A Study to Evaluate the Efficacy and Safety of CC-93538 in Adult and Adolescent Japanese Participants With Eosinophilic Gastroenteritis

Inclusion Criteria:

1. Histologic evidence of eosinophilic gastroenteritis (EGE) defined as ≥ 30 eosinophils (eos)/high-power field (hpf) in at least 5 hpf in the stomach and/or ≥ 30 eos/hpf in at least 3 hpf in the duodenum while on stable background therapy for EGE
2. Has weekly symptom scores of ≥ 4/15 for any of Gastric Pain Symptoms domain, Stomach Heaviness Symptom domains, and /or Diarrhea Symptoms domain as assessed by the Izumo Scale with electronic device for the 2 consecutive weeks before Day 1
3. Must agree to maintain a stable diet from the first Screening Visit and throughout the duration of the study, and participants must have maintained a stable diet for at least 4 weeks prior to the first Screening Visit
4. Females of childbearing potential must have 2 negative pregnancy tests as verified by the Investigator prior to starting study therapy and agree to practice a highly effective method of contraception until 5 months after the last dose

Exclusion Criteria:

1. Ascites requiring treatment or symptomatic ascites
2. History of inflammatory bowel disease, achalasia or esophageal surgery
3. Has other causes of gastric and/or duodenal eosinophilia or eosinophilic granulomatosis with polyangiitis (EGPA)

Other protocol-defined inclusion/exclusion criteria apply