TL;DR - On June 4, 2026, the Judicial Panel on Multidistrict Litigation transferred 15 actions alleging that Dupixent caused cutaneous T-cell lymphoma (CTCL) to the District of New Jersey. - Twenty-six cases had been filed in or transferred to the MDL as of July 1, 2026. - The judge set the initial case management conference for October 1, 2026.
Background
A motion to centralize the cases was filed on February 13, 2026, on behalf of 15 plaintiffs in 12 district courts. The lawsuits name Regeneron Pharmaceuticals and Sanofi-Aventis U.S. and allege that the companies knew of a possible connection between Dupixent's immune-modulating mechanism and the development or acceleration of T-cell lymphoma, a rare form of non-Hodgkin lymphoma, but failed to warn patients and doctors. The drugmakers had agreed that centralization was appropriate and disputed where the cases should go.
What happens next
In a June 11, 2026 order, the MDL judge asked the parties to confer on case-management matters before July 24. The first case management conference was set for October 1, 2026, where the schedule for discovery and early motions is usually discussed. The docket is still small compared with large MDLs, and the allegations have not been tested in court. The defendants dispute that Dupixent causes cancer.
For more on how consolidated federal litigation works, see our explainer on multidistrict litigation.
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