmask or accelerate pre-existing but undiagnosed CTCL in patients initially thought to have severe eczema, rather than causing entirely new cancers.
To date, the FDA-approved Dupixent label has not added a specific lymphoma or CTCL cancer warning, even though emerging data and case reports have prompted increased regulatory scrutiny and litigation.
FDA Monitoring CTCL Reports
In March 2025, the U.S. Food and Drug Administration (FDA) issued a safety alert after identifying a possible connection between Dupixent and CTCL. The FDA has since confirmed that it is monitoring alarming reports of CTCL in Dupixent users and evaluating whether to update the drug’s warning label.
Dupixent Litigation
As of early 2026, litigation has been initiated against Sanofi and Regeneron alleging Dupixent (dupilumab) may cause or accelerate the development of Cutaneous T-Cell Lymphoma (CTCL), a rare form of blood cancer. Plaintiffs allege that the drug manufacturers did not adequately inform patients and healthcare providers about this potential risk, citing studies indicating an elevated incidence of CTCL and other lymphomas among users.
A recent federal lawsuit involves a plaintiff who was prescribed Dupixent for atopic dermatitis and subsequently used the medication for approximately one year prior to being diagnosed with both Mycosis Fungoides and Sézary syndrome. The complaint alleges that earlier warnings or more explicit prescribing information could have facilitated earlier diagnosis and mitigated disease progression. The Dupixent lawsuits are based primarily in failure-to-warn claims, along with negligence and related product liability theories.
The lawsuits are in the early, pre-trial stages. It is anticipated that plaintiffs, together with Sanofi and Regeneron, will seek to consolidate the cases into a Multidistrict Litigation (MDL). As more patients learn about this issue, we expect the number of lawsuits to increase.
Do You Qualify for a Dupixent Lawsuit?
Patients and families may qualify to file a Dupixent lawsuit if they meet certain criteria. You may be eligible for a Dupixent claim if you:
- Were prescribed and took Dupixent for eczema, asthma or other approved uses
- Were diagnosed with Cutaneous T-Cell Lymphoma (CTCL), Mycosis Fungoides and Sézary syndrome or another T-cell lymphoma after taking Dupixent
Timing matters. In many reports, CTCL was diagnosed more than a year after Dupixent treatment began. This suggests that the drug may accelerate or unmask disease in certain patients. Filing deadlines also vary by state. It’s important to contact a lawyer experienced in injuries related to prescription medications as soon as possible to evaluate your legal options.
Dupixent Lawsuit FAQs
Currently, Dupixent claims are in the early stages of investigation. There is currently no class action or multidistrict litigation (MDL). The number of future filings will dictate whether the parties move for an MDL.
Compensation may include coverage for medical bills, lost wages, pain and suffering and loss of quality of life. Wrongful death damages for surviving family members of deceased patients may be available.
The deadline to file, known as the statute of limitations (SOL), varies by state. Many states allow two to three years from the date of diagnosis or discovery of harm. Be sure to consult with an attorney as soon as possible to avoid issues.
As of now, the FDA has not added a specific cancer warning to Dupixent’s label. However, adverse event reports and new research are under review, which may influence future label changes.
If you develop cancer or any other serious condition after taking Dupixent, seek immediate medical care. Then, contact a lawyer with experience in pharmaceutical litigation to explore whether you qualify for a Dupixent lawsuit.
Contact Us Today
At LexLegal, we are currently investigating cases involving patients who developed Cutaneous T-cell Lymphoma (CTCL) and other serious complications after using Dupixent. Our legal team is examining the scientific evidence, analyzing the drug manufacturers’ conduct, and working to hold Sanofi and Regeneron accountable for the harm their drug may have caused.
If you or a loved one was diagnosed with CTCL, Mycosis fungoides, Sézary syndrome, or another form of T-cell lymphoma after using Dupixent, contact us today. We are passionate advocates for people who were harmed by drugs that were supposed to help them. We stand ready to assist you in pursuing fair compensation for your injuries to the fullest extent allowed under the law.
LexLegal offers free, confidential case evaluations to determine whether you qualify for a Dupixent lawsuit. Complete our instant case evaluation form today. We’ll review your information and promptly respond about your legal options. Every Dupixent lawsuit we handle is taken on a contingency fee basis, which means there are no upfront costs for clients. Our firm is experienced in handling defective drug cases, and we welcome any questions you may have.
Complete our instant case evaluation today to learn whether you may be eligible to file a Dupixent lawsuit.
