Ethics statement
The study protocol was approved by the Ethics Committee of Chengdu Hospital of Integrated Traditional Chinese and Western Medicine (Approval No. 2024KT019). The trial was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants. All the materials used in this study are listed in the Table of Materials.
Study design and participants
This was a prospective, randomized, open-label, parallel-group, single-center trial conducted between June 2024 and December 2024. Eligible patients with severe allergic asthma were enrolled. Diagnosis and severity were based on national and international asthma guidelines1,17. The inclusion and exclusion criteria were as follows:
Inclusion criteria
Eligible participants were adults aged 18–65 years with physician-diagnosed severe allergic asthma who exhibited typical symptoms, including wheeze, breathlessness, chest tightness, and cough. Variable airflow limitation was confirmed by spirometry, and allergic sensitization was documented by either a positive skin prick test or elevated serum allergen-specific IgE levels. All participants had been receiving a stable medium-to-high dose inhaled corticosteroid/long-acting β₂-agonist (ICS/LABA) regimen for at least 3 months, and all participants’ total serum IgE levels fell within the approved dosing range for omalizumab.
Exclusion criteria
Participants were excluded if they had received any biologic therapy, including anti-IgE, anti-interleukin-5 (IL-5)/IL-5 receptor, or anti-interleukin-4 receptor α (IL-4Rα) agents, within the previous 12 months; required maintenance oral corticosteroid therapy; or had experienced an acute asthma exacerbation within the preceding 4 weeks. Additional exclusion criteria included a history of smoking, pregnancy or lactation, severe hepatic, renal, or cardiovascular disease, skin diseases at the intended acupoint sites, or known hypersensitivity to any of the herbal components.
Sample size
The sample size was calculated based on the primary outcome, the change in Asthma Control Test (ACT) score from baseline to week 16. Assuming a clinically meaningful between-group difference of 2.5 points and a standard deviation (SD) of 3.0 (derived from previous pilot data6,7,14), a two-sided alpha of 0.05, and 80% power required 23 participants per group. To account for an anticipated attrition rate of approximately 15%, enrollment of 26 participants per group was required, yielding a total sample size of 52.
Randomization and grouping
A computer-generated simple random sequence (1:1) was prepared by an independent team member (YT), who was not involved in recruitment, intervention delivery, or assessment. Allocation was concealed in sequentially numbered, opaque, sealed envelopes (SNOSE). After eligibility confirmation and consent, a second team member (YY) opened the next envelope and assigned the participant to it. Because of the visible and tactile nature of acupoint plaster application, blinding of participants and clinicians was not feasible. Outcome assessors and data analysts were also not blinded. The lack of blinding and sham-control is acknowledged as a limitation and discussed in the discussion section.
Background and concomitant therapy
Throughout the 16‑week intervention period, all participants maintained a fixed background asthma therapy comprising regular inhaled budesonide/formoterol (320/9 μg, one inhalation twice daily). For acute exacerbations, all participants were allowed to use the same budesonide/formoterol formulation (320/9 μg) as rescue medication on an as‑needed basis, with a maximum of 8 inhalations per day, and each use was meticulously recorded. Montelukast (10 mg once daily) was permitted as a concomitant medication, and its use remained stable from baseline through the entire follow-up period. All participants had no history of biologic agent use within the previous 12 months, no oral corticosteroid use within the previous 4 weeks prior to study enrollment, and no modifications to the baseline asthma regimen during the 16‑week trial period.
Omalizumab administration
Omalizumab was administered subcutaneously to all participants. Dose (75–600 mg per administration, divided into 1–4 injections as required) and dosing interval (every 2 or 4 weeks) were determined from baseline total serum IgE and body weight using the approved dosing table for adults and adolescents (≥12 years), per product labeling. The maximum recommended dose was 600 mg every 2 weeks. Participants whose baseline IgE or weight fell outside the approved ranges in the table were excluded. Injections were administered by designated registered nurses into the lateral deltoid muscle (alternating arms). Participants were observed for at least 2 h after the first dose, and for 30 min after each subsequent dose. If a dose is missed, it may be administered at the original dose within 3 days of the scheduled time. Any delay exceeding 3 days requires review and assessment by the study physician.
Preparation of the acupoint plaster
The herbal formulation was based on the classical prescription Bai-Jie-Zi-Gao (white mustard seed paste). The formula comprised four herbal components with the following specifications: Asarum heterotropoides var. mandshuricum, commonly known as Xi Xin, was used in the form of root and rhizome at a dose of 10 g. Euphorbia kansui, known as Gan Sui, was included as root material at 10 g. Sinapis alba L., referred to as Bai Jie Zi (white mustard seed), was stir-fried and used as seed material at 20 g. Corydalis yanhusuo W.T. Wang, known as Yan Hu Suo, was incorporated as tuber material at 20 g. All herbal materials were obtained from a single Good Manufacturing Practice-certified supplier and authenticated by a qualified Traditional Chinese Medicine pharmacist according to the Pharmacopeia of the People's Republic of China (2020 edition). Voucher specimens were retained for reference.
All herbs were obtained from a single GMP-certified supplier and authenticated by a qualified TCM pharmacist in accordance with the Pharmacopeia of the People's Republic of China (2020 edition). Voucher specimens were retained. Each batch was ground to a fine powder (< 100 mesh, ~150 µm) under controlled humidity. Fresh ginger (Zingiber officinale Roscoe) rhizome was washed, peeled, and pressed; the juice was filtered through sterile gauze and used within 4 h. Powder and ginger juice were mixed at a ratio of 1 g powder: 1 mL juice to form a homogeneous paste of moderate viscosity. Approximately 1.5 g of paste per acupoint (≈10 g total per session) was spread evenly onto disposable adhesive patches (60 × 70 mm) to a thickness of 2 mm, as verified with a calibrated thickness gauge. Patches were stored at 4 °C, protected from light, and used within 8 h of preparation.
Acupoint application procedure
Acupoints were selected per the WHO Standard Acupuncture Point Locations in the Western Pacific Region18. The points used were bilateral Feishu (BL13), bilateral Dingchuan (EX-B1), bilateral Fengmen (BL12), bilateral Zhongfu (LU1), and the midline points Tanzhong (CV17) and Tiantu (CV22). A schematic of acupoint locations is provided in Figure 1A–B. All applications were performed by a certified TCM practitioner with ≥5 years of clinical experience. Participants were seated upright with the back exposed. The skin at each acupoint was cleaned with 75% ethanol and allowed to dry. Patches were applied between 09:00 and 11:00 to align with circadian and traditional timing for acupoint therapies. Sessions were delivered three times weekly (Monday/Wednesday/Friday) for 16 consecutive weeks. Patches were retained until the participant reported localized warmth or mild flushing, typically within 1–2 h. The objective criteria for patch removal were: local erythema; stinging or burning sensation reported by the participant; elapsed time of 2 h, whichever occurred first (Figure 1C).
Safety monitoring of acupoint plaster
A skin tolerance test was performed before the first session by applying a small amount of the prepared paste to the inner forearm for 30 min; participants with marked local reactions were excluded. Contraindications included pregnancy, broken or inflamed skin at application sites, severe atopic dermatitis, and known allergy to any formulation component. A patch was considered to have detached early if it dislodged within 30 min of application; in such cases, the patch was reapplied once if the skin was intact. Local skin reactions were graded on a four-level scale: Grade 1, transient erythema or itching resolving <2 h; Grade 2, persistent erythema lasting >2 h without blistering; Grade 3, small blisters (<5 mm) or moderate burning; Grade 4, large blisters, ulceration, or systemic allergic features. Grade 1 reactions were managed by observation; Grade 2 by withholding the next session and topical care; Grade 3–4 reactions prompted study-physician evaluation, treatment, and protocol-specified discontinuation. Adverse events were collected through treatment sites, scheduled visits, telephone follow-up, and participant diaries. Each event was graded for severity (mild/moderate/severe), duration, action taken, and relationship to the study intervention (unrelated, unlikely, possibly, probably, definitely related), and assessed by an independent investigator using prespecified criteria.
Outcome assessment
Assessments were performed at baseline (week 0), week 8, and week 16. An asthma exacerbation was defined as an acute worsening of wheezing, dyspnea, cough, or chest tightness that exceeded the patient's usual day‑to‑day variation and required an increase in asthma medication. To minimize confounding from differential rescue therapies, all participants used as-needed budesonide/formoterol (320/9 μg) as the rescue medication throughout the study, and each exacerbation episode and corresponding inhalations were meticulously documented. The amount of rescue medication use was calculated as the total number of as‑needed inhalations of budesonide/formoterol (320/9 μg) within the 8 weeks preceding each study visit.
The study employed two co-primary outcomes to assess treatment efficacy. The first was the asthma control test (ACT) score19, a validated patient-reported instrument that evaluates asthma control over the preceding four weeks. The second co-primary outcome was the Traditional Chinese Medicine (TCM) symptom score, which assesses four cardinal respiratory symptoms: cough, expectoration, wheeze, and dyspnea. Each symptom is scored on a scale from 0 to 3, yielding a total score ranging from 0 to 12, with higher scores indicating greater symptom severity. Detailed scoring criteria are provided in the appendix table.
Secondary outcomes encompassed multiple domains of asthma assessment. Quality of life was evaluated using the mini asthma quality of life questionnaire (mini-AQLQ)20, a validated 15-item instrument. The frequency of rescue medication use, defined as the number of as-needed budesonide/formoterol inhalations, was systematically recorded. Type 2 inflammatory biomarkers included peripheral blood eosinophil count and fractional exhaled nitric oxide (FeNO). Pulmonary function was comprehensively assessed through multiple parameters: Forced expiratory volume in 1 s (FEV1), FEV₁ percent predicted (FEV1% predicted), the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC), and peak expiratory flow (PEF). Immunological status was evaluated by measuring the percentages of CD4⁺ T lymphocytes (CD4⁺%) and CD8⁺ T lymphocytes (CD8⁺%), and the CD4⁺/CD8⁺ ratio, using flow cytometry.
Safety outcomes were monitored throughout the study period and included assessment of local skin reactions at acupoint application sites, monitoring of vital signs, and routine laboratory tests covering hematology, hepatic, and renal function parameters.
Technical procedures
All blood samples, FeNO measurements, and pulmonary function assessments were conducted in the morning following an overnight fast. Venous blood was drawn by trained phlebotomists and processed within 2 h by the hospital's clinical laboratory, which is accredited to standard. FeNO was measured before spirometry to avoid airway perturbation, using a chemiluminescence-based analyzer at an exhalation flow of 50 mL/s. Two acceptable measurements within 10% of each other were averaged. Daily calibration and ambient NO checks were documented. Spirometry was performed by certified pulmonary function technologists according to ATS/ERS standards, with daily volume and flow calibration. Acceptability and repeatability criteria were applied; the best of three technically acceptable maneuvers was retained.
Statistical analysis
Data were analyzed according to the intention-to-treat principle, and missing data were handled using multiple imputation. Continuous variables are presented as mean±standard deviation (SD), and categorical variables as number (percentage). Baseline continuous variables were compared using the independent-samples t test, and categorical variables using the chi-square test or Fisher’s exact test, as appropriate. Repeated continuous outcomes were analyzed using linear mixed-effects models with fixed effects for group, time, and group-by-time interaction. Between-group comparisons at week 8 and week 16 were performed using independent-samples t tests, with mean differences, 95% confidence intervals, and Cohen’s d reported. Rescue medication use was analyzed using negative binomial regression and is presented as incidence rate ratios (IRRs) with 95% CIs. All tests were two-sided, and p < 0.05 was considered statistically significant.