Knemometry Assessment of Short-term Growth in Children With Asthma Receiving Fluticasone Furoate for 2 Weeks: A Randomized, Placebo-controlled, Crossover Trial

Purpose: A dry powder inhaler formulation of the inhaled corticosteroid fluticasone furoate (FF) is being evaluated for use in children. An important potential risk associated with the use of inhaled corticosteroids in children is growth suppression. Therefore, the aim of this study was to assess the short-term lower leg growth in children with asthma treated for 2 weeks with inhaled FF versus placebo from the ELLIPTA inhaler.

Methods: Prepubertal children with persistent asthma (n = 60; aged 5 to <12 years) were recruited into a randomized, double-blind, placebo-controlled, 2-way crossover, noninferiority study. The study consisted of four 2-week periods: run-in, 2 treatment periods, 1 washout period, and a 1-week follow-up period. Interventions were FF 50 µg and placebo once daily in the evening. Lower leg length was measured by using knemometry.

Findings: The randomized ITT population comprised 36 boys and 24 girls with a mean age of 8.7 (standard deviation, 1.5; range, 5-11) years; 58% had a duration of asthma ≥5 years. Fifty-eight subjects completed both treatment periods. The least squares mean growth rate was 0.31 mm/week during treatment with FF and 0.36 mm/week during the placebo period. The difference in adjusted least squares mean growth rates between FF and placebo was -0.052 mm/week with a 95% CI of -0.122 to 0.018. This finding was greater than the prespecified noninferiority margin of -0.20 mm/week. The overall incidence of adverse events was 35% with placebo and 22% with FF.

Implications: Inhaled FF 50 µg provided once daily for 2 weeks was noninferior to placebo in terms of effects on short-term lower leg growth in children with asthma. To further quantify the risk of growth suppression in children, intermediate-term growth studies should be conducted. Inhaled FF 50 µg was well tolerated in this study population. ClinicalTrials.gov identifier: NCT02502734.