Outcomes of Inhaled Amikacin-Containing Multidrug Regimens for Mycobacterium abscessus Pulmonary Disease

Abstract

Mycobacterium abscessus pulmonary disease (Mabscessus-PD) is challenging to treat because of its resistance to antibiotics. What are the outcomes of treatment-naive patients with Mabscessus-PD treated with inhaled amikacin-containing multidrug regimens? We identified 82 treatment-naive patients with Mabscessus-PD from a prospective observational cohort treated with regimens containing inhaled amikacin with or without clofazimine between March 2015 and June 2018 (ClinicalTrials.gov identifier: NCT00970801). During the initial phase, all patients received IV amikacin, imipenem (or cefoxitin), and oral azithromycin. Oral clofazimine was added in cases of (1) Mabscessus subspecies abscessus (here Mabscessus) or (2) Mabscessus subspecies massiliense (here Mmassiliense) with cavitary lesions. During the continuation phase, amikacin was changed from an injectional to inhalational form. Of 82 patients, 46 (56%) had Mmassiliense-PD and 36 (44%) had Mabscessus-PD. Among 59 patients with nodular bronchiectatic disease (72%), 23 of 59 had a concurrent cavitary lesion. The remaining 23 patients (28%) had fibrocavitary disease. Twelve months after treatment initiation, cure was achieved in 53 patients (65%): 42 of 46 patients (91%) with Mmassiliense-PD and 11 of 36 patients (31%) with Mabscessus-PD (P< .001). Symptomatic and radiologic improvements were observed in 72 patients (88%) and 64 patients (78%), respectively, with significantly greater improvement in patients with Mmassiliense-PD (symptom improvement, 96%vs78%[P= .047]; improvement on CT scanning, 93%vs61%[P= .002]). Inhaled amikacin with or without clofazimine in the regimen provides favorable treatment outcomes in Mmassiliense-PD. However, more effective treatments are needed for Mabscessus-PD.