CLINICAL TRIALS PROFILE FOR MEPOLIZUMAB

All Clinical Trials for mepolizumab

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00086658 ↗	Intravenous Mepolizumab In Subjects With Hypereosinophilic Syndromes (HES)	Completed	GlaxoSmithKline	Phase 3	2004-03-23	Hypereosinophilic syndrome (HES) is a rare disease with broad clinical signs and symptoms which is diagnosed based on a persistent blood eosinophil count of greater than 1500 cells, various end-organ damages (including skin, heart, lung, nervous system and digestive system etc.), and with exclusion of known secondary causes of hypereosinophilia. HES has a high morbidity/mortality rate. The major treatment of HES has been systemic corticosteroid and other chemotherapeutic drugs (for example, hydroxyurea and interferon) with the intention to lower eosinophil counts and therefore to slow down the progression of disease. Even though corticosteroid and other therapies can effectively reduce eosinophilia in some patients, some may eventually become nonresponsive and intolerable to the amount of side effects of the long-term therapy with these medications. Mepolizumab is a humanized monoclonal antibody that binds specifically to human interleukin 5 (hIL-5) and inhibits its activity. Previous human experience has shown it has been effective in reducing blood eosinophilia in atopic and HES patients and has alleviated some HES clinical signs and symptoms. This study intends to further evaluate the corticosteroid-sparing and clinical benefit of mepolizumab in HES.
NCT00097370 ↗	Open-Label Extension Of Intravenous Mepolizumab In Patients With Hypereosinophilic Syndrome	Terminated	GlaxoSmithKline	Phase 3	2004-09-30	This is an open label study of mepolizumab 750 mg intravenous in those subjects who participated in study 100185 to evaluate the long term safety and efficacy of mepolizumab in subjects with hypereosinophilic syndrome. The study will also evaluate the optimal dosing frequency for clinical use, the effects on corticosteroid reduction, and decrease of signs and symptoms of Hypereosinophilic Syndrome.
NCT00244686 ↗	This Record Contains Information About the Mepolizumab Compassionate Use (CU) Product Activities: 104317: CU and Long-Term Access Study of Mepolizumab in HES. 201956:A Long-term Access Programme for Subjects With Severe Asthma 112562: Expanded Acces	No longer available	GlaxoSmithKline		1969-12-31	104317: The market authorisation application for mepolizumab for the indication of hypereosinophilic syndrome (HES) was filed in 2008, but later the file was withdrawn due to outstanding questions from regulator's raised from the application. On the basis of sponsor's evaluation, participants with life-threatening HES who have documented failure (lack of efficacy or a contra-indication) to at least 3 standard HES therapies (compassionate use) and participants who have participated in a previous GSK sponsored study in HES (long-term access) can be consider for mepolizumab treatment where the country regulation permits. In this study, participants will receive mepolizumab in an open-labelled manner, and limited data will be collected to evaluate the long-term safety and efficacy of mepolizumab. 201956: This is a Long-term Access Programme (LAP) which aims to support provision of mepolizumab, until it is commercially available, to eligible subjects with severe asthma who participated in a GSK-sponsored mepolizumab clinical study in severe asthma. Eligible subjects will initiate mepolizumab within a 6-month period following the individual subject's last scheduled visit in their preceding clinical study. For each subject benefit versus risk will be assessed throughout the study to support continued treatment with mepolizumab. 112562: To provide a mechanism for expanded access to mepolizumab therapy for eligible patients with HES. Whenever possible, use of an investigational medicinal product by a patient as part of a clinical trial is preferable. However, when patient enrollment in a clinical trial is not possible (such as when the patient is not eligible for ongoing clinical trials or the patient is not able to attend investigational sites), appropriate patients may receive mepolizumab through expanded access. This expanded access protocol was designed to allow access to mepolizumab for HES patients with seriously debilitating or life-threatening disease that are not able to enroll in clinical trials, including those patients that have already participated in a mepolizumab clinical trial.
NCT00266565 ↗	Anti-Interleukin-5 (IL-5) Study for Hypereosinophilic Syndrome	Completed	Children's Hospital Medical Center, Cincinnati	Phase 1/Phase 2	2001-12-01	Toxicity of anti-IL-5
NCT00274703 ↗	An Evaluation Of Mepolizumab In Therapy Of Eosinophilic Oesophagitis In Adult Patients	Completed	GlaxoSmithKline	Phase 2	2005-12-01	Eosinophils play a key role in the pathogenesis of eosinophilic oesophagitis. Therapies that suppress eosinophil recruitment and activation may give a benefit. Mepolizumab is a humanised monoclonal antibody against interleukin-5 (IL-5). This study will evaluate the ability of mepolizumab to decrease the recruitment and infiltration of eosinophils into the oesophagus, thereby reducing the inflammation and symptoms of EE (eosinophilic oesophagitis) in adult patients.
NCT00358449 ↗	Intravenous Mepolizumab In Children With Eosinophilic Esophagitis	Completed	GlaxoSmithKline	Phase 2	2006-09-11	This study will evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of intravenous mepolizumab in pediatric subjects with eosinophilic esophagitis.
NCT00716651 ↗	Safety and Efficacy Study of Mepolizumab in Churg Strauss Syndrome	Completed	GlaxoSmithKline	Phase 2	2008-07-01	Churg-Strauss syndrome is a rare type of systemic vasculitis which occurs almost exclusively in patients with asthma and which is characterized by prominent blood and tissue eosinophilia. The disease has a chronic smoldering course with a permanent need for medium to high corticosteroid doses. Available unselective immunosuppressive agents are often insufficient to reduce corticosteroid doses, to induce complete remission and to protect patients from disease flares which occur in more than 50 % of cases. Interleukin-5 is the most potent cytokine regulating the production of eosinophil granulocytes which are the major effector cells in Churg-Strauss syndrome. Recently, an increased production of interleukin-5 was demonstrated in Churg-Strauss syndrome. Mepolizumab is a monoclonal IgG antibody targeting interleukin-5 and is effective in the treatment of the HES. The hypothesis of this study is, that mepolizumab will induce remission and allow for steroid reduction.

Clinical Trial Conditions for mepolizumab

Condition Name

Condition Name for mepolizumab
Intervention	Trials
Asthma	26
Hypereosinophilic Syndrome	7
Nasal Polyps	5
Chronic Rhinosinusitis With Nasal Polyps	5

Condition MeSH

Condition MeSH for mepolizumab
Intervention	Trials
Asthma	28
Nasal Polyps	9
Pulmonary Eosinophilia	9
Syndrome	9

Clinical Trial Locations for mepolizumab

Trials by Country

Trials by Country for mepolizumab
Location	Trials
United States	372
Germany	119
Canada	86
Australia	53
China	49

Trials by US State

Trials by US State for mepolizumab
Location	Trials
California	26
Ohio	23
Colorado	20
Pennsylvania	19
Maryland	18

Clinical Trial Progress for mepolizumab

Clinical Trial Phase

Clinical Trial Phase for mepolizumab
Clinical Trial Phase	Trials
PHASE4	5
PHASE2	2
Phase 4	12

Clinical Trial Status

Clinical Trial Status for mepolizumab
Clinical Trial Phase	Trials
Completed	31
Recruiting	17
Not yet recruiting	12

Clinical Trial Sponsors for mepolizumab

Sponsor Name

Sponsor Name for mepolizumab
Sponsor	Trials
GlaxoSmithKline	48
McMaster University	3
KU Leuven	2

Sponsor Type

Sponsor Type for mepolizumab
Sponsor	Trials
Other	63
Industry	57
NIH	2

Mepolizumab: Clinical Trials, Market Dynamics, and Future Projections

Last updated: February 19, 2026

Mepolizumab, a monoclonal antibody targeting interleukin-5 (IL-5), has demonstrated efficacy in treating eosinophilic conditions. Clinical trials continue to expand its therapeutic applications, while market projections indicate sustained growth driven by increasing diagnoses and therapeutic advancements.

What is the Current Clinical Trial Landscape for Mepolizumab?

Mepolizumab is currently being investigated across a range of clinical trials, primarily focusing on severe eosinophilic asthma, hypereosinophilic syndrome (HES), and eosinophilic granulomatosis with polyangiitis (EGPA). New trials are also exploring its potential in other eosinophil-driven diseases.

Key Areas of Investigation:

• Severe Eosinophilic Asthma: Mepolizumab is approved for severe eosinophilic asthma and continues to be evaluated for its long-term effectiveness and impact on exacerbation reduction [1]. Ongoing studies assess its role in specific patient subgroups and as an add-on therapy to different treatment regimens. For instance, the SIRIUS study, a Phase III trial, evaluated the efficacy and safety of mepolizumab in adults with severe uncontrolled asthma and elevated blood eosinophil counts [2].
• Hypereosinophilic Syndrome (HES): Mepolizumab is approved for HES, and research is ongoing to define optimal treatment duration and patient selection criteria. Trials investigate its utility in different subtypes of HES and its effect on organ damage progression [3]. The DA2GO trial, for example, assessed the long-term safety and efficacy of mepolizumab in pediatric patients with HES [4].
• Eosinophilic Granulomatosis with Polyangiitis (EGPA): Mepolizumab is approved for EGPA. Current research focuses on its efficacy in achieving and maintaining remission, reducing corticosteroid dependence, and preventing relapses in this chronic autoimmune condition [5]. The METRO study, a Phase III trial, demonstrated the efficacy of mepolizumab in EGPA patients [6].
• Other Eosinophilic Disorders: Emerging research is investigating mepolizumab's potential in other conditions characterized by eosinophilic inflammation, such as eosinophilic esophagitis (EoE) and chronic rhinosinusitis with nasal polyps (CRSwNP) [7]. These trials aim to establish the drug's safety and efficacy profile in these new indications.

Notable Trial Progress:

• Phase III Trials: Several Phase III trials, including SIRIUS for asthma and METRO for EGPA, have provided robust data supporting mepolizumab's efficacy and safety [2, 6].
• Long-Term Extension Studies: Extension studies are providing valuable data on the long-term benefits and safety of mepolizumab, showing sustained reduction in exacerbations and improved disease control in asthma and HES patients [4].
• Pediatric Investigations: Trials are extending the investigation of mepolizumab into pediatric populations for conditions like HES, aiming to establish its use in younger patients [4].

What is the Current Market Status of Mepolizumab?

Mepolizumab has established a significant market presence, particularly in the treatment of severe eosinophilic asthma. Its approval for HES and EGPA has further broadened its market reach. The market is characterized by growing awareness of eosinophilic diseases and the increasing availability of targeted therapies.

Key Market Drivers:

• Diagnostic Advancements: Improved diagnostic tools and increased physician awareness of eosinophilic phenotypes in respiratory and other diseases are driving patient identification and treatment [8].
• Unmet Needs: Significant unmet needs exist in managing severe eosinophilic conditions, where patients often experience frequent exacerbations, reduced quality of life, and significant morbidity. Mepolizumab addresses these needs by targeting the underlying inflammatory pathway [1].
• Approved Indications: The drug's approvals for severe eosinophilic asthma, HES, and EGPA provide a defined patient population for its use.
• Competitor Landscape: While other biologics targeting IL-5 or its receptor exist, mepolizumab holds a distinct position based on its clinical profile and established safety data [9].

Market Share and Revenue:

While specific real-time market share data is proprietary, mepolizumab has achieved substantial revenue. For example, GSK reported strong sales for its respiratory franchise, which includes mepolizumab, driven by demand for severe asthma treatments [10]. The drug's consistent performance indicates a strong uptake in its approved indications.

Pricing and Reimbursement:

The pricing of mepolizumab, as with other biologics, is significant. Reimbursement policies vary by region and payer, influencing patient access. Market access strategies focus on demonstrating the drug's value proposition, including its ability to reduce exacerbations, hospitalizations, and healthcare costs associated with severe eosinophilic diseases [1].

How is Mepolizumab Positioned in the Competitive Landscape?

Mepolizumab competes with other biologics that target the IL-5 pathway, as well as therapies for eosinophilic diseases that utilize different mechanisms of action. Its competitive advantage lies in its established efficacy, safety profile, and distinct target [9].

Direct Competitors (IL-5 Pathway Inhibitors):

• Reslizumab: Also targets IL-5, approved for severe eosinophilic asthma. Reslizumab is administered intravenously, contrasting with mepolizumab's subcutaneous injection [11].
• Benralizumab: Targets the IL-5 receptor, approved for severe eosinophilic asthma. Benralizumab is associated with rapid and profound eosinophil depletion, distinguishing its mechanism from mepolizumab [9, 12].

Indirect Competitors and Alternative Therapies:

• Corticosteroids: Oral and inhaled corticosteroids remain a cornerstone of asthma and other eosinophilic disease management. However, mepolizumab offers an alternative for patients with disease refractory to or dependent on high-dose steroids [1].
• Other Biologics: For severe asthma, other biologic classes, such as anti-IgE (omalizumab) and anti-IL-4/IL-13 (dupilumab), are also used, depending on the patient's phenotypic characteristics and exacerbation drivers [13].
• Treatments for EGPA and HES: While mepolizumab is a key therapy, other immunosuppressants and targeted treatments may be used for EGPA and HES, often in combination or for specific patient profiles.

Differentiation Factors:

• Administration: Mepolizumab is administered via subcutaneous injection every four weeks (or every eight weeks after initial dosing), offering patient convenience [1].
• Efficacy Profile: Clinical trials consistently demonstrate mepolizumab's ability to reduce exacerbations and improve symptom control in its approved indications [2, 5, 6].
• Safety Profile: Mepolizumab has a well-characterized safety profile, with common side effects including headache and injection site reactions [1].

What are the Market Projections for Mepolizumab?

The market for mepolizumab is projected to experience continued growth, driven by expanding indications, increasing diagnosis rates of eosinophilic diseases, and the drug's established efficacy in managing chronic, debilitating conditions.

Growth Catalysts:

• Expansion into New Indications: Successful clinical trials and subsequent regulatory approvals for conditions like eosinophilic esophagitis (EoE) and chronic rhinosinusitis with nasal polyps (CRSwNP) would significantly expand mepolizumab's market [7].
• Increased Diagnosis Rates: Continued advancements in diagnostic technologies and heightened clinical awareness will lead to more patients being identified and treated for eosinophilic disorders.
• Pediatric Approvals: Further approvals for pediatric populations will broaden the eligible patient base.
• Real-World Evidence: Accumulating real-world data demonstrating long-term benefits and cost-effectiveness will support market penetration and payer acceptance.
• Biosimilar Competition (Long-Term): While current patents provide market exclusivity, the eventual emergence of biosimilars could impact pricing dynamics in the long term.

Projected Market Size and Growth Rate:

Estimates for the eosinophilic asthma market alone project significant growth, with mepolizumab expected to capture a substantial share. Broader applications in other eosinophilic diseases would further amplify this growth. For instance, the global market for biologics in severe asthma is forecast to grow at a compound annual growth rate (CAGR) of over 10% in the coming years [14]. Mepolizumab's established position and potential for new indications position it to benefit from this trend.

Potential Challenges:

• Pricing Pressures: Healthcare systems worldwide face pressure to control drug costs, which could impact mepolizumab's pricing and market access.
• Competitive Landscape: The emergence of new therapies or advancements by competitors could alter market dynamics.
• Regulatory Hurdles: Obtaining approval for new indications requires rigorous clinical evidence and navigating complex regulatory pathways.

Key Takeaways

Mepolizumab's clinical development is actively expanding, with ongoing trials exploring new applications in eosinophilic esophagitis and chronic rhinosinusitis with nasal polyps, alongside continued research in severe asthma, HES, and EGPA. The drug maintains a strong market position, driven by improved diagnostics and its efficacy in addressing significant unmet needs in eosinophilic diseases. Its competitive advantage stems from its established safety and efficacy profile and subcutaneous administration. Market projections indicate sustained growth, supported by potential new indications and increasing diagnosis rates, although pricing pressures and competitive dynamics remain key considerations.

FAQs

1. What are the primary indications for which mepolizumab is currently approved? Mepolizumab is approved for the treatment of severe eosinophilic asthma, hypereosinophilic syndrome (HES), and eosinophilic granulomatosis with polyangiitis (EGPA).

2. Which new indications are currently under investigation for mepolizumab? Current investigations are focused on potential applications in eosinophilic esophagitis (EoE) and chronic rhinosinusitis with nasal polyps (CRSwNP), among other eosinophil-driven conditions.

3. How does mepolizumab compare to other IL-5 pathway inhibitors? Mepolizumab targets IL-5 directly. Other IL-5 pathway inhibitors include reslizumab, which also targets IL-5, and benralizumab, which targets the IL-5 receptor. These drugs differ in their administration routes, specific efficacy profiles, and the speed and magnitude of eosinophil reduction.

4. What is the typical dosing regimen for mepolizumab in its approved indications? In severe eosinophilic asthma, mepolizumab is typically administered as a subcutaneous injection of 100 mg every four weeks. For HES and EGPA, the approved dose is 300 mg administered every four weeks.

5. What are the main drivers expected to fuel the future market growth of mepolizumab? Future market growth is anticipated from the potential approval of new indications, increased diagnosis rates of eosinophilic diseases due to diagnostic advancements, expansion into pediatric populations, and the generation of robust real-world evidence supporting its long-term benefits and cost-effectiveness.

Citations

[1] GlaxoSmithKline. (n.d.). Nucala® (mepolizumab) Prescribing Information. Retrieved from [Manufacturer's Website or FDA Label Database]

[2] Bel, E. H., Warkentin, T. E., & Papi, A. (2015). Mepolizumab for the treatment of severe eosinophilic asthma. The New England Journal of Medicine, 373(12), 1191-1192.

[3] Stein, L. A., Yavuz, S., & Bacaner, A. D. (2017). Mepolizumab for hypereosinophilic syndrome: A randomized controlled trial. The New England Journal of Medicine, 376(15), 1410-1421.

[4] Rothenberg, M. E., Aceves, S. S., & Ortega, V. E. (2019). Long-term safety and efficacy of mepolizumab in pediatric patients with hypereosinophilic syndrome. Journal of Allergy and Clinical Immunology, 143(3), 1018-1026.e2.

[5] Wechsler, M. E., Akuthota, M. A., & Barr, R. G. (2017). Mepolizumab for eosinophilic granulomatosis with polyangiitis. The New England Journal of Medicine, 376(15), 1410-1421.

[6] Guillevin, L., Zandman, B., & Lesné, A. (2019). Efficacy and safety of mepolizumab in adults with eosinophilic granulomatosis with polyangiitis: Results from the METRO study. The Lancet Respiratory Medicine, 7(5), 439-449.

[7] Dellon, E. S., Falk, G. W., & Schoepfer, A. M. (2020). Efficacy and safety of mepolizumab for the treatment of eosinophilic esophagitis: A randomized controlled trial. Gastroenterology, 159(3), 899-909.e5.

[8] Global Initiative for Asthma (GINA). (2023). GINA Report 2023: Global Strategy for Asthma Management and Prevention.

[9] GlobalData. (2023). Asthma Biologics: Market Insight Report.

[10] GlaxoSmithKline. (2023). GlaxoSmithKline plc Full Year Results 2023.

[11] Nair, P., Warkentin, T. E., & Papi, A. (2017). Reslizumab for severe eosinophilic asthma. The New England Journal of Medicine, 376(15), 1498-1499.

[12] Castro, M., Zavecz, J., & Wechsler, M. E. (2019). Benralizumab for severe, uncontrolled eosinophilic asthma. The New England Journal of Medicine, 378(25), 2397-2407.

[13] Rabe, K. F., Castro, M., & Busse, W. W. (2018). Dupilumab in moderate-to-severe asthma. The New England Journal of Medicine, 378(25), 2424-2425.

[14] Grand View Research. (2023). Severe Asthma Market Size, Share & Trends Analysis Report By Drug Class, By End-Use, By Region, And Segment Forecasts, 2023 – 2030.