Mepolizumab Considered Safe, Effective for Severe Eosinophilic Asthma

Patients with severe eosinophilic asthma in the open-label extension COLUMBA study (ClinicalTrials.gov Identifier: NCT01691859) were previously randomly assigned to either ≥2 doses of mepolizumab or placebo in the DREAM study (ClinicalTrials.gov Identifier: NCT01000506).² In the current study, researchers administered 100 mg subcutaneous mepolizumab every 4 weeks to these patients, in addition to standard of care. Efficacy and long-term safety of treatment were evaluated, as well as adverse event (AE) frequency, serious AEs, and AEs of special interest. Annualized exacerbation rate, changes in the Asthma Control Questionnaire-5 score from baseline, and blood eosinophil counts comprised the efficacy end points. In addition, the researchers evaluated immunogenicity during and after therapy.

During the mean 3.5-year study period, a total of 347 patients with severe eosinophilic asthma were enrolled, all of whom had a maximum total exposure to mepolizumab of 1201 patient-years. The majority of patients reported on-treatment AEs, including respiratory tract infection (67%), headache (29%), bronchitis (21%), and asthma worsening (27%). Approximately 23% of patients had ≥1 on-treatment serious AE, and 6 deaths were recorded. In 24% of the cohort, a total of 159 serious AEs were reported.

The investigators observed a 56% reduction in the exacerbation rate from the off-treatment period between the DREAM and COLUMBIA trials. In patients with severe eosinophilic asthma who were enrolled for ≥156 weeks in the COLUMBIA study, an exacerbation rate of 0.74 events per year (weeks 0-156) was observed. The average Asthma Control Questionnaire-5 score reduced by 0.47 points at the first post-baseline assessment, demonstrating an improvement in asthma control. In addition, there was a reduction of 78% in the blood eosinophil counts at this time period.

The open-label design, lack of a placebo group, and exclusion of patients considered at risk for potentially mepolizumab-related AEs or serious AEs represent limitations of the analysis.

According to the researchers, the findings from this study “support the use of mepolizumab as a long-term treatment choice for patients with [severe eosinophilic asthma].”

Disclosures: This study was funded by GlaxoSmithKline.

References

1. Khatri S, Moore W, Gibson PG, et al. Assessment of the long-term safety of mepolizumab and durability of clinical response in patients with severe eosinophilic asthma [published online October 22, 2018]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2018.09.033
2. Pavord ID, Korn S, Howarth P, et al. Mepolizumab for severe eosinophilic asthma (DREAM): a multicentre, double-blind, placebo-controlled trial. Lancet. 2012;380(9842):651-659.