Study of HXN-1013 in Healthy Participants and Participants With Mild-to-Moderate Asthma

This is a Phase I, randomized, double-blind, placebo-controlled, single ascending dose study evaluating HXN-1013 in healthy participants and participants with mild-to-moderate asthma.

Inclusion Criteria: 1. Participants must be able to understand and comply with the study requirements and voluntarily sign the informed consent form (ICF). 2. (Healthy participants) Male or female aged 18 to 55 years (inclusive) at signing of the ICF. 3. (Healthy participants) Male participants weighing ≥ 50.0 kg or and female participants ≥ 45.0 kg, with a body mass index (BMI) between 18.0-32.0 kg/m² (inclusive). 4. (Participants with asthma) Participants must have documented physician-diagnosed asthma for ≥12 months, pre-bronchodilator FEV1 ≥60% predicted, objective evidence of variable airflow limitation, and well-controlled disease (GINA) on permitted stable background therapy. Exclusion Criteria: 1. Pregnant or breastfeeding women; women planning pregnancy within 180 days after dosing. 2. Active or suspected infection within 30 days prior to randomization; positive IGRA indicative of active tuberculosis; positive HIV, syphilis, HBsAg, or HCV antibody. 3. History of malignancy within 5 years (except resected basal/squamous cell carcinoma of the skin). 4. History of clinically significant hypersensitivity reactions (e.g., anaphylaxis, angioedema) to biologic agents or to study drug excipients. 5. Use of therapeutic antibodies within 5 half-lives prior to dosing; experimental agent within 30 days or 5 half-lives; live vaccines within 30 days or non-live vaccines within 14 days. 6. Clinically significant ECG abnormalities (e.g., QTcF ≥450 ms male / ≥470 ms female).