Mepolizumab benefits held up over time

Beyond 1 year, the humanized monoclonal antibody mepolizumab maintained real-world efficacy and safety in patients with severe eosinophilic asthma in the REALITI-A* cohort study, reports an expert at ERS 2021.

Exacerbations requiring oral steroids, emergency room visits, and hospitalizations decreased over 1 year, said lead author Dr Charles Pilette of Cliniques Universitaires Saint-Luc and UC Louvain in Brussels, Belgium, who presented outcomes from an interim analysis after a median of 366 days of follow-up.

Clinically significant exacerbations went down from 4.28 pre-exposure events/year to 1.23 post-exposure events/year, for a relative risk (RR) of 0.29 (95 percent confidence interval [CI], 0.26–0.32).

Similarly, exacerbations requiring hospitalization/emergency room visits also dropped from 0.95 to 0.23 events/year (RR, 0.24, 95 percent CI, 0.20–0.29), whereas exacerbations requiring hospitalization alone dropped from 0.45 to 0.14 events/year (RR, 0.31).

Data on the use of maintenance oral corticosteroids were available for 298 patients at baseline and 222 patients at weeks 53–56. In these patients, the median maintenance dose dropped from 10 mg/day of prednisone at baseline to 2.5 mg/day at week 53 to 56. In addition, 43 percent of patients stopped using maintenance oral corticosteroids completely.

“The data are consistent with previous studies of mepolizumab and provide further evidence of its effectiveness and safety in patients with severe eosinophilic asthma,” Pilette said.

Patients in this 2-year, global, prospective, single-arm, observational cohort study were 18 years and older with severe asthma, who were newly prescribed subcutaneous mepolizumab 100 mg. Initiation of mepolizumab was at the physician’s discretion. Patients additionally received a standard-of-care regimen. All had at least 12 months of relevant medical records available prior to enrolment.

The primary endpoint of the trial was the rate of clinically significant exacerbations, requiring oral corticosteroids and/or an emergency room (ER) visit/hospitalization. Key secondary endpoints included exacerbations requiring an ER visit/hospitalization and the use of maintenance oral corticosteroids. Investigator-determined treatment-related adverse events were also reported.

The analysis at 1 year included a cohort of 822 patients who were evaluated for efficacy and 823 for safety. They were recruited from 84 centres across seven countries.

Mean age was 54 years, 63 percent were female, and geometric mean blood eosinophil count was 353 cells/μL among the 822 patients evaluated for efficacy.  In this cohort, 60 percent were never-smokers and 40 percent were current smokers.

Overall, 39 percent were on maintenance oral corticosteroids, specifically prednisone 10 mg daily. At least 18 percent had taken omalizumab, for a mean duration of 34 months.

Mepolizumab, approved in major markets as an add-on maintenance treatment for severe eosinophilic asthma, is the first-in-class monoclonal antibody that targets human interleukin-5. It is also US FDA-approved for chronic rhinosinusitis with nasal polyps (CRSwNP) in adults.