A Study to Evaluate the Efficacy and Safety of Sitafloxacin in Adult Subjects With Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Prior treatment

• Sputum culture within the previous year indicated the presence of pathogenic microorganisms resistant to quinolones
• History of severe cardiovascular disease (e.g., congestive heart failure, clinically significant coronary heart disease, stroke, myocardial infarction and/or stroke within 6 months, clinically significant arrhythmia, previous history of aortic aneurysm or aortic dissection, positive family history, or risk factors (e.g., Marfan syndrome), poorly controlled hypertension (systolic blood pressure \> 160 mmHg or diastolic blood pressure \> 100 mmHg on 2 or more consecutive measurements)
• Concomitant or history of tendon disease or myasthenia gravis or Parkinson's disease
• Participation in other clinical trials within 3 months prior to screening
• Used antibiotics (including systemic and inhalation) 30 days before enrollment

Other illness

• Quinolone allergy
• Definite pulmonary disease other than COPD (asthma, bronchiectasis, active pulmonary tuberculosis, pulmonary embolism, pulmonary fibrosis, lung cancer)
• Severe systemic diseases, such as severe dizziness, headache and other nervous system diseases
• Malignant tumor
• History of seizure, or psychiatric condition that could affect compliance with the protocol, or risk for suicide, or history of alcohol or illicit drug abuse
• Immunocompromised participants using glucocorticoids (total dose equivalent to prednisone 20 mg daily for more than 2 weeks) or immunosuppressive agents or HIV infected participants
• Gastrointestinal disorders that may affect drug absorption (e.g., active Crohn's disease, active ulcerative colitis)

Lab values

• History of QTc prolongation, or need for medications to treat QTc prolongation (e.g., Class Ia or Class III antiarrhythmics);
• Abnormal liver function, aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) level \> 3 times the upper limit of normal, and/or total bilirubin level \>2 times the upper limit of normal
• With moderate or severe decline of renal function, endogenous creatinine clearance rate (Ccr) \< 50ml/min
• Serum potassium \< 3.5mmol/L at screening, or repeated hypokalemia that was difficult to correct in the past

Other

• Anthonisen III acute exacerbation (Have two major symptoms of worsening dyspnea and increased sputum volume or one of the two major symptoms)
• Hospitalization or intensive care unit (ICU) treatment is required
• Pregnant or lactating women or women of childbearing potential who are planning to become pregnant
• Other reasons that the investigator considered inappropriate to participate in the study.

• Age ≥ 40;
• History of moderate to very severe COPD with a post-bronchodilator Forced Expiratory Volume in One Second/Forced Vital Capacity (FEV1/FVC) \< 70% and a post-bronchodilator Forced Expiratory Volume in One Second (FEV1) \< 80% of predicted normal value within one year prior to enrollment;
• History of one or more acute exacerbations within one year prior to enrollment;
• At least 6 weeks of stable disease prior to enrollment;
• The acute exacerbation is classified as Anthonisen I (with 3 main symptoms of worsening dyspnea, increased sputum volume and sputum purulence) or II (with sputum purulence and another main symptom);
• Participants can be treated on an outpatient basis after clinical assessment.