Dupixent CTCL Lawsuits: An Emerging Pharmaceutical Docket

Plaintiffs moved to centralize lawsuits alleging that the eczema and asthma medication Dupixent (dupilumab) causes cutaneous T-cell lymphoma (CTCL) into proposed federal MDL-3180, In re: Dupixent Products Liability Litigation, according to King Law's 2026 case tracking. The claims rest on observational research identifying a 3x to 4.5x higher CTCL risk among dupilumab patients, summarized by SSKB Law.

The litigation follows a regulatory review notice. The FDA notified manufacturer Regeneron on January 15, 2025 of a newly identified safety signal. Its fourth-quarter 2024 FAERS report listed CTCL as a potential risk, stating the agency was "evaluating the need for regulatory action," according to a representative complaint. For law firms evaluating intake, initial case vetting relies on verifiable medical documentation.

The Science Behind the Claims

Dupixent, marketed by Sanofi and Regeneron, treats chronic inflammatory conditions including eczema, asthma, and COPD. Observational studies have evaluated an association with CTCL, a non-Hodgkin lymphoma primarily affecting the skin. A 2024 JAMA Dermatology analysis identified an approximate 3x increased risk, a 2024 TriNetX database study found about 3.5x, and a 2025 study reported up to a 4.5x risk elevation, SSKB Law reported.

Global pharmacovigilance data also reflects this reporting pattern. An analysis of the World Health Organization's VigiBase database identified a reporting odds ratio of 11.11 (95% confidence interval 6.77-18.23) for CTCL with dupilumab compared to other biologics, according to filed complaint records.

Competing Theories of Liability

A primary scientific question divides the litigation: does Dupixent directly cause CTCL, or does it unmask or accelerate pre-existing, undiagnosed lymphoma? Because early CTCL can clinically mimic eczema, patients and clinicians may interpret progressive symptoms as treatment-resistant atopic dermatitis, delaying biopsy. Plaintiffs' complaints advance direct causation and unmasking theories, while defense counsel argues conditions predated therapy. Both arguments depend on documenting precise diagnostic and exposure chronologies.

The FDA has not recalled Dupixent, stating that it continues to evaluate whether regulatory action is required, King Law reported.

Centralization Prospects

Whether the JPML creates proposed MDL-3180 will depend on standard statutory factors. The panel generally favors centralization when claims share a defined injury, a common mechanism, and identified corporate defendants, as Lawsuit Intelligencer's 2026 mass tort analysis noted.

Dupixent fits this profile: a single product, two primary manufacturers, and a specific diagnosis. Until the panel issues an order, law firms must evaluate incoming claimants individually.

Evidentiary Requirements for Screening

Law firms evaluating Dupixent CTCL claims require verified clinical documentation:

• Dermatology records establishing the initial eczema or atopic dermatitis diagnosis and clinical course
• Biopsy and pathology reports confirming CTCL or mycosis fungoides
• Oncology and hematology charts documenting staging, treatment plans, and disease progression
• Prescription logs and pharmacy dispense records establishing exact start and stop dates for dupilumab
• Clinical progress notes tracing symptom changes during treatment

Confirming exposure timing relative to the date of biopsy diagnosis is necessary to establish causation. LlamaLab retrieves dermatology, oncology, and pharmacy records in 4 days on average (with ~30-40% returned same-day on electronic requests) and uses insurance data to surface treatment locations clients don't always remember. Invoices are itemized per case to flow through as recoverable case disbursements on settlement statements.

Next Steps for Law Firms

Summary

The Dupixent CTCL litigation represents an emerging pharmaceutical docket with published observational data, an active FDA safety signal, and a pending JPML petition.

Firms considering intake should verify biopsy-confirmed diagnoses and exact exposure timelines through complete dermatology, oncology, and pharmacy records.

This article is for informational purposes only and does not constitute legal or medical advice. Sources: King Law, SSKB Law, Lawsuit Information Center, Durkin complaint (King Law), Harding Mazzotti, Lawsuit Intelligencer.