Does Dupixent Cause Cancer? What the Studies, the FDA Signal, and the Lawsuits Actually Say

Last Updated: July 16, 2026 | Written for patients and families trying to understand the Dupixent cancer question. This article explains what has been reported, what is being investigated, and what has not been established. It is not medical advice.

What Is the Concern With Dupixent?

Dupixent (dupilumab) is an injectable biologic made by Sanofi and Regeneron, approved since 2017 for moderate to severe eczema, asthma, chronic sinusitis with nasal polyps, and related inflammatory conditions. It works by blocking part of the immune system’s inflammatory signaling, and for many patients it has worked where nothing else did.

The concern involves a rare blood cancer of the skin called cutaneous T-cell lymphoma, or CTCL, and its subtypes mycosis fungoides and Sézary syndrome. Early CTCL looks remarkably like eczema: red, scaly, stubbornly itchy patches. That resemblance sits at the center of both the science and the lawsuits, because a drug prescribed for presumed eczema can end up being given to someone whose “eczema” was actually early-stage lymphoma that had not yet been diagnosed.

What Has the FDA Actually Said?

Two things, and it is worth being precise about both. In January 2025, the FDA notified Regeneron that it had identified and begun evaluating a newly identified safety signal regarding Dupixent therapy for atopic dermatitis being associated with an increased risk of CTCL. In March 2025, Dupixent appeared on the FDA’s quarterly list of drugs with potential signals of serious risk, based on reports submitted to the agency’s adverse event reporting system.

A safety signal is not a conclusion. It means the reporting data looks unusual enough that the agency is formally investigating. As of this writing, that investigation is ongoing, and the FDA-approved prescribing information for Dupixent still does not mention CTCL, mycosis fungoides, Sézary syndrome, or lymphoma at all. That silence is exactly what the lawsuits are about.

What Do the Studies and Reporting Data Show?

A study published in the European Respiratory Journal reported that asthma patients treated with Dupixent had a 79 percent higher risk of lymphoma overall and roughly a 4.5-fold increased risk of T-cell lymphoma specifically. Separately, analyses of the FDA’s adverse event database have found that reports of CTCL were dramatically overrepresented among Dupixent users, on the order of thirty times the reporting rate seen with comparison drugs, with some patients diagnosed less than a year after starting the medication.

These findings describe association, not proof of causation. Reporting databases have well-known limitations, and people with severe, treatment-resistant “eczema” may already include an unusual number of undiagnosed early CTCL cases, which by itself would inflate the numbers. Sorting out how much of the signal is the drug and how much is the diagnosis is precisely what the FDA review and the litigation’s experts will fight over.

The Masking Problem: Why Timing Matters So Much

The most troubling allegation is not simply that Dupixent might cause lymphoma. It is that Dupixent can hide it. Plaintiffs allege that by suppressing visible inflammation, the drug can make early CTCL look like it is improving, reinforcing the eczema diagnosis while the underlying cancer quietly advances. In several reported cases, patients improved at first, then worsened in ways eczema should not, and only later biopsies revealed lymphoma at a more advanced stage.

That is why the practical advice here is unusually concrete. If you are on Dupixent and your skin condition stops behaving like eczema, comes back in new patterns, or never fully responds, ask your dermatologist directly whether a biopsy is warranted. Early-stage CTCL and advanced CTCL are very different diseases to have.

Where Do the Lawsuits Stand?

On June 4, 2026, the Judicial Panel on Multidistrict Litigation consolidated the federal Dupixent lymphoma cases into MDL 3180 in the District of New Jersey before Judge Zahid N. Quraishi. Fifteen cases pending across twelve federal districts were transferred at formation, including filings from Alabama, Tennessee, and Georgia, and new cases can now be filed directly into the consolidated proceeding. The complaints allege Sanofi and Regeneron failed to warn patients and doctors despite the accumulating case reports and studies. The manufacturers dispute the claims, no court has ruled on the merits, and no settlements have been announced.

We cover the litigation in detail, including who qualifies and each state’s filing deadline, on our Alabama, Tennessee, and Georgia Dupixent lawsuit pages. Tennessee readers should know their deadline is generally just one year, the shortest in the country.

What Has Not Been Established

Fairness requires saying this plainly. No regulator or court has found that Dupixent causes cancer. The FDA investigation is open, not concluded. The studies show associations that have real alternative explanations still being tested. The label has not been changed. Sanofi and Regeneron deny the allegations. Anyone who tells you this question is settled, in either direction, is ahead of the evidence.

Should I Stop Taking Dupixent?

Not on your own. For many people this drug controls a miserable disease, and abruptly stopping it carries its own risks. This is a conversation for your prescriber, informed by your history and your skin’s actual behavior. What you can do today is ask two questions at your next appointment: has my diagnosis ever been confirmed by biopsy, and is there any reason to confirm it now.

Does Dupixent Cause Cancer?

The honest answer in mid-2026: it is unproven and under serious investigation. There is an FDA safety signal, published studies reporting elevated T-cell lymphoma risk, a striking disparity in adverse event reports, an active federal MDL, and a label that says nothing about any of it. That combination is why patients are asking the question, and why the courts are now asking it too.

Can I File a Dupixent Lawsuit If I Was Diagnosed With CTCL?

Potentially, yes. People diagnosed with CTCL, mycosis fungoides, or Sézary syndrome after taking Dupixent are filing claims in MDL 3180, and families are filing wrongful death claims. Deadlines vary by state and can be short. The consultation is free, and we will tell you honestly whether the timeline of your diagnosis supports a claim: (205) 407-6009.

Fob James, IV

Fob James obtained a B.S., in software engineering from Auburn University and then continued his education by getting his J.D. from Vanderbilt University School of Law. After working for a large national firm for several years, Fob found that his passion was fighting for individuals who have been seriously injured or wronged by others. Fob believes that the jury is the great equalizer to the power and influence that large corporations have in society. Many of Fob’s cases are high profile and have been featured in, among others: Bloomberg News, PlanAdvisor, AL.com, PlanSponsor, InsuranceJournal, and BusinessInsider. For his work in obtaining numerous multi-million dollar outcomes for his clients, Fob has been recognized by: National Trial Lawyers Top 100, SuperLawyers Rising Star (2020-2025), Birmingham Business Journal Who’s Who in Law (2023-2025), and TrustAnalytica – Top Personal Injury Lawyers in Alabama.