The objective of this study is to evaluate the effect of LJPC-501 infusion on mean arterial pressure (MAP) or reduction in sum norepinephrine (NE) equivalent dosing, at Hour 2 after the start of LJPC-501, in pediatric patients who remain hypotensive despite receiving fluid therapy and vasopressor therapy. In addition, this study will evaluate the safety and tolerability of LJPC-501 in pediatric patients, the change in MAP over 24 hours after the start of LJPC-501, the change in serum lactate concentrations, and the change in Pediatric Logistic Organ Dysfunction (PELOD) scores.

Inclusion Criteria:

1. Pediatric patients 2-17 years of age.
2. Patients requiring a total sum NE equivalent dose of > 0.1 μg/kg/min for a minimum of 2 hours and a maximum of 48 hours prior to initiation of LJPC-501 dosing.
3. Patients must have clinical diagnosis of distributive shock in the opinion of the treating team and the Investigator.
4. Patients are required to have central venous access, which is expected to remain present for the duration of LJPC-501 treatment.
5. Patients are required to have an indwelling arterial line, which is expected to remain present for at least the first 24 hours of LJPC-501 treatment.
6. Patients must have received at least 40 mL/kg of crystalloid or colloid equivalent over the initial 24-hour resuscitation period, and are adequately volume resuscitated in the opinion of the Investigator.
7. Parent or legal guardian is willing and able to provide informed consent and assist the patient in complying with all protocol requirements.

Exclusion Criteria:

1. Patients who are < 2 years of age or ≥ 18 years of age.
2. Patients with a standing Do Not Resuscitate order.
3. Patients diagnosed with acute occlusive coronary syndrome requiring pending intervention.
4. Patients on veno-arterial (VA) extracorporeal membrane oxygenation (ECMO).
5. Patients who have been on veno-venous (VV) ECMO for less than 6 hours.
6. Patients with a clinical suspicion of cardiogenic shock.
7. Patients who have a history of asthma or are currently experiencing bronchospasm requiring the use of inhaled bronchodilators and who are not mechanically ventilated.
8. Patients with acute mesenteric ischemia or a history of mesenteric ischemia.
9. Patients with active bleeding AND an anticipated need of multiple transfusions (within 48 hours of Screening).
10. Patients with active bleeding AND hemoglobin < 7 g/dL or any other condition that would contraindicate serial blood sampling.
11. Patients with an absolute neutrophil count (ANC) of < 500 cells/mm3.
12. Patients requiring more than 5 mg/kg daily of hydrocortisone or equivalent glucocorticoid medication as a standing dose.
13. Patients with an expected lifespan of < 12 hours or withdrawal of life support within 24 hours of Screening.
14. Patients with a known allergy to mannitol.
15. Patients who are currently participating in another investigational clinical trial.
16. Patients of childbearing potential who are known to be pregnant at the time of Screening.