Dupixent Lawsuits Consolidated Into a New Federal MDL Over a Rare Skin Cancer

For hundreds of thousands of people, Dupixent has been the thing that finally quieted the itch. It is a biologic — an injectable antibody drug — prescribed for moderate-to-severe eczema (atopic dermatitis), asthma, chronic sinus disease with nasal polyps, and several other conditions driven by a specific kind of immune inflammation. It calms an overactive immune response. But a growing group of patients now alleges, in lawsuits, that the same drug did something no one warned them about: that it caused or sped up a rare cancer of the immune system’s own cells.

In early June 2026, the U.S. Judicial Panel on Multidistrict Litigation (JPML) took the procedural step that signals this litigation has reached critical mass. According to AboutLawsuits.com and court records, the Panel ordered the 15 Dupixent lawsuits then pending across 12 federal districts to be consolidated before one judge, with roughly seven more potential “tag-along” cases identified. The new litigation is MDL No. 3180, assigned to U.S. District Judge Zahid N. Quraishi in the District of New Jersey.

What the Lawsuits Actually Allege

The consolidated cases center on cutaneous T-cell lymphoma (CTCL) — a rare cancer of the T-cells (a type of white blood cell) that first appears in the skin, often mistaken early on for stubborn eczema or a rash. The lawsuits name the drug’s makers, Sanofi and Regeneron, and allege, in substance, that the companies:

• Failed to adequately warn patients and physicians that Dupixent may be associated with an increased risk of rare blood and skin cancers, including CTCL;
• Failed to adequately test and monitor the drug for a lymphoma signal as reports accumulated; and
• Marketed the drug in a way that, plaintiffs say, downplayed or omitted that risk.

Some plaintiffs allege the drug caused a new cancer; others allege it accelerated a CTCL that was already present but undiagnosed — a particularly thorny claim, because early CTCL and the eczema Dupixent treats can look alike. The alleged subtypes include mycosis fungoides and Sézary syndrome, the two most common forms of CTCL, along with other T-cell lymphomas.

None of this has been proven. These are allegations, and both companies dispute them. That is precisely what the discovery phase of an MDL exists to test.

Where the FDA Signal Comes In

Lawsuits do not appear out of nowhere; they usually follow a safety signal. Here, the reported signal comes from the FDA Adverse Event Reporting System (FAERS) — the federal database where doctors, patients, and manufacturers log suspected drug side effects. According to an analysis of FAERS data reported by AboutLawsuits.com, the database contained roughly 298 lymphoma reports tied to Dupixent as of late 2025 — including about 138 cutaneous T-cell lymphoma reports, around 104 unspecified lymphoma reports, and roughly 41 general T-cell lymphoma reports, with additional cases of advanced CTCL and other subtypes.

Here is the honest caveat, and it matters: a FAERS report is a suspicion, not a verdict. The database captures events that happened after someone took a drug; it does not, by itself, prove the drug caused them. A signal like this is a reason to investigate — which is what regulators and courts do — not a finding that Dupixent causes cancer. Reputable reporting has described the CTCL association as a potential safety signal the FDA has been evaluating. We are reporting the signal, not endorsing a conclusion the science has not reached.

What an MDL Is — and What It Is Not

This is the part most headlines get wrong, so it is worth being precise. An MDL is not a class action. In a class action, one group of people is treated as a single unit and shares one outcome. In a multidistrict litigation, every plaintiff keeps their own individual case — their own medical records, their own diagnosis, their own timeline, their own potential result. The cases are simply pulled in front of one judge so the shared pretrial work — gathering company documents, taking expert testimony, deciding common legal questions — happens once instead of being repeated in a dozen courthouses.

For a patient, the practical takeaway is that the formation of MDL 3180 makes the litigation more organized and efficient, but it does not fold anyone’s situation into a faceless group. The JPML also left the door open: while the MDL is focused on CTCL for now, it signaled that cases involving other T-cell lymphomas could be added later through the standard transfer process. In plain terms, this litigation is early and may grow.

What to Do If You Take Dupixent

• Do not stop the drug on your own. Talk to your prescribing doctor about any concern. Stopping a biologic abruptly can cause your underlying condition to flare.
• Watch for skin changes and report them medically — new or changing patches, plaques, or a rash that behaves differently than your usual eczema. Early evaluation is a health matter first.
• Keep your records — when you started Dupixent, your dermatology and oncology notes, biopsy and pathology reports, and the date of any lymphoma diagnosis.
• Understand the difference between owning a risk and having a claim. Simply having taken Dupixent is not an injury. A lawsuit is about a diagnosis that already happened.
• Confirm your deadline. The statute of limitations varies by state and by when you knew, or should have known, of a possible link. Waiting can permanently end the right to file.

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