Alair Bronchial Thermoplasty for Severe Asthma: How It Works and What the Evidence Shows

Alair is a device for bronchial thermoplasty, a procedure that uses controlled heat to reduce the muscle around the airways in adults with severe asthma. The FDA approved it on April 27, 2010, for adults 18 and older whose severe, persistent asthma isn’t well controlled with inhaled corticosteroids and long-acting beta agonists.

It is not a medication; it’s done during three bronchoscopy sessions. Trials showed improvements in quality of life and fewer severe attacks, but medical guidelines have been cautious, the maker has stopped selling it in Europe, and today most people with severe asthma are offered biologic medicines first. This guide explains the full picture. For more, see our asthma guides.

Jump to: Quick answer · How it works · What the trials showed · Risks · Guidelines and availability · Other options · FAQ

Quick answer

• What it is: a bronchoscopic procedure that applies controlled heat to the airway walls to reduce smooth muscle.
• Who it was approved for: adults 18 and older with severe persistent asthma not well controlled on inhaled corticosteroids and long-acting beta agonists.
• Evidence: in the main sham-controlled trial, 79% of treated patients improved their asthma quality-of-life score versus 64% in the sham group, with fewer severe attacks and ER visits afterward.
• Short-term risk: 6% more treated patients were hospitalized in the weeks right after the procedures.
• Guidelines: European and American respiratory societies advised in 2014 using it only within approved registries or studies.
• Availability: Boston Scientific stopped selling it in Europe, the Middle East and Africa (catheters until the end of 2023).

How bronchial thermoplasty works

In asthma, the muscle around the airways tightens and narrows them. Bronchial thermoplasty uses a thin tube (bronchoscope) passed through the mouth or nose into the lungs. A catheter delivers controlled heat to the airway walls to reduce the amount of smooth muscle, so there is less muscle to tighten.

In the main trial, each patient had three bronchoscopy procedures. It’s done in addition to, not instead of, regular asthma medicines.

What the trials showed

The AIR2 trial (2010)

The trial that led to FDA approval, published in the American Journal of Respiratory and Critical Care Medicine, randomly assigned 288 adults with severe asthma to bronchial thermoplasty or a sham (fake) procedure. Everyone stayed on high-dose inhaled corticosteroids and long-acting beta agonists.

• Quality of life: 79% of treated patients and 64% of sham patients improved their asthma quality-of-life score by a meaningful amount (0.5 points or more).
• After treatment (6 to 52 weeks): the treated group had fewer severe exacerbations, emergency department visits and days missed from work or school than the sham group.
• During treatment (up to 6 weeks): 6% more treated patients were hospitalized.

The manufacturer’s announcements cited bigger-sounding numbers, such as a 32% reduction in severe attacks and an 84% reduction in ER visits. Those are company-reported figures; the peer-reviewed results above give the more complete picture, including the strong improvement in the sham group.

Five-year follow-up (2013)

A follow-up published in the Journal of Allergy and Clinical Immunology tracked 162 of the 190 treated patients for five years. Severe exacerbations and ER visits stayed lower than in the year before treatment, lung function (FEV1) stayed stable even though average inhaled steroid doses fell by 18%, and CT scans showed no structural problems attributed to the procedure.

Risks

The main known risk is a short-term worsening of breathing symptoms in the weeks after each session. In the AIR2 trial, 6% more treated patients than sham patients were hospitalized during the treatment period (up to 6 weeks after treatment). Reports at the time of FDA approval described this as an expected, temporary increase in respiratory symptoms that usually resolved within about a week with standard care.

Guidelines and availability

In 2014, the European Respiratory Society and the American Thoracic Society published guidelines on severe asthma. Because evidence about long-term benefits and harms and about which patients benefit most was limited, they recommended bronchial thermoplasty only within an approved independent registry or clinical study. Later data, such as the five-year follow-up, have been more reassuring. Meanwhile, several biologic medicines have been approved for severe asthma (see below).

Availability has also changed. A December 2023 notice from France’s medicines agency (ANSM) says Boston Scientific decided to stop selling the Alair system in Europe, the Middle East and Africa, citing regulatory and market conditions; catheters and accessory kits were sold until December 31, 2023. If you are in the U.S. or elsewhere, ask a severe asthma specialist whether it’s still offered near you.

Other options for severe asthma

The American Academy of Allergy, Asthma and Immunology (AAAAI) explains that several biologic medicines are approved for moderate to severe asthma. Each targets a specific antibody, molecule or cell involved in asthma, and they are given as injections or infusions every few weeks or months. Your doctor uses blood tests and allergy testing to choose one.

Before any advanced treatment, a specialist will usually check the basics: whether you’re using your inhaler correctly and taking it regularly, whether something at home or work is triggering attacks, and whether another condition is involved. See our guides to air quality and asthma and cleaning sprays and asthma.

This guide is general information, not medical advice. Read our medical disclaimer.

Frequently asked questions

Is Alair a medication?

No. Alair is a medical device used for bronchial thermoplasty, a procedure done during bronchoscopy. It is added to regular asthma medicines rather than replacing them.

Who is a candidate for bronchial thermoplasty?

The FDA approved it for adults 18 and older with severe persistent asthma that isn’t well controlled with inhaled corticosteroids and long-acting beta agonists. A severe asthma specialist can tell you whether it’s an option and how it compares with biologic medicines.

How well does bronchial thermoplasty work?

In the main trial, 79% of treated patients improved their quality-of-life score versus 64% with a sham procedure, and treated patients had fewer severe attacks and ER visits over the following year. Five-year follow-up showed those benefits lasted.

Is bronchial thermoplasty still available?

Boston Scientific stopped selling the Alair system in Europe, the Middle East and Africa at the end of 2023. Elsewhere, availability may be limited; ask a severe asthma specialist.

What are the risks?

The main risk is a temporary worsening of asthma symptoms in the weeks after each session, sometimes needing hospital care. In the main trial, 6% more treated patients were hospitalized during the treatment period.

Sources

• Castro M, Rubin AS, Laviolette M, et al. Effectiveness and safety of bronchial thermoplasty in the treatment of severe asthma: a multicenter, randomized, double-blind, sham-controlled clinical trial. Am J Respir Crit Care Med. 2010;181(2):116-124.
• Wechsler ME, Laviolette M, Rubin AS, et al. Bronchial thermoplasty: long-term safety and effectiveness in patients with severe persistent asthma. J Allergy Clin Immunol. 2013;132(6):1295-1302.
• Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014;43(2):343-373.
• U.S. Food and Drug Administration. Premarket approval P080032: Alair Bronchial Thermoplasty System. April 27, 2010.
• ANSM (French National Agency for Medicines and Health Products Safety). Alair system discontinuation notice. December 2023.
• American Academy of Allergy, Asthma and Immunology. Biologics for the management of severe asthma.

Last reviewed: October 21, 2026.