Real-World Data Confirms Long-Term Effectiveness Of Bronchial Thermoplasty
Patients with Severe Asthma Show Sustained Clinical Improvement

MARLBOROUGH, Mass., Sept. 18, 2017 /PRNewswire/ -- Boston Scientific (NYSE: BSX) today announced results from a three year follow-up cohort in its Post-FDA Approval Clinical Trial Evaluating Bronchial Thermoplasty (BT) in Severe Persistent Asthma (PAS2) study. The results showed that the 190 patients in the real-world study achieved similar reductions in severe exacerbations, hospitalizations and emergency room visits when compared to the 190 patients treated with BT in the pivotal randomized, sham-controlled Asthma Intervention Research 2 (AIR2) trial. 

The results, which were published in the European Respiratory Journal, the peer-reviewed journal of the European Respiratory Society, corroborate the AIR2 trial and demonstrate that the findings translate into meaningful outcomes in real-world practice.  PAS2 study participants had asthma symptoms that were less well-controlled than subjects in the AIR2 trial and results from the study demonstrate that, following the last BT treatment:

  • The percentage of patients experiencing severe exacerbations decreased from 74 to 40;
  • The percentage of patients with a hospitalization for at least one asthma symptom decreased from 15 to 7 percent;
  • The percentage of patients with emergency room visits decreased from 27 to 11; and that
  • The percentage of patients using daily maintenance oral corticosteroid medications decreased from 19 to 10.

"The PAS2 study confirms that BT is an effective, durable and safe treatment in severe asthmatics that have poorer asthma control at baseline compared to patients evaluated in previous clinical trials, such as AIR2," said Geoffrey Chupp, M.D., principal investigator and director, Yale Center for Asthma and Airways Disease, Yale University School of Medicine, New Haven, Connecticut. "The PAS2 study is the first large-scale, prospective study of BT performed in a post-market setting and validates the positive results from the AIR2 trial."

PAS2 is a prospective, open-label study that consecutively enrolled patients at 27 research centers in the United States and Canada. According to clinical guidelines from the European Respiratory Society and American Thoracic Society, 95 percent of PAS2 participants are considered severe asthmatics.1 In comparison to AIR2 patients, PAS2 study participants were older, with more taking systemic steroids, had a higher Body Mass Index (BMI), and were on higher doses of inhaled steroids. In the 12 months prior to treatment with BT, PAS2 study participants were also more likely than AIR2 patients to have experienced both severe exacerbations, 74 versus 52 percent, and hospitalizations, 15 versus 4 percent.

"The results of the PAS2 study confirm that treatment with BT has an enormous and positive impact in every day clinical practice and may relieve some of the burden that adults with severe asthma face," said Art Butcher, senior vice president and president, Endoscopy, Boston Scientific. "We will continue to work to make sure that patients have access and coverage for this established, important treatment that has been shown to improve asthma-related quality of life."

Asthma affects more than 230 million people globally and approximately 10 percent of cases are considered severe. 2,3  The Alair System for BT is approved by the U.S. Food and Drug Administration (FDA) and has CE Mark for adult patients with severe asthma that is not well controlled with medication. It is the first non-pharmacologic, device-based treatment for severe, persistent asthma. Studies have shown that BT can reduce severe asthma attacks for at least 5 years.4 Earlier this year, initial positive outcomes from the PAS2 full-study cohort were presented at the American Thoracic Society International Conference in Washington, D.C.

  1. Chung, K F. "International ERS/ATS Guidelines On." TASK FORCE REPORT, American Thoracic Society ERS/ATS GUIDELINES ON SEVERE ASTHMA, 10 Apr. 2014,
  2. WHO. Asthma Fact sheet N°307. April 2017. Available at:
  3. "The Prevalence of Severe Refractory Asthma | AAAAI." The American Academy of Allergy, Asthma & Immunology. The Journal of Allergy and Clinical Immunology, Oct. 2014. Web. 05 May 2017. < >. 
  4. Wechsler M et al. J Allergy Clin Immunol. 2013 Dec;132(6):1295-302

About Boston Scientific
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Catherine Brady 
Media Relations                         

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