Intranasal corticosteroids are used widely for the treatment of allergic rhinitis because they are effective and well tolerated. However, their potential to suppress growth of pediatric subjects with allergic rhinitis continues to be a concern, particularly in light of reports of growth suppression after treatment with intranasal beclomethasone dipropionate or intranasal budesonide (see the article by Skoner et al in this month's issue).
A 1-year study of prepubertal patients between 3 and 9 years of age with perennial allergic rhinitis was conducted to assess the effects on growth of mometasone furoate aqueous nasal spray (MFNS), a new once-daily (QD) intranasal corticosteroid with negligible bioavailability.
This was a randomized, placebo-controlled, double-blind, multicenter study. Ninety-eight subjects were randomized to treatment with either MFNS 100 μg QD or placebo for 1 year. Each subject's height was required to be between the 5th and 95th percentile at baseline, and skeletal age at screening was required to be within 2 years of chronological age, as determined by left wrist x-rays. Washout periods for medications that affect either childhood growth or allergic rhinitis symptoms were established based on estimated period of effect, and these medications were prohibited during the study. However, short courses of either oral prednisone lasting no longer than 7 days or low-potency topical dermatologic corticosteroids lasting no longer than 10 days were permitted if necessary.
Height was measured with a calibrated stadiometer at baseline and at 4, 8, 12, 26, 39, and 52 weeks, and the primary safety variable was the change in standing height. The rate of growth was also calculated for each subject as the slope (linear regression) of the change in height from baseline using data from all visits of subjects who had at least 2 visits. Hypothalamic-pituitary-adrenocortical- (HPA)-axis function was assessed via cosyntropin stimulation testing at baseline and at 26 and 52 weeks. All analyses were based on all randomized subjects (intent-to-treat principle). The change from baseline in standing height was analyzed by a 2-way analysis of variance that extracted sources of variation attributable to treatment, center, and treatment-by-center interaction.
Demographic characteristics were similar at baseline. Eighty-two subjects completed the study (42 in the MFNS group and 40 in the placebo group), and 93% of subjects achieved at least 80% compliance with therapy. After 1 year of treatment, no suppression of growth was seen in subjects treated with MFNS, and mean standing heights were similar for both treatment groups at all time points. For the primary safety variable (change in height from baseline), both treatment groups were similar at all time points except for weeks 8 and 52. Subjects treated with MFNS had a slightly greater mean increase in height than subjects treated with placebo at these time points: the change in height was 6.95 cm versus 6.35 cm at the 1-year time point. However, the rate of growth (.018 cm/day) averaged for all time points over the course of the study was similar for both treatment groups. Additional analyses found that MFNS did not retard growth in any sex or age subgroup of subjects. The use of exogenous corticosteroids other than the study drug was also similar among the 2 treatment groups.
Results from cosyntropin stimulation testing confirmed the absence of systemic effects of MFNS. The change from baseline in the difference between prestimulation and poststimulation levels was similar for both treatment groups after 1 year of treatment, with no evidence of HPA-axis suppression in MFNS-treated subjects at any time point. Incidences of treatment-related adverse events were similar for both treatment groups, with 16% of MFNS-treated subjects reporting adverse events, compared with 22% of placebo-treated subjects.
In summary, 1 year of treatment with MFNS 100 μg QD was found to be well tolerated, with no evidence of retardation of growth or suppression of HPA-axis function in perennial allergic rhinitis subjects as young as 3 years of age. These findings may be particularly relevant for children with co-morbid atopic disorders, such as asthma and eczema. Such patients may be treated concurrently with inhaled and/or dermatologic corticosteroids, thereby increasing the risk of systemic adverse events, including growth suppression. The absence of systemic adverse events found in this study, combined with the established efficacy and safety profile of MFNS in children, indicates that it may be an appropriate therapy for children as young as 3 years of age.3,4