Dupixent
“When an eczema drug is linked to lymphoma.”
Dupixent is one of the best-selling biologics in the world. A growing body of research links it to a rare blood-and-skin cancer — and plaintiffs allege patients were never warned.
Cutaneous T-cell lymphoma (mycosis fungoides, Sézary syndrome)
Dupixent patients later diagnosed with CTCL
Sanofi & Regeneron Pharmaceuticals
MDL formed June 2026 — District of New Jersey
What is alleged
Dupixent (dupilumab) is a biologic used to treat eczema/atopic dermatitis, asthma, and related conditions. The core mass-tort allegation is that Dupixent causes or accelerates cutaneous T-cell lymphoma (CTCL) — including mycosis fungoides and Sézary syndrome — and that its early symptoms so closely mimic eczema that patients are kept on the drug while cancer quietly advances.
An important note on accuracy: this link is alleged, not established. Support comes from retrospective observational studies suggesting elevated CTCL risk, with the highest reported risk concentrated in the first year of treatment. The defense will argue the drug merely unmasks pre-existing cancer that was misdiagnosed as eczema — but plaintiffs contend that distinction does not excuse a missing warning.
Who may have a claim
Patients treated with Dupixent — most often for atopic dermatitis — who were later diagnosed with cutaneous T-cell lymphoma, mycosis fungoides, or Sézary syndrome. Because Dupixent is prescribed to an enormous population, even a small relative risk implicates a very large number of people.
The legal theory
Failure to warn is the centerpiece: plaintiffs allege Sanofi and Regeneron knew or should have known of the CTCL signal and did not adequately warn patients or physicians, alongside design-defect and negligence theories.
Where the litigation stands
The Judicial Panel on Multidistrict Litigation created a Dupixent MDL in June 2026 in the District of New Jersey, before Judge Zahid N. Quraishi — a fast consolidation reflecting rapid case accumulation. The FDA has not withdrawn or restricted the drug. Cases are being investigated and filed now.
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