What the New Dupixent MDL Means for Patients Diagnosed With CTCL

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.

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.

Why CTCL diagnosis can be complicated

CTCL is a group of non-Hodgkin T-cell lymphomas that primarily affect the skin. In its early stages, CTCL can sometimes resemble eczema, dermatitis, psoriasis, or other inflammatory skin conditions. Patients may experience rashes, plaques, itching, redness, or persistent skin symptoms before a biopsy or specialist evaluation leads to a CTCL diagnosis.

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 diagnoses are currently included?

The JPML order focuses on lawsuits involving CTCL and CTCL subtypes. The Panel noted that the cases before it involved CTCL or one of its subtypes.

The Panel also addressed whether the MDL should include other T-cell lymphoma diagnoses. Defendants asked to limit the litigation to CTCL. Plaintiffs agreed that the MDL should not include B-cell lymphoma, Hodgkin’s lymphoma, or diseases that are not T-cell lymphomas, but opposed limiting the MDL only to CTCL.

The JPML did not decide whether future cases involving non-cutaneous T-cell lymphomas should be included. The Panel stated that future expansion beyond CTCL cases can be addressed through the conditional transfer process. Future claims involving other T-cell lymphoma diagnoses may therefore require separate review.

What happens next in the Dupixent MDL?

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.

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.