This study is researching an experimental drug called REGN7544 (called "study drug"). The study is focused on adult patients (18 to 85 years) hospitalized due to a serious infection (called "sepsis") and receiving standard-of-care medications for low blood pressure (called "vasopressors") due to sepsis.

The aim of the study is to see how safe, tolerable, and effective the study drug is by observing the effects on blood pressure and the total amount of vasopressor dose received during the stay in the hospital.

The study is looking at several other research questions, including:

• How the study drug changes the blood pressure and the amount of intravenous (IV) fluids given to participants with low blood pressure due to sepsis
• What side effects may happen from taking the study drug
• How much study drug is in the blood at different times
• Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)

Key Inclusion Criteria:

1. Proven or suspected infection defined as administration or planned administration of antimicrobial therapy within the screening period
2. Sepsis-induced hypotension that has not responded to Intravenous (IV) fluids, receiving 1 or 2 vasopressors and maintaining a Mean Arterial Pressure (MAP) of ≥ 65 mm Hg for at least 2 consecutive hours immediately prior to randomization, as defined in the protocol

Key Exclusion Criteria:

1. Unable to obtain informed consent by participant or Legally Authorized Representative (LAR)
2. Clinical status requires vasopressor and/or Blood Pressure (BP) management inconsistent with the study protocol
3. Primary cause of hypotension suspected to be due to non-sepsis cause (eg, hemorrhage, burns, or cardiogenic shock), including shock after cardiac arrest
4. Ejection fraction <20% in the most recent known echocardiogram
5. Acute coronary syndrome based on clinical symptoms and/or electrocardiogram (ECG) during hospitalization
6. History of hospitalization due to heart failure, myocardial infarction, stroke, clinically significant ventricular arrhythmia, transient ischemic attack, or unstable angina within the preceding 3 months
7. Any prior diagnosis of severe pulmonary hypertension, as defined in the protocol
8. Receiving 3 or more vasopressors or exceeding the maximal combined dose as defined in the protocol, during the screening period or at the time of study drug administration
9. Received bone marrow transplant during the preceding 6 months or chemotherapy during the preceding 30 days for lymphoma or leukemia

NOTE: Other Protocol-Defined Inclusion-Exclusion Criteria Apply

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf