Published
June 20, 2026
Allegations Only · Causation Unproven · No Settlement
This article describes a mass-tort litigation. The statements below are unproven allegations. Sanofi and Regeneron have not been found liable, the science is an association under study rather than established causation, there is no certified class, and nothing to claim. This page is informational and is not legal or medical advice — do not stop taking a prescribed medication without talking to your doctor.
Status
New MDL — Early Stage
MDL No. 3180 created June 4, 2026 · D.N.J. · Judge Quraishi
Allegation
Failure to warn of a lymphoma (CTCL) association
Against Sanofi & Regeneron · causation contested and unproven
Can I Claim?
No — nothing to claim yet
No settlement, no fund, no claim form · individual mass-tort claims, not a class action
What Is This About?
A newly formed multidistrict litigation alleges that the makers of Dupixent — a widely used prescription biologic — failed to warn patients and doctors that the drug is associated with an increased risk of a rare skin lymphoma. The cases are consolidated as In re: Dupixent (Dupilumab) Products Liability Litigation, MDL No. 3180, in the U.S. District Court for the District of New Jersey before Judge Zahid N. Quraishi.It is important to be clear at the outset: this is an early-stage mass tort built on a contested scientific theory. The drug's makers, Sanofi and Regeneron, have not been found liable, no court has decided the science, and whether Dupixent causes lymphoma has not been established. There is no settlement and nothing to claim.
What Is Dupixent?
Dupixent (dupilumab) is a fully human monoclonal antibody, co-developed and co-marketed by Sanofi and Regeneron, first approved by the FDA in 2017. It blocks signaling by two proteins (IL-4 and IL-13) involved in type-2 inflammation and is one of the best-selling drugs in the world. Its FDA-approved uses include moderate-to-severe atopic dermatitis (eczema), certain asthma, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, prurigo nodularis, and COPD with type-2 inflammation, in adults and — for several uses — children.What the Lawsuits Allege
The plaintiffs allege that Sanofi and Regeneron knew or should have known of an association between dupilumab and cutaneous T-cell lymphoma (CTCL) — a rare lymphoma of the skin, such as mycosis fungoides — and failed to warn patients and prescribers. The claims sound in product liability and failure-to-warn: that the drug's labeling was inadequate because it did not disclose the alleged risk. The MDL began with roughly 15 to 18 individual actions and is at a very early, pretrial-coordination stage, with additional "tag-along" cases expected.These are allegations only. A failure-to-warn claim does not require proof that the drug is unsafe for everyone — but the plaintiffs will still have to establish that dupilumab can cause CTCL, which is the contested scientific core of the case.
The Science: Association, Not Proven Causation
Important: it has not been established that Dupixent causes lymphoma. Some observational studies report a higher rate of CTCL among dupilumab users — one 2024 cohort study described a roughly four-fold association — but observational studies show correlation, not proven causation, and they carry significant confounding concerns. Two competing explanations are actively debated:• Unmasking / misdiagnosis. Early-stage CTCL (mycosis fungoides) can closely mimic atopic dermatitis. Some patients may have had undiagnosed CTCL that only became apparent after dupilumab cleared their eczema — meaning the drug may have revealed a pre-existing cancer rather than caused it. The often-short time from starting the drug to a CTCL diagnosis is consistent with this.
• Possible progression. Some case reports hypothesize the drug's effect on the immune system could accelerate an underlying CTCL. This remains a hypothesis, not a proven mechanism.
Both possibilities are under study. Responsible coverage describes the link as "associated with," not "causes."
What the FDA Label Says
As of this writing, the FDA-approved Dupixent prescribing information does not carry a lymphoma or CTCL warning, and the absence of such a warning is precisely what the failure-to-warn claims target. Separately, the FDA has listed dupilumab on a quarterly FAERS ("FDA Adverse Event Reporting System") potential-signals report in connection with CTCL, indicating it is evaluating whether regulatory action — possibly including a label update — is warranted. A FAERS potential signal is a monitoring flag based on reported events; it is not an FDA conclusion that the drug causes the condition, and it is not a recall.Is There a Dupixent Settlement?
No. This is a newly created MDL, not a settlement.That means:
• There is no settlement fund.
• There is no claim form.
• There is no payout, and no deadline to act.
An MDL coordinates many individual product-liability claims for pretrial efficiency; it is not a class action and there is no class to "join" and no global payout. The litigation is at the beginning of the process, with no bellwether trials scheduled. If it ever produces settlements or verdicts, those would be reported separately.
What Should Patients Do?
Do not stop taking a prescribed medication based on a lawsuit. Dupixent treats serious conditions, and stopping it can carry its own risks. Patients with questions or new skin symptoms should talk to their prescribing physician or a dermatologist, who can evaluate whether any change or additional testing is appropriate. This page is informational and is not legal or medical advice.Frequently Asked Questions
Is there a Dupixent lawsuit settlement?
No. MDL 3180 is a newly formed mass tort with no settlement, fund, or claim form. Sanofi and Regeneron have not been found liable, and there is nothing to claim.Does Dupixent cause lymphoma?
That has not been established. Some studies report an association with cutaneous T-cell lymphoma, but observational data show correlation, not proven causation — and one leading explanation is that the drug may unmask a pre-existing CTCL rather than cause it.Does the Dupixent label warn about lymphoma?
Not currently — and that absence is what the failure-to-warn suits target. The FDA has flagged dupilumab/CTCL on a FAERS potential-signals report, which is a monitoring flag, not a finding of causation.Sources
• U.S. Judicial Panel on Multidistrict Litigation — panel orders (MDL 3180)• FDA — FAERS "Potential Signals of Serious Risks" (dupilumab / CTCL)
• PubMed — 2024 cohort study on dupilumab and cutaneous T-cell lymphoma (association)
• Court records — In re: Dupixent (Dupilumab) Products Liability Litigation, MDL No. 3180 (D.N.J.)
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Status
MDL created June 4, 2026 — early stage
Caption
In re: Dupixent (Dupilumab) Products Liability Litigation
MDL Number
MDL No. 3180
Court
U.S. District Court, District of New Jersey
Judge
Hon. Zahid N. Quraishi
Defendants
Sanofi & Regeneron
