Tobramycin inhalation powder in cystic fibrosis patients: response by age group

Abstract

Background: Tobramycin powder for inhalation (TIP) is a drug-device combination designed to reduce treatment time and improve ease of use compared with tobramycin inhalation solution (TIS) in cystic fibrosis (CF) patients. However, the ability of patients to use dry powder inhalers, and the efficacy of the treatments, may vary by age.

Methods: The "Establish a New Gold Standard for Efficacy and Safety With Tobramycin in Cystic Fibrosis" (EAGER) trial was a randomized, 24-week, multicenter, open-label, parallel-group study designed to evaluate the safety of TIP versus TIS in 553 subjects, ages ≥ 6 years, with CF and P. aeruginosa infection. The main efficacy end point was percent-of-predicted FEV1 at week 20 (end of third cycle of treatment). A post hoc analysis was undertaken in 517 subjects who took ≥ 1 dose of study medication, to evaluate the relative efficacy and safety of TIP and TIS by age group: ≥ 6 to < 13 y (children, n = 46); ≥ 13 to < 20 y (adolescents, n = 114); and ≥ 20 y (adults, n = 357).

Results: Improvements in percent-of-predicted FEV1 from baseline to end of cycle 3 were greatest in the children for both TIP and TIS. The treatment differences (TIP - TIS) were 4.7% (85% CI -1.2 to 10.6), 3.7% (85% CI -0.1 to 7.5), and -0.8% (85% CI -3.1 to 1.5) in children, adolescents, and adults, respectively. Sputum P. aeruginosa density decreased from baseline with both treatments, with comparable treatment differences across the age groups after 3 cycles: children -0.93 (85% CI -2.4 to 0.5), adolescents -0.17 (85% CI -1.2 to 0.8), and adults -0.89 (85% CI -1.3 to -0.4). Overall, subject satisfaction scores were greater in all subjects with TIP, irrespective of age group. With the exception of cough and dysphonia, the safety profile of TIP was comparable to TIS, irrespective of age.

Conclusions: TIP is comparable to TIS in efficacy outcomes and safety profile but had greater patient satisfaction in all the age groups.

Keywords: Pseudomonas aeruginosa; age groups; cystic fibrosis; drug delivery systems; tobramycin inhalation powder; topical anti-infective agents.