As Conditions of Approval of the PMA for the Alair System, the FDA requires Boston Scientific to generate data to assess the durability of the BT treatment effect as well as safety data in the intended use population in the United States.

This is a multicenter, open-label, single arm study designed to demonstrate durability of the treatment effect and to evaluate the short-term and longer-term safety profile of the Alair System in the United States in the intended use population (patients 18 years and older with severe persistent asthma).

Inclusion Criteria:

1. Subject is an adult between the ages of 18 to 65 years.

2. Subject is able to read, understand, and sign a written Informed Consent to participate in the study and able to comply with the study protocol.

3. Subject has asthma and is taking regular maintenance medication that includes:

   1. Inhaled corticosteroid (ICS) at a dosage greater than 1000μg beclomethasone per day or equivalent, AND long acting β2-agonist (LABA) at a dosage of ≥80μg per day Salmeterol or equivalent.
   2. Other asthma medications such as leukotriene modifiers, or anti-IgE, are acceptable (Subjects on Xolair® must have been on Xolair for greater than 1 year).
   3. Oral corticosteroids (OCS) at a dosage of up to, but not greater than 10mg per day are acceptable.*

4. Subject has a pre-bronchodilator FEV1 of greater than or equal to 60% of predicted.

5. Subject is a non-smoker for 1 year or greater (if former smoker, less than 10 pack years total smoking history).

6. Subject is able to undergo outpatient (same day) bronchoscopy in the opinion of the investigator or per hospital guidelines.

7. Subject has at least 2 days of asthma symptoms in the last 4 weeks.

8. Subject has an AQLQ score during the baseline period of 6.25 or less.

   • NOTE: Subjects on a dosage regimen of 20mg OCS every other day may be included as this is equivalent to an average daily dosage of 10mg.

Exclusion Criteria:

1. Subject is participating in another clinical trial within 6 weeks of the Baseline Period involving respiratory intervention that could affect the outcome measures of this Study.

2. Over the last 7 days of a 4 week medication stable period, subject requirement for rescue medication use other than for prophylactic use for exercise exceeds an average of:

   1. 8 puffs per day of short-acting bronchodilator, or
   2. 4 puffs per day of long-acting rescue bronchodilator, or
   3. 2 nebulizer treatments per day. At the discretion of the Principal Investigator, subjects considered as unstable on baseline medications may have medications adjusted and re-evaluated after a 4 week medication stabilization period.

3. Subject has a post-bronchodilator FEV1 of less than 65%.

4. Subject has a history of life-threatening asthma, defined by past intubation for asthma, or ICU admission for asthma within the prior 2 years.

5. Subject has 3 or more hospitalizations for exacerbations of asthma in the previous year.

6. Subject has had 4 or more infections of lower respiratory tract (LRTI) requiring antibiotics in the past 12 months.

7. Subject has had 4 or more pulses of systemic corticosteroids (tablets, suspension or injection) for asthma symptoms in the past 12 months.

8. Subject has a known sensitivity to medications required to perform bronchoscopy (such as lidocaine, atropine and benzodiazepines).

9. Subject has other respiratory diseases including emphysema, cystic fibrosis, vocal cord dysfunction, mechanical upper airway obstruction, Churg-Strauss syndrome, and allergic bronchopulmonary aspergillosis (asthma, immediate cutaneous reactivity to A. fumigatus, total serum IgE of >1000ng/mL, elevated specific IgE and IgG to A. fumigatus with or without evidence of central bronchiectasis).

10. Subject has segmental atelectasis, lobar consolidation, significant or unstable pulmonary infiltrate, or pneumothorax, confirmed on x-ray.

11. Subject currently has clinically significant cardiovascular disease, including myocardial infarction, angina, cardiac dysfunction, cardiac dysrhythmia, conduction defect, cardiomyopathy, or stroke.

12. Subject has a known aortic aneurysm.

13. Subject has significant co-morbid illness such as cancer, renal failure, liver disease, or cerebral vascular disease.

14. Subject has uncontrolled hypertension (>200mm Hg systolic or >100mm Hg diastolic pressure).

15. Subject has an implanted electrical stimulation device (e.g., a pacemaker, cardiac defibrillator, or deep nerve or deep brain stimulator).

16. Subject has coagulopathy (INR > 1.5).

17. Subject has any other medical condition that would make them inappropriate for study participation, in the Investigator's opinion.

Following Last Patient Out, when Results are posted.