Background: Mepolizumab (100 mg delivered s.c. every 4 weeks) is indicated for add-on maintenance treatment for patients with severe eosinophilic asthma. Mepolizumab has been shown to reduce exacerbations and the requirement for daily oral corticosteroids, and improve asthma control and symptoms. However, data on the durability of the response to mepolizumab during dosing periods are limited. The aim of this study was to investigate the efficacy profile in patients with severe eosinophilic asthma over the 4-weekly dosing period for various fixed mepolizumab doses., Methods: This was a post hoc analysis of data from the phase IIb/III DREAM study. Patients ≥12 years of age with severe eosinophilic asthma were randomised (1:1:1:1) to receive intravenous mepolizumab 75 mg (equivalent to 100 mg s.c.), 250 mg, 750 mg or placebo, plus standard of care, every 4 weeks for 52 weeks. The number of exacerbations and eDiary data (peak expiratory flow, rescue medication use and symptom scores) from two periods in each 4-weekly dosing interval (days 1-14 and 15-28) over the 52-week treatment period were analysed., Findings: eDiary data and the proportion of patients experiencing ≥1 exacerbation were similar during the first and second 2 weeks of a dosing period across all mepolizumab doses., Interpretation: These results demonstrate that the response to mepolizumab is sustained over the 4-weekly dosing period with no differences across a 10-fold dose range and supports the use of the current mepolizumab dosing regimen in patients with severe eosinophilic asthma., Competing Interests: Conflict of interest: I.D. Pavord reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. In addition, he reports speaking fees from AstraZeneca, Boehringer Ingelheim, Aerocrine, Almirall, Teva, Sanofi, Regeneron, and GSK; fees for organising educational events, honoraria for attending advisory panels and sponsorship to attend international scientific meetings AstraZeneca; honoraria for attending advisory panels and sponsorship to attend international scientific meetings from Boehringer Ingelheim; a research grant, sponsorship to attend international scientific meetings, honoraria for attending advisory panels and speaking fees from Chiesi; honoraria for attending advisory panels from Circassia and Genentech; honoraria for attending advisory panels and sponsorship to attend international scientific meetings from GSK; honoraria for attending advisory panels from Knopp and Merck; speaking fees and honoraria for attending advisory panels from Novartis and Regeneron; fees for organising educational events and honoraria for attending advisory panels from Sanofi; and fees for organising educational events, honoraria for attending advisory panels and sponsorship to attend international scientific meetings from Teva, all outside the submitted work. Conflict of interest: E.R. Bleecker reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. In addition, he reports consultancy fees from ALK-Abello; grants for clinical trials administered through Wake Forest and University of Arizona, and consultancy fees from AstraZeneca; grants for clinical trials administered through Wake Forest and University of Arizona from Boehringer Ingelheim and Genentech; consultancy fees from GSK; grants for clinical trials administered through Wake Forest and University of Arizona, and consultancy fees from MedImmune, Novartis, Regeneron and Sanofi Genzyme; and consultancy fees from Teva, all outside the submitted work. Conflict of interest: R. Buhl reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. In addition, he reports personal fees from AstraZeneca, grants and personal fees from Boehringer Ingelheim, personal fees from Chiesi and Cipla, grants and personal fees from GlaxoSmithKline, Novartis and Roche, and personal fees from Sanofi and Teva, outside the submitted work. Conflict of interest: P. Chanez reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. In addition, he reports personal fees for advisory boards from Almirall, grants and personal fees for lectures from Alk-Abello, grants and personal fees for consultancy, advisory boards and lectures from AstraZeneca and Boehringer Ingelheim, grants and personal fees for lectures from Boston Scientific and Centocor, grants and personal fees for consultancy, advisory boards and lectures from Chiesi and GSK, personal fees for consultancy and advisory boards from Johnson & Johnson, consultancy fees from Merck Sharp & Dohme, grants and personal fees for consultancy, advisory boards and lectures from Novartis, an industry-sponsored grant from Roche, personal fees for consultancy and advisory boards from Sanofi, and grants and personal fees for consultancy, advisory boards and lectures from Teva, outside the submitted work. Conflict of interest: E.H. Bel reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. In addition, she reports speaking and consulting fees from AstraZeneca, GSK, Novartis and Sanofi, and an unrestricted grant for research from Teva, outside the submitted work. Dr. Bel reports other from GlaxoSmithKline, non-financial support from GlaxoSmithKline, during the conduct of the study; grants and personal fees from AstraZeneca, grants and personal fees from GSK, grants and personal fees from Novartis, personal fees from Sanofi, grants from Teva, personal fees from AstraZeneca, outside the submitted work. Conflict of interest: P. Howarth reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. He is an employee of and holds shares/options in GSK. Conflict of interest: D.J. Bratton reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. He is an employee of and holds shares/options in GSK. Conflict of interest: F.C. Albers this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. He is a former employee of and owns stocks/shares in GSK, and a current employee of Avillion US Inc. Conflict of interest: S. Yancey reports this study was funded by GlaxoSmithKline (GSK). Medical writing support by Fishawack Indicia Ltd was also funded by GSK. He is an employee of and holds shares/options in GSK., (Copyright ©ERS 2020.)