Here, we aimed to provide a thorough preclinical profiling of APR in comparison to AMK by describing their MIC distributions for the most common NTM and defining tentative epidemiologic cutoffs (TECOFFs), by challenging in vitro activity in the presence of mucin or sputum, by further assessing their in vitro activity in planktonic and intracellular time-kill kinetic experiments, by comparing the frequencies of resistance, and by studying the therapeutic potential of APR against M. abscessus in a cystic fibrosis (CF) mouse model. The gene discussed is MUC5AC; the disease is cystic fibrosis.