Dupixent Lawsuit

Dupixent (dupilumab) is a biologic medication manufactured by Sanofi and Regeneron, approved by the FDA to treat atopic dermatitis (eczema), asthma, and several other inflammatory conditions. It works by blocking interleukin-4 and interleukin-13 signaling, two pathways involved in allergic inflammation. Since its 2017 approval, Dupixent has become one of the best-selling drugs in the world.

Why Are Dupixent Lawsuits Being Filed?

Lawsuits allege that Dupixent may unmask, accelerate, or delay the diagnosis of cutaneous T-cell lymphoma (CTCL), a rare blood cancer that appears in the skin. Early-stage CTCL, including mycosis fungoides, is frequently misdiagnosed as eczema because the two conditions can look nearly identical. Plaintiffs allege that patients whose skin condition was actually undiagnosed CTCL were prescribed Dupixent, and that the drug’s suppression of immune signaling may have allowed the lymphoma to progress. Plaintiffs further allege that Sanofi and Regeneron failed to warn patients and physicians about case reports and published literature describing CTCL diagnosed after Dupixent treatment. The U.S. prescribing information does not currently include a CTCL warning, which plaintiffs cite as central to their failure-to-warn claims. The manufacturers deny the allegations and maintain that Dupixent is safe when used as directed.

MDL 3180: Where the Litigation Stands

On June 4, 2026, the Judicial Panel on Multidistrict Litigation consolidated federal Dupixent CTCL lawsuits into MDL 3180 in the U.S. District Court for the District of New Jersey, before Judge Zahid N. Quraishi. The MDL is in its earliest stage: leadership appointments, case management structure, and discovery are just beginning. No trials have been held and no settlements have been reached. Because the litigation is new, individuals diagnosed with CTCL after Dupixent use are being evaluated now, while claims are timely in most states.

Injuries in the Dupixent Litigation

The litigation focuses on cutaneous T-cell lymphoma and its subtypes, including mycosis fungoides and Sézary syndrome. Warning signs reported in the medical literature include persistent patches or plaques that do not respond to eczema treatment, worsening rash after starting Dupixent, skin tumors or nodules, and enlarged lymph nodes. A CTCL diagnosis is typically confirmed by skin biopsy.

Who May Qualify?

You may qualify for a free case review if you used Dupixent for eczema, asthma, or another condition and were later diagnosed with cutaneous T-cell lymphoma, mycosis fungoides, Sézary syndrome, or another T-cell lymphoma. Medical records showing your Dupixent prescriptions and your biopsy-confirmed diagnosis are the core evidence in these cases.

Important: Do not stop taking Dupixent or any prescription medication without talking to your doctor first. Stopping a prescribed medication on your own can be dangerous.

Claims reviewed by Baker Legal Team
Robert B. Baker, Esq., B.C.S. — Board-Certified Civil Trial Lawyer. 30+ years of trial experience, more than $400 million recovered for clients. About Robert Baker →