This phase IIa trial is meant to evaluate the pharmacokinetics, pharmacodynamics and safety of JYB1904 in patients with allergic asthma.

Inclusion Criteria:

• Able to provide written informed consent voluntarily;
• Aged 18-75 years, weight ≥ 40 kg, male or female;
• Diagnosed Allergic asthma.

Exclusion Criteria:

• Prior exposure to anti-IgE therapy within 1 year;
• Allergic to anti-IgE biologics;
• Current smokers, or quit smoking within 1 year;
• Combined with other non-allergic diseases that cause IgE elevation；
• History of malignancy, autoimmune diseases, Immune complex mediated diseases, Hypereosinophilic syndrome;
• Other conditions unsuitable for the trial judged by the investigator.