This open-label study will evaluate the pharmacodynamic and pharmacokinetic profile of CM4620-IE in patients with acute pancreatitis. The first five (5) patients will receive ≤ 2.08 mg/kg of CM4620-IE by continuous IV infusion on Day 1. If necessary, up to an additional 4 patients may be treated at a different dose of CM4620-IE as determined by the obtained PK and PD data. The infusion of CM4620-IE will start within 12 hours from the time the patient or LAR provides informed consent.

Inclusion Criteria:

1. Diagnosis of acute pancreatitis established by the presence of abdominal pain consistent with acute pancreatitis, and 1 of the following 2 criteria:

   1. Serum lipase and/or serum amylase > 3 times the upper limit of normal (ULN);
   2. Characteristic findings of acute pancreatitis on abdominal imaging;

2. Adults ≥ 18 years of age;

3. A female patient of child-bearing potential who is sexually active with a male partner must be willing to practice acceptable methods of birth control for 365 days after the last dose of CM4620-IE;

4. A male patient who is sexually active with a female partner of childbearing potential must be willing to practice acceptable methods of birth control for 365 days after the last dose of CM4620-IE and must not donate sperm for 365 days;

5. Willing and able to, or have a legal authorized representative (LAR) who is willing and able to, provide informed consent to participate, and cooperate with all aspects of the protocol.

Exclusion Criteria:

1. Any concurrent clinical condition that a study physician believes could potentially pose an unacceptable health risk to the patient while involved in the study or may limit expected survival to < 6 months;

2. Suspected presence of cholangitis in the judgment of the treating investigator;

3. Any malignancy being treated with chemotherapy or immunotherapy;

4. Any autoimmune disease being treated with immunosuppressive medication or immunotherapy (Section 5.3 for list of prohibited medications);

5. History of:

   1. Chronic pancreatitis, pancreatic necrosectomy, or pancreatic enzyme replacement therapy;
   2. Biopsy proven cirrhosis, portal hypertension, hepatic failure/hepatic encephalopathy;
   3. Known hepatitis B or C, or HIV;
   4. History of organ or hematologic transplant;
   5. Myocardial infarction, revascularization, cardiovascular accident (CVA) in the 30 days prior to Day 1;

6. Current renal replacement therapy;

7. Current known abuse of cocaine or methamphetamine;

8. Known to be pregnant or are nursing;

9. Participated in another study of an investigational drug or therapeutic medical device in the 30 days prior to Day 1;

10. History of allergy to eggs or known hypersensitivity to any components of CM4620-IE;

11. Prior treatment with CM4620-IE.

Adverse event data were collected over 90 days per subject, from the start of dosing until the 30-day follow-up.