Dupixent Cancer Risks Lead Experts to Recommend Skin Biopsies Before Treatment

Experts recommend screening certain eczema patients for CTCL before prescribing Dupixent, monitoring for signs of lymphoma during treatment and discontinuing the drug if cancer is confirmed.

A panel of skin disease and cancer specialists are recommending doctors conduct a thorough diagnosis of patients for signs of a rare form of cancer, known as cutaneous T-cell lymphoma (CTCL), before prescribing the eczema treatment Dupixent.

The findings were published earlier this year in the Journal of the European Academy of Dermatology & Venereology, with researchers also recommending that doctors regularly monitor patients for signs of CTCL throughout their treatment with the eczema drug.

Dupixent Cancer Risks

Dupixent (dupilumab) belongs to a class of drugs known as monoclonal antibodies and was originally developed for the treatment of atopic dermatitis, more commonly known as eczema. Developed by Sanofi-Aventis and Regeneron, it was approved by the U.S. Food and Drug Administration (FDA) in 2017.

Over the years, the agency has allowed the medication to be marketed for an increasing number of skin and respiratory conditions, including asthma, chronic obstructive pulmonary disorder (COPD), eosinophilic esophagitis and more. As a result, Dupixent is now a blockbuster drug, with second quarter 2026 sales of $5.74 billion.

However, a study published in JAMA Dermatology in April 2024 determined that Dupixent users were more than four times more likely to develop CTCL than those who do not receive the injections. Studies, such as the TriNetX database study published later that year, appeared to confirm those findings, indicating a 3.5 times increased risk of Dupixent CTCL.

In light of these health concerns, the manufacturers now face a growing number of Dupixent lawsuits filed by individuals nationwide who say they developed CTCL after receiving the injections. Each claim alleges that neither patients nor the medical community were given adequate warning of the potential cancer risks, meaning either that the companies knew about the problem but hid it or that they failed to put Dupixent through sufficient testing.

Dupixent Cancer Study

For the new study, researchers reviewed 51 studies published through January 2, 2025, identifying 547 reported cases of CTCL and related lymphoid conditions following Dupixent exposure. Led by Florent Amatore, the team analyzed the findings and presented them to a panel of 37 experts, including dermatologists and pathologists.

According to the data, patients developed new or worsening skin lesions an average of 8.9 months after starting Dupixent. Among cases with a classified diagnosis, 72% involved mycosis fungoides, while approximately 11% involved Sézary syndrome, another form of CTCL.

Among 63 patients with available follow-up information, 44 achieved remission after discontinuing Dupixent and/or receiving additional cancer treatment, representing approximately 70% of the group. However, researchers cautioned that the findings do not establish whether stopping Dupixent contributed to those remissions.

“Current evidence suggests that dupilumab may unmask latent disease or worsen existing CTCL and therefore should be initiated only in cases of typical atopic dermatitis. Clinicians should perform comprehensive diagnostic evaluations in adults presenting with atypical, treatment-resistant or late-onset dermatitis, both before initiating and during dupilumab therapy.”

– Florent Amatore, Cutaneous T-cell lymphomas and dupilumab for atopic dermatitis: A systematic review and expert consensus

Dupixent CTCL Screening

After reviewing the data, the panel crafted a joint consensus on new prescribing protocols that doctors should use before putting a patient on Dupixent.

Experts recommended that doctors consider additional CTCL testing, including skin biopsies when appropriate, before prescribing Dupixent to adults who develop eczema after age 40, have no previous history of atopic disease or exhibit unusual symptoms that could indicate an underlying malignancy.

The researchers noted that while more than half of known cases were detected in the early stages, doctors should carefully review any signs of worsening, new or atypical skin lesions, since signs of CTCL can mimic those of atopic dermatitis. They also warned that CTCL and eczema can occur at the same time if the patient is dupilumab-resistant, complicating diagnosis further.

The panel also recommended that doctors continue monitoring patients throughout Dupixent treatment, particularly if new or worsening skin lesions appear. Nearly 97% of the experts agreed that Dupixent should be discontinued immediately when CTCL is confirmed, although physicians should carefully evaluate alternative treatments.

Data indicates some previous Dupixent patients with CTCL in remission saw the cancer return when given JAK inhibitors, like Xeljanz or Rinvoq. The panel warned that similar eczema drugs like Adbry (tralokinumab) and Ebglyss (lebrikizumab) may also carry CTCL risks, with at least one case report of a patient on Adbry developing mycosis fungoides. Both drugs are also monoclonal antibodies with similar mechanisms of action.

Dupixent Lawsuits

These screening recommendations also raise questions about whether doctors received adequate information concerning the potential for Dupixent to unmask or worsen previously undiagnosed CTCL, particularly because early symptoms of the cancer can resemble eczema. Many individuals allege that stronger warnings and earlier testing recommendations could have helped physicians identify the disease sooner and avoid continued treatment with a drug they claim may aggravate the condition.

The consensus report appears to back up allegations listed in dozens of Dupixent CTCL lawsuits filed in federal courts nationwide. These complaints have been centralized in the District of New Jersey as part of a multidistrict litigation (MDL) before U.S. District Judge Zahid N. Qurashi, where they are undergoing coordinated discovery and other pretrial proceedings.

Judge Qurashi is eventually expected to order the selection of several representative claims to serve as early test trials. These “bellwether” trials will be used to get a feel for how juries are likely to process expert testimony, evidence and arguments likely to be repeated across most of the litigation.

The results of these trials could lead to a Dupixent lawsuit settlement agreement, or else the judge will remand the cases back to the federal districts where they were originally filed for separate trials.

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