Enlarged Lymph Nodes Led to Dupixent CTCL Diagnosis, Lawsuit Claims

Woman had to undergo multiple biopsies, hospitalizations and testing before receiving a diagnosis of CTCL caused by Dupixent side effects.

A Florida woman has filed a product liability lawsuit indicating that, instead of taming her dermatitis, the side effects of Dupixent led to health problems that were eventually discovered to be a rare form of T-cell lymphoma, known as CTCL or cutaneous T-cell lymphoma.

The complaint (PDF) was brought by Sandra Jaeger in the U.S. District Court for the Middle District of Florida on March 4. It names Regeneron Pharmaceuticals Inc. and Sanofi-Aventis U.S. LLC as defendants, claiming the manufacturers failed to conduct adequate research or provide sufficient warnings about the potential Dupixent health risks that users may experience.

Dupixent (dupilumab) was first approved in 2017 as an injection for treatment of atopic dermatitis, a form of eczema. The label was later expanded to include use for treatment of asthma, chronic obstructive pulmonary disease (COPD) and other inflammation-based respiratory tract and skin conditions, resulting in wide use of the medication among an estimated 800,000 people.

Even though Dupixent was, and is, marketed as safe and effective by the manufacturers, Dupixent side effects have been linked to T-cell lymphoma, a rare form of cancer that affects the body’s white blood cells, which are essential for the functioning of the immune system. Recent data has suggested the drug may increase the risk of cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL).

Jaeger’s complaint joins a growing number of similar Dupixent CTCL lawsuits now being filed by former users, who say the manufacturers knew about the T-cell lymphoma risks, yet failed to adequately warn patients or the medical community while continuing to aggressively promote the drug for more and more treatments.

According to her lawsuit, Jaeger was prescribed Dupixent in February 2022 for the treatment of intrinsic atopic dermatitis. She received the injections every two weeks until July 2022.

However, just a month after beginning to receive the shots, Jaeger developed enlarged axillary and inguinal lymph nodes and elevated white blood cell count, resulting in her being hospitalized in late March. Cytogenic testing revealed she had lymphoma, which led to a biopsy in April 2022 that provided additional evidence Jaeger had T-cell lymphoma.

She was ultimately diagnosed with CTCL in June 2022 and stopped receiving Dupixent shots the next month after again being hospitalized due to pain and discoloration of her palms and feet. In February 2025, she underwent further testing that led to an anaplastic large cell lymphoma diagnosis.

“Defendants should have warned patients and prescribers, including Plaintiff and Plaintiff’s treating physicians, that Dupixent may result in the development or exacerbation of T-cell lymphoma, which can lead to accelerated disease progression. Defendants were on notice of these risks from the peer-reviewed literature, reports of adverse events, presentations at professional conferences, and their own studies.”

– Sandra Jaeger v. Regeneron Pharmaceuticals Inc. et al

Jaeger presents claims of failure to warn, negligence, negligent misrepresentation and breach of warranty.

Dupixent Cancer Lawsuits

The complaint comes as a group of plaintiffs who have filed similar Dupixent lawsuits seek to have all federal claims centralized before one federal judge in the Northern District of Georgia as part of a multidistrict litigation (MDL). This would allow the court to coordinate discovery and pretrial proceedings for potentially hundreds or thousands of lawsuits brought by former users who developed CTCL or other forms of T-cell lymphoma.

If a Dupixent lawsuit MDL is formed, the appointed judge would likely establish a bellwether trial process, where a group of representative claims are used to gauge how juries may respond to evidence and testimony likely to be repeated throughout the litigation. However, each case would remain an individual lawsuit, and plaintiffs would retain their own counsel to prove that their injuries were directly caused by the medication’s side effects.

Meanwhile, as the litigation continues to expand, Dupixent lawyers provide no-cost consultations to help former users determine whether they may be eligible for a claim or settlement. These claims are handled on a contingency basis, meaning there are no upfront legal costs and attorney fees are only paid if a settlement or verdict is obtained.

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