Hypereosinophilic Syndrome - Market Insight, Epidemiology, and Market Forecast - 2034

Key Highlights

• Hypereosinophilic syndrome (HES) is a rare, complex group of heterogeneous disorders characterized by persistently elevated eosinophil counts and associated tissue infiltration leading to organ damage.
• Glucocorticoids remain the first-line treatment, achieving remission in most patients, though long-term use may require steroid-sparing strategies. For FIP1L1-PDGFRA–positive HES, imatinib is highly effective.
• NUCALA (mepolizumab) is the only FDA-approved treatment specifically for HES and holds orphan drug designation, granting it seven years of market exclusivity in the US, which protects it from generic or biosimilar competition during this period.
• Key companies involved in the development of therapies for the management of HES are AstraZeneca, GlaxoSmithKline, and others.
• Few emerging therapies for HES include Depemokimab, a long-acting anti–IL-5 antibody in Phase III (DESTINY) enabling six-month dosing, and Benralizumab, an anti–IL-5Rα antibody in Phase III (NATRON) offering steroid-sparing potential through rapid eosinophil depletion; other agents in earlier stages are also being explored, reflecting growing pipeline interest in this underserved space.

DelveInsight's “Hypereosinophilic Syndrome (HES) – Market Insight, Epidemiology and Market Forecast – 2034” report delivers an in-depth analysis of HES epidemiology, market, and clinical development in HES. In addition to this, the report provides historical and forecasted epidemiology and market data as well as a detailed analysis of the HES market trends in the United States, EU4 (Germany, France, Italy, and Spain ), the United Kingdom, and Japan.

The HES market report provides real-world prescription pattern analysis, emerging drugs assessment, market share, and uptake/adoption pattern of individual therapies, as well as historical and forecasted HES market size from 2020 to 2034 in 7MM. The report also covers current HES treatment practices/algorithms and unmet medical needs to curate the best opportunities and assess the market’s underlying potential.

Geography Covered

• The United States
• EU4 (Germany, France, Italy, and Spain) and the United Kingdom
• Japan

Hypereosinophilic Syndrome Understanding and Treatment Algorithm

Hypereosinophilic Syndrome Overview and Diagnosis

HES is a rare, complex group of heterogeneous disorders characterized by persistently elevated eosinophil counts and associated tissue infiltration leading to organ damage. Central to the disease is dysregulated eosinophilopoiesis, contributing to inflammatory processes across various organ systems. Diagnostic criteria include an absolute eosinophil count greater than 1.5 × 10⁹/L on at least two occasions, one month apart, bone marrow eosinophils comprising over 20% of all nucleated cells, and histological evidence of extensive eosinophilic infiltration or granule protein deposition. Additionally, organ or tissue damage must be attributable to hypereosinophilia, and other potential causes of such damage must be excluded to confirm the diagnosis.

The HES report provides an overview of HES pathophysiology and diagnostic approaches, along with a real-world scenario of a patient’s journey beginning from the first symptom, the time taken for diagnosis, to the entire treatment process.

Further details related to country-based variations in diagnosis are provided in the report.

Hypereosinophilic Syndrome Treatment

Treatment of HES depends on disease severity, underlying cause, and HES subtype. Mild or pauci-symptomatic cases may only require close monitoring, while severe presentations, characterized by high eosinophil counts and organ involvement, necessitate immediate intervention, typically with high-dose corticosteroids. Glucocorticoids remain the first-line treatment, achieving remission in most patients, though long-term use may require steroid-sparing strategies. For FIP1L1-PDGFRA–positive HES, imatinib is highly effective. In steroid-refractory or F/P–negative cases, second-line options include hydroxyurea or interferon-α, although the latter’s side effects can limit use. Importantly, NUCALA is now FDA-approved for HES in patients aged 12 years and older and has shown significant efficacy as a steroid-sparing agent in F/P–negative HES, reducing disease activity and steroid dependency. Other biologics like benralizumab are being explored but remain off-label. Timely, individualized treatment is essential to prevent organ damage and improve outcomes.

Further details related to treatment are provided in the report.

Hypereosinophilic Syndrome Epidemiology

The HES epidemiology chapter in the report provides historical as well as forecasted epidemiology segmented as total Prevalent cases of HES, gender-specific cases of HES, type-specific cases of HES, age-specific cases of HES, and total treated cases of HES in the 7MM, covering the United States, EU4 (Germany, France, Italy, and Spain), and the United Kingdom, and Japan from 2020 to 2034.

• The prevalence of HES varies greatly, with estimates of between 0.32 and 6.3 cases per 100,000 people in the United States, 1.5 cases per 100,000 people in the European Union, and between 0.15 and 0.89 cases per 100,000 people in the United Kingdom.
• There is a male predominance in HES, with a male-to-female ratio of 9:1.
• HES is most commonly diagnosed in patients aged 20-50 years, with a peak prevalence in the fourth decade. It is rare in children.
• The most common cause of eosinophilia in the United States is an allergic reaction or allergic disease. Worldwide, the most common cause of eosinophilia is parasitosis.

Hypereosinophilic Syndrome Drug Chapters

The drug chapter segment of the HES report encloses a detailed analysis of HES marketed drugs and late-stage (Phase III and Phase II) pipeline drugs. It also deep dives into HES pivotal clinical trial details, recent and expected market approvals, patent details, the latest news, and recent deals and collaborations.

Marketed Drugs

NUCALA (mepolizumab): GlaxoSmithKline

NUCALA (mepolizumab) is an interleukin-5 antagonist monoclonal antibody (IgG1 kappa) approved by the US FDA in September 2020 for the treatment of adults and adolescents aged 12 years and older with HES lasting six months or more, without an identifiable non-hematologic secondary cause. Recognizing the high unmet need in this rare condition, NUCALA was granted orphan drug designation, along with fast track and priority review status, supporting its accelerated development and regulatory approval.

Note: A Detailed market therapy assessment will be provided in the final report.

Emerging Drugs

Depomimab: GlaxoSmithKline

Depemokimab is an investigational ultra–long-acting monoclonal antibody targeting interleukin-5 (IL-5), currently in late-stage development for multiple eosinophil-driven conditions, including HES, asthma with type 2 inflammation, chronic rhinosinusitis with nasal polyps (CRSwNP), and eosinophilic granulomatosis with polyangiitis (EGPA). Engineered for high binding affinity and potency, depemokimab features an extended half-life that allows for dosing every six months. In HES, it is being evaluated in the ongoing Phase III DESTINY trial, where it is administered subcutaneously alongside standard therapy to reduce disease flares in patients with elevated eosinophil counts.

Benralizumab: AstraZeneca

Benralizumab is a humanized, afucosylated monoclonal antibody targeting the interleukin-5 receptor α (IL-5Rα), inducing rapid and near-complete depletion of eosinophils via antibody-dependent cell-mediated cytotoxicity (ADCC). While currently approved for severe eosinophilic asthma, benralizumab has shown promising eosinophil-lowering effects in patients with HES, particularly those without the FIP1L1-PDGFRA mutation. It is currently being evaluated in the Phase III NATRON trial for HES, aiming to address the high unmet need for effective, steroid-sparing treatments in this rare and potentially life-threatening condition.

Hypereosinophilic Syndrome Market Outlook

The HES treatment market remains highly underserved, with NUCALA (mepolizumab) as the only FDA-approved therapy, highlighting significant unmet need. Emerging biologics like depemokimab (GSK), with its ultra–long-acting IL-5 inhibition and six-month dosing, and benralizumab (AstraZeneca), targeting IL-5Rα with potent eosinophil depletion, are in Phase III trials and poised to expand treatment options. As reliance on corticosteroids continues and biologics demonstrate promising efficacy and safety, the HES market is set for growth, driven by the demand for targeted, steroid-sparing therapies.

• In 2024, the United States accounts for the largest market size of HES, in comparison to EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan.
• Among the EU4 and the UK, Germany had the highest market size, while France had the smallest market size for HES in 2024.

Hypereosinophilic Syndrome drug uptake

This section focuses on the uptake rate of potential drugs expected to be launched in the market during 2025–2034, which depends on the competitive landscape, safety, and efficacy data, along with the order of entry. It is important to understand that the key players evaluating their novel therapies in the pivotal and confirmatory trials should remain vigilant when selecting appropriate comparators to stand the greatest chance of a positive opinion from regulatory bodies, leading to approval, smooth launch, and rapid uptake.

Further detailed analysis of emerging therapies' drug uptake in the report…

Hypereosinophilic Syndrome Activities

The report provides insights into different therapeutic candidates in the Phase III and Phase II stages. It also analyzes key players involved in developing targeted therapeutics.

Pipeline Development Activities

The report covers information on collaborations, acquisitions and mergers, licensing, and patent details for HES therapies.

KOL Views

To keep up with the real-world scenario in current and emerging market trends, we take opinions from Key Industry leaders working in the domain through primary research to fill the data gaps and validate our secondary research. Industry Experts were contacted for insights on the evolving treatment landscape, patient reliance on conventional therapies, patient therapy switching acceptability, and drug uptake, along with challenges related to accessibility, including Medical/scientific writers, Professors, and Others.

DelveInsight’s analysts connected with 10+ KOLs to gather insights; however, interviews were conducted with 5+ KOLs in the 7MM. Centers such as the National Institute of Allergy and Infectious Diseases, the University of Michigan, etc., were contacted. Their opinion helps understand and validate current and emerging therapy treatment patterns or HES market trends.

Qualitative Analysis

We perform Qualitative and market Intelligence analysis using various approaches, such as SWOT analysis and Conjoint Analysis. In the SWOT analysis, strengths, weaknesses, opportunities, and threats in terms of gaps in disease diagnosis, patient awareness, physician acceptability, competitive landscape, cost-effectiveness, and geographical accessibility of therapies are provided.

Conjoint Analysis analyzes multiple approved and emerging therapies based on relevant attributes such as safety, efficacy, frequency of administration, route of administration, and order of entry. Scoring is given based on these parameters to analyze the effectiveness of therapy.

In efficacy, the trial’s primary and secondary outcome measures are evaluated; for instance, in event-free survival, one of the most important primary outcome measures is event-free survival and overall survival.

Further, the therapies’ safety is evaluated, wherein the acceptability, tolerability, and adverse events are majorly observed, and it sets a clear understanding of the side effects posed by the drug in the trials. In addition, the scoring is also based on the probability of success and the addressable patient pool for each therapy. According to these parameters, the final weightage score and the ranking of the emerging therapies are decided.

Market Access and Reimbursement

Reimbursement may be referred to as the negotiation of a price between a manufacturer and a payer that allows the manufacturer access to the market. It is provided to reduce the high costs and make the essential drugs affordable. Health technology assessment (HTA) plays an important role in reimbursement decision-making and recommending the use of a drug. These recommendations vary widely throughout the seven major markets, even for the same drug. In the US healthcare system, both Public and Private health insurance coverage are included. Also, Medicare and Medicaid are the largest government-funded programs in the US. The major healthcare programs, including Medicare, Medicaid, Health Insurance Program (CHIP), and the state and federal health insurance marketplaces, are overseen by the Centers for Medicare & Medicaid Services (CMS). Other than these, Pharmacy Benefit Managers (PBMs) and third-party organizations that provide services and educational programs to aid patients are also present.

The report further provides detailed insights on the country-wise accessibility and reimbursement scenarios, cost-effectiveness scenario of currently used therapies, programs making accessibility easier and out-of-pocket costs more affordable, insights on patients insured under federal or state government prescription drug programs, etc.

Scope of the Report

• The report covers a segment of key events, an executive summary, a descriptive overview of HES, explaining its causes, signs and symptoms, pathogenesis, and currently available therapies.
• Comprehensive insight has been provided into the epidemiology segments and forecasts, the future growth potential of the diagnosis rate, and disease progression along treatment guidelines.
• Additionally, an all-inclusive account of both the current and emerging therapies, along with the elaborate profiles of late-stage and prominent therapies, will have an impact on the current treatment landscape.
• A detailed review of the HES market, historical and forecasted market size, market share by therapies, detailed assumptions, and rationale behind our approach is included in the report, covering the 7MM drug outreach.
• The report provides an edge while developing business strategies, by understanding trends, through SWOT analysis and expert insights/KOL views, patient journey, and treatment preferences that help in shaping and driving the 7MM HES market.

Hypereosinophilic Syndrome Report Insights

• Patient Population
• Therapeutic Approaches
• HES Pipeline Analysis
• HES Market Size and Trends
• Existing and future Market Opportunity

Hypereosinophilic Syndrome Report Key Strengths

• 10 Years Forecast
• 7MM Coverage
• HES Epidemiology Segmentation
• Key Cross Competition
• Conjoint analysis
• Drugs Uptake and Key Market Forecast Assumptions

Hypereosinophilic Syndrome Report Assessment

• Current Treatment Practices
• Unmet Needs
• Pipeline Product Profiles
• Market Attractiveness
• Qualitative Analysis (SWOT and Conjoint Analysis)

FAQs

• What is the historical and forecasted HES patient pool/patient burden in the United States, EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan?
• Which treatment approaches will have a significant impact on the HES drug treatment market size?
• How would the market drivers, barriers, and future opportunities affect the market dynamics and subsequent analysis of the associated trends?
• What are the current and emerging options for the treatment of HES?
• How many companies are developing therapies for the treatment of HES?
• What are the recent novel therapies, targets, mechanisms of action, and technologies developed to overcome the limitations of existing therapies?
• Patient acceptability in terms of preferred treatment options as per real-world scenarios?
• What are the country-specific accessibility issues of expensive, recently approved therapies?

Reasons to buy

• The report will help in developing business strategies by understanding the latest trends and changing treatment dynamics driving the HES market.
• Insights on patient burden/disease prevalence, evolution in diagnosis, and factors contributing to the change in the epidemiology of the disease during the forecast years.
• Understand the existing market opportunities in varying geographies and the growth potential over the coming years.
• Distribution of historical and current patient share based on real-world prescription data along with reported sales of approved products in the US, EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan.
• Identifying strong upcoming players in the market will help devise strategies to help get ahead of competitors.
• Detailed analysis and ranking of class-wise potential current and emerging therapies under the conjoint analysis section to provide visibility around leading classes.
• Highlights of access and reimbursement policies of approved therapies, barriers to accessibility of expensive off-label therapies, and patient assistance programs.
• To understand Key Opinion Leaders’ perspectives around the accessibility, acceptability, and compliance-related challenges of existing treatment to overcome barriers in the future.
• Detailed insights on the unmet needs of the existing market so that the upcoming players can strengthen their development and launch strategy.

Please Note: It will take 7-10 business days to complete the report upon order confirmation. Show more