The study was prematurely terminated by the Sponsor based on difficulties in meeting enrollment goals, especially during the COVID-19 pandemic, and not for reasons relating to any concerns regarding quality, safety, or efficacy.

To determine the efficacy and safety of AR201 in a characterized oral desensitization immunotherapy (CODIT™) regimen in hen egg-allergic subjects aged 4 to 26 years, inclusive.

This is a phase 2, randomized, double-blind, placebo-controlled study of the efficacy and safety of AR201 in a CODIT regimen in hen egg-allergic subjects aged 4 to 26 years, inclusive. The study was conducted at 8 sites in the United States.

Key Inclusion Criteria:

• Age 4 to 26 years, inclusive
• Written informed consent from subjects, as appropriate per local requirements, and parent/guardian
• Written assent from subjects who are minors, as appropriate per local requirements
• History of physician-diagnosed hen egg allergy
• Elevated egg specific IgE and/or mean wheal diameter on SPT to egg
• Experience dose-limiting symptoms at or before the 300 mg challenge dose of dried egg white protein on Screening DBPCFC
• Use of effective birth control by sexually active female subjects of childbearing potential

Key Exclusion Criteria:

• History of severe or life-threatening anaphylaxis within 60 days before screening
• History of non-IgE mediated hen egg allergy such as food protein-induced enterocolitis syndrome (FPIES)
• History of eosinophilic esophagitis (EoE), other eosinophilic gastrointestinal disease, chronic, recurrent, or severe gastroesophageal reflux disease (GERD), symptoms of dysphagia or recurrent gastrointestinal symptoms of unknown etiology
• History of a mast cell disorder including systemic mastocytosis, urticaria pigmentosa, chronic idiopathic or chronic physical urticaria beyond simple dermatographism (e.g., cold urticaria, cholinergic urticaria), and hereditary or idiopathic angioedema
• History of chronic disease (except asthma, atopic dermatitis, or allergic rhinitis) which may require a change in immunosuppressive medication regimen or chronic corticosteroid use
• History of cardiovascular disease, including uncontrolled or inadequately controlled hypertension
• Developing dose-limiting symptoms to placebo challenge during the Screening DBPCFC
• Having the same place of residence as another subject in the study
• Any other condition that, in the opinion of the Investigator, precludes participation for reasons of safety

Double-Blinded