The purpose of this study is to evaluate the safety, tolerability, PK, and PD following subcutaneous injections of YH35324 in atopic healthy subjects or adult subjects with mild allergic diseases. Eligible subjects will be randomized to the YH35324 group, the placebo group, or the omalizumab group.

YH35324 is a drug under development as a novel therapeutic agent for various IgE-mediated allergic diseases. Since YH35324 has a high binding affinity to human IgE, it prevents serum IgE from binding to receptors on mast cells and basophil, thereby inhibiting histamine release caused by degranulation when exposed to allergens Based on its non-clinical study results, this study aims to evaluate the safety, tolerability, PK, and PD following subcutaneous injections of YH35324 in atopic healthy subjects or subjects with mild allergic diseases.

Inclusion Criteria:

• 19~55 years old, Atopic Healthy Subjects or Subjects With Mild Allergic Diseases
• Serum total IgE level of 30 to 700 IU/mL or > 700 IU/mL
• Signed the informed consent form

Exclusion Criteria:

• Hyperimmunoglobulin E syndrome or malignancy
• Positive drug screen result
• AST or ALT > 1.5 * Upper normal range
• eGFR < 60mL/min/1.73m2
• Allergy immunotherapy initiated or Administration of a live vaccine within 3 months prior to randomization
• History of participation in another clinical trial within 6 months prior to randomization

De-identified individual participant data (including data dictionaries) that underline the results reported in study-related publications will be made available during the period beginning 1 year and ending 5 years after all trial primary and secondary endpoints were assessed. Only requests from researchers who provide a methodologically sound proposal will be reviewed and approved by the sponsor. The analysis type should be in accordance with aims in the proposal approved by the sponsor. Proposals should be directed to yhcho@yuhan.co.kr.

A summary of the study results will be posted in the publicly accessible database (i.e. clinicaltrials.gov) no later than 1 year after the study's primary completion date.

Beginning 1 year and ending 5 years after all trial endpoints were assessed

Only requests from researchers who provide a methodologically sound proposal will be reviewed and approved by the sponsor. The analysis type should be in accordance with aims in the proposal approved by the sponsor. Proposals should be directed to yhcho@yuhan.co.kr.