Azithromycin reverses airflow obstruction in established bronchiolitis obliterans syndrome

Introduction:A recent pilot study noted clinical benefit of macrolide therapy in the management of six lung transplant recipients with bronchiolitis obliterans syndrome (BOS), a condition previously regarded as irreversible. Objective: To examine the effect of low-dose macrolides on lung function in lung allograft recipients with established BOS and to assess whether this benefit is sustained. Methods: We retrospectively evaluated the effect of azithromycin (250 mg alternate days) on clinical status and lung function in 20 allograft recipients with established BOS, confirmed by decline in FEV1 or FEF25-75; consistent high-resolution computed tomography findings; and exclusion of acute rejection, infection, or anastomatic complications. Azithromycin was introduced at mean 82 months after transplantation. BOS staging at initiation of treatment was BOS 3 (10), BOS 2 (2), BOS 1 (6), and BOSO-p (2). All patients were on maintenance immunosuppression comprising cell-cycle inhibitor, oral corticosteroids, and calcineurin inhibitor. Results: There was a significant increase in FEV1 of median 110 ml (range, -70 to 730 ml) between baseline and 3 months of azithromycin therapy (p = 0.002). This improvement was sustained beyond 3 months in the majority of patients, who had initially benefited from azithromycin (up to 11 months follow up). Conclusions: This case series confirms the benefit of azithromycin in not only halting, but reversing the declining lung function seen in patients with BOS. This benefit appears to be maintained over time. Low-dose macrolides offer a new and exciting therapeutic strategy for the treatment of progressive BOS, and further clinical and translational mechanistic studies are required.