ASK0912 Versus Polymyxin B for Injection in Adults With Hospital-Acquired or Ventilator-Associated Bacterial Pneumonia

Inclusion Criteria: * 1\. Aged 18-75 years on the day of informed consent signature; * 2\. Require intravenous antibiotic therapy for hospital-acquired bacterial pneumonia (HABP)/ventilator-associated bacterial pneumonia (VABP). * 3\. At least one clinical sign or symptom of HABP/VABP. * 4\. At least one laboratory abnormality of HABP/VABP. * 5\. Chest imaging at screening demonstrating new or progressive infiltrates consistent with pneumonia. * 6\. APACHE II score ≤ 30. * 7\. Appropriate lower respiratory tract specimen obtained at screening for Gram stain and bacterial culture. * 8\. Subjects receiving HABP/VABP-active antibiotics within 72h pre-enrollment may enroll if ≤24h therapy, or ≥48h with persistent/worsening HABP/VABP signs/symptoms at screening. * 9\. Women of childbearing potential must have a negative pregnancy test (serum or urine) prior to enrollment. * 10\. Male subjects must use highly effective contraception throughout the study period. Exclusion Criteria: * 1\. Subjects with known allergy to polymyxins or carbapenems, regardless of the severity of the reaction; or subjects with a severe hypersensitivity reaction to any other β-lactam agent. * 2\. Subjects who have received any investigational product within 3 months prior to enrollment, or subjects who have previously participated in this clinical study. * 3\. Has a baseline lower respiratory tract specimen Gram stain that shows the presence of Gram-positive cocci only. * 4\. Known or suspected pneumoni…