What Is Dupixent (Dupilumab)?

Dupixent is the brand name for dupilumab, a monoclonal antibody injection manufactured by Sanofi and Regeneron. It works by blocking two proteins in the body, interleukin-4 and interleukin-13, that contribute to inflammation in a range of conditions.

The FDA first approved Dupixent in March 2017 to treat moderate-to-severe atopic dermatitis (commonly called eczema). Since then, the approved uses have expanded considerably. Dupixent is now used to treat:

• Moderate-to-severe atopic dermatitis (eczema)
• Moderate-to-severe asthma
• Chronic rhinosinusitis with nasal polyps
• Eosinophilic esophagitis
• Prurigo nodularis
• Chronic obstructive pulmonary disease in patients with high blood eosinophil counts
• Chronic spontaneous urticaria
• Bullous pemphigoid
• Allergic fungal rhinosinusitis in patients who’ve had nose or sinus surgery

Dupixent is given by injection under the skin, typically in the thigh, abdomen, or upper arm. It’s commonly prescribed when topical treatments haven’t worked or aren’t appropriate.

The Link Between Dupixent and Cutaneous T-Cell Lymphoma

Research linking Dupixent to CTCL has been building for several years across multiple peer-reviewed studies and adverse event reports:

• Journal of the American Academy of Dermatology (2024): A 2024 study found that eczema patients who used Dupixent were about four times more likely to develop CTCL than eczema patients who never took the drug. In most of these cases (about 2 in 3), the diagnosis came more than a year after starting Dupixent.
• Dermatologic Therapy (2024): A larger 2024 study comparing more than 39,000 eczema patients reached a similar conclusion. Dupixent users were about 4.6 times more likely to develop CTCL than eczema patients who never took it. Most CTCL diagnoses (61%) showed up within the first year of starting the drug.
• European Respiratory Journal (2025): A 2025 study extended these concerns to asthma patients. Compared to those on standard inhaled steroid treatments, asthma patients on Dupixent were about 1.8 times more likely to develop any type of lymphoma. For T-cell and NK-cell lymphomas (the categories that include CTCL), Dupixent users were about 4.6 times more likely to be diagnosed.

In their motion to consolidate Dupixent cases into a federal MDL, plaintiffs allege that Sanofi and Regeneron knew or should have known about these risks and failed to update Dupixent’s warning label to disclose them to patients and prescribing physicians.

How Dupixent May Contribute to CTCL

The medical research identified a few different proposed mechanisms for how Dupixent may cause or worsen CTCL:

• Masking cancer symptoms. Dupixent may reduce the visible skin inflammation caused by early-stage CTCL without addressing the underlying cancer, delaying diagnosis.
• Impairing immune surveillance. By blocking the IL-4 and IL-13 signaling pathways, the drug may weaken the body’s ability to identify and destroy abnormal cells.
• Redirecting cell signaling. Research suggests IL-13 signaling may be redirected toward receptors found on malignant T-cells, potentially promoting cancer cell growth.
• Delaying diagnosis through symptom overlap. Because early CTCL looks almost identical to eczema, patients prescribed Dupixent for what was diagnosed as eczema may continue treatment for months or years while CTCL progresses undetected.

Two patterns emerged from the research:

In some cases, patients developed CTCL after starting Dupixent. This raises questions about whether the drug can cause the disease in people who are susceptible.

In others, patients who already had CTCL (sometimes undiagnosed) saw their condition progress rapidly while on the drug, suggesting Dupixent can worsen an existing cancer or hide its early signs.

What Is CTCL (Cutaneous T-Cell Lymphoma)?

Cutaneous T-Cell Lymphoma is a group of rare cancers that begin in the T-cells of the skin. The most common subtypes include:

• Mycosis fungoides
• Sézary syndrome
• Lymphomatoid papulosis
• Granulomatous slack skin disease
• Pagetoid reticulosis

Early-stage CTCL often presents with skin symptoms that can look almost identical to eczema: red, scaly patches; persistent itching; dry skin; sometimes raised lesions. This similarity is part of what makes the Dupixent connection particularly concerning. Patients prescribed Dupixent for what was diagnosed as eczema may actually have had early CTCL that went unrecognized, and the medication may have allowed the disease to progress.

When CTCL advances, it can spread beyond the skin to lymph nodes, blood, and internal organs. Treatment depends on the stage and subtype, but options can include phototherapy, topical or systemic chemotherapy, radiation, immunotherapy, and stem cell transplantation in more advanced cases.

Dupixent Lawsuit Update

Dupixent lawsuits have now been formally grouped into a single coordinated court proceeding called a multidistrict litigation, or MDL. An MDL combines similar lawsuits from across the country into one federal court to make the process more efficient. Each case still keeps its own facts and outcome, but the early stages (like discovery and pretrial motions) happen in one place under one judge.

Here’s how the Dupixent litigation has developed:

• March 2025: The FDA placed Dupixent on its watchlist of drugs with potential safety concerns, citing more than 300 reports of CTCL among Dupixent users.
• October 2025: The first wrongful death lawsuit was filed in Tennessee. It was brought by the family of a patient who developed T-cell lymphoma after starting Dupixent and died months later.
• February 2026: Plaintiffs’ attorneys formally asked the federal panel that handles these decisions (the JPML) to combine the cases. Sanofi and Regeneron agreed that combining the cases made sense but argued for New York, where they’re headquartered. Plaintiffs requested Georgia. The JPML ultimately chose New Jersey because Sanofi’s main offices are there.
• June 2026: Federal judges officially combined the Dupixent cases into MDL No. 3180 in the District of New Jersey. The cases are now overseen by Judge Zahid N. Quraishi. The MDL started with 15 lawsuits, with 7 more expected to follow, drawn from courts across 12 states.

The MDL currently covers cases involving CTCL. Cases involving other T-cell lymphoma subtypes can be added later if the court allows.

Who May Be Eligible to File a Dupixent Lawsuit

Eligibility for a Dupixent claim depends on the specific facts of each case. Generally, a potential claim requires documentation establishing:

• A diagnosis of Cutaneous T-Cell Lymphoma or a related skin lymphoma
• Use of Dupixent (dupilumab) before or around the time of the diagnosis
• A timeline that connects the drug’s use to the onset or progression of the disease
• Medical records sufficient to support each of the above

A free case review with one of our attorneys is the most reliable way to determine whether your situation fits the criteria being pursued in active litigation. The review involves a confidential conversation about your medical history and treatment, followed by an evaluation of your prescription and diagnosis records.

Failure to Warn: The Legal Basis for These Claims

Dupixent lawsuits are based on a product liability theory called “failure to warn.” Under this theory, a drug manufacturer can be held liable when:

• The manufacturer knew or reasonably should have known about a risk associated with the drug
• The manufacturer failed to provide adequate warnings to patients, prescribing physicians, or both
• That failure caused the plaintiff to use the drug under circumstances they wouldn’t have otherwise accepted
• The plaintiff suffered harm as a result

Plaintiffs in the Dupixent litigation argue that Sanofi and Regeneron had access to studies and case reports suggesting an increased risk of CTCL but didn’t update the product warnings to reflect those risks. Establishing this involves discovery into internal manufacturer documents, FDA communications, and the medical literature available at the time the drug was being prescribed.

How a Dupixent Lawsuit Attorney Can Help

The diagnosis of any cancer is difficult enough on its own. The treatment is demanding, and the financial impact compounds quickly. Pursuing a legal claim on top of that can feel like an added weight, but most of the work happens on the attorney’s side once the case is underway.

An experienced Dupixent attorney can help with:

• Reviewing claim eligibility during a free initial consultation
• Collecting medical records and prescription history to support the claim
• Coordinating with treating physicians for opinions on causation
• Preparing and filing the claim before applicable deadlines expire
• Responding to discovery requests and inquiries from the defendants
• Negotiating with the manufacturer counsel toward a settlement
• Trying the case if a fair settlement isn’t reached

If your case is part of consolidated litigation, your attorney also coordinates with lead counsel and follows the case management orders issued in the multidistrict proceeding.

Statute of Limitations Considerations

Each state has its own statute of limitations for product liability and personal injury claims, and pharmaceutical cases often involve a discovery rule that affects when the deadline begins to run. In most states, the clock starts when the patient knew or reasonably should have known that the drug caused or contributed to the injury.

That said, statute of limitations deadlines can pass before a patient connects their diagnosis to the medication. The safer path is to consult an attorney as soon as a possible connection becomes apparent, rather than waiting to see how the litigation develops. Once a deadline passes, the right to file is generally lost regardless of how strong the underlying case is.

Talk to a Dupixent Lawsuit Attorney at Shaheen & Gordon

If you or a loved one has been diagnosed with CTCL after using Dupixent for eczema, asthma, nasal polyps, or any other condition, the time to evaluate your legal options is now. Lawsuits are actively moving through the courts, and joining one before key deadlines pass requires preparation that starts well before any filing.

Call (800) 451-1002 or contact us online to request a free case review with our Dupixent lawsuit attorneys.

Frequently Asked Questions About Dupixent Lawsuits

How much does it cost to hire a Dupixent lawsuit attorney?

Our Dupixent cases are handled on a contingency fee basis. Clients don’t pay attorney fees unless and until a recovery is made through settlement or judgment.

What if my Dupixent prescription was years ago?

Many CTCL diagnoses linked to Dupixent come months or years after the drug was prescribed. The discovery rule in most states means the statute of limitations doesn’t start until the harm is reasonably knowable. A consultation can clarify whether your case still falls within the filing window.

Do I need to stop taking Dupixent to pursue a claim?

That’s a medical decision to be made with your treating physician, not a legal one. Any decision about continuing or stopping the medication should be based on medical advice, and we don’t make medical recommendations.

What kind of compensation may be available?

Damages in Dupixent claims can include medical expenses already incurred and reasonably anticipated, lost income and earning capacity, pain and suffering, loss of enjoyment of life, and, in some cases, punitive damages where the manufacturer’s conduct supports it.

What if my family member died from CTCL after using Dupixent?

Wrongful death claims may be available to surviving family members when a Dupixent user dies from CTCL. The eligible family members and the available damages depend on the law of the state where the case is filed.

Is this a class action or an individual lawsuit?

Most current Dupixent cases are being filed as individual personal injury lawsuits, though many are being consolidated into multidistrict litigation (MDL) for efficiency in discovery and pretrial proceedings. The cases generally remain individual for purposes of settlement and trial.