Lawsuits claiming that the eczema and asthma drug Dupixent caused a rare blood cancer are now running on two tracks in New Jersey. Federal cases are grouped before one judge in the U.S. District Court for the District of New Jersey, and plaintiffs’ lawyers have asked the state’s courts to group the New Jersey state court cases as well.
The lawsuits allege that Dupixent (dupilumab), made by Regeneron Pharmaceuticals and Sanofi, can cause or speed up cutaneous T-cell lymphoma (CTCL), and that the companies did not warn patients or doctors.
The federal Dupixent MDL
On June 4, 2026, the Judicial Panel on Multidistrict Litigation created In re Dupixent (Dupilumab) Products Liability Litigation, MDL No. 3180, and assigned it to U.S. District Judge Zahid N. Quraishi in New Jersey. The transfer order covered 15 lawsuits from 12 federal districts.
The plaintiffs who asked for the MDL wanted it in Atlanta. Regeneron, Sanofi and Genzyme preferred New York. The panel chose New Jersey because Sanofi’s U.S. headquarters is there and Regeneron has corporate offices in the state, so many witnesses and documents are likely nearby.
The companies also asked the panel to limit the MDL to CTCL claims. Plaintiffs opposed that, arguing that the medical literature also points to other T-cell lymphomas, including peripheral T-cell lymphoma. The panel left the question open, noting that every plaintiff before it alleged CTCL, and said cases involving other T-cell lymphomas can be addressed if they are filed.
The MDL has grown since June. The panel’s October 1, 2026 report lists 38 pending cases. In late September, plaintiffs’ lawyers asked the court to approve a 12-member leadership structure, with two co-lead counsel, an executive committee, a steering committee and a federal-state liaison. Judge Quraishi held the first management conference in the MDL in early October, and on October 23 the New Jersey firm Seeger Weiss announced that its founding partner, Christopher Seeger, had been appointed one of the plaintiffs’ co-lead counsel.
Cases in New Jersey state court
Not every Dupixent case can go to federal court. Federal courts generally hear these lawsuits only when the person suing and the companies are from different states, so people in states where the companies are based often file in state court instead.
Sanofi reported in its mid-year 2026 financial filing that, in addition to about 30 federal cases, eight Dupixent cases were pending in New Jersey state court. In mid-September, plaintiffs’ lawyers applied to have the state court cases designated as multicounty litigation, New Jersey’s version of an MDL, and handled by one judge in Middlesex County. The state’s courts have not yet ruled on the request.
What the lawsuits claim
The FDA approved Dupixent in 2017 for moderate to severe atopic dermatitis, a form of eczema. It is now also prescribed for asthma, chronic sinusitis with nasal polyps and several other conditions.
Most plaintiffs used Dupixent for eczema and were later diagnosed with CTCL. Others are spouses or surviving family members of users. Each alleges that Dupixent caused the cancer or made an existing one worse. Because early CTCL can look like eczema, with red, scaly and itchy patches of skin, the lawsuits allege that it can be mistaken for the condition Dupixent is meant to treat.
Plaintiffs point to published research, including a 2024 study in the Journal of the American Academy of Dermatology that found higher odds of CTCL among eczema patients treated with Dupixent. They also point to the FDA. In its quarterly list of potential safety signals covering October through December 2024, the agency listed CTCL for Dupixent and said it was evaluating the need for regulatory action. The Warnings and Precautions section of the U.S. label, last revised in April 2026, does not mention lymphoma.
Sanofi has told investors that it is not possible at this stage to reliably assess the outcome of the cases. LegalScoops reported on an early wrongful death lawsuit over Dupixent in November 2025.
What comes next
The parties were directed to submit a proposed initial management order by November 1, 2026, which will set the early schedule for the MDL. The central question in the coming months is general causation, meaning whether the science shows Dupixent can cause CTCL at all. In most drug MDLs, the court decides whether each side’s experts on that question can testify before any case goes to trial.
Common Questions About the Dupixent Lawsuits
Is there a Dupixent class action?
Many people search for a Dupixent class action, but the cancer claims are a mass tort. Each person files an individual lawsuit, and the federal cases are grouped in MDL No. 3180 for pretrial proceedings. Each claim is evaluated on the person’s own diagnosis and history.
Which cancers are involved?
The cases in the MDL so far involve cutaneous T-cell lymphoma, including mycosis fungoides and Sézary syndrome. Plaintiffs’ lawyers have argued that peripheral T-cell lymphoma and other T-cell lymphomas belong in the litigation too, and the panel left that question open.
Has the Dupixent label been changed to warn about lymphoma?
Not in the United States. The FDA listed CTCL as a potential safety signal for Dupixent and said it was evaluating whether regulatory action is needed, but the current U.S. label’s Warnings and Precautions section does not mention lymphoma.
Should I stop taking Dupixent?
Do not stop a prescribed medication without talking to your doctor. If you have new or worsening skin patches, rashes that do not respond to treatment, or swollen lymph nodes, ask your doctor whether a skin biopsy is appropriate.
Have there been any Dupixent settlements or trials?
No. The litigation is at an early stage. No trial dates have been set, and Sanofi and Regeneron have not announced any settlements.
Is there a deadline to file a Dupixent lawsuit?
Yes. Each state has a statute of limitations, and the time limit often runs from when a person was diagnosed or learned the cancer may be linked to the drug. The deadlines vary, so people with a diagnosis should not wait to have a claim reviewed.
Doyle APC is investigating Dupixent lymphoma lawsuits nationwide.
Diagnosed With Lymphoma After Using Dupixent?
Doyle APC is investigating Dupixent lymphoma claims nationwide. If you or a family member used Dupixent and were later diagnosed with cutaneous T-cell lymphoma or another T-cell lymphoma, you can request a free, confidential case review below. There are no fees or costs unless the firm recovers compensation for you.
