Dupixent lawsuits are now moving forward in federal court for patients who allege the drug caused, accelerated, or unmasked cutaneous T-cell lymphoma and related T-cell lymphomas. On June 4, 2026, the Judicial Panel on Multidistrict Litigation centralized the federal Dupixent cases in MDL No. 3180, In re: Dupixent (Dupilumab) Products Liability Litigation, in the District of New Jersey before Judge Zahid N. Quraishi.
Dupixent, also known as dupilumab, is a biologic medication used to treat atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, prurigo nodularis, COPD, bullous pemphigoid, allergic fungal rhinosinusitis, and other inflammatory conditions. For many patients, Dupixent has provided real relief where other treatments failed. But for some patients, the story has been very different.
The lawsuits allege that Regeneron and Sanofi failed to warn doctors and patients that cutaneous T-cell lymphoma, often called CTCL, can mimic eczema and that Dupixent may mask, accelerate, or delay diagnosis of an underlying lymphoma. Plaintiffs argue that patients with adult-onset, atypical, or treatment-resistant dermatitis should have been warned to rule out lymphoma before starting Dupixent and to stop and investigate if symptoms worsened or changed during treatment.