Methods: Growth rate data were collected in a randomized, 1-year study that evaluated MF-DPI 110 µg twice-daily (BID), MF-DPI 220 µg and 110 µg (both QD morning doses), and placebo in 187 children (4-9 years) with asthma (previously maintained on inhaled beta-agonists). Peak inspiratory flow rate (PIFR) data were collected in an in vivo study of PIFRs and airflow profiles through a functional model of the MF-DPI in 55 children (5-12 years) with mild persistent asthma.
Results: Mean growth rates for MF-DPI 110 µg BID, 220 µg QD, 110 µg QD, and placebo were 5.34, 5.93, 6.15, and 6.44 cm/y, respectively. The difference in growth rates (95% CI) between active drug and placebo for MF-DPI 110 µg BID, 220 µg QD, and 110 µg QD were -1.11
(-2.34, 0.12), -0.51 (-1.69, 0.67), and -0.30 (-1.48, 0.89), respectively. The mean PIFR through the MF-DPI for children aged 5-8 years was >50 L/min (minimum, 46 L/min) and for children aged 9-11 years was >60 L/min (minimum, 48 L/min). All of the measured rise times (rapidity of inhalation) were lower than the maximum rise time (300 msec) shown in vitro to provide delivery of respirable particles.
Conclusions: Study evidence shows that MF-DPI has negligible growth effects and that children are able to use the inhaler properly to achieve drug delivery to the lungs. The characteristics of MF-DPI indicate it is a valuable treatment option for children with asthma.