Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) and Sanofi today presented positive results from the pivotal ADEPT Phase 2/3 trial evaluating the investigational use of Dupixent® (dupilumab) in adults with moderate-to-severe bullous pemphigoid (BP). The data were shared in a late-breaking oral presentation at the 2025 American Academy of Dermatology (AAD) Annual Meeting. BP is a chronic, debilitating and relapsing skin disease with underlying type 2 inflammation and characterized by intense itch and blisters, reddening of the skin and painful lesions.

“People with bullous pemphigoid live with unrelenting itch, blisters and painful lesions that can be debilitating and make it difficult to function daily. Moreover, current treatment options can be challenging for this primarily elderly patient population because they work by suppressing their immune system,” said Victoria Werth, M.D., Chief of the Division of Dermatology at the Philadelphia Veterans Administration Hospital, Professor of Dermatology and Medicine at the Hospital of the University of Pennsylvania and the Veteran's Administration Medical Center, and principal investigator of the study. “By targeting the underlying type 2 inflammation, which is a key driver for bullous pemphigoid, Dupixent is the first investigational biologic to show sustained disease remission and reduce disease severity and itch compared to placebo in a clinical trial.”

The ADEPT trial met all primary and key secondary endpoints, enrolling 106 adults with moderate-to-severe BP who were randomized to receive Dupixent 300 mg (n=53) every two weeks after an initial loading dose or placebo (n=53) added to standard-of-care oral corticosteroids (OCS). During treatment, all patients underwent a protocol-defined OCS tapering regimen if control of disease activity was maintained. Sustained disease remission was defined as complete clinical remission with completion of OCS taper by week 16 without relapse and no rescue therapy use during the 36-week treatment period.

As presented at AAD, results for Dupixent-treated patients at 36 weeks, compared to those treated with placebo, were as follows:

• 20% experienced sustained disease remission, the primary endpoint, compared to 4% (p=0.0114).
• 40% achieved ≥90% reduction in disease severity compared to 10% (p=0.0003).
• 40% achieved clinically meaningful itch reduction compared to 11% (p=0.0006).
• 1678 mg reduction in cumulative OCS exposure (p=0.0220) on average, and a 54% lower risk of rescue medication use (p=0.0016).

In this elderly population, overall rates of adverse events (AEs) were 96% (n=51) for Dupixent and 96% (n=51) for placebo. AEs more commonly observed with Dupixent compared to placebo in at least 3 patients included peripheral edema (n=8 vs. n=5), arthralgia (n=5 vs. n=3), back pain (n=4 vs. n=2), blurred vision (n=4 vs. n=0), hypertension (n=4 vs. n=3), asthma (n=4 vs. n=1), conjunctivitis (n=4 vs. n=0), constipation (n=4 vs. n=1), upper respiratory tract infection (n=3 vs. n=1), limb injury (n=3 vs. n=2) and insomnia (n=3 vs. n=2). There were no AEs leading to death in the Dupixent group and 2 AEs leading to death in the placebo group.

In February, the U.S. Food and Drug Administration (FDA) accepted for Priority Review the supplemental Biologics License Application for Dupixent to treat BP. The FDA decision is expected by June 20, 2025. Dupixent was previously granted Orphan Drug Designation by the FDA for BP, which applies to investigational medicines intended for the treatment of rare diseases that affect fewer than 200,000 people in the U.S. Additional applications are also under review around the world, including in the European Union.

The safety and efficacy of Dupixent in BP are currently under clinical investigation and have not been evaluated by any regulatory authority.

About Bullous PemphigoidBP is a chronic, debilitating, and relapsing skin disease with underlying type 2 inflammation that typically occurs in an elderly population. It is characterized by intense itch and blisters, reddening of the skin, and painful lesions. The blisters and rash can form over much of the body and cause the skin to bleed and crust, resulting in patients being more prone to infection and affecting their daily functioning. Approximately 27,000 adults in the U.S. live with BP that is uncontrolled by systemic corticosteroids.

About the Dupixent BP Pivotal Trial ADEPT is a randomized, Phase 2/3, double-blind, placebo-controlled trial evaluating the efficacy and safety of Dupixent for a 52-week treatment period in 106 adults with moderate-to-severe BP. After randomization, patients received Dupixent or placebo every two weeks, along with OCS treatment. During treatment, OCS taper was initiated after patients experienced two weeks of sustained control of disease activity. OCS tapering could start between four to six weeks after randomization and was continued as long as disease control was maintained, with the intent of completion by 16 weeks. After OCS tapering, patients were only treated with Dupixent or placebo for at least 20 weeks, unless rescue treatment was required.

The primary endpoint evaluated the proportion of patients achieving sustained disease remission at 36 weeks. Sustained disease remission was defined as complete clinical remission with completion of OCS taper by 16 weeks without relapse and no rescue therapy use during the 36-week treatment period. Relapse was defined as appearance of ≥3 new lesions a month or ≥1 large lesion or urticarial plaque (>10 cm in diameter) that did not heal within a week. Rescue therapy could include treatment with high-potency topical corticosteroids, OCS (including increase of OCS dose during the taper or re-initiation of OCS after completion of the OCS taper), systemic non-steroidal immunosuppressive medications or immunomodulating biologics.

Select secondary endpoints evaluated at 36 weeks included:

• Proportion of patients achieving ≥90% reduction in Bullous Pemphigoid Disease Area Index (BPDAI; scale: 0-360)
• Proportion of patients with ≥4-point reduction in Peak Pruritus Numerical Rating Scale (PP-NRS; scale 0-10) score
• Total cumulative OCS dose
• Time to first use of rescue medication

About DupixentDupixent, 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 (AD), asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic esophagitis (EoE), prurigo nodularis (PN), chronic spontaneous urticaria (CSU), and chronic obstructive pulmonary disease (COPD) in different age populations. More than 1,000,000 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, bullous pemphigoid, and lichen simplex chronicus. 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 atopic dermatitis 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 chronic rhinosinusitis with nasal polyps 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 eosinophilic esophagitis 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 prurigo nodularis 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 chronic obstructive pulmonary disease under 18 years of age.

DUPIXENT is not used to relieve sudden breathing problems and will not replace an inhaled rescue medicine.

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 atopic dermatitis, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis, prurigo nodularis, or chronic obstructive pulmonary disease 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 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, joint pain, general ill feeling, itching, skin rash, swollen lymph nodes, nausea or vomiting, 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. It is not known whether this is caused by DUPIXENT. Tell your healthcare provider right away if you have: rash, chest pain, worsening shortness of breath, a feeling of pins and needles or numbness of your arms or legs, or persistent fever.
• 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 and eyelid inflammation, including redness, swelling, and itching, sometimes with blurred vision, dry eye, 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 and eyelid inflammation, including redness, swelling, and itching, sometimes with blurred vision, high count of a certain white blood cell (eosinophilia), 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 and eyelid inflammation, including redness, swelling, and itching, sometimes with 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, gastritis, joint pain (arthralgia), toothache, headache, and urinary tract infection.

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 RegeneronRegeneron (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 We are an innovative global healthcare company, driven by one purpose: we chase the miracles of science to improve people’s lives. Our team, across the world, is dedicated to transforming the practice of medicine by working to turn the impossible into the possible. We provide potentially life-changing treatment options and life-saving vaccine protection to millions of people globally, while putting sustainability and social responsibility at the center of our ambitions.

Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY.

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