Mepolizumab and benralizumab were biological therapies that reduced eosinophilic inflammation in severe eosinophilic asthmatic patients. For a study, researchers sought to see how total IgE levels between 4 and 2 months changed after starting mepolizumab (primary outcome) or benralizumab (secondary outcome). Changes in blood inflammatory cell counts, lung function, and the asthma control test (ACT) were also evaluated and associated with changes in total IgE levels where available. The study included severe eosinophilic atopic asthmatic patients treated with mepolizumab or benralizumab. About 3 months of treatment with mepolizumab (n=104) or benralizumab (n=82) resulted in significantly lower blood eosinophil and basophil levels in benralizumab-treated patients compared to mepolizumab-treated patients. Mepolizumab did not affect blood total IgE levels during the research period, whereas benralizumab dramatically lowered total IgE levels (−35%, P<0.001). The reduction of blood total Ig-E levels was associated with a decrease in blood basophils (but not eosinophils) and a weak correlation with asthma control in individuals treated with benralizumab. Treatment with benralizumab, but not mepolizumab, resulted in a significant decrease in circulating IgE levels. Anti-IL5-pathway therapies have various and specific methods of action, according to the study.