A Study to Explore the Efficacy and Safety of HWH486 in Adults With Chronic Spontaneous Urticaria

Inclusion Criteria:

1. Age ≥18, ≤70 years old;
2. Participants with chronic spontaneous urticaria (CSU) at the time of randomization asdefined by the following: presence of itch and hives for ≥ 6 consecutive weeks priorto screening, despite second generation H1-antihistamine during this period; UrticariaActivity Score (UAS7) (range 0-42) ≥16, Hives Severity Score (HSS7) (range 0-21) ≥ 6and Itch Severity Score (ISS7) (range 0-21) ≥ 6 during 7 consecutive days prior torandomization; CSU duration ≥6 months prior to screening (defined as the onset of CSUas determined by the investigator based on all available supporting documentation).
3. Willing and able to complete the Urticaria Participant Daily eDiary (UPDD) for theduration of the study;
4. Willing to take background medication and emergency medication according to the studyprotocol.

6. Written informed consent signed voluntarily by the patient or their legalrepresentatives.

Exclusion Criteria:

1. Previous use of HWH486 or other Bruton's tyrosine kinase(BTK) inhibitors;
2. Participants having a predominant or sole trigger of their chronic urticaria (chronicinducible urticaria);
3. Any other skin disease associated with chronic itching that might influence in theinvestigator's opinion the study evaluations and results, e.g. atopic dermatitis,bullous pemphigoid, dermatitis herpetiformis, senile pruritus or psoriasis
4. With symptoms or signs of progressive or uncontrolled kidney, liver, blood,gastrointestinal, endocrine, lung, heart, neurological, psychiatric, or brain disease,or with a history of gastrointestinal bleeding that is associated with a significantrisk of bleeding or coagulopathy, or is clinically significant (such as requiringhospitalization or blood transfusion), or with other chronic medical conditions thatare not eligible for participation in this clinical trial, or having a history ofmalignancy, other than non-metastatic basal cell carcinoma or skin squamous cellcarcinoma or carcinoma in situ of the cervix with appropriate treatment and no signsof recurrence;
5. Clinically important laboratory test indicators are abnormal, including: abnormalblood routine: hemoglobin (Hb) < 100g/L, or white blood cell count (WBC) < 3.5×10^9/L;Abnormal liver function: aspartate aminotransferase (AST) ≥1.5×ULN, or alanylaminotransferase (ALT) ≥1.5×ULN, or total bilirubin (TBIL) ≥1.5×ULN; Abnormal renalfunction: creatinine (Cr) ≥1×ULN; any other laboratory test indicators thatresearchers think may affect the evaluation of test results;
6. Active and uncontrolled viral and bacterial infections at the time of screening, suchas human immunodeficiency virus(HIV), hepatitis B virus(HBV), hepatitis C virus (HCV),syphilis, tuberculosis test results, or if there are any clinical symptoms ofbacterial, viral, parasitic or fungal infection requiring treatment;
7. Pregnant or breastfeeding women; having pregnancy plans during the clinical trial andwithin 1 month after the last dose, and do not want to take medically acceptedreliable contraceptive methods;
8. History of allergy to any investigational therapeutic drug or its excipients;
9. History or evidence of alcohol or drug abuse within the six months prior torandomization;
10. Use of other immunosuppressive drugs, including but not limited to hydroxychloroquine,methotrexate, cyclosporin A, cyclophosphamide, tacrolimus, mycophenolate,tripterygium, and compound glycyrrhizin, within 30 days or 5 half-lives (whichever isolder) prior to screening;
11. The investigator determines that the subjects have any conditions that make them unfitto participate in the experiment (such as weak health, poor compliance, etc.).