The primary purpose of this study is to gather additional safety data for subjects who previously completed the one-year study entitled: "Multicenter Randomized Clinical Trial of the Alair System for the Bronchial Thermoplasty Treatment of Asthma" (Protocol #0602-20, NCT00214526) sponsored by Asthmatx, Inc. Study Subjects who were assigned to the Control Group who elect to participate in this extension study will be followed for an additional two (2) - year period beyond the PREDECESSOR STUDY'S one-year endpoint. Subjects treated with the Alair System who elect to participate in this extension study will be followed for an additional four (4)- year period beyond the PREDECESSOR STUDY'S one-year endpoint.

All treatments with the Alair System were completed in the PREDECESSOR STUDY (NCT00214526). The current study is designed solely to collect longer-term follow-up data on the effects of the treatments. The data will be of the same type that was collected in the PREDECESSOR STUDY (NCT00214526), including spirometry, physical examinations, review of symptoms, use of maintenance and rescue medications, and response to Methacholine challenge.

This will be a multicenter study conducted only at the clinical sites that participated in the PREDECESSOR STUDY (NCT00214526).

Written, informed consent will be obtained prior to performing any study procedures. Enrollment will be limited to only those subjects who were in either the Control or Treatment groups of the PREDECESSOR STUDY (NCT00214526).

The present study will extend the follow-up evaluation of subjects from the PREDECESSOR STUDY (NCT00214526) to 3 years post-treatment for the Control Subjects and 5 years post-treatment for Alair-Treated Subjects. These evaluations will consist of two (Control Group) to four (Alair Group) additional study visits corresponding to the two-year, three-year, four-year and five-year time points following completion of Alair treatments (or similar time point for control subjects) in the PREDECESSOR STUDY (NCT00214526). For consistency with the PREDECESSOR STUDY (NCT00214526), ideally the subject's drug therapy should continue to be consistent with the Global Initiative for Asthma (GINA) Guidelines for the severity of the subject's asthma. Any changes in maintenance levels of asthma medications should be documented.

The goal of this follow-up study is to enroll all subjects who participated in the PREDECESSOR STUDY (NCT00214526). Inclusion of subjects from the treatment arm will allow for the assessment of long-term safety of the Alair procedure for up to 5 years post treatment with the Alair System. Inclusion of subjects from the Control arm will allow for appropriate analysis of long-term effectiveness data for up to 3 years post "treatment".

Inclusion Criteria:

1. Subject who participated in the PREDECESSOR STUDY entitled "Multicenter Randomized Clinical Trial of the Alair System for the Bronchial Thermoplasty Treatment of Asthma"(Protocol # 0602-20, NCT00214526).
2. Subject who is able to read, understand, and provide written Informed Consent.
3. Subject who is able to comply with the study protocol, including requirements for taking and abstaining from medications, and complete all study required visits.

Exclusion Criteria:

1. Subject participating in another clinical trial involving respiratory intervention that could affect the outcome measures of this study, either within 6 weeks of study enrollment, or during the study period.
2. Subject with a newly diagnosed (since exiting from the PREDECESSOR STUDY) psychiatric disorder which in the judgment of the investigator could interfere with provision of informed consent, completion of tests, therapy, or follow-up.

Year 1 Post-Treatment out to 5 years for Alair participants, Year 1 Post-Treatment out to 3 years for Control participants.