For patients with uncontrolled, severe eosinophilic asthma, “almost all” who switched to mepolizumab after receiving omalizumab had an improvement in at least one clinical outcome, according to recent post hoc analysis of the OSMO study published in Respiratory Research.
“Improvements were observed regardless of baseline characteristics,” Mark C. Liu, MD, of the Divisions of Allergy and Clinical Immunology, Pulmonary and Critical Care Medicine at Johns Hopkins Asthma and Allergy Center in Baltimore, and colleagues wrote in their study.
The phase 4 OSMO study enrolled 145 participants with uncontrolled severe eosinophilic asthma who were receiving omalizumab for at least 4 months without achieving control of their asthma. After enrollment, participants entered a run-in period where they continued omalizumab for 2 weeks then switched to subcutaneous mepolizumab (100 mg) every 4 weeks for up to 28 weeks.
The results showed patients had “clinically significant improvements in asthma control, HRQoL, lung function and the rate of clinically significant exacerbations, with no tolerability issues reported,” Dr. Liu and colleagues explained. “It is of clinical interest to determine what proportion of patients respond to mepolizumab treatment, and whether patient characteristics affect this response, after switching from omalizumab.”
In their post hoc analysis, Liu and colleagues determined what proportion of participants who responded to mepolizumab with an Asthma Control Questionnaire (ACQ)-5 score of ≥ 0.5 points, a St. George’s Respiratory Questionnaire (SGRQ) total score of ≥ 4 points), a pre-bronchodilator forced expiratory volume in 1 second (FEV1) of ≥ 100 mL), and a 50% decrease in annualized rate of clinically significant exacerbations.
Liu and colleagues found 94% of participants were responders for one or more outcomes, 83% were responders for two or more outcomes, 63% were responders for three or more outcomes, and 31% were responders for all four outcomes. Of these, 75% of participants met ACQ-5 response criteria, 78% met SGRQ response criteria, 50% met FEV1 response criteria, and 69% met criteria for decreased annualized exacerbations.
The researchers noted these improvements were seen regardless of a participant’s blood eosinophil count at baseline, regimen and how long they were on omalizumab, patient comorbidity, history of exacerbations, whether they used maintenance oral corticosteroids, their ACQ-5 and SGRQ scores, and their body mass index or body weight.
“In summary, this analysis demonstrates that patients with severe eosinophilic asthma who are uncontrolled on omalizumab can be effectively switched to mepolizumab to achieve clinically important improvement in efficacy outcomes, irrespective of the patient baseline characteristics studied,” the researchers concluded. “The analysis also suggests that patients with higher baseline blood eosinophil counts or comorbid nasal polyps may benefit the most from a direct switch to mepolizumab from omalizumab.”