Systematic Review and Meta-analyses of the Effect of Chemotherapy on Pulmonary Mycobacterium abscessus Outcomes and Disease Recurrence

In pharmacokinetic/pharmacodynamic models of pulmonary Mycobacterium abscessus complex, the recommended macrolide-containing combination therapy has poor kill rates. However, clinical outcomes are unknown. We searched the literature for studies published between 1990 and 2017 that reported microbial outcomes in patients treated for pulmonary M. abscessus disease. A good outcome was defined as sustained sputum culture conversion (SSCC) without relapse. Random effects models were used to pool studies and estimate proportions of patients with good outcomes. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Sensitivity analyses and metaregression were used to assess the robustness of findings. In 19 studies of 1,533 patients, combination therapy was administered to 508 patients with M. abscessus subsp. abscessus, 204 with M. abscessus subsp. massiliense, and 301 with M. abscessus with no subspecies specified. Macrolide-containing regimens achieved SSCC in only 77/233 (34%) new M. abscessus subsp. abscessus patients versus 117/141 (54%) M. abscessus subsp. massiliense patients (OR, 0.108 [95% CI, 0.066 to 0.181]). In refractory disease, SSCC was achieved in 20% (95% CI, 7 to 36%) of patients, which was not significantly different across subspecies. The estimated recurrent rates per month were 1.835% (range, 1.667 to 3.196%) for M. abscessus subsp. abscessus versus 0.683% (range, 0.229 to 1.136%) for M. abscessus subsp. massiliense (OR, 6.189 [95% CI, 2.896 to 13.650]). The proportion of patients with good outcomes was 52/223 (23%) with M. abscessus subsp. abscessus versus 118/141 (84%) with M. abscessus subsp. massiliense disease (OR, 0.059 [95% CI, 0.034 to 0.101]). M. abscessus subsp. abscessus pulmonary disease outcomes with the currently recommended regimens are atrocious, with outcomes similar to those for extensively drug-resistant tuberculosis. Therapeutically, the concept of nontuberculous mycobacteria is misguided. There is an urgent need to craft entirely new treatment regimens.