Role of nemonoxacin as a therapeutic option for community-acquired pneumonia in the era of atypical pathogens

To systematically summarize the clinical data from phase II–IV studies of nemonoxacin malate and comprehensively evaluate the clinical efficacy of nemonoxacin in treating pneumonia caused by atypical pathogens, so as to inform empirical antimicrobial selection in clinical practice. A retrospective analysis was performed on the results of four phase II/III clinical studies of nemonoxacin malate in patients with community-acquired pneumonia (CAP) and on the composition and clinical outcomes of atypical pathogen–infected patients in one phase IV clinical study; subgroup efficacy analyses were conducted by age and by presence or absence of co-pathogen infection. This study included four phase II/III controlled trials and one phase IV single-arm trial, with a primary analysis population of 1769 CAP patients, of whom 994 were male (56.2%) and 775 were female (43.8%), with a mean age of 47.83 ± 16.39 years. In the phase II/III studies, 370 patients (27.8%) were positive for atypical pathogens, including Mycoplasma pneumoniae (MP) in 265 cases (19.9%), Chlamydia pneumoniae (CP) in 68 cases (5.1%), and Legionella pneumophila (LP) in 85 cases (6.4%). In the phase IV study, 172 patients (39.7%) were positive for atypical pathogens, including PM in 141 cases (32.6%), CP in 14 cases (3.2%), and LP in 50 cases (11.5%).Efficacy analysis showed that nemonoxacin 500 mg oral and injectable formulations had clinical success rates against atypical pathogens of 98.0% vs levofloxacin 95.5% (oral) and 97.7% vs levofloxacin 95.8% (injectable), respectively; against MP the rates were 99.0% vs 94.1% (oral) and 97.6% vs 100.0% (injectable), respectively, suggesting that the clinical efficacy of the two formulations of nemonoxacin is slightly superior to or comparable with levofloxacin. Additionally, subgroup analyses stratified by age and by presence of co-pathogen infection showed that nemonoxacin demonstrated good clinical efficacy in patients aged both < 60 years and ≥ 60 years, regardless of whether the infection was solely due to atypical pathogens or accompanied by other pathogens. Nemonoxacin demonstrated good clinical efficacy in CAP patients with atypical pathogen infections, with effects comparable to or superior to levofloxacin, and may be considered as one of the options for empirical CAP treatment or as a therapeutic choice after confirmation of atypical pathogen infection.