A Study to Evaluate Safety and Efficacy of AMZ002 Treatment, Compared With Vigabatrin in Participants With Infantile Spasms

• AMZ002 injectable solution, 0.5mg/mL (Drug): Injectable solution
• Vigabatrin, oral (Drug): Oral administration

Primary outcomes

• Proportion of Participants with Absence of Clinical Spasms as Assessed by Video Electroencephalogram (EEG) at Day 14 [At Day 14]
• Proportion of Participants with Resolution of Hypsarrhythmia or Significant Abnormality Compatible with Infantile Spasms (IS) as Assessed by Video EEG at Day 14 [At Day 14]

Secondary outcomes

• Time from Treatment Initiation to Absence of Clinical Spasms as Assessed by Parent/Guardian Diary [Baseline up to Day 58]
• Proportion of Participants with Absence of Clinical Spasms as Assessed by Parent/Guardian Diary at Day 14 [At Day 14]
• Proportion of Participants with Recurrence of Clinical Spasms After Initial Response as Assessed by Video EEG/ by Parent/Guardian Diary [From Day 14 up to Day 58]
• Time from Initial Response to Recurrence of Clinical Spasms [From Day 14 up to Day 58]

Sex: All, ages: 2 Months to 24 Months

Inclusion Criteria:

* Participant has been diagnosed with IS within 6 weeks prior to Screening. Diagnostic criteria include both clinical spasms and an EEG pattern consistent with hypsarrhythmia or significant abnormality compatible with IS
* Participant has normal renal function as defined by an estimated glomerular filtration rate (eGFR) greater than \[>\] 60 milliliter/minute (mL/min)/1.73 m\^2, calculated as eGFR = 0.413 × (height \[Centimeter (cm)\]/serum creatinine \[milligrams per deciliter {mg/dL}\])
* Participant's legally authorized representative (that is \[i.e.\], parent or guardian) must provide written informed consent obtained per Institutional Review Board (IRB) policy and requirements, consistent with the International Council for Harmonisation (ICH)
* Participant's parent/guardian is able to understand and willing to comply with study procedures and restrictions

Exclusion Criteria:

* Participant has been diagnosed with tuberous sclerosis
* Participant has acute illness considered clinically significant by the Investigator within 30 days prior to Screening
* Participant 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
* Participant has a preplanned surgery or procedure(s) that would interfere with the conduct of the study
* Participant has received any prior treatment for IS
* Participant has been previously treated with adrenocorticotropic hormone (ACTH), corticosteroids, or Vigabatrin for seizures;
* Participant has been previously treated with a course of corticosteroids for an indication other than seizures within 30 days prior to Screening
* Participant has a known or suspected allergy to ACTH or Vigabatrin or any component of AMZ002 or Vigabatrin
* Participant 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)
* Participant' s parent/guardian is unable to provide written informed consent and/or to complete the daily diary
* Participant has any other disease, condition, or therapy that, in the opinion of the Investigator, might compromise safety or compliance, preclude the participant from successfully completing the study, or interfere with the interpretation of the results