Efficacy and Safety of SR1375 in Adult Patients With CAP

Key Inclusion Criteria:

• The subject or their legally acceptable representative (LAR) has voluntarily signedthe informed consent form (ICF) prior to any study-related procedures, and thesubject is willing and able to comply with all study requirements, restrictions, andprocedures. If consent is provided by an LAR for a subject with limited or nocapacity to consent, re-consenting may be performed if the subject regains capacity.

• Aged 18 to 85 years.

• Diagnosis of CAP

• Prior to screening, the subject has been receiving standard-of-care treatment forpneumonia in a medical institution, including at least 3 days of intravenous (IV)anti-infective therapy, with no clinical improvement.

• Chest CT showing multi-lobar infiltrates, and for subjects not receiving invasivemechanical ventilation, an oxygenation index (PaO2/FiO2 ratio) between 100 and 300mmHg.

• Expected to require continued hospitalization for at least 7 days from the time ofsigning the ICF.

• Baseline NIAID-OS 8-point scale score of 5 points and transcutaneous oxygensaturation ≤ 93% without oxygen inhalation, 6 points or 7points. (5 points refer tohospitalization with oxygen therapy; 6 points refer to hospitalization with highflow oxygen therapy or non-invasive mechanical ventilation. 7 points refer tohospitalization with invasive mechanical ventilation).High oxygen flow refers to ≥ 4L/min.)

• With ≥ 1 high risk factors including chronic obstructive pulmonary disease (COPD),pulmonary fibrosis, type 2 diabetes, chronic kidney disease, coronary heart disease,age ≥ 65 years, moderate obesity (body mass index>32.5kg/m2), etc.

• Participants of women of childbearing potential(WOCBP) and male participants withWOCBP partners must agree to use one or more effective contraceptive methods duringthe treatment period and until 90 days after the last administration.

Key Exclusion Criteria:

• Patients who are currently receiving or are expected to require ECMO treatmentwithin 24 hours.

• Presence of active tuberculosis (TB) or severe asthma.

• History of unstable angina or acute myocardial infarction within 3 months prior toscreening, or stroke within 4 weeks prior to screening.

• Received chemotherapy and/or immunotherapy for a malignant tumor within 4 weeksprior to randomization, or are planned to receive such treatment during the studyperiod; presence of a hematological malignancy not in complete remission; or a lungtumor with concurrent obstructive pneumonia.

• Presence of any concomitant disease that is expected to result in death within 12weeks after randomization.

• Prior use of JAK inhibitors (e.g., Baricitinib), interleukin receptor inhibitors (e.g., Tocilizumab), or any investigational drug in another clinical trial, wherethe last dose was administered less than 5 half-lives before the first dose of thestudy drug in this trial.

• ALT) or AST > 3 times the upper limit of normal (ULN).

• eGFR < 30 mL/min/1.73 m² (calculated using the Chronic Kidney Disease EpidemiologyCollaboration [CKD-EPI] formula); however, patients undergoing dialysis may beincluded upon the investigator's assessment of their suitability for the trial.

• Presence of clinically significant abnormalities on ECG that may seriously affectsubject safety, e.g., QTcF > 480 ms.

• Female subjects who are pregnant, lactating, or have a positive serum β-HCGpregnancy test.

• Presence of any severe systemic disease or clinical condition that, in theinvestigator's judgment, makes the subject unsuitable for participation in thisstudy.