The Scientific Evidence Behind Dupixent and CTCL

• Dermatologic Therapy (2024) — a cohort analysis reported a roughly 4.59 fold higher relative risk of CTCL in dupilumab treated eczema patients compared with eczema patients who did not use the drug.
• Journal of the American Academy of Dermatology (2024) — reported about a 4.1 fold higher odds of CTCL after dupilumab use.
• Journal of Allergy and Clinical Immunology (2025) — identified a very strong disproportionate reporting signal for CTCL in the FDA adverse event database (FAERS) and proposed a biological mechanism.
• Multiple systematic reviews and case reports describe CTCL appearing or worsening after starting dupilumab.

The FDA added Dupixent and cutaneous T cell lymphoma to its quarterly list of Potential Signals of Serious Risks / New Safety Information and stated it is evaluating the need for regulatory action. As of 2026 the U.S. Dupixent label carried no cancer warning.

Dupixent blocks the IL 4 receptor alpha subunit, which interrupts both IL 4 and IL 13 signaling. However, IL 13 can still bind a second receptor, IL 13 receptor alpha 2, which Dupixent does not block. That receptor is overexpressed in CTCL and may help drive tumor cell proliferation, immune evasion, and fibrosis.

A complementary hypothesis is that Dupixent does not cause CTCL but unmasks a preexisting CTCL that had been misdiagnosed and treated as eczema. Both ideas remain under active study.

Eczema patients may have higher baseline CTCL risk, early CTCL is easily mistaken for eczema, and certain benign skin reactions to the drug can resemble lymphoma on biopsy. Each potential case must be reviewed individually by qualified medical and legal professionals.