Dupixent Side Effects: Cancer Risk and Legal Options
What are the most serious side effects of Dupixent?
The most serious side effect of Dupixent is an increased risk of cutaneous T-cell lymphoma (CTCL), a rare form of cancer affecting the skin.
Research published in JAMA Dermatology in 2023 found that Dupixent users face a 4.5 times higher risk of CTCL compared to non-users.
This finding has prompted hundreds of lawsuits against manufacturers Sanofi and Regeneron.
Other serious side effects reported with Dupixent include eye problems (conjunctivitis, keratitis), joint pain and arthralgia, severe allergic reactions including anaphylaxis, and parasitic infections.
However, the cancer risk represents the most significant long-term safety concern.
What is cutaneous T-cell lymphoma (CTCL)?
Cutaneous T-cell lymphoma is a rare form of non-Hodgkin lymphoma where cancerous T-cells (a type of white blood cell) accumulate in the skin.
The disease typically develops slowly over months or years.
The most common types of CTCL linked to Dupixent are mycosis fungoides and Sézary syndrome.
Mycosis fungoides accounts for approximately 50% of all CTCL cases and typically presents as patches, plaques, or tumors on the skin.
Sézary syndrome is a more aggressive form characterized by widespread red, itchy rash covering most of the body, along with cancerous cells in the blood.
In advanced stages, CTCL can spread beyond the skin to lymph nodes, blood, and internal organs, significantly impacting survival rates.
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What symptoms should Dupixent users watch for?
Early detection of CTCL is critical for better treatment outcomes.
Warning signs include:
- Persistent skin rashes that do not improve with treatment
- Red, scaly patches on the skin, especially on the trunk, buttocks, or other sun-protected areas
- Severe, unrelenting itching (pruritus)
- Skin lesions or tumors that may ulcerate or become infected
- Thickened, leathery skin texture
- Enlarged lymph nodes, particularly in the neck, armpits, or groin
- Unexplained weight loss
- Night sweats
- Fatigue
These symptoms may appear months or even years after starting Dupixent treatment.
The latency period between drug exposure and cancer diagnosis varies significantly among patients.
Any Dupixent user experiencing persistent or worsening skin symptoms should seek immediate medical evaluation, including possible skin biopsy.
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What do medical studies show about Dupixent cancer risk?
The landmark 2023 study published in JAMA Dermatology analyzed data from over 150,000 patients treated for atopic dermatitis.
Researchers found that patients treated with Dupixent had a hazard ratio of 4.5 for developing cutaneous T-cell lymphoma compared to those who did not receive the drug.
The study controlled for age, sex, disease severity, and other confounding factors.
Notably, the risk appeared to increase with longer duration of Dupixent use, suggesting a dose-response relationship.
A 2024 case series published in the Journal of the American Academy of Dermatology documented 12 cases of CTCL that developed in Dupixent users with no prior history of lymphoma.
The median time from Dupixent initiation to CTCL diagnosis was 18 months, with a range of 6 to 36 months.
Additional research from the European Academy of Dermatology and Venereology identified similar patterns in European patient populations.
These studies provide substantial scientific evidence linking Dupixent to increased cancer risk.
View medical studies and citations
How common is CTCL in Dupixent users?
Cutaneous T-cell lymphoma is considered a rare cancer in the general population, affecting approximately 6-10 per million people annually in the United States.
However, the rate among Dupixent users appears significantly elevated.
The 2023 JAMA Dermatology study documented a 4.5-fold increase in risk, translating to approximately 27-45 cases per million Dupixent users per year.
Given that millions of patients worldwide use Dupixent, this elevated risk represents hundreds of potential cancer cases attributable to the medication.
The absolute risk remains relatively low, but for those affected, the consequences are devastating.
Dupixent was prescribed to treat a chronic but non-life-threatening condition (eczema or asthma), making the development of cancer an unacceptable outcome.
What other complications can CTCL cause?
Beyond the skin manifestations, cutaneous T-cell lymphoma can lead to serious complications:
Infection risk increases due to compromised skin barrier function and immune suppression from cancer treatments.
Sepsis from bacterial skin infections is a leading cause of death in advanced CTCL patients.
Lymphedema (swelling) can occur when cancer spreads to lymph nodes, causing fluid retention and discomfort.
Psychological impact is significant, with studies showing high rates of depression and anxiety among CTCL patients due to visible skin changes and chronic symptoms.
Advanced disease can spread systemically, affecting internal organs and bone marrow, reducing survival significantly.
Five-year survival rates for early-stage CTCL exceed 80%, but drop to below 30% for advanced-stage disease.
What should Dupixent users do if they develop symptoms?
If you are currently using Dupixent and develop concerning skin symptoms:
Consult your dermatologist immediately for evaluation.
Request a skin biopsy if lesions persist or worsen despite treatment.
Discontinue Dupixent only under medical supervision—sudden cessation may cause disease flare.
Document all symptoms, medical visits, and treatments for potential legal claims.
Consider genetic testing and imaging studies if CTCL is suspected.
Seek second opinions from oncologists or hematologists experienced in treating cutaneous lymphomas.
Early diagnosis dramatically improves treatment outcomes and may strengthen potential legal claims.
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What treatments are available for CTCL?
Treatment for cutaneous T-cell lymphoma depends on disease stage:
Early-stage CTCL may be treated with topical corticosteroids, phototherapy (PUVA or UVB light therapy), or topical chemotherapy agents.
Advanced disease often requires systemic treatments including chemotherapy, targeted therapy with drugs like brentuximab vedotin or mogamulizumab, or stem cell transplantation.
Clinical trials are investigating new immunotherapies and combination treatments.
Treatment is often prolonged, expensive, and can cause significant side effects.
Many patients require lifelong monitoring and maintenance therapy.
The physical, emotional, and financial toll of CTCL treatment is substantial.
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Did Sanofi and Regeneron know about the cancer risk?
Evidence suggests the manufacturers may have been aware of potential cancer risks but failed to adequately warn patients and physicians.
Pre-market clinical trials showed signals of immune system dysregulation that could theoretically increase lymphoma risk.
Post-market surveillance data revealed emerging cases of CTCL in Dupixent users.
Plaintiffs allege the companies downplayed these risks to protect blockbuster drug sales exceeding $11 billion annually.
Internal documents obtained through litigation discovery may reveal what the companies knew and when they knew it.
Failure to warn about known risks constitutes product liability and may support punitive damages claims.
If you developed CTCL after using Dupixent, you may be entitled to compensation.
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References
This information is based on peer-reviewed medical research and court filings:
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Hasan, I., Parsons, L., Duran, S., & Zinn, Z. (2024). Dupilumab therapy for atopic dermatitis is associated with increased risk of cutaneous T cell lymphoma: A retrospective cohort study. Journal of the American Academy of Dermatology, 91(2), 255-258. View study
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Mandel, J., Mehta, J., Hafer, R., Ayub, M., Nusrat, F., Yang, H., Porcu, P., & Nikbakht, N. (2024). Increased Risk of Cutaneous T-Cell Lymphoma Development after Dupilumab Use for Atopic Dermatitis. Dermatologic Therapy, 2024, 9924306. View study
Information last updated: November 2025