A Prospective, Single-centre, Observational Cohort Study on the Efficacy and Safety of Bacterial Lysate (OM-85) in Combination With Antihistamines for the Treatment of Chronic Spontaneous Urticaria (CSU)

A Prospective Clinical Study on the Efficacy and Safety of Bacterial Lysate (OM-85) Combined With Antihistamines in the Treatment of Chronic Spontaneous Urticaria (CSU): A Single-Centre, Observational, Cohort Study

A Prospective Clinical Study on the Efficacy and Safety of Bacterial Lysate (OM-85) Combined with Antihistamines in the Treatment of Chronic Spontaneous Urticaria (CSU): A Single-Centre, Observational, Cohort Study

Study Overview

• Status: Not yet recruiting
• Conditions: Chronic Spontaneous Urticaria (CSU)

• Study Type: Observational
• Enrollment (Estimated): 132

Contacts and Locations

• Study Contact: Name: Liu; Phone Number: 0579-89979999; Email: 2197055@zju.edu.cn

Study Locations

• China
  • Zhejiang
    • Yiwu, Zhejiang, China, 322000
      • The Fourth Affiliated Hospital Zhejiang University School of Medicine
      • Contact: Liu; Phone Number: 0579-89979999; Email: 2197055@zju.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The inclusion and exclusion criteria for the study participants are as set out above

Description

Inclusion Criteria:

1. The participants were fully informed of the purpose, procedure and risks of the study and voluntarily signed the informed consent form.
2. Aged 18 to 65 (inclusive), no gender restrictions.
3. Meets the CSU diagnostic criteria, with a disease duration of ≥6 weeks.
4. Antihistamine resistance: Regular use of a standard dose (as recommended in the package leaflet) of a second-generation H1 antihistamine (e.g. desloratadine 5 mg, levocetirizine 5 mg, etc.) for at least 2 weeks prior to screening, but with symptoms still not effectively controlled. Defined as: a UAS7 score of ≥7 within 7 days prior to the screening visit (V1) and baseline visit (V2).
5. Agree to maintain the type and dose of the baseline antihistamine throughout the trial.
6. Agree not to consume any products that may significantly affect the gut microbiota during the trial (such as yoghurt containing probiotics, or probiotic/prebiotic supplements).
7. At the baseline visit, the treatment regimen was clearly defined, and exposure status (OM-85 exposure group or non-exposure group) could be determined based on actual prescriptions and medication records.

Exclusion Criteria:

1. Special types of urticaria: These primarily include physical urticaria (such as artificial urticaria, cold contact urticaria and cholinergic urticaria), urticarial vasculitis, and angioedema caused by hereditary or acquired C1 esterase inhibitor deficiency;
2. Systemic use of glucocorticoids (oral or injectable) within the four weeks prior to screening;
3. Exclude patients who have used immunosuppressants (such as cyclosporine, methotrexate, or Tripterygium wilfordii) within the previous four weeks;
4. Exclude patients who have used biologics (such as omazulimab, dupilumab, etc.) within the previous three months;
5. Exclude those who have used bacterial lysates (such as Panfuxu or Pidomod) or received vaccinations within the past three months;
6. Key exclusion criteria for the microbiome study: use of oral or intravenous antibiotics within the four weeks prior to screening, or continuous use of probiotic supplements for more than one week.
7. Patients with severe systemic autoimmune diseases (such as systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, etc.) may interfere with the assessment of immune mechanisms;
8. A history of serious liver, kidney, heart, lung or blood disorders, or malignant tumours;
9. Individuals known to be allergic to bacterial lysates and their excipients.
10. Special populations: pregnant or breastfeeding women, or participants of childbearing age who do not intend to use contraception during the trial.
11. Other: Participants who have taken part in other clinical trials involving medicinal products within the past 30 days; or where the investigator considers that there is poor compliance, a mental health condition, or any other circumstance rendering the participant unsuitable for the trial.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Exposure group; Bacterial lysate capsules + second-generation antihistamines (loratadine tablets, cetirizine hydrochloride tablets, levocetirizine hydrochloride tablets, ebastine tablets, olopatadine hydrochloride tablets, fexofenadine hydrochloride tablets)
Non-exposure group; Second-generation antihistamines (loratadine tablets, cetirizine hydrochloride tablets, levocetirizine hydrochloride tablets, ebastine tablets, olopatadine hydrochloride tablets, fexofenadine hydrochloride tablets)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
UAS7 score at week 12 of treatment (90 days)	Assessed using the 7-day Urticaria Activity Score (UAS7)，score is calculated between 0 (best score possible) and 42 (worstscore possible), compared with baseline	From baseline to weeks 4, 8, and 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of subjects with UAS7 ≤ 6 at week 12 of treatment (disease well controlled)	Assessed using the 7-day Urticaria Activity Score (UAS7)，score is calculated between 0 (best score possible) and 42 (worstscore possible)	Week 12 (90 days)
Changes in the CU-Q2oL score	Assessed using the Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL)，score is calculated between 0 (best score possible) and 92 (worst score possible)	From baseline to week 12
Proportion of subjects with UCT ≥ 12 at week 12 of treatment	Assessment using the Urticaria Control Test (UCT), score is calculated between 0 (worst score possible) and 16 (best score possible). A UCT score of 12 or higher indicates that chronic urticaria is well controlled	From baseline to weeks 4, 8, and 12

Collaborators and Investigators

• Sponsor: The Fourth Affiliated Hospital of Zhejiang University School of Medicine

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): June 1, 2027

Study Registration Dates

• First Submitted: April 22, 2026
• First Submitted That Met QC Criteria: April 22, 2026
• First Posted (Actual): April 30, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Immune System Diseases; Hypersensitivity, Immediate; Hypersensitivity; Skin Diseases; Urticaria; Skin Diseases, Vascular; Pathological Conditions, Signs and Symptoms; Skin and Connective Tissue Diseases; Chronic Urticaria
• Other Study ID Numbers: KY-2026-081

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No