Taking a low dose of the antibiotic azithromycin for six months reduces symptoms for patients with the chronic lung condition primary ciliary dyskinesia (PCD), according to new research.

The findings were presented this week at the European Respiratory Society International Congress.

PCD is a rare inherited disease that affects people from birth. It causes coughing, a build-up of mucus in the lungs, and frequent chest and ear infections that can lead to permanent lung damage and hearing loss. The new findings come from a randomized controlled clinical trial comparing the therapy to a placebo in patients across Europe.

The study was presented by Helene Kobbernagel, MD,  from the Paediatric Pulmonary Service, Department of Paediatrics and Adolescent Medicine, Copenhagen University Hospital in Rigshospitalet, Denmark.

“PCD is a serious and chronic condition that begins early in life and tends to deteriorate over time. Because it is a rare disease, there is a lack of good evidence on how to treat children and adults to relieve symptoms and prevent longer term damage,” says Kobbernagel.

PCD affects tiny hair-like structures, called cilia, that line the airways. In healthy people, billions of these cilia move rhythmically to pass mucus out of the chest, which helps to remove bacteria and dirt.

In people with PCD, the cilia either do not work properly or they do not move at all. Patients cannot effectively remove mucus, and the bacteria it contains, from their lungs, leaving them vulnerable to frequent respiratory infections. The infections can cause irreversible lung damage, which further increases the likelihood of more infections.

Kobbernagel and her colleagues wanted to see if they could use the antibiotic azithromycin as a form of ‘maintenance therapy’ to keep infections at bay over an extended period, hopefully improving symptoms in PCD patients.

“We know that azithromycin is effective in treating a number of infections that occur in people with PCD, as well as having anti-inflammatory effects. It is also simple to administer and has mild side-effects. These are important considerations if you are asking children and adults to take a drug for an extended period. We wanted to see whether taking azithromycin over a period of time could also work to prevent infections and reduce symptoms,” she says.

The study included 90 patients, ranging in age from seven to 50 years old, who were being treated at six hospitals across Europe. Forty-nine of the patients were randomly assigned to take the antibiotic for six months, while the other 41 took a placebo. All patients were checked for symptoms, the presence of infection-causing bacteria in their sputum, lung function, hearing and quality of life.

Patients taking azithromycin suffered an average (mean) 0.63 episodes of symptoms that were serious enough to require treatment during the study. Among those taking the placebo, patients suffered an average of 1.37 such episodes. This equates to a 50% reduction in episodes in patients taking the treatment. People taking the antibiotic also had fewer infection-causing bacteria in their sputum samples, but they were more likely to suffer with mild diarrhea.

“Our results show that azithromycin is safe for patients with PCD and that it could offer an effective maintenance therapy, reducing ill health and helping children and adults get on with their daily lives,”says Kobbernagel.