Summary of findings for the main comparison.
Mepolizumab subcutaneous (SC) compared to placebo for asthma
| Mepolizumab (SC) compared to placebo for asthma | ||||||
| Patient or population: people with asthma Setting: community Intervention: mepolizumab (SC) Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with mepolizumab (SC) | |||||
| Rate of exacerbations requiring systemic corticosteroids Follow‐up: range 24 to 32 weeks | The mean rate in the placebo group was 1.48 events per participant per yeara | The mean rate in the intervention group was 0.81 fewer events per participant per year (95% CI 0.66 fewer to 0.94 fewer) | Rate ratio 0.45 (0.36 to 0.55) | 936 (2 RCTs) | ⊕⊕⊕⊕ High | |
| Rate of exacerbations requiring emergency department treatment or admission Follow‐up: range 24 to 32 weeks | The mean rate in the placebo group was 0.15 events per patient per yearb | The mean rate in the intervention group was 0.10 fewer events per participant per year (95% CI 0.05 fewer to 0.12 fewer) | Rate ratio 0.36 (0.20 to 0.66) | 936 (2 RCTs) | ⊕⊕⊕⊕ High | |
| Health‐related quality of life (ACQ) Scale from: 0 to 6 (lower is better) Follow‐up: range 24 to 32 weeks | The mean change in the placebo group ranged from −0.4 to −0.5 units | The mean in the intervention group was ‐0.42 units fewer (‐0.56 fewer to ‐0.28 fewer) | ‐ | 936 (2 RCTs) | ⊕⊕⊕⊝ Moderatec | A change of ≥ 0.5 is considered the minimum clinically significant difference |
| Health‐related quality of life (SGRQ) Scale from: 0 to 100 (lower is better) Follow‐up: range 24 to 32 weeks | The mean change in the placebo group ranged from −7.9 to −9.0 units | The mean change in the intervention group was ‐7.4 units fewer (‐9.5 fewer to ‐5.29 fewer) | ‐ | 936 (2 RCTs) | ⊕⊕⊕⊕ High | A change of ≥ 4 is considered the minimum clinically significant difference |
| Pre‐bronchodilator FEV1 (L) Follow‐up: range 24 to 32 weeks | The mean change in the placebo group ranged from 0.086 L (± 0.031 L) to 0.120 L (0.047 to 0.192 L) | The mean difference from placebo was a further 0.11 L (0.06 L to 0.17 L) | ‐ | 936 (2 RCTs) | ⊕⊕⊕⊕ High | |
| Adverse events leading to discontinuation Follow‐up: range 24 to 32 weeks | 15 per 1000 | 7 per 1000 (2 to 27) | Risk ratio 0.45 (0.11 to 1.80) | 936 (2 RCTs) | ⊕⊕⊕⊝ Moderated | |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). ACQ: Asthma Control Questionnaire; CI: confidence interval; FEV1 : forced expiratory volume in 1 second; RR: risk ratio; SC: subcutaneous; SGRQ: St. George's Respiratory Questionnaire | ||||||
| GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low quality: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect | ||||||
aRounded mean of the rate in the placebo group of the two studies: 1.21 and 1.74. bRounded mean of the rate in the placebo group of the two studies: 0.10 and 0.20. cThe mean difference (‐0.42) is smaller than the minimum clinically significant difference (a reduction of 0.5 points). dThe 95% CI crosses the line of no effect, thus we downgraded the quality of evidence to moderate because of imprecision.