Dupixent® (dupilumab) Approved as the First Targeted Medicine in the European Union (EU) in Over a Decade for Chronic Spontaneous Urticaria (CSU)

Rhea-AI Summary

Regeneron (NASDAQ: REGN) and Sanofi announced on November 25, 2025 that the European Commission approved Dupixent (dupilumab) for moderate-to-severe chronic spontaneous urticaria (CSU) in patients aged 12+ with inadequate response to H1 antihistamines who are naïve to anti-IgE therapy.

Approval is based on the LIBERTY-CUPID Phase 3 program: two pivotal trials (Study A and Study C, combined n=284) and an additional safety study (Study B, n=108) showing significant reductions in itch and hives at 24 weeks, higher rates of well-controlled disease and complete response, and a safety profile consistent with prior Dupixent indications. Approximately 270,000 EU patients may be eligible.

Positive

• EC approval expands Dupixent to CSU for patients 12+
• Trials showed significant itch and hive reduction at 24 weeks
• Approximately 270,000 EU patients eligible for targeted therapy
• Dupixent now approved across seven chronic type 2 diseases in EU

Negative

• Safety evidence from 392 trial patients (284+108)
• Common adverse reactions include injection site reactions and conjunctivitis

Insights

Regulatory and Clinical Strategy Expert

EU approval of Dupixent for CSU adds a first targeted option in over a decade, supported by Phase 3 efficacy and safety data.

Dupixent gained European Commission approval on Nov. 25, 2025 for moderate‑to‑severe chronic spontaneous urticaria (CSU) in patients aged 12 and older with inadequate response to H1 antihistamines and who are anti‑IgE naïve. The decision rests on two Phase 3 trials (Study A and Study C) and a supporting safety study (Study B). Studies A and C enrolled 284 symptomatic patients and showed statistically meaningful reductions in a composite urticaria activity measure (itch and hives), plus higher rates of well‑controlled disease and complete response at 24 weeks versus placebo.

The approval changes the treatment pathway by authorizing Dupixent as an eligible first‑line targeted option for the defined CSU subgroup. Key dependencies include uptake among clinicians comfortable prescribing a biologic earlier in therapy and alignment of local reimbursement for a targeted biologic in place of, or after, antihistamines. Safety signals reported across the CSU program match the established profile, with the most common adverse reactions including injection site reactions, conjunctivitis, arthralgia, oral herpes and eosinophilia; Study B (108 patients) provided additional safety data for those intolerant or nonresponsive to anti‑IgE therapy.

Watch for three concrete near‑term items: dissemination of the full 24‑week endpoints and responder rates from Study A and Study C to regulators and clinicians, national reimbursement decisions across EU member states following the Nov. 25, 2025 approval, and real‑world safety reports as use expands beyond trial populations. Expect initial adoption signals over the next 6–18 months as prescribing, payer coverage, and guideline updates evolve.

Approval based on Phase 3 trials showing Dupixent significantly reduced itch and hives at 24 weeks compared to placebo

In the EU, there are approximately 270,000 adults and adolescents aged 12 years and older living with CSU who remain symptomatic despite standard-of-care antihistamine treatment

Dupixent, which inhibits IL-4 and IL-13, two key and central drivers of type 2 inflammation, is now approved for patients across seven chronic, inflammatory diseases in the EU

TARRYTOWN, N.Y. and PARIS, Nov. 25, 2025 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) and Sanofi today announced that the European Commission (EC) has approved Dupixent^® (dupilumab) for the treatment of moderate-to-severe chronic spontaneous urticaria (CSU) in adult and adolescent patients 12 years and above with inadequate response to histamine-1 antihistamines (H1AH) and who are naïve to anti-immunoglobulin E (IgE) therapy for CSU. Eligible patients can use Dupixent as a first-line targeted treatment option.

“The unpredictable nature of chronic spontaneous urticaria leaves patients guessing when they’ll have their next outbreak of disruptive, debilitating hives and itch, which can make life challenging,” said Tonya Winders, President & CEO, Global Allergy & Airways Patient Platform. “Dupixent is proven to reduce these intense symptoms and has the potential to make a positive impact on people struggling to control this disease.”

“The approval of Dupixent for certain adults and adolescents with chronic spontaneous urticaria in the European Union represents the first innovation for patients with this disease in over a decade,” said George D. Yancopoulos, M.D., Ph.D., Board co-Chair, President and Chief Scientific Officer at Regeneron, and a principal inventor of Dupixent. “Physicians now have a new approach for CSU with Dupixent, as the only treatment that inhibits IL-4 and IL-13, two key drivers of type 2 inflammation, and can offer patients significant improvement in debilitating itch and hives. This approval further demonstrates the ability of Dupixent to advance the treatment landscape for yet another chronic type 2 inflammatory disease, with a well-established safety profile across its indications.”

The approval is based on data from two Phase 3 clinical trials in the LIBERTY-CUPID program. Study A and Study C included 284 patients aged 12 years and older who were symptomatic despite the use of antihistamines and who were naïve to anti-IgE therapy. Both trials assessed Dupixent as an add-on therapy to standard-of-care antihistamines compared to antihistamines alone and demonstrated Dupixent significantly reduced urticaria activity (a composite of itch and hives), and individual measures of itch and hive severity compared to placebo at 24 weeks. Dupixent also increased the percentage of patients with well-controlled disease and complete response at 24 weeks compared to placebo. Study B included 108 patients and provided additional safety data and evaluated Dupixent in patients aged 12 years and older who were inadequate responders or intolerant to anti-IgE therapy and symptomatic despite antihistamine use.

Safety results from Study A, Study B and Study C were generally consistent with the known safety profile of Dupixent in its approved indications. The most common adverse reactions for Dupixent overall are injection site reactions, conjunctivitis, conjunctivitis allergic, arthralgia, oral herpes and eosinophilia. Additional adverse reactions of injection site induration, injection site dermatitis and injection site hematoma were reported in the CSU adult and adolescent trials. Adverse events more commonly observed with Dupixent (≥5%) than placebo in patients with CSU were injection site reaction, COVID-19, hypertension, CSU and accidental overdose.

“Standard-of-care, first-line treatment options like antihistamines offer limited relief for many people living with uncontrolled chronic spontaneous urticaria, leaving them to face unrelenting cycles of itch and hives,” said Alyssa Johnsen, M.D., Ph.D., Global Therapeutic Area Head, Immunology Development at Sanofi. “Dupixent significantly reduced these symptoms of CSU and led to more patients experiencing well-controlled disease or a complete response compared to placebo in two Phase 3 studies. Now, eligible patients with CSU in the EU have a new option that is proven to reduce itch and hives.”

Beyond the European Union (EU), Dupixent is also approved for CSU in certain adults and adolescents in several countries including the United States and Japan.

About CSU
CSU is a chronic, inflammatory skin disease driven in part by type 2 inflammation, which causes sudden and debilitating hives and recurring itch. CSU is typically treated with H1AH, medicines that target H1 receptors on cells to control symptoms of itch and urticaria. However, the disease remains uncontrolled despite H1AH treatment in many patients, some of whom are left with limited alternative treatment options. These individuals continue to experience symptoms that can be debilitating and significantly impact their quality of life. More than 270,000 people in the EU aged 12 years and older suffer from CSU that is inadequately controlled by antihistamines.

About the Dupixent CSU Phase 3 Trial Program
The LIBERTY-CUPID Phase 3 program evaluating Dupixent for CSU consists of Study A, Study B and Study C. These trials were randomized, double-blind, placebo-controlled clinical trials that evaluated the efficacy and safety of Dupixent as an add-on therapy to standard-of-care antihistamines compared to antihistamines alone. Studies A and C were replicate trials that assessed patients aged 6 years and older who remained symptomatic despite the use of antihistamines and were naïve to anti-IgE therapy. Study B was conducted in patients aged 12 years and older who were symptomatic despite use of antihistamines and were inadequate responders or intolerant to anti-IgE therapy. During the 24-week treatment period in all three trials, all patients received an initial loading dose followed by either 300 mg Dupixent every two weeks or 200 mg every two weeks for adolescents weighing <60 kg.

The primary endpoint in all three studies assessed the change from baseline in itch and hives (weekly urticaria activity score [UAS7], 0-42 scale). The key secondary endpoint (also assessed at 24 weeks) was change from baseline in itch (measured by the weekly itch severity score [ISS7], 0-21 scale). Additional secondary endpoints assessed at 24 weeks evaluated:

• Change from baseline in hives (measured by the weekly hive severity score [HSS7], 0-21 scale)
• Proportion of patients achieving well-controlled disease status (UAS7 ≤6)
• Proportion of patients with complete response (UAS7=0).
  

The results from Studies A and B were published in The Journal of Allergy and Clinical Immunology. 

About Dupixent
Dupixent is an injection administered under the skin (subcutaneous injection) at different injection sites. In adults with CSU who remain symptomatic despite H1AH treatment, Dupixent 300 mg is administered every two weeks after an initial loading dose. In patients aged 12 to 17 years with CSU who remain symptomatic despite H1AH treatment, Dupixent is administered every two weeks based on weight (200 mg for adolescents ≥30 to <60 kg, 300 mg for adolescents ≥60 kg) after an initial loading dose. Dupixent is intended for use under the guidance of a healthcare professional and can be given in a clinic or at home after training by a healthcare professional. In adolescents aged 12 to 17 years, Dupixent should be administered under the supervision of an adult.

Dupixent, which was invented using Regeneron’s proprietary VelocImmune^® technology, is a fully human monoclonal antibody that inhibits the signaling of the interleukin-4 (IL-4) and interleukin-13 (IL-13) pathways and is not an immunosuppressant. The Dupixent development program has shown significant clinical benefit and a decrease in type 2 inflammation in Phase 3 trials, establishing that IL-4 and IL-13 are two of the key and central drivers of the type 2 inflammation that plays a major role in multiple related and often co-morbid diseases.

Dupixent has received regulatory approvals in more than 60 countries in one or more indications including certain patients with atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic esophagitis (EoE), prurigo nodularis, chronic spontaneous urticaria (CSU), chronic obstructive pulmonary disease (COPD) and bullous pemphigoid (BP) in different age populations. More than 1,300,000 patients are being treated with Dupixent globally.¹

About Regeneron's VelocImmune Technology
Regeneron's VelocImmune technology utilizes a proprietary genetically engineered mouse platform endowed with a genetically humanized immune system to produce optimized fully human antibodies. When Regeneron's co-Founder, President and Chief Scientific Officer George D. Yancopoulos was a graduate student with his mentor Frederick W. Alt in 1985, they were the first to envision making such a genetically humanized mouse, and Regeneron has spent decades inventing and developing VelocImmune and related VelociSuite^® technologies. Dr. Yancopoulos and his team have used VelocImmune technology to create a substantial proportion of all original, FDA-approved fully human monoclonal antibodies. This includes Dupixent^® (dupilumab), Libtayo^® (cemiplimab-rwlc), Praluent^® (alirocumab), Kevzara^® (sarilumab), Evkeeza^® (evinacumab-dgnb), Inmazeb^® (atoltivimab, maftivimab and odesivimab-ebgn) and Veopoz^® (pozelimab-bbfg). In addition, REGEN-COV^® (casirivimab and imdevimab) had been authorized by the FDA during the COVID-19 pandemic until 2024.

Dupilumab Development Program
Dupilumab is being jointly developed by Regeneron and Sanofi under a global collaboration agreement. To date, dupilumab has been studied across more than 60 clinical trials involving more than 10,000 patients with various chronic diseases driven in part by type 2 inflammation. 

In addition to the currently approved indications, Regeneron and Sanofi are studying dupilumab in a broad range of diseases driven by type 2 inflammation or other allergic processes in Phase 3 trials, including chronic pruritus of unknown origin, lichen simplex chronicus and allergic fungal rhinosinusitis. These potential uses of dupilumab are currently under clinical investigation, and the safety and efficacy in these conditions have not been fully evaluated by any regulatory authority. 

U.S. INDICATIONS 
DUPIXENT is a prescription medicine used:

• to treat adults and children 6 months of age and older with moderate-to-severe eczema (atopic dermatitis or AD) that is not well controlled with prescription therapies used on the skin (topical), or who cannot use topical therapies. DUPIXENT can be used with or without topical corticosteroids. It is not known if DUPIXENT is safe and effective in children with AD under 6 months of age.
• with other asthma medicines for the maintenance treatment of moderate-to-severe eosinophilic or oral steroid dependent asthma in adults and children 6 years of age and older whose asthma is not controlled with their current asthma medicines. DUPIXENT helps prevent severe asthma attacks (exacerbations) and can improve your breathing. DUPIXENT may also help reduce the amount of oral corticosteroids you need while preventing severe asthma attacks and improving your breathing. It is not known if DUPIXENT is safe and effective in children with asthma under 6 years of age.
• with other medicines for the maintenance treatment of chronic rhinosinusitis with nasal polyps (CRSwNP) in adults and children 12 years of age and older whose disease is not controlled. It is not known if DUPIXENT is safe and effective in children with CRSwNP under 12 years of age.
• to treat adults and children 1 year of age and older with eosinophilic esophagitis (EoE), who weigh at least 33 pounds (15 kg). It is not known if DUPIXENT is safe and effective in children with EoE under 1 year of age, or who weigh less than 33 pounds (15 kg).
• to treat adults with prurigo nodularis (PN). It is not known if DUPIXENT is safe and effective in children with PN under 18 years of age.
• with other medicines for the maintenance treatment of adults with inadequately controlled chronic obstructive pulmonary disease (COPD) and a high number of blood eosinophils (a type of white blood cell that may contribute to your COPD). DUPIXENT is used to reduce the number of flare-ups (the worsening of your COPD symptoms for several days) and can improve your breathing. It is not known if DUPIXENT is safe and effective in children with COPD under 18 years of age.
• to treat adults and children 12 years of age and older with chronic spontaneous urticaria (CSU) who continue to have hives that are not controlled with H1 antihistamine treatment. It is not known if DUPIXENT is safe and effective in children with CSU under 12 years of age, or who weigh less than 66 pounds (30 kg).
• to treat adults with bullous pemphigoid (BP). It is not known if DUPIXENT is safe and effective in children with BP under 18 years of age.

DUPIXENT is not used to relieve sudden breathing problems and will not replace an inhaled rescue medicine or to treat any other forms of hives (urticaria).

IMPORTANT SAFETY INFORMATION

Do not use if you are allergic to dupilumab or to any of the ingredients in DUPIXENT^®.

Before using DUPIXENT, tell your healthcare provider about all your medical conditions, including if you:

• have eye problems.
• have a parasitic (helminth) infection.
• are scheduled to receive any vaccinations. You should not receive a “live vaccine” right before and during treatment with DUPIXENT.
• are pregnant or plan to become pregnant. It is not known whether DUPIXENT will harm your unborn baby.
  • A pregnancy registry for women who take DUPIXENT during pregnancy collects information about the health of you and your baby. To enroll or get more information call 1-877-311-8972 or go to https://mothertobaby.org/ongoing-study/dupixent/.
• are breastfeeding or plan to breastfeed. It is not known whether DUPIXENT passes into your breast milk.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your healthcare provider if you are taking oral, topical, or inhaled corticosteroid medicines; have asthma and use an asthma medicine; or have AD, CRSwNP, EoE, PN, COPD, CSU, or BP and also have asthma. Do not change or stop your other medicines, including corticosteroid medicine or other asthma medicine, without talking to your healthcare provider. This may cause other symptoms that were controlled by those medicines to come back.

DUPIXENT can cause serious side effects, including:

• Allergic reactions. DUPIXENT can cause allergic reactions, including skin reactions, that can sometimes be severe. Stop using DUPIXENT and tell your healthcare provider or get emergency help right away if you get any of the following signs or symptoms: breathing problems or wheezing, swelling of the face, lips, mouth, tongue or throat, fainting, dizziness, feeling lightheaded, fast pulse, fever, hives, skin rash, including rash that looks like a bullseye, painful red or blue bumps under the skin, or red pus-filled spots on the skin, general ill feeling, itching, swollen lymph nodes, nausea or vomiting, joint pain, or cramps in your stomach area.
• Eye problems. Tell your healthcare provider if you have any new or worsening eye problems, including eye pain or changes in vision, such as blurred vision. Your healthcare provider may send you to an ophthalmologist for an exam if needed.
• Inflammation of your blood vessels. Rarely, this can happen in people with asthma who receive DUPIXENT. This may happen in people who also take a steroid medicine by mouth that is being stopped or the dose is being lowered. Tell your healthcare provider right away if you get: rash, chest pain, worsening shortness of breath, brown or dark colored urine, persistent fever, or a feeling of pins and needles or numbness of your arms or legs.
• Psoriasis. This can happen in people with atopic dermatitis and asthma who receive DUPIXENT. Tell your healthcare provider about any new skin symptoms. Your healthcare provider may send you to a dermatologist for an examination if needed.
• Joint aches and pain. Some people who use DUPIXENT have had trouble walking or moving due to their joint symptoms, and in some cases needed to be hospitalized. Tell your healthcare provider about any new or worsening joint symptoms. Your healthcare provider may stop DUPIXENT if you develop joint symptoms.
  

The most common side effects include:

• Eczema: injection site reactions, eye problems, including eye and eyelid inflammation, redness, swelling, itching, eye infection, dry eye, and blurred vision, cold sores in your mouth or on your lips, and high count of a certain white blood cell (eosinophilia).
• Asthma: injection site reactions, high count of a certain white blood cell (eosinophilia), pain in the throat (oropharyngeal pain), and parasitic (helminth) infections.
• Chronic Rhinosinusitis with Nasal Polyps: injection site reactions, eye problems, including eye and eyelid inflammation, redness, swelling, itching, eye infection, and blurred vision, high count of a certain white blood cell (eosinophilia), stomach problems (gastritis), joint pain (arthralgia), trouble sleeping (insomnia), and toothache.
• Eosinophilic Esophagitis: injection site reactions, upper respiratory tract infections, cold sores in your mouth or on your lips, and joint pain (arthralgia).
• Prurigo Nodularis: eye problems, including eye and eyelid inflammation, redness, swelling, itching, and blurred vision, herpes virus infections, common cold symptoms (nasopharyngitis), dizziness, muscle pain, and diarrhea.
• Chronic Obstructive Pulmonary Disease: injection site reactions, common cold symptoms (nasopharyngitis), high count of a certain white blood cell (eosinophilia), viral infection, back pain, inflammation inside the nose (rhinitis), diarrhea, stomach problems (gastritis), joint pain (arthralgia), toothache, headache, and urinary tract infection.
• Chronic Spontaneous Urticaria: injection site reactions.
• Bullous Pemphigoid: joint pain (arthralgia), eye problems, including eye and eyelid inflammation, redness, swelling, itching, and blurred vision, and herpes virus infections.

Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of DUPIXENT. Call your doctor for medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

Use DUPIXENT exactly as prescribed by your healthcare provider. It’s an injection given under the skin (subcutaneous injection). Your healthcare provider will decide if you or your caregiver can inject DUPIXENT. Do not try to prepare and inject DUPIXENT until you or your caregiver have been trained by your healthcare provider. In children 12 years of age and older, it’s recommended DUPIXENT be administered by or under supervision of an adult. In children 6 months to less than 12 years of age, DUPIXENT should be given by a caregiver.

Please see accompanying full Prescribing Information including Patient Information.

About Regeneron
Regeneron (NASDAQ: REGN) is a leading biotechnology company that invents, develops and commercializes life-transforming medicines for people with serious diseases. Founded and led by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to numerous approved treatments and product candidates in development, most of which were homegrown in our laboratories. Our medicines and pipeline are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, neurological diseases, hematologic conditions, infectious diseases, and rare diseases.

Regeneron pushes the boundaries of scientific discovery and accelerates drug development using our proprietary technologies, such as VelociSuite, which produces optimized fully human antibodies and new classes of bispecific antibodies. We are shaping the next frontier of medicine with data-powered insights from the Regeneron Genetics Center^® and pioneering genetic medicine platforms, enabling us to identify innovative targets and complementary approaches to potentially treat or cure diseases.

For more information, please visit www.Regeneron.com or follow Regeneron on LinkedIn, Instagram, Facebook or X.

About Sanofi
Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and delivering compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time.  

Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY 

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¹ Data on File

FAQ

What did Regeneron/SANOFI announce about Dupixent (REGN) on November 25, 2025?

The European Commission approved Dupixent for moderate-to-severe CSU in patients 12+ with inadequate response to H1 antihistamines and naïve to anti-IgE therapy.

How effective was Dupixent (REGN) in Phase 3 CSU trials at 24 weeks?

Two pivotal Phase 3 studies reported significant reductions in itch and hives and higher rates of well-controlled disease and complete response at 24 weeks versus placebo.

How many patients were enrolled in the LIBERTY-CUPID CSU trials supporting the REGN Dupixent approval?

The program included Study A and Study C (combined n=284) plus Study B (n=108) for additional safety data.

Who in the EU is eligible for Dupixent (REGN) for CSU?

Adults and adolescents aged 12 years and older symptomatic despite H1 antihistamines who are naïve to anti-IgE therapy.

What safety issues were reported for Dupixent (REGN) in CSU trials?

Common adverse reactions included injection site reactions, conjunctivitis, arthralgia, oral herpes, eosinophilia and additional injection-site events in CSU trials.

How many EU patients could benefit from Dupixent (REGN) for CSU?

The press material cites approximately 270,000 adults and adolescents in the EU who remain symptomatic despite antihistamines.