Benefit of switching to mepolizumab from omalizumab in severe eosinophilic asthma based on patient characteristics

Background

The OSMO study assessed the efficacy of switching to mepolizumab in patients with severe eosinophilic asthma that was uncontrolled whilst receiving omalizumab. The objective of this analysis was to assess the proportion of patients achieving pre-defined improvements in up to four efficacy outcomes and the relationship between patient baseline characteristics and treatment response.

Methods

This was a post hoc analysis of OSMO study data (GSK ID:204471; ClinicalTrials.gov No. NCT02654145). Patients with severe eosinophilic asthma uncontrolled by high-dose inhaled corticosteroids, other controller(s) and omalizumab subcutaneously (≥ 4 months) were switched to mepolizumab 100 mg administered subcutaneously. Endpoints included the proportion of responders—i.e. patients achieving a pre-defined clinical improvement in ≥ 1 of the following outcomes: (1) Asthma Control Questionnaire (ACQ)-5 score (≥ 0.5-points), (2) St George’s Respiratory Questionnaire (SGRQ) total score (≥ 4-points), (3) pre-bronchodilator forced expiratory volume in 1s (FEV₁; ≥ 100 mL), all at Week 32, and (4) annualised rate of clinically significant exacerbations (≥ 50% reduction).

Results

Of the 145 patients included, 94%, 83%, 63% and 31% were responders for ≥ 1, ≥ 2, ≥ 3 and 4 outcomes, respectively; 75% and 78% were ACQ-5 and SGRQ score responders, and 50% and 69% were FEV₁ and exacerbation responders. Subgroup analyses demonstrated improvements irrespective of baseline blood eosinophil count, prior omalizumab treatment regimen/duration, comorbidities, prior exacerbation history, maintenance oral corticosteroid use, ACQ-5 and SGRQ scores, and body weight/body mass index.

Conclusions

After switching to mepolizumab, almost all patients with uncontrolled severe eosinophilic asthma on omalizumab achieved a beneficial response in ≥ 1 clinical outcome. Improvements were observed regardless of baseline characteristics.

Trial registration This manuscript is a post hoc analysis of data from the OSMO study. ClinicalTrials.gov, NCT02654145. Registered January 13, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01733-9.

The clinical benefit of mepolizumab replacing omalizumab in uncontrolled severe eosinophilic asthma

Background

Mepolizumab and omalizumab are treatments for distinct but overlapping severe asthma phenotypes.

Objective

To assess if patients eligible for both biologics but not optimally controlled with omalizumab experience improved asthma control when switched directly to mepolizumab.

Methods

OSMO was a multicenter, open‐label, single‐arm, 32‐week trial in patients with ≥2 asthma exacerbations in the year prior to enrollment, despite receiving high‐dose inhaled corticosteroids and other controller(s), plus omalizumab (≥4 months). At baseline, patients with blood eosinophil counts ≥150 cells/µL (or ≥300 cells/µL in the prior year) and an Asthma Control Questionnaire (ACQ)‐5 score ≥1.5 discontinued omalizumab and immediately commenced mepolizumab 100 mg subcutaneously every 4 weeks. Endpoints included change from baseline in ACQ‐5 score (primary), St George's Respiratory Questionnaire (SGRQ) score and the proportions of ACQ‐5 and SGRQ responders, all at Week 32, and the annualized exacerbation rate over the study period.

Results

At Week 32 (intent‐to‐treat population [n = 145]), the least squares (LS) mean changes (standard error [SE]) in ACQ‐5 and SGRQ total scores were −1.45 (0.107) and −19.0 (1.64) points; with 77% and 79% of patients achieving the minimum clinically important differences (ACQ‐5: ≥0.5 points; SGRQ: ≥4 points), respectively. The annualized rate of clinically significant exacerbations was 1.18 events/year, a 64% reduction from 3.26 events/year during the previous year. Safety and immunogenicity profiles were consistent with previous trials.

Conclusion

After directly switching from omalizumab to mepolizumab, patients with uncontrolled severe eosinophilic asthma experienced clinically significant improvements in asthma control, health status, and exacerbation rate, with no tolerability issues reported.