To evaluate the safety and efficacy of a bronchial radiofrequency ablation system (SyMap Medical (Suzhou) Ltd) in a population of subjects with severe asthma who are still symptomatic despite being managed on high-dose Inhaled Corticosteroids (ICS) and Long-Acting β2-adrenergic Agonists (LABA).

This will be a prospective, multicenter, randomized, clinical study comparing the SyMap bronchial radiofrequency ablation system to the Boston Scientific Bronchial Thermoplasty System (Alair System). The study population consisted of subjects with severe asthma who are still symptomatic despite being managed on high dose ICS and LABA. Patients with severe asthma who still have symptoms, despite the standard drug maintenance recommended by the guidelines, after signing the informed consent, who meet the inclusion exclusion criteria enter the baseline period and continued to use uniform ICS and LABA, which will last at least 4 weeks. Patients with at least two days asthma symptoms during the baseline period, and meet the eligibility criteria are assigned to the experimental or control group at a 1:1 ratio based on a central randomized system. A total of 160 subjects will be enrolled, 80 in the experimental group and 80 in the control group. The experimental group is treated with SyMap radiofrequency ablation system, and the control group is treated with the same procedure using Boston Scientific Bronchial Thermoplasty Aliar System. For subjects in the experimental group and the control group, follow-up by telephone call will be performed at 1, 2, 7 days after each procedure and at 1, 2, 4, 5, 7, 8, 9, 10, 11, 15, 18, 21, 27, 30, 33, 39, 42, 45, 51, 54, and 57 months after the third procedure, and outpatient follow-up will be performed at 6 weeks, 3, 6，12，24, 36, 48 and 60 months after the third procedure. ICS and LABA are administered within five years after the third procedure. The difference in the rate of severe asthma exacerbations per year (the number of severe asthma exacerbations per person per year), at 12 months after bronchial radiofrequency ablation, is the primary endpoint of the study, and the success rate of procedure, postoperative adverse events, and serious adverse events are safety endpoints.

This study is conducted by an independent clinical monitoring organization, a data management and statistical center to collect and statistically analyze all relevant clinical and laboratory data.

Inclusion Criteria:

• Subject is an adult between the ages of 18 to 65 years;
• Diagnosed with asthma who required regular asthma maintenance medication in the past 6 months as follows:

ICS ≥1000 μg/day beclomethasone or equivalent and LABA ≥1000μg /day salmeterol or equivalent.

Other medications were allowed, including leukotriene modifiers, and Oral Corticosteroids (OCS) ≤ 10mg/day.

• At least two days of asthma symptoms during 4-weeks of the baseline period.
• Pre-bronchodilator Forced Expiratory Volume in one second (FEV1) of greater than or equal to 45% of predicted.
• Non-smoker (less than 10 pack per year) last for 1 year or greater.
• Baseline AQLQ Score less than or equal to 6.25
• Willingness and ability to comply with the outpatient follow-up.

Exclusion Criteria:

• Pre-bronchodilator Forced Expiratory Volume in one second (FEV1) of less than 45% of predicted.
• 3 or more hospitalizations for exacerbations of asthma in the past 12 months;
• More than 3 lower respiratory tract infections requiring antibiotics in the past 12 months
• More than 4 of oral steroid use for exacerbations of asthma in the past 12 months
• Chronic sinusitis
• Uncontrolled gastroesophageal reflux disease, defined as a significant increase in treatment over the past 6 weeks
• Sensitivity to medications required to perform bronchoscopy (such as lidocaine and benzodiazepines)
• Use of an implantable electrical stimulation device, such as a pacemaker, a cardiac defibrillator or a deep nerve or deep brain stimulator;
• Severe emphysema caused by chronic obstructive pulmonary disease (COPD).
• Use of systemic immunosuppressants, beta adrenergic blockers, or anticoagulants.
• History of fatal asthma.
• Uncontrolled obstructive sleep apnea
• Intubation or admission to the ICU for asthma exacerbations within 2 years prior to treatment
• Hemorrhagic or malignant tumors or Coagulopathy.
• Lower bronchial stenosis or distal complete atelectasis or other severe bronchial and pulmonary lesions, as Thoracic spiral CT showed
• Poor compliance judged by the investigator, or other medical conditions that are not suitable for the study
• Related contraindications for bronchoscopy
• Pregnant, lactating women, or patients with a birth plan in the next year
• Previously undergone bronchial thermoplasty

Our decision on whether to share the individual participant data depends on the opinions of the regulatory authorities in China, but so far the regulatory agencies have no clear instructions yet, thus we cannot make a decision at present.

The enrolled patients are blinded until 12 months after procedure. Physicians who perform post-procedure patient management and physicians who perform bronchial ablation/ bronchial thermoplasty procedures are blinded to each other.