Inclusion Criteria:
* 1\. Able and willing to sign the ICF. If the subject is unable to do so, the family, a trusted person or a relative should provide consent, as per local regulations.
2\. Subjects with 18 years old, or older.
3\. Subjects with VAP, with stable ventilatory requirements defined as:
* PaO2/FiO2 not lower than 200 mm Hg;
* FiO2 ≤ 0.60
* Compliance not lower than 30 mL/cm H2O;
* Positive End-Expiratory Pressure (PEEP) equal or lower than 10 cm H2O;
* If receiving vasoactive drugs, these must be on a stable dose for the last 24 hours.
AND at least one of the following:
i. Hypoxemia \[e.g., PaO2\<60 mmHg while the patient is breathing room air, as determined by Arterial Blood Gas (ABG), or worsening of PaO2/FiO2\]; and/or ii. Need for acute changes in the ventilator support system to enhance oxygenation, as determined by worsening oxygenation (need to increase FiO2 by 20% or more to maintain oxygen saturation), or needed changes in the amount of PEEP; and/or iii. New onset of suctioned respiratory secretions.
AND at least one of the following signs:
iv. Documented fever (i.e., core body temperature \[tympanic, rectal, esophageal\] ≥ 38° C \[100.4ºF\], oral temperature ≥ 37.5°C \[99.5ºF\], or axillary temperature ≥ 37°C \[98.6ºF\]); and/or v. Hypothermia (i.e., core body temperature \[tympanic, rectal, esophageal\] ≤ 35°C \[95°F\]); and/or vi. White Blood Cell (WBC) count ≥ 10,000 cells/mm³; and/or vii. Leukopenia with total WBC count ≤ 4500 cells/mm³; and/or viii. Greater than 15% immature neutrophils (bands) noted on peripheral blood smear.
4\. Microbiological diagnosis of P. aeruginosa infection in the LRT, before randomization.
1. Diagnosis: cultures obtained by Endotracheal Aspirates (ETA), Mini Bronchoalveolar Lavage (BAL) or standard BAL throughout fiberoptic bronchoscopy, subjected to Gram staining and/or Polymerase Chain Reaction (PCR) test (e.g., BIOFIRE® FILMARRAY® Pneumonia Panel plus (Biomerieux)).
5\. Subjects with childbearing potential must have a negative highly sensitive serum pregnancy test at screening.
Exclusion Criteria:
* 1\. History of any cancer requiring systemic chemotherapy or radiation, in the 5 previous years.
2\. A condition that, in the opinion of the Investigator, could compromise the well-being of the subject, or the course of the study, or prevent the subject from meeting/performing any study requirements/procedures.
3\. Immunocompromised subjects due to illness, organ transplant, or immunosuppressive therapies (e.g., oral or parenteral corticosteroids, methotrexate, immunomodulators), in the last 3 months prior to screening.
4\. Treatment with ad hoc low dose inhaled corticosteroids, in the last 2 weeks prior to randomization (except hydrocortisone and equivalent doses of prednisone and methylprednisolone).
5\. Being pregnant or breastfeeding. 6. Currently participating in another clinical trial or having participated in a clinical trial with receipt of an IP in the last 30 days prior to randomization or in the last '5 half-lives of the IP' prior to randomization (whichever is longer).
7\. Subjects with known community-acquired bacterial pneumonia, or viral or fungal (including Pneumocystis jiroveci) pneumonia (except for subjects that had SARS-CoV-2 related pneumonia more than 6 months before randomization, that do not require Long-Term Oxygen Therapy (LTOT)), or tracheobronchitis (without documented pneumonia), or chemical pneumonitis, or post-obstructive pneumonia (except for subjects with a mild severity disease, that do not require pulmonary function tests); or tracheostomy (except for subjects that have tracheostomy performed while being hospitalised in the ICU).
8\. Subjects requiring Airway Pressure Release Ventilation or High Frequency Oscillatory Ventilation.
9\. Subjects with pleural effusions (or empyema) requiring therapeutic drainage, or lung abscess, or bronchiectasis; or cystic fibrosis, or acute exacerbation of chronic bronchitis, or active pulmonary tuberculosis; or with stage IV congestive heart failure, or cirrhotic liver disease.
