Did Dupixent Cause Your T-Cell Lymphoma?

Dupixent promised relief to people with chronic eczema, asthma, or other inflammatory conditions unresponsive to standard treatment.

Millions of prescriptions have been written since the FDA approved it in 2017, and for many patients, it worked. For others, the story is far more troubling.

A growing body of medical research has linked Dupixent to a rare and aggressive form of blood cancer called cutaneous T-cell lymphoma, or CTCL.

Patients diagnosed with this cancer after taking Dupixent, along with their families, are taking action through a Dupixent lawsuit against the drug's manufacturers, Sanofi and Regeneron Pharmaceuticals, alleging that the companies knew or should have known about the cancer risk and failed to warn them.

If you were diagnosed with T-cell lymphoma after using Dupixent, contact The Oshman Firm at (212) 233-2100 for a free consultation.

What Is Dupixent?

Dupixent (dupilumab) is a prescription biologic medication developed jointly by Sanofi and Regeneron Pharmaceuticals. Unlike traditional drugs, biologics are made from living cells and work by targeting specific pathways in the immune system. Dupixent works by blocking two proteins, IL-4 and IL-13, that drive inflammatory immune responses.

The FDA first approved Dupixent in March 2017 for adults with moderate-to-severe atopic dermatitis (eczema) that doesn't respond adequately to topical treatments. Since then, its approved uses have expanded significantly to include:

• Moderate-to-severe asthma,
• Chronic rhinosinusitis with nasal polyposis,
• Eosinophilic esophagitis,
• Prurigo nodularis,
• Chronic obstructive pulmonary disease (COPD),
• Chronic spontaneous urticaria (CSU), and
• Alopecia areata.

More than 800,000 patients have used Dupixent since its approval, making it one of the best-selling biologic drugs in the world. Dupixent sales are projected to reach $20 billion in 2026, accounting for more than one-third of Sanofi's total revenue.

Despite that commercial success, serious safety questions have emerged that the manufacturers have not adequately addressed.

What Is Cutaneous T-Cell Lymphoma?

Cutaneous T-cell lymphoma (CTCL) is a rare form of non-Hodgkin lymphoma that arises from white blood cells of the immune system. Malignant T cells migrate to the skin, where they can cause a range of symptoms that, in early stages, closely mimic common inflammatory skin conditions like eczema and psoriasis.

The two most common subtypes of CTCL are:

• Mycosis fungoides: The most prevalent form of CTCL. It typically presents as flat, scaly patches on the skin, which can progress to raised plaques and, in advanced stages, tumors.
• Sézary syndrome: A more aggressive, systemic form of CTCL in which malignant T cells spread throughout the bloodstream as well as the skin. Sézary syndrome is characterized by severe itching, widespread skin reddening, and a significantly worse prognosis.

CTCL can be difficult to diagnose in early stages, as it often resembles eczema. This diagnostic overlap is part of the concern regarding Dupixent side effect claims: the medication may reduce visible inflammation without addressing an underlying malignancy, potentially allowing cancer to advance without early detection.

Patients in this situation may have grounds for both a pharmaceutical injury claim and a cancer misdiagnosis claim, depending on the circumstances of their case.

Does Dupixent Cause Lymphoma? What the Research Shows

The link between Dupixent and lymphoma has been documented in multiple peer-reviewed studies and flagged by the FDA.

2020 — Early Case Reports

The Journal of the American Academy of Dermatology published case reports describing patients whose presumed eczema later proved to be CTCL after starting Dupixent treatment. In several of these cases, the drug appeared to "unmask" a hidden lymphoma, accelerating its progression once therapy began.

May 2024 — JAMA Dermatology Study

Researchers found that among patients with eczema, those using Dupixent were approximately 3 times more likely to develop CTCL than those who did not use it. This increased risk remained even after accounting for differences in patient backgrounds and treatment histories.

August 2024 — TriNetX database Study

This large-scale analysis followed more than 19,000 patients with atopic dermatitis. Among these, patients treated with Dupixent were 4.59 times more likely to be diagnosed with CTCL than those who did not receive Dupixent. Of the patients ultimately diagnosed with CTCL, 27 out of 41 had taken Dupixent for more than a year.

March 2025 — FDA Safety Signal Designation

The FDA placed Dupixent on its quarterly FAERS "Potential Signals of Serious Risks/New Safety Information" list, specifically identifying cutaneous T-cell lymphoma as a safety concern requiring evaluation. The agency confirmed it is "evaluating the need for regulatory action."

This formal designation followed more than 300 adverse event reports involving lymphoma diagnoses in Dupixent users. Safety experts note that voluntary adverse event reports may represent only a small fraction of actual cases, suggesting more patients could be affected.

May 2025 — FAERS Adverse Event Analysis

A separate analysis of FDA adverse-event data determined that the rate of reported cutaneous T-cell lymphoma cases among Dupixent users was about 30 times higher than the average rate for users of all other medications tracked in the FDA database during the same period.

June 2025 — European Respiratory Journal

A study led by Dr. Sheng-Kai Ma examined asthma patients treated with Dupixent compared to other medications. In the Dupixent group, asthma patients had a 4.5-fold higher risk of developing cutaneous T-cell lymphoma (CTCL) than the control group. 

For patients treated with Dupixent for 16 weeks or longer, the risk of mature T-cell and NK-cell lymphomas was 14 times higher than for those in the control group.

Researchers believe Dupixent's mechanism of blocking IL-4 and IL-13 signaling may interfere with the immune system's ability to detect and suppress malignant T cells, a process called tumor immunosurveillance. By suppressing inflammation, Dupixent may mask the early signs of CTCL, delaying diagnosis and allowing the cancer to advance.

What Dupixent Lawsuits Allege

Plaintiffs in Dupixent lymphoma lawsuits allege that Sanofi and Regeneron were aware of the connection between their drug and T-cell lymphoma, yet failed to update prescribing information or warn patients and their doctors about the risk.

Under product liability law, drug manufacturers have a duty to disclose all known or reasonably foreseeable risks associated with their medications. When a company fails to provide adequate warnings about a serious side effect, injured patients may have the right to seek compensation.

Specific allegations include:

• Sanofi and Regeneron were aware of early case reports linking Dupixent to cutaneous T-cell lymphoma (CTCL) as early as 2020;
• The companies failed to fully investigate or disclose the potential cancer risk as additional evidence emerged;
• Patients and physicians were not provided sufficient information to make informed treatment decisions; and
• Earlier warnings may have led to different treatment choices or closer monitoring for early signs of lymphoma.

In October 2025, the first Dupixent wrongful death lawsuit was filed in Tennessee. The case involves a woman who began taking Dupixent in June 2024, was later diagnosed with T-cell lymphoma, and passed away less than 5 months later. Her family alleges the drug triggered or accelerated her cancer and that the manufacturers failed to provide adequate warnings.

As additional cases have been filed, attorneys representing multiple plaintiffs moved in March 2026 to consolidate Dupixent lymphoma lawsuits in federal court in Georgia.

If approved, the Judicial Panel on Multidistrict Litigation would establish a multidistrict litigation (MDL), allowing cases to proceed more efficiently through coordinated discovery and shared expert evidence while preserving each plaintiff’s right to pursue compensation based on their specific injuries, instead of through one Dupixent class action lawsuit.

Drug manufacturers have a responsibility to warn you about the risks of the medications they sell. When they fail to do that, your health and your family's well-being pay the price.

If you've been harmed by Dupixent, The Oshman Firm has the experience and resources to pursue full compensation for your losses. Contact us at (212) 233-2100 for a free, confidential case review.

Who May Qualify for a Dupixent Lawsuit?

You may be eligible to file a Dupixent lawsuit if:

• You were prescribed Dupixent for eczema, asthma, COPD, or any other FDA-approved indication;
• You were later diagnosed with cutaneous T-cell lymphoma (CTCL), mycosis fungoides, Sézary syndrome, or another T-cell malignancy;
• Your lymphoma diagnosis came during Dupixent treatment or within a reasonable period after stopping the drug; or
• A family member died from T-cell lymphoma following Dupixent use.

Research suggests that the risk may increase with longer-term use, particularly among patients who have used Dupixent for a year or more. However, some diagnoses have also been reported after shorter treatment durations.

Although some people search for a “Dupixent class action lawsuit,” these cases are currently being handled as individual claims rather than a traditional class action. This allows each case to be evaluated based on the specific medical history, timing of diagnosis, and extent of harm involved.

Because eligibility depends on several factors, a case evaluation can help determine whether you may have a claim and what types of compensation may be available.

What Compensation May Be Available in a Dupixent Lymphoma Lawsuit?

A successful Dupixent lymphoma lawsuit may allow you to recover damages for:

• Medical expenses, including diagnosis, biopsies, imaging, chemotherapy, radiation, and ongoing care
• Lost income and reduced earning capacity
• Pain and suffering
• Emotional distress
• Loss of quality of life
• Wrongful death damages for families who have lost a loved one

The Oshman Firm works on a contingency fee basis, meaning you pay no attorney's fees unless we recover compensation for you. Our team will evaluate your case at no cost and walk you through your legal options.

Warning Signs: Symptoms That May Indicate CTCL

Because CTCL can look so much like eczema in its early stages, many patients don't realize something more serious may be happening. Contact your doctor promptly if you are using Dupixent and experience:

• Persistent red, scaly patches or raised plaques that are not responding to treatment;
• Skin lesions that spread or change in character over time;
• Unusual itching, particularly if it becomes severe and widespread;
• Swollen lymph nodes;
• Reddening of the skin across large areas of the body (a sign of Sézary syndrome);
• Unexplained fatigue or weight loss; or
• Joint pain or throat pain accompanying skin changes.

Skin symptoms that worsen, shift, or fail to behave like typical eczema during Dupixent treatment warrant further evaluation by a dermatologist or hematologist with experience in lymphoma.

Patients who received a delayed or incorrect diagnosis may also want to speak with a Dupixent attorney about whether a dangerous medication error contributed to their harm.

Why Choose The Oshman Firm?

For more than 35 years, The Oshman Firm has represented people harmed by defective drugs, dangerous medical devices, and corporate negligence. We have secured millions of dollars in verdicts and settlements for clients across the country, including significant recoveries in pharmaceutical litigation cases involving serious and life-altering harm.

Our practice includes cases involving drugs like Xolair and Reglan, which caused serious harm to patients who were not adequately warned. Whether you are pursuing a personal injury claim or your family has lost a loved one and is considering a wrongful death lawsuit, we are prepared to fight for the accountability you deserve.

Contact The Oshman Firm for a Free Dupixent Case Review

Statutes of limitations vary by state, and our Dupixent attorneys can help you understand the deadline that applies to your situation.

If you or someone you love developed Dupixent T-cell lymphoma or another form of lymphoma after using this drug, call The Oshman Firm today at (212) 233-2100 or fill out our online form for a free, confidential case review.

We represent clients nationwide on a contingency fee basis, meaning there are no attorney's fees unless we recover compensation for you.