What the New Dupixent MDL Means for Patients Diagnosed With CTCL

What the Dupixent MDL is about

The lawsuits generally involve people who used Dupixent, also known as dupilumab, and were later diagnosed with CTCL, as well as certain spouses or survivors. Many plaintiffs allege Dupixent was used for atopic dermatitis, commonly known as eczema, before a CTCL diagnosis.

Plaintiffs allege that Dupixent may have caused or accelerated CTCL in some patients and that the manufacturers failed to provide adequate warnings about alleged CTCL-related risks. Some patient histories may also raise questions about whether CTCL was difficult to recognize before or during Dupixent treatment.

These are allegations. The defendants are expected to contest causation, warning adequacy, and other legal and scientific issues as the litigation moves forward.

For the litigation overview, including how MDL No. 3180 differs from a class action, see the Dupixent lawsuit overview.

Why CTCL diagnosis can be complicated

CTCL is a group of non-Hodgkin T-cell lymphomas that primarily affect the skin. Its skin findings can sometimes resemble eczema, dermatitis, psoriasis, or other inflammatory skin conditions. Symptoms alone do not establish a CTCL diagnosis; clinical evaluation, skin biopsy, and blood testing may be part of the diagnostic process.

That overlap may matter in individual Dupixent histories because many patients received Dupixent for what was believed to be eczema or another inflammatory condition. Some lawsuits allege that patients continued treatment while their CTCL progressed or while the underlying condition remained difficult to identify.

For case review purposes, the question is specific to the individual: when Dupixent was used, when symptoms began or changed, when CTCL was diagnosed, and what the medical records show.

What happens next in the Dupixent MDL?

Public docket listings indicate that Initial Procedure Order No. 1 was entered on June 11, 2026, consolidating listed civil actions for pretrial purposes only and setting an Initial Management Conference for October 1, 2026 before Judge Zahid N. Quraishi and Magistrate Judge J. Brendan Day.

Related federal cases can now be transferred for coordinated pretrial proceedings. In a product liability MDL, this process may include:

• organizing the docket and case-management structure
• coordinating discovery between plaintiffs and defendants
• addressing preservation and production of documents
• handling motions that affect many cases
• managing expert issues and scientific evidence
• creating procedures for individual plaintiff information
• later determining whether bellwether or trial-selection procedures are appropriate

Not every MDL follows the same path. Some involve bellwether trials or settlement discussions, while others are narrowed or dismissed after major legal or scientific rulings. At this stage, the Dupixent MDL remains early, and no particular outcome is guaranteed.

What information may matter for patients and families

Useful information for an initial review may include:

• when Dupixent treatment began and ended
• why Dupixent was prescribed
• whether the patient was treated for eczema, atopic dermatitis, asthma, or another condition
• when skin symptoms began, changed, worsened, or failed to improve
• whether CTCL, mycosis fungoides, Sézary syndrome, or another T-cell lymphoma was diagnosed
• the date of diagnosis
• biopsy, pathology, dermatology, oncology, and prescription records
• whether another attorney already represents the matter
• the state where treatment and diagnosis occurred

A person does not need every record before requesting an initial review. Diagnosis records, biopsy reports, dermatology notes, oncology records, and prescription history may become important if the matter moves forward.

For the site’s latest verified litigation developments, see Dupixent litigation updates.

Requesting an initial review

If you or a family member used Dupixent and were later diagnosed with CTCL, mycosis fungoides, Sézary syndrome, or another related T-cell lymphoma, you may submit basic information for an initial review.

Submitting information does not create an attorney-client relationship and does not guarantee that a claim will be accepted. Review depends on the specific facts, medical records, timing, applicable law, and current litigation criteria.

Why the cases were centralized in New Jersey

Plaintiffs asked the JPML to centralize federal Dupixent cases in the Northern District of Georgia, with the District of New Jersey and Northern District of Illinois proposed as alternatives. Defendants Regeneron, Sanofi-Aventis U.S., and Genzyme supported centralization but proposed other districts, including the Southern District of New York.

The Panel selected the District of New Jersey. In its order, the JPML noted that Sanofi’s principal place of business is in New Jersey and that Regeneron, headquartered nearby in Tarrytown, New York, also has corporate offices in New Jersey. The Panel concluded that relevant witnesses and evidence are likely to be located in or near New Jersey and that the district is accessible for nationwide litigation.