Link Between Dupixent and Cancer Withheld From Doctors and Users, Lawsuit Alleges

A panel of federal judges is scheduled to hear arguments later this month over whether Dupixent CTCL lawsuits filed nationwide should be consolidated before one judge.

A new product liability lawsuit alleges that the makers of Dupixent withheld critical safety information from doctors and patients about a potential link between the drug and certain forms of cancer, including cutaneous T-cell lymphoma (CTCL).

The complaint (PDF) was brought by Charity Njambi Kamoche in the U.S. District Court for the Northern District of Illinois on May 5. It names Regeneron Pharmaceuticals Inc., Sanofi-Aventis U.S. LLC and Genzyme Corporation as defendants.

Kamoche claims Regeneron and Sanofi failed to warn that Dupixent may increase the risk of developing CTCL, or accelerate the progression of undiagnosed cases of the rare skin lymphoma.

Dupixent Cancer Links

Dupixent (dupilumab) received FDA approval in 2017 as a treatment for atopic dermatitis, a chronic form of eczema. In the years that followed, its approved uses expanded to include asthma, chronic obstructive pulmonary disease (COPD) and other inflammatory conditions affecting the skin and respiratory system.

Promoted as a safe and effective therapy, the drug quickly became a widely used, high-revenue treatment in the United States. However, recent reports have linked Dupixent side effects to T-cell lymphomas, rare cancers that affect white blood cells critical to immune function. These findings have raised concerns that use of the medication may increase the risk of both cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL).

As a result, Kamoche’s lawsuit is one of a growing number of similar Dupixent lawsuits now being filed nationwide. Most of these claims allege that the manufacturers knew or should have known about potential cancer risks, yet failed to provide adequate warnings to doctors and patients about the possibility of severe, life-altering or fatal complications.

Dupixent CTCL Allegations

In the complaint, Kamoche indicates she was prescribed Dupixent for atopic dermatitis and used the injections from approximately April 2023 through October 2025, before being diagnosed with cutaneous T-cell lymphoma. The lawsuit suggests the timing of her diagnosis after starting the medication raises concerns that the drug may have played a role in the development or progression of her cancer. 

The lawsuit alleges that the drug manufacturers had access to a growing body of scientific evidence, including post-marketing adverse event reports and published studies, indicating a strong association between Dupixent and CTCL. However, they failed to update the prescribing information or provide adequate warnings to the medical community.

In addition, the filing claims the manufacturers did not instruct healthcare providers to conduct adequate diagnostic testing, such as biopsies, to rule out underlying lymphoma before starting patients on Dupixent, or to monitor for signs of cancer during treatment.

Kamoche indicates that if proper warnings had been provided, doctors would have either avoided prescribing the medication or taken additional steps to screen and monitor patients, potentially preventing serious injury.

She points to multiple scientific studies and analyses that have identified elevated rates of CTCL among Dupixent users. According to one analysis cited in the lawsuit, adverse event reporting data indicated patients were more likely to report CTCL when using Dupixent compared to other medications.

Other research cited in the filing suggests Dupixent users may face a seriously increased risk of developing certain lymphomas, including mycosis fungoides and Sézary syndrome, which are subtypes of CTCL.

“Plaintiff was prescribed Dupixent to treat atopic dermatitis. Plaintiff was injected with Dupixent from approximately April 2023 until October 2025. Following Plaintiff’s initiation of Dupixent, she was diagnosed with CTCL.”

— Charity Njambi Kamoche v. Regeneron Pharmaceuticals et al

The case raises allegations of strict liability—failure to warn, negligence, negligent misrepresentation, breach of express warranty, and breach of implied warranty. It seeks compensation for past and future economic and non-economic losses, including medical expenses, pain and suffering, mental anguish and emotional distress.

Dupixent Cancer Lawsuits

Kamoche’s complaint is not the first incident of Dupixent being linked to a CTCL diagnosis. As a result, several plaintiffs filed a motion in February seeking to centralize Dupixent CTCL lawsuits in the Northern District of Georgia. They asked that all related federal cases be assigned to a single judge for coordinated discovery and pretrial proceedings.

On April 16, the U.S. Judicial Panel on Multidistrict Litigation (JPML) announced it will consider the request during oral arguments scheduled for May 28. If the panel approves consolidation, one federal judge would be appointed to oversee the litigation and likely direct the parties to prepare a group of representative cases for early trial.

These bellwether cases are intended to test how juries respond to common evidence and legal arguments presented throughout the litigation. Although the results are not binding on other claims, they often influence the direction of the proceedings and play a key role in shaping potential settlement discussions.

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