Asthma symptom re-emergence after omalizumab withdrawal correlates well with increasing IgE and decreasing pharmacokinetic concentrations.

BACKGROUND: Physicians have questioned whether omalizumab can be discontinued or the dose reduced after clinical improvement is seen in patients with severe asthma. OBJECTIVES: To examine the relationships among omalizumab, free IgE, and clinical outcomes in a randomized, placebo-controlled trial in patients with severe persistent allergic asthma following a posology based on pretreatment total IgE and body weight. METHODS: A pharmacokinetic-pharmacodynamic binding model was used to calculate free IgE, omalizumab, and total IgE concentrations during the 28-week treatment and 16-week follow-up of the INvestigation of Omalizumab in seVere Asthma TrEatment (INNOVATE) study. These were plotted against the mean changes in the total asthma symptom score, morning peak expiratory flow, and rescue medication use for physician-defined treatment responders and nonresponders. RESULTS: The model accurately fitted omalizumab and free and total IgE, allowing reconstruction of the entire time course for each patient. Free IgE was rapidly suppressed below the 50 ng/mL (20.8 IU/mL) target, although there was a notable period before clinical measures stabilized. After treatment cessation, free IgE and omalizumab returned toward baseline and, after a delay, asthma symptoms re-emerged. Model-derived omalizumab and free IgE concentrations correlated well with changes in clinical outcomes, particularly in omalizumab-treated responders. Asthma symptoms exhibited different correlations during response onset compared with response offset (hysteresis), indicative of physiological time delays between changes in IgE levels and pulmonary function. CONCLUSION: Omalizumab and free IgE correlated well with clinical symptoms. Reducing omalizumab doses below those in the dosing table cannot be recommended; the resulting increase in free IgE would cause a deterioration in asthma control.

Effect of a specific cysteinyl leukotriene-receptor 1-antagonist (montelukast) on the transmigration of eosinophils across human umbilical vein endothelial cells.

BACKGROUND: Leukotrienes have been implicated in the selective infiltration of eosinophils into the bronchial mucosa in asthma. OBJECTIVE: We studied whether eosinophil transmigration through cultured human umbilical vein endothelial cells (HUVECs) can be blocked by a specific cysteinyl LT1-receptor-antagonist. METHODS: Unstimulated and stimulated eosinophils from patients with asthma and normal controls were subjected to confluent human umbilical vein endothelial cell (HUVEC) monolayers separating the upper and lower chamber of Transwell culture plates. Unstimulated eosinophils or cells pre-incubated in the presence of the eosinophil activating cytokines GM-CSF or IL-13 were placed in the upper chambers while PAF, a potent chemoattractant factor for eosinophils, was added to the lower chamber. Migration of eosinophils was quantified by a beta-glucuronidase assay. RESULTS: The assumption that eosinophils express CysLT1 (cysteinyl-leukotriene 1)-receptors was based on our demonstration of mRNA-expression for the CysLT-1-receptor by polymerase chain reaction on purified eosinophils. The chemotactic response to PAF was significantly reduced when eosinophils were pre-incubated with montelukast for 15 min. When eosinophils were pre-incubated with GM-CSF and/or IL-13, the migratory response to PAF was also significantly reduced by montelukast. CONCLUSION: From these data we conclude that the specific cysteinyl LT1-receptor antagonist montelukast can inhibit PAF-induced eosinophil transmigration through cultured HUVEC monolayers.

Nebulized saline solution of dry powder formoterol is useful for acute bronchospasm

Dos nuevos beta agonistas de efecto prolongado son actualmente usados clínicamente: salmeterol y formoterol. El primero no ha demostado efectividad en los casos de asma aguda mientras que el segundo, formoterol, comparable en su período de latencia al albuterol, no ha sido empleado en el manejo de las crisis de asma. En este estudio utilizamos mediciones de flujo espiratorio pico antes y después de la administración de 12 microgramos de fumarato de formoterol (ForadilR) en polvo seco vía nebulización, inmediatamente después de su dilución en solución salina estéril, a treinta pacientes con crisis de asma y grados variables de obstrucción bronquial. Los resultados muestran mejoría significativa a los 5 y 30 minutos después de su administración, sugiriendo estabilidad de este producto así como un novedoso enfoque costo efectivo por su menor dosificación y posible impacto sobre la frecuencia de readmisiones debido a una broncodilatación prolongada