Lugogo N et al. Clin Ther. 2016; 38 (9): 2058–2070.1
COSMOS was a 52-week, open-label extension study in patients who received mepolizumab or placebo in MENSA or SIRIUS that assessed the long-term safety and efficacy of mepolizumab1.
A total of 651 patients participated in the COSMOS study. Of these patients, 414 had received mepolizumab in either the 32-week phase III MENSA (MEA115588)2exacerbation study or the 24-week SIRIUS (MEA115575)3 steroid-reduction study, providing up to 84 weeks of on-treatment safety and efficacy data1.
The study also included 237 patients who had received placebo in the previous phase III trials1. For patients switching from placebo to mepolizumab, findings from COSMOS showed similar improvements in asthma control to those in the mepolizumab arms of the previous studies1.
All participants in COSMOS received a 100mg dose of mepolizumab subcutaneously every four weeks in addition to their standard of care respiratory medications. This is the same dose and administration regimen for which mepolizumab is licensed, under the brand name Nucala4.
Key safety findings
The primary objective of the study was to describe the safety profile of long-term mepolizumab treatment. Findings from COSMOS showed that the safety profile of mepolizumab was similar to that reported in the previous Phase III randomised studies. The most frequently reported adverse events during the treatment period were nasopharyngitis (30%), upper respiratory tract infection (16%) and headache (14%).1
Key efficacy findings
The secondary objective of the study was to evaluate the effect of long-term dosing on clinical markers of asthma control.
In patients continuing mepolizumab from the MENSA trial, exacerbation rates per year remained consistent with the pivotal studies – the exacerbation rate was 0.91 exacerbations per year at the end of MENSA and 0.92 per year at the end of the combined 84-week period1. Improvements in asthma control, measured by the Asthma Control Questionnaire-5 (ACQ-5) score, seen in earlier trials were also maintained1.
For patients previously treated with placebo, their risk of an exacerbation was nearly halved when they switched to mepolizumab, decreasing over time from 1.94 per year to 1.04 per year, which was consistent with previous data1. In addition, ACQ-5 scores improved by 0.30 points by week 4 compared to baseline (where a minimal clinically important change is 0.50 points) and the change maintained through to week 52 for patients previously treated with placebo1.
A post-hoc analysis evaluated the durability of steroid reduction following open-label mepolizumab treatment among the sub-set of subjects from the SIRIUS study1 that completed COSMOS. The impact of mepolizumab on oral corticosteroid dose seen in SIRIUS was consistent with that seen in COSMOS. For patients who continued treatment with mepolizumab, the median oral corticosteroid dose was maintained at 2.5mg/day, having been reduced from 10mg at the start of the SIRIUS study1.
These data demonstrate a favourable safety profile of mepolizumab and indicate durable and stable effect overtime, supporting long-term treatment in patients with severe eosinophilic asthma1.
▼This medical product is subject to additional monitoring.
- Lugogo N et al. Clin. Ther. 2016; 38 (9): 2058–2070 [PubMed]
- Ortega HG, et al. N Engl J Med. 2014;371:1198-1207
- Bel EL, et al. N Engl J Med. 2014; 371:1189-1197.
- Nucala Summary of Product Characteristics; GlaxoSmithKline2016