Long term azithromycin therapy in patients with cystic fibrosis

Inflammation is a central contributor to the pathogenesis of cystic fibrosis (CF) pulmonary disease; so limiting the excessive production of inflammatory mediators represents a major therapeutic strategy for slowing the decline in lung function and improving survival. The macrolide antibiotic azithromycin (AZM) has anti-inflammatory properties and immunomodulatory effects that may be beneficial in CF. The aim of this study was to document the long term use of AZM effect on pulmonary function, nutritional status and number of pulmonary exacerbations in patients with CF. Twenty four patients with CF aged 4-23 years followed at Hacettepe University Department of Pediatric Pulmonology between May 2007- December 2014 enrolled in the study from 630 CF patients. They received 10 mg/kg/day of AZM three times a week. Pulmonary function parameters, sputum cultures, body mass index (BMI) Z scores and number of pulmonary exacerbations were analyzed at different time intervals (at the visits at months 6, 9 and 12). Median age of the patients was 14.7 (range 4-23 years) years and median treatment duration was 14 months (range 6-60 months). Initially, median FEV1% was found 68% (range 30%-100%), BMI was found 17.05 (range 13.3-26.5) and oxygen saturation was found 95% (range 84%-99%). At the end of the 6th, 9th and 12th months of the AZM therapy; no significant differences in FEV1% and oxygen saturation parameters were found compared to the initial time, however BMI increased significantly (p=0.03), also the number of pulmonary exacerbations (p < 0.001) and severe exacerbations (p < 0.001) needing intravenous antibiotic treatment were significantly reduced at the 6th and 12th month. At the end of the 12th month of AZM; Methicillin sensitive S. aureus (MSSA) colonization was significantly increased (p=0.005) and increased macrolide resistance was detected (p=0.008). Although, this study could not be designed as a placebo controlled study, the results showed that at least 6 months of AZM treatment led to a significiant reduction in the number of pulmonary exacerbations requiring antibiotics and improvement on nutritional status. Despite increased P. aeruginosa antibiotic resistance and MSSA colonization rates, the lower incidence of acute exacerbations in patients receiving AZM is an important and clinically relevant measure of beneficial effect. Therefore, long term use of AZM may be considered to slow pulmonary deterioration in CF patients with P. aeruginosa colonization.