After omalizumab, 18 patients showed FEV<sub>1</sub> normalization (reversible airway obstruction; RAO+) already at T1 (88.7 ± 14.9 %, p < 0.0001) that persisted up to T4 (83.2 ± 7.9, p < 0.01), while 14 patients (RAO-) had FEV<sub>1</sub> persistently decreased, from T1 (65.2 ± 8.4%, p < 0.05) up to T4 (61.4 ± 6.2%, not significant).