Inclusion Criteria:

• Patient is male or female and is 2 months to 24 months of age, inclusive.
• Patient has been diagnosed with IS within 6 weeks prior to Screening. Diagnostic criteria include both clinical spasms and an electroencephalogram (EEG) pattern consistent with hypsarrhythmia or significant abnormality compatible with IS.
  • NOTE: If a video EEG is performed at the clinical site within 48 hours prior to the patient's parent/guardian providing written informed consent, and it meets the criteria, this video EEG may be used as the screening/baseline EEG for the study.
• Patient has normal renal function as defined by an estimated glomerular filtration rate (eGFR).
• > 60 mL/min/1.73 m^2, calculated as eGFR = 0.413 x (height [cm]/ serum creatinine [mg/dL]).
• Patient's legally authodzed representative (i.e., parent or guardian) must provide written informed consent obtained per Institutional Review Board policy and requirements, consistent with the International Council for Harmonisation.
• Patient's parent/guardian is able to understand and willing to comply with study procedures and restrictions.

Exclusion Criteria:

• Patient has been diagnosed with tuberous sclerosis.
• Patient has acute illness considered clinically significant by the Investigator within 30 days prior to Screening.
• Patient has a diagnosis of recent systemic fungal infection; history of ocular herpes simplex; history of or current peptic ulcer; uncontrolled hypertension or congestive heart failure; or any other condition that would be significantly impacted by the study drug.
• Patient has a preplanned surgery or procedurc(s) that would interfere with the conduct of the study.
• Patient has received any prior treatment for IS.
• Patient has been previously treated with adrenocorticotropic honnonc (ACTH), corticosteroids, or vigabatrin for seizures.
• Patient has been previously treated with a course of corticosteroids for an indication other than seizures within 30 days prior to Screening.
• Patient has a known or suspected allergy to ACTH or vigabatrin or any component of AMZ002 or vigabatrin.
• Patient has used any other investigational drug within 30 days or 5 half-lives prior to the first dose of AMZ002 or vigabatrin (whichever is longer).
• Patient's parent/guardian is unable to provide written informed consent and/or to complete the daily diary.
• Patient has any other disease, condition, or therapy that, in the opinion of the Investigator, might compromise safety or compliance, preclude the patient from successfully completing the study, or interfere with the interpretation of the results.

Eligibility last updated 9/15/21. Questions regarding updates should be directed to the study team contact.