Dupixent® (dupilumab) Approved in Japan as the First Targeted Medicine to Treat Adults with Bullous Pemphigoid (BP)

Rhea-AI Summary

Regeneron (NASDAQ: REGN) and Sanofi announced that Japan's MHLW approved Dupixent (dupilumab) for adults with moderate-to-severe bullous pemphigoid (BP), the first targeted therapy for BP in Japan and Dupixent's seventh Japanese indication.

Approval was based on the LIBERTY-BP-ADEPT Phase 2/3 trial where Dupixent plus corticosteroid taper showed sustained remission at Week 36 in 18% vs 4% with placebo (p=0.0250). Treatment-related adverse events occurred in 26% of Dupixent patients versus 15% for placebo; conjunctivitis was reported in 4% of Dupixent patients.

Positive

• First targeted therapy for bullous pemphigoid in Japan
• Regulatory approval supported by pivotal Phase 2/3 data
• Dupixent achieved sustained remission: 18% vs 4% at Week 36
• Seventh approved Dupixent indication in Japan

Negative

• Treatment-related adverse events higher: 26% with Dupixent
• Absolute sustained remission rate modest at 18% in treated patients
• Trial sample size limited: 53 patients per arm

News Market Reaction – REGN

+0.70%

+0.70% Session close to close

In the Mar 24 session, REGN gained 0.70%, reflecting a mild positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

This announcement adds bullous pemphigoid as the seventh Dupixent indication in Japan, supported by ...

Analysis

This announcement adds bullous pemphigoid as the seventh Dupixent indication in Japan, supported by LIBERTY-BP-ADEPT data showing a remission rate of 18% vs. 4% on placebo with a primary endpoint p-value of 0.0250. It extends Dupixent’s presence beyond atopic dermatitis, asthma and other conditions. In context of recent positive Dupixent and obesity-trial updates, key areas to watch include safety profile evolution, further regulatory decisions, and how franchise breadth contributes to overall revenue momentum.

Key Figures

Dupixent dose: 300 mg Dupixent arm size: 53 patients (n=53) Placebo arm size: 53 patients (n=53) +5 more

8 metrics

Dupixent dose 300 mg Dose used in LIBERTY-BP-ADEPT Phase 2/3 trial arm

Dupixent arm size 53 patients (n=53) Moderate-to-severe BP patients on Dupixent plus OCS

Placebo arm size 53 patients (n=53) Moderate-to-severe BP patients on placebo plus OCS

Sustained remission rate 18% Dupixent patients with sustained disease remission at Week 36

Placebo remission rate 4% Placebo patients with sustained disease remission at Week 36

P-value p=0.0250 Primary endpoint comparison of remission at Week 36

Treatment-related AEs Dupixent 26% Proportion of Dupixent-treated patients with treatment-related AEs

Treatment-related AEs placebo 15% Proportion of placebo-treated patients with treatment-related AEs

Historical Context

5 past events · Latest: Mar 10 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Mar 10	STEM competition awards	Positive	+0.3%	Regeneron-funded Science Talent Search awards over $1.8M to finalists.
Mar 09	Obesity trial data	Positive	+2.9%	Positive Phase 3 olatorepatide obesity results with strong weight-loss efficacy.
Mar 05	Investor conference	Neutral	-0.7%	Announcement of Barclays healthcare conference webcast and replay availability.
Feb 27	Dupixent EU opinion	Positive	+1.4%	Positive CHMP opinion for Dupixent in pediatric chronic spontaneous urticaria.
Feb 26	STS sponsorship renewal	Positive	-1.7%	Renewal of Science Talent Search sponsorship with additional $150M commitment.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

In 3 of the last 5 events, positive or constructive news aligned with modest positive 24h price reactions; two philanthropy/CSR-related items saw negative or flat moves.

Recent Company History

Recent news for REGN highlighted philanthropy, clinical progress, and franchise expansion. On Feb 27, a positive CHMP opinion for Dupixent in pediatric CSU corresponded with a 1.41% gain. Positive Phase 3 obesity data on Mar 9 saw a 2.86% rise. Science Talent Search sponsorship and renewal headlines on Feb 26 and Mar 10 involved sizeable commitments but produced mixed reactions, including a -1.72% move. Today’s Japan BP approval adds another Dupixent indication alongside this pattern of pipeline and franchise milestones.

Key Terms

pivotal trial, phase 2/3, oral corticosteroids, placebo, +4 more

8 terms

pivotal trial medical

"Approval in moderate-to-severe patients was based on pivotal trial results showing..."

A pivotal trial is a key test of a new medicine or treatment to see if it works and is safe enough to be approved by health authorities. It's like a final exam for a new product, and passing it is essential for bringing the treatment to the public.

phase 2/3 medical

"based on data from the pivotal LIBERTY-BP-ADEPT Phase 2/3 trial, which evaluated..."

A phase 2/3 trial is a combined clinical study that first evaluates how well a treatment works and the best dose, then expands into a larger test to confirm those results and safety. For investors, it matters because moving into a phase 2/3 signals that an experimental therapy has shown initial promise and will be tested at scale, which can materially change the odds and timeline for regulatory approval and commercial potential.

oral corticosteroids medical

"Patients were randomized to receive Dupixent 300 mg or placebo added to standard-of-care oral corticosteroids (OCS)."

Oral corticosteroids are prescription medicines taken by mouth that quickly reduce inflammation and calm an overactive immune response—think of them as temporarily turning down an overly sensitive alarm system in the body. For investors, they matter because their effectiveness, side effects and safety concerns influence how often they are prescribed, regulatory scrutiny, reimbursement rules and demand for alternative therapies, all of which affect sales, market share and healthcare costs.

placebo medical

"Patients were randomized to receive Dupixent 300 mg or placebo added to standard-of-care..."

A placebo is an inactive pill, injection or procedure that looks and feels like the real treatment but contains no therapeutic ingredient, often called a sugar pill. Investors care because comparing a drug to a placebo reveals whether observed benefits come from the medicine itself or from expectation; clear superiority over placebo reduces regulatory and commercial risk, much like a blind taste test proves a new recipe really tastes better.

treatment-related adverse events medical

"Treatment-related adverse events (AEs) occurred in 26% of Dupixent patients..."

Treatment-related adverse events are harmful or unwanted health effects that doctors or regulators determine were caused by a drug, vaccine, device, or other medical therapy. Investors care because how often and how severe these side effects are can shape regulatory approval, labeling, sales potential and legal risk — similar to how product defects can stop or damage a company's ability to sell an item.

conjunctivitis medical

"The treatment-related AE most commonly reported with Dupixent was conjunctivitis (4%)."

Inflammation or infection of the conjunctiva, the thin clear tissue that covers the white of the eye and the inside of the eyelid, causing redness, tearing, discharge, itching and light sensitivity—think of it like a rash or sunburn for the eye. For investors it matters because outbreaks or seasonal spikes can change demand for over‑the‑counter remedies, prescription drugs, clinic visits and workplace absences, influencing sales and service volumes for companies in eye care, pharmaceuticals and healthcare services.

standard-of-care medical

"placebo added to standard-of-care oral corticosteroids (OCS)."

The standard-of-care is the widely accepted medical treatment or procedure that doctors typically use for a particular illness, based on current evidence and clinical practice. For investors it matters because new drugs or devices must beat or match this baseline to be adopted, reimbursed and widely sold—think of it as the default recipe a market expects; a new product must prove it’s tastier, cheaper, or faster to replace it.

type 2 inflammation medical

"BP is a chronic, relapsing skin disease with underlying type 2 inflammation..."

An immune response driven by a specific set of cells and signaling molecules that causes allergic-type inflammation in tissues such as the lungs, skin and sinuses; think of it as the body’s alarm system stuck in the “allergy” mode. It matters to investors because drugs that reduce or block this pathway can treat common, chronic conditions (asthma, eczema, chronic sinusitis) and represent large, targeted markets with potential for premium-priced, specialty medicines.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Approval in moderate-to-severe patients was based on pivotal trial results showing over four times more Dupixent patients experienced sustained disease remission through Week 36 compared with placebo

BP is a chronic, relapsing skin disease with underlying type 2 inflammation characterized by intense itch alongside painful blisters and other lesions

BP is the seventh approved indication for Dupixent in Japan

TARRYTOWN, N.Y. and PARIS, March 24, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) and Sanofi today announced that the Ministry of Health, Labour and Welfare (MHLW) in Japan has approved Dupixent^® (dupilumab) for the treatment of adults with moderate-to-severe bullous pemphigoid (BP).

The approval in Japan is based on data from the pivotal LIBERTY-BP-ADEPT Phase 2/3 trial, which evaluated Dupixent in adults with moderate-to-severe BP. Patients were randomized to receive Dupixent 300 mg (n=53) 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. For the primary endpoint, more than four times as many patients on Dupixent experienced sustained disease remission compared to placebo (18% vs. 4%; p=0.0250) at Week 36 in the companies’ core dataset used for the regulatory submission in Japan.

Treatment-related adverse events (AEs) occurred in 26% of Dupixent patients and 15% of placebo patients. The treatment-related AE most commonly reported with Dupixent was conjunctivitis (4%).

In addition to BP, Dupixent is approved in Japan in certain patients with atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), prurigo nodularis, chronic spontaneous urticaria (CSU) and chronic obstructive pulmonary disease (COPD).

About BP
BP is a rare skin disease that primarily affects elderly patients, and is characterized by intense itch, painful blisters and lesions, as well as reddening of the skin. It can be chronic and relapsing with underlying type 2 inflammation. The blisters and rash can form over much of the body and cause the skin to bleed and break down, resulting in patients being more prone to infection and affecting their daily functioning. Available treatment options are limited and can add to overall disease burden by suppressing a patient’s immune system.

About ADEPT
ADEPT was a randomized, double-blind, placebo-controlled Phase 2/3 trial evaluating the efficacy and safety of Dupixent in 106 adults with moderate-to-severe BP for a 52-week treatment period. After randomization, patients received Dupixent or placebo every two weeks after an initial loading dose, 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 if disease control was maintained, with the intent of completion by Week 16. After OCS tapering, patients were only treated with Dupixent or placebo for the rest of the trial (rescue treatment could be used if required).

The primary endpoint evaluated the proportion of patients achieving sustained disease remission at Week 36. Sustained disease remission was defined as complete clinical remission with completion of OCS taper by Week 16 without relapse after completion of the OCS taper 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) or systemic non-steroidal immunosuppressive medications or immunomodulating biologics.

About Dupixent
Dupixent is now available in Japan as a 300 mg pre-filled syringe or pre-filled pen for adults with bullous pemphigoid. Dupixent is intended for injection under the skin (subcutaneous injection) and is given every two weeks after an initial loading dose. It can be given in a clinic or at home by self-administration after training by a healthcare professional.

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, CRSwNP, eosinophilic esophagitis (EoE), prurigo nodularis, CSU, COPD, BP and allergic fungal rhinosinusitis (AFRS) in different age populations. More than 1,400,000 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, Board co-Chair, 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 12,000 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 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 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.
• to treat adults and children 6 years of age and older with allergic fungal rhinosinusitis (AFRS), who have had surgery on their nose or sinuses in the past. It is not known if DUPIXENT is safe and effective in children with AFRS under 6 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.
• 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, BP, or AFRS 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.
• Allergic Fungal Rhinosinusitis: 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.
  
  

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. 

Regeneron Forward-Looking Statements and Use of Digital Media
This press release includes forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. (“Regeneron” or the “Company”), and actual events or results may differ materially from these forward-looking statements. Words such as “anticipate,” “expect,” “intend,” “plan,” “believe,” “seek,” “estimate,” variations of such words, and similar expressions are intended to identify such forward-looking statements, although not all forward-looking statements contain these identifying words. These statements concern, and these risks and uncertainties include, among others, the nature, timing, and possible success and therapeutic applications of products marketed or otherwise commercialized by Regeneron and/or its collaborators or licensees (collectively, “Regeneron’s Products”) and product candidates being developed by Regeneron and/or its collaborators or licensees (collectively, “Regeneron’s Product Candidates”) and research and clinical programs now underway or planned, including without limitation Dupixent^® (dupilumab) for the treatment of adults with bullous pemphigoid; the likelihood, timing, and scope of possible regulatory approval and commercial launch of Regeneron’s Product Candidates and new indications for Regeneron’s Products, including Dupixent for the treatment of chronic pruritus of unknown origin, lichen simplex chronicus, and other potential indications; uncertainty of the utilization, market acceptance, and commercial success of Regeneron’s Products (such as Dupixent) and Regeneron’s Product Candidates and the impact of studies (whether conducted by Regeneron or others and whether mandated or voluntary), including the studies discussed or referenced in this press release, on any of the foregoing; the ability of Regeneron’s collaborators, licensees, suppliers, or other third parties (as applicable) to perform manufacturing, filling, finishing, packaging, labeling, distribution, and other steps related to Regeneron’s Products and Regeneron’s Product Candidates; the ability of Regeneron to manage supply chains for multiple products and product candidates and risks associated with tariffs and other trade restrictions; safety issues resulting from the administration of Regeneron’s Products (such as Dupixent) and Regeneron’s Product Candidates in patients, including serious complications or side effects in connection with the use of Regeneron’s Products and Regeneron’s Product Candidates in clinical trials; determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron’s ability to continue to develop or commercialize Regeneron’s Products and Regeneron’s Product Candidates; ongoing regulatory obligations and oversight impacting Regeneron’s Products, research and clinical programs, and business, including those relating to patient privacy; the availability and extent of reimbursement or copay assistance for Regeneron’s Products from third-party payors and other third parties, including private payor healthcare and insurance programs, health maintenance organizations, pharmacy benefit management companies, and government programs such as Medicare and Medicaid; coverage and reimbursement determinations by such payors and other third parties and new policies and procedures adopted by such payors and other third parties; changes to drug pricing regulations and requirements and Regeneron’s pricing strategy; other changes in laws, regulations, and policies affecting the healthcare industry; competing products and product candidates (including biosimilar products) that may be superior to, or more cost effective than, Regeneron’s Products and Regeneron’s Product Candidates; the extent to which the results from the research and development programs conducted by Regeneron and/or its collaborators or licensees may be replicated in other studies and/or lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval; unanticipated expenses; the costs of developing, producing, and selling products; the ability of Regeneron to meet any of its financial projections or guidance and changes to the assumptions underlying those projections or guidance; the potential for any license, collaboration, or supply agreement, including Regeneron’s agreements with Sanofi and Bayer (or their respective affiliated companies, as applicable), to be cancelled or terminated; the impact of public health outbreaks, epidemics, or pandemics on Regeneron's business; and risks associated with litigation and other proceedings and government investigations relating to the Company and/or its operations (including the pending civil proceedings initiated or joined by the U.S. Department of Justice and the U.S. Attorney's Office for the District of Massachusetts), risks associated with intellectual property of other parties and pending or future litigation relating thereto (including without limitation the patent litigation and other related proceedings relating to EYLEA^® (aflibercept) Injection), the ultimate outcome of any such proceedings and investigations, and the impact any of the foregoing may have on Regeneron’s business, prospects, operating results, and financial condition. A more complete description of these and other material risks can be found in Regeneron’s filings with the U.S. Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2025. Any forward-looking statements are made based on management’s current beliefs and judgment, and the reader is cautioned not to rely on any forward-looking statements made by Regeneron. Regeneron does not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

Regeneron uses its media and investor relations website and social media outlets to publish important information about the Company, including information that may be deemed material to investors. Financial and other information about Regeneron is routinely posted and is accessible on Regeneron's media and investor relations website (https://investor.regeneron.com) and its LinkedIn page (https://www.linkedin.com/company/regeneron-pharmaceuticals).

Sanofi Disclaimers or Forward-Looking Statements
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Regeneron Contacts:  Media Relations  Kailey Kilmartin Tel: +1 914-652-0679 Kailey.Kilmartin@regeneron.com	Investor Relations  Mark Hudson Tel: +1 914-847-3482  Mark.Hudson@regeneron.com
Sanofi Contacts:  Media Relations  Sandrine Guendoul Tel: +33 6 25 09 14 25 Sandrine.Guendoul@sanofi.com	Investor Relations  Thomas Kudsk Larsen Tel: +44 7545 513 693 Thomas.Larsen@sanofi.com
Evan Berland  Tel: +1 215-432-0234 Evan.Berland@sanofi.com	Alizé Kaisserian Tel: +33 6 47 04 12 11 Alize.Kaisserian@sanofi.com
Léo Le Bourhis Tel: + 33 6 75 06 43 81 leo.lebourhis@sanofi.com	Keita Browne Tel: +1 781-249-1766 Keita.Browne@sanofi.com
Victor Rouault   Tel: +1 617 356 4751 Victor.Rouault@sanofi.com	Nathalie Pham  Tel: +33 7 85 93 30 17  Nathalie.Pham@sanofi.com
Timothy Gilbert  Tel: +1 516-521-2929 Timothy.Gilbert@sanofi.com	Nina Goworek Tel: +1 908 569 7086 Nina.Goworek@sanofi.com
Léa Ubaldi Tel: + 33 6 30 19 66 46 lea.ubaldi@sanofi.com	Thibaud Châtelet  Tel: +33 6 80 80 89 90  Thibaud.Chatelet@sanofi.com
Ekaterina Pesheva Tel: +1 410 926 6780 ekaterina.pesheva@sanofi.com	Yun Li  Tel: +33 6 84 00 90 72  Yun.Li3@sanofi.com

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FAQ

What did Regeneron (REGN) and Sanofi announce about Dupixent approval in Japan on March 24, 2026?

They announced MHLW approval of Dupixent for adults with moderate-to-severe bullous pemphigoid. According to the company, approval was based on the LIBERTY-BP-ADEPT Phase 2/3 trial showing higher sustained remission versus placebo at Week 36.

How effective was Dupixent in the LIBERTY-BP-ADEPT trial for bullous pemphigoid (REGN)?

Dupixent showed sustained remission in 18% of patients versus 4% with placebo at Week 36. According to the company, results are from the core dataset used for the regulatory submission in Japan (p=0.0250).

What safety results did Regeneron report for Dupixent in the BP trial (REGN)?

Treatment-related adverse events occurred in 26% of Dupixent patients versus 15% with placebo. According to the company, the most common Dupixent-related adverse event was conjunctivitis, reported in 4% of treated patients.

How large was the pivotal BP trial that supported Dupixent's Japan approval (REGN)?

The LIBERTY-BP-ADEPT trial randomized 106 adults total, 53 to Dupixent and 53 to placebo. According to the company, all patients received standard-of-care oral corticosteroids plus protocol-defined tapering if disease control was maintained.

What does Dupixent's approval mean for Regeneron's (REGN) product portfolio in Japan?

Dupixent now has seven approved indications in Japan, expanding its labeled use. According to the company, approvals span multiple type 2 inflammatory conditions including atopic dermatitis, asthma, CRSwNP, and now bullous pemphigoid.

Will Dupixent replace oral corticosteroids for bullous pemphigoid patients in Japan (REGN)?

Dupixent is approved as an add-on to standard-of-care oral corticosteroids with tapering protocols used in the trial. According to the company, patients received Dupixent or placebo in addition to oral corticosteroids with protocol-defined tapering when disease control allowed.