Dupixent Class Action Lawsuit: CTCL Cancer Risks and Legal Action

In 2017, the FDA approved Dupixent, a prescription biologic drug manufactured by Regeneron Pharmaceuticals and Sanofi Genzyme. You may have heard of it referred to by its generic name, dupilumab.

Biologic drugs are made from living organisms. These drugs are often used to treat autoimmune conditions. Doctors typically prescribe Dupixent to treat inflammatory conditions such as atopic dermatitis, asthma, and chronic sinusitis with nasal polyps.

Dupixent is a monoclonal antibody that targets the interleukin-4 alpha receptor, a pathway involved in allergic inflammation. Blocking this receptor can help reduce immune overreactions that cause chronic conditions.

Why Are Patients Filing Lawsuits?

You may have seen commercials that promote Dupixent as a breakthrough alternative to steroids and other immunosuppressants. However, some patient reports and medical studies indicate that Dupixent may carry serious risks.

In recent lawsuits, plaintiffs allege that Dupixent may increase the risk of developing Cutaneous T-cell Lymphoma (CTCL). CTCL is a rare and sometimes fatal form of skin cancer. Plaintiffs claim that the manufacturers didn't warn doctors and patients about the potential dangers, even after early research raised red flags.

Understanding Cutaneous T-Cell Lymphoma (CTCL)

Cutaneous T-cell lymphoma (CTCL) is a type of non-Hodgkin’s lymphoma. This cancer begins in white blood cells that help regulate the immune system - T-lymphocytes. While other types of lymphoma affect internal organs, this type of lymphoma typically starts in the skin.

Here are some common CTCL symptoms:

• Red patches on the skin
• Scaly patches on the skin
• Persistent itching or pain
• Tumor-like skin lesions
• Swollen lymph nodes
• Unexplained weight loss
• Fatigue
• Night sweats

As CTCL progresses to the later stages, it can spread to other parts of the body. It may progress to the lymph nodes, blood, liver, or spleen. Patients who are diagnosed with this chronic disease often require lifelong monitoring and treatment.

Research Linking Dupixent to Lymphoma

Dermatologists reported multiple cases of patients developing CTCL while receiving Dupixent for eczema and other conditions. A 2024 study in the Journal of the American Academy of Dermatology found that patients with atopic dermatitis who used Dupixent were about four times more likely to develop CTCL than those who did not.[1] Most cases appeared more than a year after starting therapy. This suggests a possible link between long-term use of Dupixient and CTCL.

Although the study did not establish direct causation, it identified a clear statistical association between dupilumab use and CTCL risk. These findings led to increased concern that manufacturers may have understated risks and didn't give doctors and patients adequate warnings.

What Are the Allegations in the Dupixent Lawsuit?

Plaintiffs in the Dupixent (dupilumab) lawsuit claim that Regeneron and Sanofi:

• Marketed Dupixent as safe despite emerging reports of cancer risk
• Failed to include adequate warnings about the risk of developing CTCL on the drug's label
• Knew or should have known that Dupixent could cause or worsen lymphoma
• Didn't conduct sufficient post-marketing studies to investigate the link

Attorneys argue that incomplete safety information misled patients and physicians. Since CTCL and eczema have similar symptoms, this may have led to diagnosis delays or misdiagnosis of CTCL as eczema.

Legal complaints describe patients who continued using Dupixent for extended periods after developing early signs of lymphoma. These patients believed that their symptoms were due to worsening dermatitis.

Who May Qualify for the Dupixent CTCL Lawsuit?

Individuals may be eligible to join the Dupixent CTCL lawsuit if they:

• Used Dupixent (dupilumab) for at least one month
• Were later diagnosed with Cutaneous T-cell Lymphoma (CTCL), mycosis fungoides, or
• Sézary syndrome
• Had no prior diagnosis of lymphoma before starting Dupixent

If you meet the above conditions, you may be entitled to compensation for:

• Medical expenses
• Pain and suffering
• Lost income
• Emotional distress
• Long-term care and monitoring costs

Law firms are currently filing claims nationwide. Some of these firms have a long history of litigating defective drug and cancer misdiagnosis lawsuits, recovering billions in verdicts and settlements for injured consumers.

Dupixent Misdiagnosis Risks

One troubling factor in these cases is the reported eczema misdiagnosis. Both CTCL and eczema have symptoms such as:

• Rashes
• Itching
• Inflamed skin

Many patients receive Dupixent as a treatment for what doctors believe to be severe atopic dermatitis.[2]

For patients with undiagnosed early-stage CTCL, Dupixent may temporarily suppress symptoms while the cancer progresses. The cancer misdiagnosis lawsuit claims manufacturers should have warned physicians about this diagnostic challenge and the need for pretreatment biopsies or cancer screening.

The Growing Legal Action and Potential Settlements

As of late 2025, lawsuits are being filed in multiple states. These lawsuits may be consolidated into a Dupixent MDL (multidistrict litigation) for efficiency. While no global Dupixent settlement has been reached yet, attorneys expect the number of claims to rise as awareness spreads.

If courts determine that Regeneron and Sanofi failed to provide adequate warnings or acted negligently, affected individuals could receive compensation similar to other defective drug cases involving cancer risks.

Plaintiffs and legal experts believe the Dupixent litigation may follow the pattern of other major pharmaceutical lawsuits. These lawsuits typically start with individual filings and then expand into MDL proceedings. An MDL may result in a large-scale settlement as evidence accumulates.

Biologic Therapy Risks and Public Awareness

Dupixent is part of a new class of biologic therapies primarily designed to control immune overreactions. While biologic drugs can be effective for many patients, these drugs can also alter key immune responses that help the body identify and destroy cancerous cells.

The biologic therapy risks highlighted in recent research are raising questions about how these treatments are regulated. It also raises questions about how long-term side effects are tracked. Some patients who used Dupixent for conditions like eczema, asthma, or nasal polyps treatment are now seeking legal and medical guidance about their potential exposure and options for testing.

What You Can Do If You Used Dupixent

If you or a loved one developed CTCL symptoms such as red patches, scaly skin, or tumors after using Dupixent, it is important to speak with a doctor immediately. You should request an evaluation for lymphoma.

You can also reach out to an attorney familiar with Dupixent to learn more about your legal rights and eligibility for compensation. Law firms representing plaintiffs can help determine whether your case fits into current or future litigation. Early claims may help build the foundation for broader accountability and compensation.

The Bottom Line

The Dupixent CTCL lawsuit represents a growing effort to hold pharmaceutical companies accountable for the hidden dangers of biologic drugs. As more studies connect Dupixent cancer risks to CTCL, patients and families are stepping forward to demand justice and transparency.

If you believe you have been harmed by Dupixent, medical evaluation and legal advice can help you understand your rights and protect your health.

For more information, visit OnlyClassActions.com to stay updated on ongoing Dupixent lawsuits and other major consumer protection cases.