Claims Made in Dupixent Lawsuits
- Failure to warn: It is alleged by lawsuits that Regeneron and Sanofi failed to adequately warn about a risk of developing cutaneous T-cell lymphoma (CTCL) associated with taking Dupixent.
- Inadequate testing: Lawsuits allege that the drug makers did not conduct adequate testing and failed to conduct proper post-marketing surveillance in order to fully understand the drug’s long-term cancer risks.
- Downplaying risks: Lawsuits claim that the drug makers downplayed or ignored safety signals while marketing the drug.
- Negligent marketing and design: Plaintiffs are asserting that Dupixent was negligently marketed and designed despite evidence existing regarding an increased risk of cancer.
Key Details of Dupixent Lawsuits
- Cancer risk: Dupilumab lawsuits focus on patients who have been diagnosed with CTCL. CTCL is a type of skin cancer which can move to other organs. Evidence suggests the drug may accelerate or “unmask” existing lymphomas.
- Litigation is at the early stages: The Dupixent litigation is still in its early stages. The first lawsuits have recently been filed.
- No settlement yet: There have not been settlements, since the lawsuits are new. How the litigation unfolds will determine the outcome, including if cases get settled out of court or go to trial.
- Your options: If you or a loved one was diagnosed with CTCL after taking Dupixent, it’s recommended that you consult with an attorney to learn about your eligibility and your potential for recovering financial compensation. Attorneys are taking these cases on a contingency fee basis, which means you won’t pay any upfront costs.
Nadrich Accident Injury Lawyers is representing those who have been diagnosed with cutaneous T-cell lymphoma (CTCL) after taking Dupixent (dupilumab). Recent research suggests that Dupixent could be associated with an increased risk of CTCL in some patients. Health experts also warn the drug’s symptom-reducing effects can make early cancer signs more difficult to detect.
Call us today for a FREE consultation at (800) 718-4658 or contact us if you or a loved one:
- Have a confirmed, biopsy-proven CTCL diagnosis (including a diagnosis of mycosis fungoides or Sézary syndrome, which are subtypes of CTCL)
- Took Dupixent for at least six months prior to your diagnosis
- Have not previously been diagnosed with a lymphoproliferative disorder
Our experienced dangerous drugs lawyers can recover financial compensation for:
- Medical bills
- Lost wages
- Loss of earning capacity
- Pain and suffering
- Wrongful death
Reasons To Hire Nadrich Accident Injury Lawyers To Handle Your Dupixent Case
- We have been successfully recovering compensation for victims of dangerous drugs such as Keytruda and Ozempic since 1990.
- Our lawyers have recovered over $750,000,000 for clients.
- Our only fee is a percentage of any compensation we recover, and we won’t charge any fee until we win your case.
- We provide clients with communication they can rely on and are available 24/7.
- We have the resources and experience to take on pharmaceutical giants in court and win.
Past results do not guarantee future outcomes. All cases are unique and results depend on cases’ specific facts.
Call us today for a FREE consultation at (800) 718-4658.
Table of Contents
- Latest Update
- Can Dupixent Cause Cancer?
- Cutaneous T-Cell Lymphoma Warning Signs and Symptoms
- Who Qualifies for a Dupixent Lawsuit?
- Compensation for a Dupixent Lawsuit
- How Long Do I Have to File a Claim?
- FAQs
- Contact Our Dupixent CTCL Injury Lawyers
- Dupixent Lawsuit Updates
Latest Update
August 23, 2026 Update
A lawsuit filed on August 12 in California by a California woman alleges that Dupixent’s manufacturers knew that she as well as other patients may develop a rare type of cancer after receiving injections of the drug for just a few months, yet held back vital warnings from the medical community and consumers.
The lawsuit names Genzyme Corporation, Regeneron Pharmaceuticals and Sanofi-Aventis as defendants.
The lawsuit alleges that the drug makers knew that Dupixent’s side effects were dangerous to patients, but care more about profit than a higher risk of death or the possible need for cancer treatments and life-long monitoring.
The lawsuit claims that the woman was prescribed the drug in August 2023 for atopic dermatitis. The plaintiff has indicated that her doctor and herself weren’t warned about lymphoma risks linked to the drug.
The woman allegedly received the injections until January 2024, but was allegedly diagnosed with mycosis fungoides in February 2026, needing extensive medical treatment as a result, including chemotherapy, phototherapy and medications. The woman will allegedly likely need monitoring and treatment for the remainder of her life.
The lawsuit is arguing that enough scientific data existed long before her diagnosis for the defendants to know that there was an increased cancer risk linked with the drug, claiming the defendants intentionally downplayed and ignored this data in order to profit.
Can Dupixent Cause Cancer?
Recent studies have suggested a link between Dupixent, which is used to treat inflammatory skin diseases, and a higher risk of developing CTCL.
There have been examples showing that Dupixent may exacerbate or accelerate pre-existing CTCL, and may mask its early signs.
Key Findings and Evidence
- Increased risk of CTCL: Numerous studies, such as one in the Journal of the American Academy of Dermatology, have reported that there is a higher risk of developing CTCL in those receiving dupilumab treatment. Some analyses have suggested that this risk may be several times higher than in those not receiving dupilumab therapy.
- Journal of the American Academy of Dermatology study: The study found that atopic dermatitis patients taking dupilumab were over four times more likely to develop CTCL than atopic dermatitis patients who did not take the drug.
- Dermatologic Therapy study: A study published in Dermatologic Therapy found that atopic dermatitis patients taking dupilumab were 4.59 times more likely to develop CTCL than atopic dermatitis patients not taking the drug. The study found that while all CTCL cases in the untreated cohort were in those over 60 years old, only 54.5 percent of the cases in the group taking dupilumab were. The study also found that 62 percent of those taking dupilumab who were diagnosed with CTCL were diagnosed in the first year of treatment.
- The European Respiratory Journal study: A study published in The European Respiratory Journal found that asthma patients taking dupilumab were 4.58 times more likely to develop a T-cell or natural killer lymphoma than asthma patients not taking the drug.
- World Allergy Organization Journal review: A review published in World Allergy Organization Journal found that while dupilumab probably didn’t have a significant negative effect on the majority of solid tumors, a specific group of cancer patients receiving dupilumab saw relatively unfavorable outcomes: CTCL patients.
- FDA investigation: The FDA, in March 2025, placed dupilumab on its “Potential Signals” list. The drug is now being reviewed by the FDA to determine if an additional warning is needed for the risk of CTCL.
- Potential for masking the early signs of CTCL: CTCL’s early-stage symptoms, like persistent scaly or itchy patches, may be similar to the symptoms of conditions such as eczema which Dupixent treats. This may lead to a delayed cancer diagnosis, since the drug could mask CTCL or its signs, or might even accelerate cancer progression once cancer develops.
- Need for continued monitoring: It is advised by medical experts that patients who take Dupixent should get closely monitored for unusual or new skin changes. Doctors should remain vigilant for CTCL’s early signs.
Potential Mechanisms
- Altered immune signaling: Dupilumab works by blocking IL-13 and IL-4 signaling. It is being investigated by scientists if this immune signaling change can allow malignant T-cells or tumor tissues to more easily grow in some people by removing natural tumor surveillance.
- Histopathologic shifts: It is theorized that the cancer risk may be linked with CD30 overexpression and abnormal CD4:CD8 ratios.
What to Do if You’re Concerned
- Contact a doctor: If you are on dupilumab and develop swollen lymph nodes, unusual skin changes, fatigue or unexplained itching, immediately contact your healthcare provider for a CTCL evaluation.
- Request a biopsy: Ask your healthcare provider to consider CTCL and perform a biopsy in order to rule cancer out. Early cases are commonly misdiagnosed as eczema.
- Keep detailed medical records: Be sure to document when you first started taking dupilumab, the symptoms’ onset, and all test results and doctor visits.
- Report adverse events: You can report serious side effects to the MedWatch program that the FDA runs. Your healthcare provider can as well.
- Consult with a lawyer: If you or your loved one took Dupixent then was diagnosed with CTCL, you may qualify for financial compensation. It’s recommended to contact an experienced dangerous drug law firm for a free consultation.
Cutaneous T-Cell Lymphoma Warning Signs and Symptoms
The symptoms and signs of CTCL include:
- Patches of skin which look gray, brown, red or pink. It may be more difficult to see the color on brown and black skin.
- Patches of scaly or raised skin which might itch. These patches happen most commonly on skin which doesn’t get a lot of sun.
- Patches of skin which look lighter in color compared to skin around them. This could be more easily seen on brown and black skin.
- Lymph nodes which get bigger.
- Lumps which form on the skin. They might break open.
- Thickened skin on the soles of the feet and palms of the hands.
- Hair loss.
- A full-body rash which is itchy and scaly.
Who Qualifies for a Dupixent Lawsuit?
You may qualify for financial compensation in a Dupixent lawsuit if you or a loved one:
- Have a confirmed diagnosis, which is biopsy-proven, of CTCL (including a diagnosis of Sézary syndrome or mycosis fungoides, which are CTCL subtypes)
- Used Dupixent for a minimum of six months prior to diagnosis
- Haven’t been diagnosed with a lymphoproliferative disorder before
Call us today for a FREE case evaluation at (800) 718-4658 or contact us if you or a loved one fit the above criteria.
Compensation for a Dupixent Lawsuit
There have not yet been any publicly-reported settlement amounts, as the Dupixent litigation is still in its early stages.
However, our lawyers are estimating the following potential values for Dupixent cases:
- Stage I CTCL: $100,000 to $300,000
- Stage II CTCL: $500,000 to $1,000,000
- Stage III or IV CTCL or death: $1,500,000 to $3,000,000
If you or a loved one was diagnosed with CTCL after taking Dupixent, you may qualify for financial compensation for:
- Medical bills: Past and future medical expenses related to your CTCL diagnosis. This includes compensation for the costs of cancer treatments, medications, doctor visits, diagnostic testing, etc.
- Lost wages: Wages you were unable to earn due to being too sick to work or having to take time off work to attend medical appointments.
- Loss of earning capacity: The loss or reduction of your earning capacity caused by a disability which was caused by CTCL.
- Pain and suffering: Physical pain, mental suffering, emotional distress and reduced quality of life related to your CTCL.
- Wrongful death: Funeral and burial costs, the medical bills, pain and suffering of your loved one prior to their passing, and the loss of your loved one’s income, companionship, love, spousal benefits and household services.
How Long Do I Have to File a Claim?
There is a time limit to file a claim regarding an injury caused by a drug like Dupixent. This time limit varies from state to state and is called a statute of limitations.
- In California, for example, you have two years from the date that you discovered that Dupixent caused you to develop CTCL to file a lawsuit. Failure to file a lawsuit within this time frame can prevent you from being able to recover financial compensation.
- Families filing wrongful death claims will have two years from the date they discovered that Dupixent caused their loved one’s death to file a lawsuit.
- Don’t wait – contact our lawyers as soon as possible. Contacting us today helps to preserve evidence, gives our lawyers as much time as possible to build a strong case for you, and ensures that all legal deadlines are met.
FAQs
Has Dupixent Been Recalled by the FDA?
Dupixent has not been recalled by the FDA as of November 2025. However, the FDA is investigating whether a CTCL warning is necessary for Dupixent’s label.
Are There Any Long-Term Side Effects of Dupixent?
Several scientific studies have suggested that Dupixent may be linked with the development of CTCL, a type of skin cancer.
Psoriasis appears to be a rare, potentially long-term side effect of Dupixent.
The most common side effects associated with Dupixent include:
- Upper respiratory tract infections
- Injection site reactions
- Herpes virus infections
- Eye problems
- High white blood cell count
- Cold-like symptoms
- Back pain
- Viral infection
- Dizziness
- Nose inflammation
- Diarrhea
- Muscle pain
- Gastritis
- Throat pain
- Insomnia
- Joint pain
- Parasitic infections
- Toothache
- Urinary tract infection
- Headache
How Do I Prove Dupixent Caused My Cancer?
You will need the following to prove that Dupixent caused your cancer:
- Medical records as well as treatment documentation which show the timeline of your Dupixent use and your cancer diagnosis
- Biopsy reports confirming CTCL
- Expert testimony which links Dupixent to your cancer
Our lawyers can take care of gathering evidence, including expert testimony, for you and putting together a strong, convincing case on your behalf.
Who Is Liable for the Dupixent Lawsuits?
Sanofi and Regeneron Pharmaceuticals are the primary defendants named in Dupixent cancer lawsuits. They jointly developed and marketed the drug, and are accused of failing to warn consumers and doctors about the potential risk of CTCL associated with the drug.
What Does It Cost to Hire a Dupixent Attorney?
It will cost you nothing out of your own pocket to hire Nadrich Accident Injury Lawyers.
We are a contingency fee law firm who only charges a percentage of any recovery obtained.
We do not charge any fee until we win the case.
Contact Our Dupixent CTCL Injury Lawyers
A cancer diagnosis can be emotionally and financially devastating, and you shouldn’t have to bear this burden alone, especially when it was the negligence of a pharmaceutical company who caused it.
Call us today for a FREE consultation at (800) 718-4658 or contact us if you or a loved one was diagnosed with CTCL after taking Dupixent.
Why Clients Choose Our Dangerous Drug Attorneys
- We’ve been taking on pharmaceutical giants and winning since 1990.
- We’ve recovered hundreds of millions of dollars for our clients.
- We’re contingency fee lawyers so you’ll owe us nothing out of your own pocket.
- You can rely on our communication and our 24/7 availability.
- No defendant is too large for us as we possess extensive experience and resources, including a network of the finest experts and specialists who can provide you with expert testimony that links your cancer with Dupixent.
- We’re committed to obtaining compensation and justice for those who have been hurt by the negligent conduct of pharmaceutical companies.
Past results do not guarantee future outcomes. All cases are unique and results depend on cases’ specific facts.
Call us today for a FREE consultation at (800) 718-4658.
Dupixent Lawsuit Updates
August 12, 2026 Update
A lawsuit filed on August 3 in New Jersey by a Colorado woman alleges that the makers of Dupixent knew for many years that the drug could cause users to develop cancer, yet held back information about this cancer risk in order to protect the drug’s profits.
The lawsuit names Regeneron Pharmaceuticals Inc., Genzyme Corporation and Sanofi-Aventis U.S. LLC as defendants.
The plaintiff alleges she was prescribed Dupixent for atopic dermatitis and was then diagnosed with cutaneous T-cell lymphoma (CTCL), a rare type of cancer which she claims the drug caused.
The lawsuit claims she was prescribed the drug in March 2021 and was diagnosed with cancer in February 2023.
The woman has allegedly needed to go through “extensive treatments” such as radiation, chemotherapy and phototherapy. The lawsuit claims she’ll probably need medical monitoring for the remainder of her life.
The plaintiff claims her doctor wouldn’t have prescribed the drug if the drug’s maker had warned adequately about the alleged cancer risk.
The plaintiff alleges the drug’s makers knew the drug carried a cancer risk before it was approved, but decided to hide that information.
The lawsuit notes that Dupixent’s phase II clinical trials noted that a patient ended up developing CTCL well prior to the medication being sold on the market.
August 4, 2026 Update
A lawsuit filed on July 17 in New Jersey by a Virginia woman claims that a mere few injections of Dupixent were enough to cause her to develop mycosis fungoides, a form of cancer.
The lawsuit names Regeneron Pharmaceuticals Inc., Genzyme Corporation and Sanofi-Aventis LLC as defendants.
The lawsuit claims that the woman started using the drug in October to treat atopic dermatitis, and that she wasn’t ever warned the drug could increase her risk of developing cancer.
The lawsuit alleges she was diagnosed with mycosis fungoides in February 2026 and has since needed extensive cancer treatment such as topical medications, phototherapy and chemotherapy.
She indicates that her doctors told her she’ll need ongoing healthcare and medical treatment for the remainder of her life.
The lawsuit claims this diagnosis was unnecessary and may have been avoided if proper warnings were given, arguing the manufacturer knew for years about the cancer risk but deceived the public and regulators about the drug’s safety.
The lawsuit alleges that when the woman was prescribed the drug, there was enough scientific data available that the defendants should have known that reasonable evidence existed regarding a causal association between the drug and cancer.
Prior to November 2018, under two years after the placing of Dupixent on the market, the drug’s makers knew about at least 10 reports of patients taking the drug and developing CTCL. This number has increased over the years, with over 200 cases reported by 2024’s end.
The lawsuit alleges that, despite numerous calls for more testing of the drug, the manufacturers didn’t allocate adequate resources to investigate the issue. The lawsuit alleges that the drug’s label still doesn’t have an appropriate warning.
July 22, 2026 Update
A lawsuit filed on July 10 in New Jersey by a Massachusetts man alleges that the man developed mycosis fungoides, a rare form of cancer, after receiving injections of Dupixent for three years.
The lawsuit names Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit alleges that the drug’s manufacturers failed to properly test the drug prior to releasing it on the market, placing profit over safety and rushing the drug to market while failing to provide adequate safety warnings.
According to the lawsuit, the man developed an itchy rash, then was diagnosed with mycosis fungoides, a type of cancer which attacks the immune system.
The complaint claims that the drug’s manufacturers knew or should have known that the drug could cause, exacerbate or accelerate cancer.
The lawsuit alleges that the manufacturers ignored evidence from epidemiologic articles, case studies and peer-reviewed reports that linked the drug with cancer.
The lawsuit will be consolidated into an MDL in New Jersey.
July 1, 2026 Update
An initial case management conference in the Dupixent MDL will be held on October 1, 2026. This will be the first time that lawyers will appear in the multidistrict litigation court.
The MDL currently has around two dozen lawsuits in it against the manufacturers of Dupixent.
The October 1 Initial Management Conference will involve the parties meeting for the first time in order to address discovery, pretrial proceedings and the litigation’s overall direction.
Attorneys have been directed to meet and confer by July 24 to agree where possible upon issues listed in the agenda of the Initial Management Conference.
The parties have been ordered to submit an Initial Management Report by September 10. The report should include a need for lawyers to get appointed to positions of leadership, that leadership’s structure and the timing of these appointments, in addition to if those appointments should periodically be reviewed. It should also include information on previously entered orders and schedules, future case management conference scheduling and additional key items which have to be discussed to start moving the MDL forward.
June 7, 2026 Update
A lawsuit filed on May 27 in New Jersey by a Louisiana woman alleges that the woman developed cancer due to injections of Dupixent.
The lawsuit names Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit alleges that Dupixent caused the woman to develop cutaneous T-cell lymphoma (CTCL), a type of non-Hodgkin lymphoma.
According to the lawsuit, the woman started using Dupixent after being diagnosed with eczema, and received injections of the drug for five years, until 2022, when she was diagnosed with CTCL.
The woman has needed chemotherapy and total body skin radiation treatments, and claims these treatments could have been avoided, claiming the drug’s manufacturers should have sufficiently warned about the drug’s cancer risks.
The lawsuit accuses the defendants of intentionally misrepresenting the effectiveness and safety of the drug despite scientific studies and case reports which should have raised concerns.
May 18, 2026 Update
A lawsuit filed on May 5 in Illinois alleges that critical safety information was withheld from patients and doctors by pharmaceutical companies regarding a possible link between cancer and Dupixent, including evidence that it could lead to a higher risk of developing CTCL.
The lawsuit names Genzyme Corporation, Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit alleges that Sanofi and Regeneron didn’t warn that the drug could increase CTCL risks or accelerate the progression of the cancer.
According to the complaint, the woman used the drug from April 2023 through October 2025, when she was diagnosed with CTCL.
The lawsuit claims the drug’s manufacturers had access to scientific evidence that indicated a strong link between the drug and CTCL, yet failed to adequately warn patients or the medical community and failed to update the drug’s prescribing information.
The lawsuit also alleges the manufacturers failed to instruct healthcare providers to do proper diagnostic testing like biopsies to rule out lymphoma before giving patients Dupixent, and failed to instruct healthcare providers to monitor patients for signs of cancer.
May 1, 2026 Update
A lawsuit filed on April 28 in New Jersey by a Louisiana woman alleges that the woman developed mycosis fungoides, a form of CTCL, because of side effects from using Dupixent.
The lawsuit names Genzyme Corporation, Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit alleges that the defendants sold, manufactured and developed a defective medication which can cause cancer.
According to the lawsuit, the woman started using the drug in October 2022 to treat atopic dermatitis, using it until May 2024.
Doctors, in May 2025, allegedly diagnosed her with mycosis fungoides, a form of cancer which causes itchy, scaly and red patches on the skin which doctors commonly confuse for the skin issues the drug is intended to treat. Since this can lead to delayed diagnoses, proper label warnings are very important.
Since being diagnosed with mycosis fungoides, the woman has also allegedly been diagnosed with Sézary syndrome, a leukemic, aggressive type of CTCL. The lawsuit is blaming Dupixent for both diagnoses.
February 20, 2026 Update
Plaintiffs in Dupixent lawsuits are asking a judges’ panel to centralize and consolidate all claims regarding lymphoma side effects before a single federal judge for coordinated pretrial proceedings and discovery.
February 13 saw three plaintiffs file a motion to transfer, submitting it to the United States Judicial Panel on Multidistrict Litigation, asking for all federal Dupixent lymphoma lawsuits to be consolidated into an MDL in Georgia.
The motion argues that consolidation is needed to serve the conveniences of courts, witnesses and common parties, avoid contradictory rulings, and reduce duplicative discovery.
The motion claims that at least 15 federal lawsuits are pending in 12 courts, with four being filed in Georgia’s Northern District. The lawsuits assert similar claims regarding the same product, made by the same defendants, and involve similar cancer diagnoses.
Should the panel grant the motion, the litigation would get consolidated before a single judge who would lead the litigation through discovery, pretrial proceedings and possibly bellwether trials.
Each claim would stay an individual lawsuit. Each plaintiff would keep their individual lawyer.
February 4, 2026 Update
A lawsuit filed on January 30 in Florida by a Florida man alleges that two years of using Dupixent led to him developing a rare type of blood cancer, and that the manufacturers knew about this risk.
The lawsuit claims defendants Genzyme Corporation, Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. didn’t warn the public that the side effects of Dupixent could exacerbate or cause cancer.
The lawsuit claims that the man was prescribed the drug in December 2019, and while he was diagnosed with Mycosis Fungoides, a type of cutaneous T-cell lymphoma (CTCL), he kept using the medication of October 2021, not aware of a possible connection.
The man has allegedly endured prolonged and extensive treatments including phototherapy and chemotherapy since the diagnosis.
The lawsuit claims that his physician would have probably chosen a different medication had the manufacturers properly warned about the CTCL risk associated with their drug.
The complaint alleges that the manufacturers started receiving CTCL reports in March 2018, and had received 15 CTCL reports by the end of 2018.
The lawsuit claims that the drug was linked with over 200 CTCL reports by the end of 2024.
January 14, 2026 Update
A lawsuit filed on January 8 in California alleges that a man who received a Dupixent prescription four years ago and wasn’t warned about a higher cancer risk only discovered this risk after he was diagnosed with Mycosis Fungoides, a form of T-cell lymphoma.
The lawsuit alleges that defendants Genzyme Corporation, Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. failed to warn as well as probably purposefully hid Dupixent’s adverse health risks from the medical community and patients.
The lawsuit states that the man was prescribed the drug in May 2022 and used it until February 2023, when he was diagnosed with the cancer.
The man has allegedly needed numerous treatments, including cancer inhibitors, topical steroids, radiation phototherapy, chemotherapy, and numerous other drugs.
The man’s healthcare providers, according to the lawsuit, have advised him that he will probably need ongoing healthcare services and treatments for the cancer indefinitely.
The lawsuit alleges that the man has continued suffering new tumor growth since his initial diagnosis.
The lawsuit is alleging that enough evidence existed prior to the man receiving the prescription for the drug’s manufacturers to have updated the drug’s label to warn about a cancer risk. However, the man alleges he didn’t learn that the manufacturers knew about these risks until a March 2025 post by the FDA about a possible safety signal.
The lawsuit notes that the manufacturers have still not updated the label to warn about a cancer risk.
January 8, 2026 Update
A recent study evaluated if Dupixent could be associated with the progression or onset of CTCL.
In the study, the drug showed a 30-fold increase in CTCL’s proportional reporting ratio. This is significantly higher than every other medication’s background rate.
The signal was the strongest in men between the ages of 45 and 65.
The study is proposing that local IL13 levels may be inadvertently increased by IL13 receptor blockade, possibly accelerating or unmasking CTCL in individuals who are susceptible.
December 30, 2025 Update
A lawsuit was filed on December 22 in Georgia by a Georgia woman who alleges that she was diagnosed with cutaneous T-cell lymphoma (CTCL) as a direct result of taking Dupixent.
The lawsuit names Genzyme Corporation, Sanofi-Aventis U.S. LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit alleges the woman started taking the drug in August 2018 and was diagnosed with CTCL in December 2018. However, the lawsuit alleges she continued receiving injections of Dupixent until August 2019 because she wasn’t aware of a potential connection between her cancer diagnosis and the drug.
The woman has allegedly been advised that she’ll require medical monitoring and medical treatment for the remainder of her life, and has suffered new tumor growths in the time since her diagnosis.
The lawsuit claims that the drug’s manufacturers received numerous reports which linked the drug to cancer in the months prior to her receiving the injections. The lawsuit alleges her cancer could have been avoided if the manufacturers properly warned her doctors about those reports.
December 19, 2025 Update
A lawsuit was filed on December 16 in Illinois by an Illinois woman who claims she was diagnosed with two forms of T-cell lymphoma, Sézary syndrome and mycosis fungoides, after receiving injections of Dupixent.
The lawsuit names Sanofi-Aventis LLC and Regeneron Pharmaceuticals Inc. as defendants.
The lawsuit claims that the woman received injections of Dupixent from July 2017 to February 2018, as well as from November 2018 to January 2019.
It is alleged she experienced little or no improvement from the injections, and, in May 2021, was diagnosed with the two types of cutaneous T-cell lymphoma. The cancer was allegedly stage IV when it was diagnosed.
The woman has undergone numerous treatments, including cancer medications and radiation therapy, since the diagnosis.
It wasn’t until October 2025, however, that her healthcare provider told her the cancer may have been caused by Dupixent.
The lawsuit alleges that the woman could have received earlier treatment or altogether avoided cancer had the drug’s manufacturers warned doctors regarding what to look out for.
The lawsuit claims that the defendants failed to adequately and timely warn about the drug’s propensity to cause cancer or accelerate its progression.
