The purpose of this study is to evaluate the safety and efficacy of delafloxacin compared to moxifloxacin in the treatment of adult patients with community-acquired pneumonia.

The purpose of this study is to determine if delafloxacin, an investigational drug, is safe and effective in the treatment of community-acquired bacterial pneumonia compared with moxifloxacin, or linezolid in the case of confirmed MRSA.

Inclusion Criteria:

1. Male or female 18 years of age or older

2. Evidence of acute onset of CABP with 2 or more of the following symptoms (new or worsening)

   • Cough
   • Production of purulent sputum consistent with bacterial infection
   • Difficulty breathing
   • Chest pain due to pneumonia

   AND have at least 2 of the following findings:

   • Fever (oral temperature >38.0°C)
   • Hypothermia (oral temperature <35.0°C)
   • Tachycardia (heart rate >100 beats/min)
   • Tachypnea (respiratory rate >18 breaths/min)

   AND have at least 1 of the following findings:

   • Hypoxemia (oxygen saturation <90% or PaO2 < 60 mmHg) on room air or with subject's baseline (pre-CABP under study) supplemental oxygen
   • Clinical evidence of pulmonary consolidation and/or presence of pulmonary rales
   • An elevated white blood cell count (WBC) >10,000/mm3 or 15% immature neutrophils (bands), regardless of total peripheral WBC count or leukopenia with WBC <4500/mm^3

3. Presence of lobar, multilobar, or patchy parenchymal infiltrate(s) consistent with acute bacterial pneumonia on a pulmonary imaging study within 48 hours before the first dose of study drug

4. PORT risk class of II to V (PSI score >50)

5. Must be a suitable candidate for possible IV to oral switch antibiotic therapy and must also be able to swallow large tablets/capsules intact without crushing

Exclusion Criteria:

1. A medical history of significant hypersensitivity or allergic reaction to antibiotics of the quinolone or oxazolidinone class or study drug excipients according to the investigator

2. Any infection expected to require other systemic antibiotics in addition to study drug

3. Receipt of systemic antibiotic therapy in the 7 days before enrollment unless 1 of the following is documented:

   • Received at least 48 hours of antibiotic therapy for CABP and clinic notes document treatment failure (i.e., not by patient history or pulmonary imaging alone) with new or worsening symptoms while on pre-study therapy
   • Received 1 dose of a single, potentially effective, short-acting antibacterial drug or drug regimen for CABP within 24 hours before enrollment (limited to 25% of enrolled patients)

4. Respiratory infection confirmed or suspected to be secondary to hospital-acquired or ventilator-associated pneumonia OR requires treatment in an intensive care setting, OR requires mechanical ventilation

5. Current or suspected diagnosis of viral, fungal, or aspiration pneumonia, noninfectious causes of pulmonary infiltrates, lung cancer, cystic fibrosis, tuberculosis, empyema (not including sterile parapneumonic effusions)

6. Known anatomical or pathological bronchial obstruction OR history of bronchiectasis OR GOLD Stage 4 COPD OR history of post obstructive pneumonia

7. Severely compromised immune system

8. Known history of Child-Pugh Class B or C liver disease

9. History of post-antibiotic colitis within last 3 months

10. Other exclusions include those described in the safety label for drugs in the quinolone and/or oxazolidinone classes such as QT prolongation, proarrhythmic conditions, concomitant use of drugs known to cause QT prolongation, peripheral neuropathy, tendon disorders, history of myasthenia gravis, liver disease, severe renal disease, seizures and concomitant use of MAO A or B inhibitor agents and adrenergic serotonergic agents