Treating the small airways

A novel approach to partition central and peripheral airway nitric oxide

BACKGROUND

Determining the site of airways inflammation may lead to the targeting of therapy. Nitric oxide (NO) is a biomarker of airway inflammation and can be measured at multiple exhalation flow rates to allow partitioning into bronchial (large/central airway maximal nitric oxide flux [J'awno]) and peripheral (peripheral/small airway/alveolar nitric oxide concentration [Cano]) airway contributions by linear regression. This requires a minimum of three exhalations. We developed a simple and practical method to partition NO.

METHODS

In 29 healthy subjects (FEV1, 97% ± 3% predicted), 13 patients with asthma (FEV1, 90% ± 4% predicted), 14 patients with COPD (FEV1, 59% ± 3% predicted), and 12 patients with cystic fibrosis (CF) (FEV1, 60% ± 3% predicted), we measured the area under the curve of the NO concentration/exhalation time plot (AUC-NO) at exhalation flow rates of 50, 100, 200, and 300 mL/s. We determined the change of the total AUC-NO production (ΔAUC-NO) among the four different exhalation flow rates and compared these levels to Cano and J'awno indices measured conventionally by linear regression.

RESULTS

The change in AUC-NO between increasing exhalation flow rates of 50 to 200 mL/s (ΔAUC-NO50-200) was strongly correlated with J'awno in all patient groups as follows: healthy subjects (r = 0.94, P < .001), patients with asthma (r = 0.98, P < .001), patients with COPD (r = 0.93, P < .001), and patients with CF (r = 0.74, P < .05). In all subjects, AUC-NO at an exhalation flow rate of 200 mL/s (AUC-NO200) correlated with Cano (r = 0.69, P < .01).

CONCLUSIONS

The bronchial production of NO can be determined by measuring ΔAUC-NO50-200, whereas AUC-NO200 measures its peripheral concentration. This approach is simple, quick, and does not require sophisticated equipment or mathematical models.

Stepping-across controlled asthmatic patients to extrafine beclometasone/formoterol combination

BACKGROUND

Asthma management focuses on achieving and maintaining asthma control. Few studies have assessed whether complete and sustained asthma control is maintained in clinical practice after stepping-across ICS/LABA fixed combinations. Aim of this double-blind, double-dummy, randomized, parallel group, controlled study was to demonstrate clinical equivalence between equipotent doses of extrafine beclometasone/formoterol (BDP/F) pMDI and fluticasone/salmeterol (FP/S) Diskus® in maintaining lung function and asthma control.

METHODS

A total of 416 asthmatic patients already controlled with FP/S 500/100 μg/day (Diskus®, pMDI or separate inhalers) were randomized to a 12-week treatment with extrafine BDP/F 400/24 μg/day pMDI or FP/S 500/100 μg/day Diskus®. Pre-dose 1-s forced expiratory volume (FEV(1)) was the primary efficacy variable; secondary variables included asthma control questionnaire (ACQ-7) and FEV(1)0-1 h area under the curve (FEV(1)AUC(0-1h)). Safety was assessed through adverse events monitoring and vital signs.

RESULTS

After 12 weeks of treatment, pre-dose FEV(1) did not differ between treatments (difference between means 0.01 L; 95% CI -0.03-0.06 L) with no significant changes from baseline in both groups (p = 0.726 and p = 0.783 in BDF/F arm and FP/S, respectively). ACQ-7 score showed that control was maintained after stepping-across to extrafine BDP/F. FEV(1)AUC(0-1h) was significantly higher in BDP/F arm at the beginning (p = 0.004) and at the end of the 12-week treatment period (p = 0.019). No safety issues were reported in both groups.

CONCLUSIONS

Patients previously controlled with FP/S in any device formulation can effectively step-across to extrafine BDP/F pMDI, maintaining lung function and asthma control with a 5-min onset of action.