A dosing range of 75–100 mg offers a favorable benefit–to–risk profile. Baseline blood eosinophil count emerges as a useful predictive biomarker for treatment response, supporting personalized therapy. Further studies are needed to define optimal dosing strategies and assess long-term safety.
The findings, published in the Journal of Thoracic Disease, come from a systematic review and meta-analysis led by Yubing Li from the Department of Respiratory and Critical Care Medicine, Jianli People’s Hospital, China Three Gorges University, and colleagues. Severe eosinophilic asthma, a subtype characterized by persistent type 2 inflammation and high interleukin-5 (IL-5)–mediated eosinophil activity, accounts for over half of all asthma cases and often remains uncontrolled despite high-dose corticosteroid therapy.
Mepolizumab, an anti–IL-5 monoclonal antibody, offers a targeted approach, but previous studies have shown inconsistent results regarding improvements in lung function and long-term outcomes.
To address these uncertainties, the researchers systematically analyzed randomized controlled trials assessing mepolizumab in patients aged 12 years or older with baseline blood eosinophils of at least 150 cells/µL. Ten trials involving 4,471 patients were included. Key outcomes measured were lung function, using forced expiratory volume in 1 second (FEV1), asthma exacerbation rates, and symptom control via the Asthma Control Questionnaire-5 (ACQ-5), along with safety assessments. Subgroup analyses explored the impact of baseline eosinophil counts and dosing regimens on efficacy and safety.
The meta-analysis revealed the following findings:
- Mepolizumab significantly improved lung function, with a mean FEV1 increase of 0.06 L compared to placebo.
- Exacerbation rates were reduced by 42% in patients receiving mepolizumab.
- Asthma control improved, with ACQ-5 scores decreasing by 0.29 points.
- Low-dose mepolizumab (75–100 mg) provided greater improvements in FEV1 and exacerbation reduction than higher doses.
- The 75–100 mg regimen reduced the risk of serious adverse events by 61% compared with higher-dose treatments.
- Patients with baseline eosinophil counts ≤300 cells/µL showed a better response to mepolizumab, supporting biomarker-guided, individualized therapy.
The analysis confirms that mepolizumab is both effective and well-tolerated, supporting its use as a targeted biologic therapy in severe eosinophilic asthma. Importantly, the study resolves previous uncertainties regarding lung function benefits and establishes that low-dose regimens offer the optimal balance of efficacy and safety. The findings also reinforce the value of baseline blood eosinophil levels as a predictive biomarker to guide clinical decision-making.
The authors recommend adopting low-dose mepolizumab (75–100 mg) as a first-line biologic for severe eosinophilic asthma, with treatment decisions guided by blood eosinophil counts. They emphasize the need for further large-scale studies with long-term follow-up to determine optimal dosing intervals and assess extended safety profiles, aiming to refine personalized treatment approaches for this challenging patient population.
Reference:
Li Y, Li J, Yang H, Wu L. Efficacy and safety of mepolizumab in severe eosinophilic asthma: a systematic review and meta-analysis. J Thorac Dis 2025;17(11):9425-9438. doi: 10.21037/jtd-2025-1596
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