The purpose of this study is to evaluate the efficacy, safety and pharmacokinetics of intravenous nemonoxacin compared with intravenous moxifloxacin in adult patients with community-acquired pneumonia (CAP).

Community-acquired Pneumonia (CAP) remains a leading cause of death in both developing and developed countries. In the choice of antibacterial agents used to treat CAP, fluoroquinolones have received considerable attention because of their wide spectrum of bactericidal activity. TG-873870 (Nemonoxacin), a non-fluorinated quinolone (NFQ), is a selective bacterial topoisomerase inhibitor.

This study will evaluate the clinical efficacy, microbiological efficacy and safety of Intravenous nemonoxacin compared with Intravenous levofloxacin in adult patients with community-acquired pneumonia.

Besides, the populationpharmacokinetics (PPK) of nemonoxacin in adult patients with CAP after continuous IV Infusion and the pharmacokinetic (PK)/pharmacodynamic (PD)are to be determined.

Inclusion Criteria:

1. Ages between 18 and 80;
2. Weighs between 40 ~ 100 kg, and BMI ≥ 18 kg/m2;
3. Must have a clinical diagnosis of CAP
4. Chest X-ray and /or CT scan show new or persist/progressive infiltrates
5. Patients with PORT/PSI score II, III or IV.
6. If female, non-lactating and at no risk or pregnancy (post-menopausal or must use adequate birth control)
7. Male must use a reliable form of contraception.
8. Able to receive an intravenous infusion of the drug
9. Able to provide an adequate sputum and blood samples
10. Able to provide written informed consent

Exclusion Criteria:

1. Patients with PORT/PSI score I or VI.
2. Severe CAP is present if a patient needs invasive mechanical ventilation or requires vasopressors.
3. Healthcare-associated pneumonia, hospital-acquired pneumonia, or hospitalized within 14 days before enrollment
4. Virus pneumonia, aspiration pneumonia, ventilator associated pneumonia, or intersstitial lung disease
5. Bronchial bostruction (exclusive of COPD), bronchiectasis, cystic fibrosis, known or suspected pneumocystis pneumonia, known or suspected tuberculosis, primary empyema thoracis, lung abscess, known or suspected lung cancer, or lung disease associated with autoimmune disorders.
6. Medical history of QT prolongation, require the treatment of arrhythmia using class IA or class III drugs, or NYHA functional class >/= III
7. Clinically significant findings on 12-lead ECG, QTc interval>450ms or potassium is < 3.5 mmol/L or lower limit of normal at Screening
8. Immunocompromising illness, such as HIV infection
9. Fatal progressive disease or neurodegenerative diseases that prevent patients from effectively clearing pulmonary secretions
10. Have medical history of seizure, alcohol or drug abuse, suicide tendency, or psychosis that can effect the compliance
11. Have diseases that may affect intravenous infusion.
12. Active hepatitis or decompensated cirrhosis with ascites (Child-Pugh score 10-15/class C);
13. Renal Insufficiency or creatinine >/= 1.1 ULN within 24 hr before first dose
14. ALT or AST >/= 3x ULN, or BUN >/= 30 mg/dL within 24 hr before first dose
15. Neutrophil < 1000 mm3 within 24 hr before first dose
16. Received systemic antibiotics within 72 hr before first dose
17. Received probenecid within 24 hr before first dose or require the treatment with probenecid during study
18. Received quinolones or fluoroquinolones within 14 days before first dose
19. Received any investigational drugs within 30 days before first dose
20. Require the treatment with other systemic antibiotics during study
21. Patients who are being or will be on a long-term medication (over 2 weeks) of steroids (20mg/day)
22. Medical history of hypersensitivity to any quinolone, fluoroquinolone-associated tendinitis and tendon rupture, or myasthenia gravis
23. Current condition or abnormality that, in the opinion of the investigator, would compromise the safety of the subject or the quality of the data
24. Participated and received the study medication in previous clinical trials