Failure to warn
Plaintiffs allege that Dupixent labeling did not adequately warn patients or doctors about reported CTCL or T-cell lymphoma risks.
Dupixent CTCL Litigation
Dupixent Lawsuit: CTCL and T-Cell Lymphoma Claims
Lawsuits involving Dupixent allege that patients and doctors were not adequately warned about reported CTCL and T-cell lymphoma risks. This page explains the current litigation posture, the core allegations, and what an initial case review may consider.
What is the Dupixent lawsuit about?
The Dupixent litigation focuses on allegations involving CTCL or related T-cell lymphoma diagnoses after Dupixent use and claims that the drug's labeling did not adequately warn about those reported risks. Filed JPML materials describe allegations involving warnings, labeling, marketing, safety-signal context, and related common issues.
This page provides general litigation background. Individual medical history, diagnosis records, timing, and other facts still need case-specific review. For science-focused background, see Dupixent & CTCL.
Current litigation status — June 2026
On June 4, 2026, the JPML granted centralization for federal Dupixent cases involving alleged CTCL and related claims. The litigation is now proceeding as MDL No. 3180, In re: Dupixent (Dupilumab) Products Liability Litigation, in the District of New Jersey, before Judge Zahid N. Quraishi.
MDL centralization means related federal cases will move together for coordinated pretrial proceedings, including discovery, motions, expert issues, and other case-management steps. The transfer order states that possible future expansion beyond CTCL cases can be addressed through the conditional transfer process.
Centralization does not decide whether Dupixent caused CTCL or any related T-cell lymphoma, whether defendants are liable, or whether any individual claim will succeed. Those issues remain to be litigated.
As of May 2026, no CTCL warning appears in the Dupixent prescribing label, despite the FDA FAERS safety signal published March 31, 2025.
We also published a detailed explainer on what the new Dupixent MDL may mean for patients diagnosed with CTCL.
Who are the defendants in the Dupixent litigation?
Filed JPML materials identify Regeneron Pharmaceuticals, Sanofi-Aventis U.S. LLC, and Genzyme Corporation in the litigation context. These descriptions summarize allegations and procedural background from filed materials and should not be read as findings by a court.
For related medical background, visit Dupixent & CTCL.
What do plaintiffs allege?
Scientific and safety signals
Filed materials reference published studies, adverse-event data, and regulatory reporting that plaintiffs say raised questions about CTCL-related risks.
Marketing and labeling
Plaintiffs allege that defendants promoted Dupixent across approved uses while failing to provide adequate warnings about reported T-cell lymphoma risks.
Common factual questions
The JPML motion and supporting brief describe common factual and legal questions across the actions.
What diagnoses may be relevant to this review?
This review is focused on CTCL and related T-cell lymphoma diagnoses, including mycosis fungoides, Sézary syndrome, peripheral T-cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, primary cutaneous anaplastic large cell lymphoma, and extranodal natural killer/T-cell lymphoma. This review is focused on CTCL and related T-cell lymphoma diagnoses. Other cancers or unrelated lymphoma diagnoses may involve different medical and legal questions.
If your records include one of these diagnoses after Dupixent use, your history may warrant review through the initial review form.
What may matter in an initial review?
An initial review may consider whether the person used Dupixent, the approved indication for which it was prescribed, the diagnosis received, the timing between treatment and diagnosis, whether medical records show a delayed diagnosis, worsening symptoms, progression, or specialist evaluation, and whether pathology or specialist records are available.
These facts can help reviewers understand whether a history may warrant closer review. You can start with basic details at the initial review form.
Sources reviewed for this page
- Motion for Transfer of Actions, Brief in Support, and Schedule of Actions, In re Dupixent Products Liability Litigation, MDL No. 3180, filed February 13, 2026.
- Notice of Hearing Session and Hearing Session Order, In re Dupixent (Dupilumab) Products Liability Litigation, MDL No. 3180, Document 40, filed April 16, 2026, scheduling the matter for the May 28, 2026 JPML hearing session.
- JPML Transfer Order, In re: Dupixent (Dupilumab) Products Liability Litigation, MDL No. 3180, filed June 4, 2026.
- October–December 2024 Potential Signals of Serious Risks/New Safety Information Identified by the FDA Adverse Event Reporting System (FAERS), listing Dupixent (dupilumab) injection and cutaneous T-cell lymphoma as a potential signal under FDA evaluation.
- Lavin et al., Cutaneous T-Cell Lymphoma after Dupilumab Use: A Real-World Pharmacovigilance Study of the FDA Adverse Event Reporting System, Journal of Investigative Dermatology, 2025.
- DUPIXENT® (dupilumab) Prescribing Information, Revised 06/2025, Reference ID 5611202.
Helpful next pages
Dupixent & CTCL
Learn the scientific and medical background behind the CTCL-focused review.
Read Dupixent & CTCLDo I Qualify?
Review the basic facts that may matter before submitting an inquiry.
Read Do I Qualify?Initial Review
Submit basic information for an initial review.
Start Free Case ReviewLast reviewed by Keke Feng, Esq. — June 9, 2026
Frequently Asked Questions
Is there a Dupixent MDL?
Yes. On June 4, 2026, the JPML granted centralization for federal Dupixent cases involving alleged CTCL and related claims. The litigation is now proceeding as MDL No. 3180 in the District of New Jersey.
What is the lawsuit alleging?
Plaintiffs allege failure-to-warn and related claims involving reported CTCL and T-cell lymphoma risks, with allegations tied to safety data, labeling, and marketing issues described in filed court materials.
Does this lawsuit cover every cancer after Dupixent?
No. This review is focused on CTCL and related T-cell lymphoma diagnoses, not every cancer or every lymphoma diagnosis.
Who are the defendants named in filed JPML materials?
Filed JPML materials identify Regeneron Pharmaceuticals, Sanofi-Aventis U.S. LLC, and Genzyme Corporation in the litigation context. These references summarize filed allegations and procedural materials and should not be read as findings by a court.
What information may help an initial review?
Helpful information may include Dupixent treatment history, diagnosis records, and timeline details about symptoms and confirmation of a CTCL-related diagnosis.
Does submitting a case review form mean my case has been accepted?
No. Submitting a form requests an initial review only and does not create an attorney-client relationship or mean a matter has been accepted.
Start Free Case Review
If you used Dupixent and were later diagnosed with CTCL or another related T-cell lymphoma, you may submit basic information for a focused initial review. You do not need to have every record ready before starting, although additional records may be needed later.