A Phase 2 Randomized Double-blind Placebo-controlled Study To Evaluate The Efficacy And Safety Of Adjunctive Recombinant Human Plasma Gelsolin With Standard Care For Moderate-to-Severe ARDS Due To Pneumonia Or Other Infections

Potential subjects hospitalized with pneumonia or other infections are to be screened within 24 hours of diagnosis of ARDS. The Sponsor aims to identify as early as possible patients in the hospital who have developed acute hypoxemic respiratory failure within 7 days of the precipitating infection (often fever, rigors, chills, increased heart rate, increased respiratory rate, pain, cough, etc.) leading to ARDS resulting in mechanical or noninvasive ventilation or high-flow nasal oxygen (HFNO) supplementation with ≥50% O2 at a flow rate of ≥30 L/min. Patients who do not qualify for the study at the initial screening visit because of mild ARDS may subsequently progress to moderate-to-severe ARDS and should be reassessed at least daily for the 7 days following the precipitating infection.

Once informed consent is obtained, the following assessments/procedures will be performed:

1. Confirm the potential participant has acute hypoxemic respiratory failure qualifying as moderate-to-severe ARDS for ≤48 hours following a suspected or confirmed infection within the preceding week. Moderate-to-severe ARDS is defined by the calculated or estimated ratio of arterial pressure of O2 to the fraction of inspired O2 [P/F ratio] ≤150. The P/F ratio will be computed from the most recent arterial blood gas obtained no more than 12 hours earlier than randomization. For potential subjects on high-flow nasal oxygen with ≥50% O2 at a flow rate of ≥30 L/min, the P/F ratio will be estimated assuming 50% delivered O2. If eligible and entered in the trial, the following steps should be taken.
2. Record medical history, including concomitant medications and current clinical status. Specify the site and etiology (if known) of infection, indicating if the lung ("direct ARDS") or another organ ("indirect ARDS") is the primary site of infection.
3. Perform pregnancy test (urine or blood) for women of childbearing potential if not already performed during the current hospitalization.
4. Collect pretreatment blood samples for measurement of baseline pGSN and analysis of antibodies against pGSN.
5. Perform physical examination and document results of the chest x-ray (CXR) and/or computed tomography (CT) scan, if CXR is inadequate if not already available as per SOC.
6. Obtain blood and sputum cultures and electrocardiogram (EKG) per SOC (if not already performed). Document the site of infection by collecting specimens as indicated: sputum (bacterial, viral, and mycobacterial, as indicated) and blood cultures, sputum Gram-stains, antigen detection on respiratory and urine specimens, and syndromic nucleic acid amplification tests (NAATs) on respiratory specimens (including a viral and other respiratory pathogen polymerase chain reaction [PCR] panel), where possible. Other specimens from possible sites of infection (e.g., urine, intra-abdominal drainage, skin or soft-tissue abscesses) should be cultured when available.
7. Measure routine lab tests at local (hospital) laboratory per local custom/SOC collect aliquots f- blood for subsequent biomarker assays (including, but not limited to C-reactive protein [CRP], procalcitonin, interleukin [IL]1β, IL6, IL10, and tumor necrosis factor [TNF]) for analysis at the central laboratory.
8. If eligibility criteria are satisfied, the subject will be randomized 1:1 (rhu-pGSN:placebo) by site to a treatment group and treated within 12 hours of randomization and no later than 48 hours after the diagnosis of moderate-to-severe ARDS.

Randomized subjects will receive the assigned dose of rhu-pGSN or an equal volume of visibly indistinguishable sterile saline placebo as soon as possible but beginning no later than 48 hours after the diagnosis of moderate-to-severe ARDS. After reconstitution, rhu-pGSN is not to be kept at room temperature for >2 hours prior to beginning study drug administration.

A single loading dose of rhu-pGSN at 24 mg/kg followed by 5 daily doses of rhu-pGSN at 12 mg/kg of measured or estimated actual body weight starting 24 hours after the loading dose or an equal volume of indistinguishable saline placebo will be administered. A window of ±2 hours will be allowed around dosing times. Study drug is administered by an IV push through a 0.2 μm filter. The syringe, filter, and extension tubing for administration of study drug are to be connected as close to the subjects as possible.