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Azithromycin prevents airway complications of antibody deficiency



– Low-dose azithromycin prophylaxis significantly reduced exacerbations and hospitalizations in patients with primary antibody deficiency relative to placebo, according to a randomized multicenter phase 2 trial.

Dr. Cinzia Milito

The study results support routine use of low-dose azithromycin in patients with primary antibody deficiency, according to Cinzia Milito, MD, PhD, department of molecular medicine, Sapienza University, Rome. Perhaps more importantly, the long-term benefits might be even greater.

“In patients with primary antibody deficiency, the respiratory tract is the major target of acute infections, leading to inflammation, increased airway reactivity, and over time to tissue remodeling and chronic lung disease,” Dr. Milito said at the annual congress of the European Respiratory Society. “Chronic lung disease is a major cause of death in this population.”

In this study 89 patients with primary antibody deficiency were randomized at seven centers in Italy to 250 mg per day of azithromycin or placebo administered on three consecutive days of each week for three years. Patients were maintained on other treatments, such as IgG replacement.

At the end of study, 33 of the 44 patients randomized to azithromycin and 34 of the 45 patients randomized to placebo remained on therapy. When compared for the primary endpoint of exacerbations, the median incidence rates were 3.6 episodes in the azithromycin group and 5.2 episodes in the placebo group, providing a 1.6 episode or 31% relative reduction (P=0.02).

The median number of hospitalizations for any cause, which was a secondary endpoint, was also significantly lower in the azithromycin arm (0.1 vs. 0.3 episodes).

In addition, the number of additional courses of antibiotics was significantly lower (2.3 vs. 3.6), and the time to the first course of antibiotic course was significantly longer (181.5 vs. 122.4 days) in the azithromycin group, reported Dr. Milito, whose study is now published (Milito C et al. J Allergy Clin Immunol 2019;144: 584-593).

“In a six-month washout at the end of the study, the relative advantages seen for azithromycin were lost,” Dr. Milito said.

Quality of life measured with the St. George’s Respiratory Questionnaire showed an association between low-dose azithromycin prophylaxis and significant improvement in the symptom domain when evaluated during and at the end of the study. Improvement on the Short-Form 36, which was observed one year into the study, was no longer significant at the end of the study.

Azithromycin was well tolerated with no significant differences in the rate of serious adverse events observed between the experimental and control arms of the study. Over the course of the study, however, azithromycin was associated with a significant protective effect against diarrhea (13% vs. 53%) and acute rhinosinusitus (4% vs. 27%).

There was no observed increase in macrolide resistance associated with azithromycin prophylaxis.

Macrolides have been evaluated for preventing progression of several chronic lung diseases, including chronic obstructive pulmonary disease, bronchiectasis, and cystic fibrosis. Like other drugs in its class, “azithromycin, in addition to its antimicrobial effect, has anti-inflammatory properties,” Dr. Milito said. This increases its potential to slow the time to airway damage in patients with primary antibiotic deficiency.

“Chronic lung disease is the result of a vicious cycle that begins with the inflammatory response to infection,” Dr. Milito explained. On the basis of these data, she believes azithromycin “should be considered a valuable addition to usual treatment” for primary antibody deficiencies.


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