Overview
Federal lawsuits alleging that Dupixent caused or accelerated cutaneous T-cell lymphoma (CTCL) have been consolidated into a multidistrict litigation in New Jersey. The cases claim that Regeneron Pharmaceuticals and Sanofi failed to warn patients and doctors about the risk. No court has ruled on the merits of these claims, and the companies dispute that the drug causes lymphoma.[1][2]
First Filing
The first Dupixent lymphoma case was filed on October 1, 2025, in the United States District Court for the Middle District of Tennessee. The case, Richardson v. Regeneron Pharmaceuticals, No. 3:25-cv-01125, was brought as a wrongful death claim.[1]
Motion to Consolidate
On February 13, 2026, plaintiffs in 15 cases filed across 12 different federal district courts asked the Judicial Panel on Multidistrict Litigation (JPML) to consolidate their lawsuits.[2]
The JPML is a panel of federal judges with authority to transfer related cases pending in different federal courts into a single district for coordinated pretrial proceedings. Consolidation is designed to avoid duplicative discovery, prevent inconsistent rulings, and conserve judicial resources when many cases raise common questions of fact.
The motion described the cases as alleging that Dupixent caused or sped up cutaneous T-cell lymphoma and that Regeneron and Sanofi failed to warn about that risk.[2]
The Allegations
The lawsuits allege that Dupixent caused or accelerated CTCL, a type of cancer affecting the skin. Plaintiffs claim the manufacturers failed to provide adequate warnings about this risk.[2]
One theory advanced in the cases is that Dupixent unmasked lymphoma that had previously been mistaken for eczema.[1]
The Dupixent prescribing information that was revised in April 2026 did not contain any warning about lymphoma, CTCL, or cancer. The companies dispute that the drug causes lymphoma.[1]
These remain allegations. No court has made findings of fact or ruled on whether Dupixent causes lymphoma or whether any warning was required.
MDL Creation
On June 4, 2026, the JPML created MDL No. 3180, formally titled In re Dupixent, and assigned it to the United States District Court for the District of New Jersey. The MDL was assigned to Judge Zahid N. Quraishi.[1]
At the time the MDL was created, 15 actions were transferred into the consolidated proceeding. The JPML also identified 7 potential tag-along cases that might be transferred later.[1]
A multidistrict litigation does not merge the individual cases into a single lawsuit. Each plaintiff retains a separate case. The MDL groups them together under one judge for pretrial proceedings such as motion practice, discovery, and bellwether trial selection. If cases are not resolved during the MDL, they can be sent back to their original courts for trial.
What Is Not Known Yet
The record we track does not show that any pretrial orders, case management schedules, or bellwether trial selections have been entered in MDL No. 3180.
The record does not show whether additional cases have been filed or transferred into the MDL since its creation.
The record does not show a trial date for any case.
The record does not show any settlement, proposed settlement, or settlement negotiations.
The record does not show any rulings on the merits of the claims, any motion to dismiss, or any summary judgment decision.
No court has determined whether Dupixent causes or accelerates lymphoma, whether the manufacturers were required to provide warnings, or whether any plaintiff is entitled to damages.
Where Things Stand
As of the most recent information in the record, the Dupixent lymphoma cases are consolidated in the District of New Jersey under Judge Quraishi in MDL No. 3180. The MDL was created with 15 transferred cases and 7 potential tag-alongs.[1]
The litigation is in its early stages. The cases involve allegations that have not been proven and defenses that have not been tested in court.
Sources
- Richardson v. Regeneron Pharmaceuticals, No. 3:25-cv-01125 (M.D. Tenn.) (2025-10-01). Secondary report: tavrn.ai
- JPML motion (2026-02-13). Secondary report: verusllc.com
Litigation facts on this page come from the TortIntel litigation record and the documents linked above. Last checked against that record on 2026-10-24. If you see an error, tell us and we will correct it.