Persistent asthma patients may benefit from add-on oral azithromycin

Adults with persistent symptomatic asthma experienced fewer asthma exacerbations and improved quality of life when treated with oral azithromycin for 48 weeks, a study found.

Researchers sought to assess safety and efficacy of oral azithromycin as add-on therapy in patients with uncontrolled persistent asthma on medium-to-high dose inhaled corticosteroids plus a long-acting bronchodilator. Researchers conducted a randomized, double-blind, placebo controlled parallel group trial. Four hundred and twenty patients were randomly assigned 1:1 from June 2009 to January 2015 to receive azithromycin 500 mg or placebo three times per week for 48 weeks.

Primary efficacy endpoints were the rate of total (severe and moderate) asthma exacerbations over 48 weeks and asthma quality of life. Severe exacerbations were defined as:

• worsening of asthma symptoms that led to at least three days of systemic corticosteroid treatment of at least 10 mg/day or an equivalent temporary increase in a stable oral corticosteroid maintenance dosage;
• an asthma-specific hospitalization; or,
• an emergency department visit requiring systemic corticosteroids.

Moderate exacerbations were defined as:

• any temporary increase in inhaled corticosteroids or antibiotics in conjunction with a deterioration in asthma symptoms or both (change in asthma control score 6 of at least 0.5 or increased diary symptom score), or
• any increase in beta2-agonist use for at least two days, or an emergency department visit not requiring systemic corticosteroids

Data were analyzed on an intention-to-treat basis. Results appeared at The Lancet on July 4.

Azithromycin reduced asthma exacerbations (1.07 per patient-year; 95% CI, 0.85 to 1.29) compared with placebo (1.86 per patient-year; 95% CI, 1.54 to 2.18; incidence rate ratio [IRR], 0.59; 95% CI, 0.47 to 0.74; P<0.0001). The proportion of patients experiencing at least one asthma exacerbation was reduced by azithromycin treatment (127 [61%] patients in the placebo group compared to 94 [44%] patients in the azithromycin group, P<0.0001). Also, azithromycin treatment significantly reduced severe asthma exacerbations. The placebo group experienced 1.07 severe asthma exacerbations per person-year, compared to the azithromycin treated group, which experienced 0.61 severe asthma exacerbations per person-year (IRR, 0.59; 95% CI, 0.42 to 0.83; P=0.002).

Azithromycin significantly improved asthma-related quality of life (adjusted mean difference, 0.36; 95% CI, 0.21 to 0.52; P=0.001). Diarrhea was more common in azithromycin-treated patients (72 [34%] compared to 39 [19%]; P=0.001). The study was not powered to detect changes in antibiotic resistance.

Azithromycin might be a useful add-on therapy in persistent asthma, the researchers wrote.

“Given the major impact of asthma exacerbations on patients and the community, and the ongoing risk posed by these events in patients who remain symptomatic on maintenance therapy, we consider that azithromycin is a valuable addition to existing regimens for treating asthma,” they wrote.