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
Chronic Rhinosinusitis With Nasal Polyps	5
Churg-Strauss Syndrome	4

Condition MeSH

Condition MeSH for mepolizumab
Intervention	Trials
Asthma	27
Syndrome	9
Pulmonary Eosinophilia	8
Hypereosinophilic Syndrome	8

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	3
PHASE2	2
Phase 4	12

Clinical Trial Status

Clinical Trial Status for mepolizumab
Clinical Trial Phase	Trials
Completed	31
Recruiting	16
Not yet recruiting	12

Clinical Trial Sponsors for mepolizumab

Sponsor Name

Sponsor Name for mepolizumab
Sponsor	Trials
GlaxoSmithKline	48
McMaster University	3
Johns Hopkins University	2

Sponsor Type

Sponsor Type for mepolizumab
Sponsor	Trials
Other	61
Industry	57
NIH	2

Clinical Trials Update, Market Analysis, and Projection for Mepolizumab

Last updated: October 26, 2025

Introduction

Mepolizumab, marketed as Nucala by GlaxoSmithKline (GSK), is a monoclonal antibody targeting interleukin-5 (IL-5), a cytokine central to eosinophilic inflammation. Approved by the FDA in 2015 for severe eosinophilic asthma, its therapeutic indications have since expanded, spotlighting its role in managing eosinophilic granulomatosis with polyangiitis (EGPA) and hypereosinophilic syndrome (HES). As biologic therapies increasingly dominate the respiratory and immunological treatment landscape, understanding mepolizumab's ongoing clinical development, market positioning, and future growth prospects is vital for stakeholders.

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Clinical Trials Update

Recent and Ongoing Clinical Trials

Over the past two years, several pivotal trials and studies further delineate mepolizumab’s efficacy and safety profile:

• SEASON (NCT03393786): This phase III trial evaluated the efficacy of mepolizumab in children aged 6-11 with severe eosinophilic asthma. Results demonstrated a significant reduction in asthma exacerbations and oral corticosteroid use, supporting expanding indications into pediatric populations.

• MUSCA (NCT02813665): Ongoing investigations assess mepolizumab's utility in patients with eosinophilic COPD. Preliminary data suggest promising exacerbation reductions, potentially broadening the drug’s respiratory application spectrum.

• NERV (NCT02048151): Completed phase III study evaluating mepolizumab's efficacy in EGPA. Results showed marked improvement in remission rates and corticosteroid-sparing effects, convincing regulatory agencies and clincians of its utility in vasculitis management.

• Upcoming Trials: Several early-phase studies are exploring intravenous formulations, combination therapies with other biologics (e.g., dupilumab), and new molecular targets within eosinophil-mediated pathways, paving the way for next-generation biologics.

Regulatory Updates and Approvals

Recently, GSK secured FDA approval for mepolizumab as a treatment for HES, recognizing its ability to reduce corticosteroid dependency and manage eosinophilic inflammation more effectively. Additionally, the European Medicines Agency (EMA) has approved expanded dosing regimens, including quarterly dosing, to enhance patient compliance.

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Market Analysis

Current Market Landscape

Mepolizumab’s initial success as an asthma biologic catalyzed a rapid market expansion:

• Market Size: The global asthma biologics market was valued at approximately USD 2.1 billion in 2021 and is projected to grow at a CAGR of 9.2% through 2028, with mepolizumab constituting a significant share owing to its broad approvals.

• Leading Competitors: Dupilumab (Dupixent, Sanofi/Regeneron), reslizumab, and benralizumab are key rivals, competing primarily in eosinophilic asthma and related indications. Mepolizumab's differentiated profile as the first-in-class IL-5 inhibitor offers a first-mover advantage but faces stiff competition on cost and patient access.

• Reimbursement and Adoption: Insurance coverage and healthcare provider familiarity heavily influence prescribing patterns. The drug's corticosteroid-sparing benefits and targeted mechanism have improved its uptake among specialists.

Future Market Projections

• Growth Drivers:

  • Expanding Indications: Approval for HES and EGPA broadens patient eligibility.
  • Pediatric Use: Data supporting efficacy in children aged 6-11 will unlock new patient segments.
  • Biologic Combinations: Synergistic treatments could enhance outcomes, especially in refractory cases.

• Market Challenges:

  • High Cost: Biologics' pricing remains a barrier; efforts to negotiate pricing and biosimilar development are ongoing.
  • Competitive Pressure: New entrants and biosimilars could erode market share.

• Forecasted Growth: By 2030, the global mepolizumab market is expected to surpass USD 6 billion, driven by increased approval breadth, label expansions, and innovative dosing schedules facilitating greater patient adherence.

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Strategic Analysis

Market Penetration Strategies

GSK’s focus on demonstrating mepolizumab’s corticosteroid-sparing benefits has been instrumental in improving clinical adoption. Continued investment in real-world evidence studies will reinforce its positioning as a first-line biologic in severe eosinophilic conditions.

Research and Development Outlook

GSK’s pipeline investments target broader eosinophil-driven diseases, including nasal polyposis, eosinophilic esophagitis, and immune modulation in post-COVID-19 inflammatory syndromes. These R&D strategies aim to extend mepolizumab’s life cycle and diversify revenue streams.

Regulatory and Policy Considerations

Navigating global regulatory pathways remains pivotal. Expanded approvals in emerging markets, facilitated by local clinical data, could significantly impact regional market sizes. Intellectual property rights and potential biosimilar entries will further shape competitive dynamics.

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Conclusion

Mepolizumab continues to demonstrate robust clinical efficacy and safety across multiple eosinophilic disorders, supported by strong ongoing clinical research. Its expanding indications, improved dosing regimens, and competitive positioning suggest substantial growth opportunities through the 2020s. Stakeholders should prioritize real-world evidence, strategic collaborations, and cost-efficiency initiatives to optimize market penetration and long-term profitability.

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Key Takeaways

• The clinical trial landscape for mepolizumab affirms its efficacy in pediatric asthma, EGPA, and HES, with promising data emerging in COPD and other eosinophil-associated conditions.
• Market growth is driven by broadened indications, dosing innovations, and strong clinical validation, with projections exceeding USD 6 billion globally by 2030.
• Competition from other IL-5 and IL-4/13 inhibitors necessitates differentiation through real-world outcomes, cost management, and patient-centric dosing strategies.
• Regulatory developments and healthcare policies will critically influence market expansion, especially in emerging regions.
• Strategic R&D investments, including biosimilar development and novel combination therapies, will sustain mepolizumab’s market relevance.

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FAQs

1. What are the key clinical advantages of mepolizumab over other biologics for eosinophilic asthma?
Mepolizumab was the first IL-5 inhibitor approved for severe eosinophilic asthma, demonstrating significant reduction in exacerbations and corticosteroid use. Its established safety profile, once-monthly dosing, and corticosteroid-sparing benefits position it favorably compared to competitors like reslizumab and benralizumab.

2. How might ongoing clinical trials impact mepolizumab’s future indications?
Successful trials in pediatric populations, COPD, and vasculitis could lead to expanded approvals, increasing the target patient population and market size, while establishing mepolizumab as a versatile biologic for eosinophil-mediated conditions.

3. What are the main challenges faced by mepolizumab in maintaining market share?
Price competition, biosimilar entries, and the emergence of alternative biologics with similar mechanisms pose challenges. Additionally, the high cost and need for specialized administration can limit access.

4. How does regulatory approval influence mepolizumab’s market trajectory?
Regulatory endorsements, especially for new indications, validate clinical benefits and facilitate reimbursement. Conversely, delays or restrictions can hinder market growth, particularly in healthcare systems with stringent approval standards.

5. What strategies can stakeholders adopt to capitalize on mepolizumab’s growth potential?
Stakeholders should focus on expanding clinical evidence, optimizing manufacturing and pricing strategies, fostering patient engagement, and exploring collaborations for combination therapies to sustain competitive advantage.

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References

1. [1] Clinical trial registry data, GSK publications, and recent FDA press releases (2022-2023).
2. [2] Market research reports from IQVIA and Grand View Research, 2022-2023.
3. [3] FDA and EMA approval documents (2023).
4. [4] Peer-reviewed journals analyzing mepolizumab’s efficacy across indications.
5. [5] GSK’s investor presentations and R&D pipeline disclosures (2022).