Effects of Nemonoxacin on Thorough ECG QT/QTc Interval: A Randomized, Placebo- and Positive-controlled Crossover Study in Healthy Chinese Adults

Abstract Purpose Nemonoxacin, a nonfluorinated quinolone, has been approved in Taiwan and mainland China for the treatment of bacterial infection. Whether nemonoxacin is associated with the adverse events of other quinolones, such as the risk for QT-interval prolongation, which has led to the withdrawal of several fluoroquinolones from the market, needs to be elucidated. Methods The effects of nemonoxacin on thorough QT/QTc interval was investigated in this randomized, placebo- and positive-controlled crossover study conducted according to the International Conference on Harmonisation E14 guideline. Forty-eight healthy adults received a single oral dose of nemonoxacin 500 mg (therapeutic dose), nemonoxacin 750 mg (supratherapeutic dose), moxifloxacin 400 mg (positive control), or placebo in 1 of 4 cohorts (Williams Latin square design) in the fasted condition. After a 7-day washout, 6 male and 6 female subjects were orally administered a 500-mg dose of nemonoxacin after high-fat food intake. The primary end point was the change in QT interval corrected for heart rate using the Fridericia formula (QTcF). The secondary end point was the change in QT interval corrected for heart rate using the Bazett formula (QTcB). Findings The study revealed that nemonoxacin was classified as not likely dangerous at the therapeutic dose (500 mg) and as potentially dangerous at the supratherapeutic dose (750 mg). The T max of nemonoxacin was 1 to 2 hours after administration, and the elimination half-life was 5 to 7 hours, in the fasted conditions. High-fat food intake had significant effects on the T max , C max , AUC 0–∞, and QT/QTc interval of nemonoxacin compared with these values in the fasted condition. A correlation between QTcF and the plasma drug concentration of nemonoxacin was not observed. Implications Nemonoxacin at the clinically therapeutic and supratherapeutic doses had a prolongation effect on QT/QTc. ClinicalTrials.gov identifier: NCT03362853.