Maj Christensen and Dr. Ott are physicians at Eglin Air Force Hospital in Valparasio, Florida.
Author disclosures The authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the U.S. Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.
Three large phase 3 clinical trials have evaluated the efficacy of bronchial thermoplasty (BT). The AIR (Asthma Intervention Research) trial in 2007 was a randomized controlled study of 112 patients with moderate or severe asthma that showed improved exacerbation rates, symptom-free days and QOL scores (1.3 ± 1.0 vs 0.6 ± 1.1; P = .003), but no difference in prebronchodilator FEV1 or AHR.57 There was a significant reduction in the rate of mild exacerbations and increase in morning PEF rates.57 Findings at 5 years showed improved AHR but no difference in frequency of need for oral corticosteroids and frequency of hospital or emergency department (ED) visits.58
The Research in Severe Asthma (RISA) clinical trial was a randomized controlled study (n = 32, 15 randomly assigned to BT) that showed improved prebronchodilator FEV1 in patients with severe, symptomatic asthma and baseline FEV1 of 62% to 66% with half the patients requiring oral corticosteroids (percentage predicted; 14.9 ± 17.4 vs -0.9 ± 22.3; P =.04).57 Quality of life scores were also significantly improved. At 5 years (14 BT patients were followed), the frequency of hospitalizations and ED visits decreased.59
The 2010 AIR2 study was a randomized, double blind, sham-controlled study (n = 288) developed to address the limitations of the 2 previous studies. It excluded the severest asthma cases, and its blinded nature was created with sham bronchoscopy to eliminate possible placebo effect. The study questionnaires showed improved QOL overall (79% vs 64%); however, there was a definite placebo effect noted.60 Decreased frequency of severe exacerbations as well as ED visits and days lost from work or school also were documented as secondary endpoints. At 5 years, decreased frequency of severe exacerbations and ED visits continued in the control group (85% consented to follow-up).61 Importantly, despite the placebo effect in QOL scores, there were no improvements in exacerbation rates or hospitalizations in those receiving sham bronchoscopy at the 1-year mark.61
Although more longitudinal studies need to be planned, including evaluation of those with the most severe asthma, there seems to be a sustained improvement in patients. Those who have received BT generally are found to have reduced airway smooth muscle with lower concentration of key inflammatory cytokines on follow-up bronchoscopy. However, variability in response has been documented.56 There has been no documented deterioration in pulmonary function with BT, and no significant structural abnormalities have been seen on high-resolution computed tomography.56,58 Both GINA 2016 and ERS/ATS support the use of BT in the context of adults with severe asthma, calling for more long-term studies to address delayed benefits and safety.
LABA Inhalers
A multicenter, double-blind, 26-week study of 11,693 patients randomized to ICS + LABA (budesonide/formoterol) vs ICS (budesonide) alone has shown no increased AEs in either arm. The study found that treatment with budesonide/formoterol was associated with lower risk of asthma exacerbations than using budesonide alone (16.5%; P = .002).62
The safety of adding a LABA to fluticasone also has been evaluated recently. A 2016 study of almost 12,000 patients (aged > 12 years) compared fluticasone proprionate alone vs fluticasone with salmeterol.63 There were no asthma-related deaths, but 2 patients in the fluticasone-only group were intubated with asthma complications. The risk of a severe asthma exacerbation seemed to be lower in the combination group (8% vs 10%; P < .001).63
A 2014 Cochrane Review supported the view that LABAs in adults seem to be safe when used concurrently with an ICS with a A-level recommendation, based on consistent good-quality, patient-oriented evidence.64 Multiple organizations have issued guidelines to this effect in the past, but previous results of studies showed that asthma deaths and a small increase in nonfatal serious AEs were noted in those using LABA monotherapy alone.64
NAEPP (EPR-3) and ERS/ATS recommend stepwise increases in the dose of ICS in combination with a LABA. The GINA guidelines recommend controller therapy to include combination IHS and LABA but with the consideration of higher doses of ICS than are routinely recommended for general use.
Inhaler and Inhaler Combinations
Many different inhalers of ICS alone and ICS/LABA combinations exist on the market today. There are differences in delivery that affect patient preference but these differences have not been found to improve delivery. Small particle ICS therapy could possibly correlate with improved delivery to the small airways.65 There are 3 preparations of inhaled steroids that fit in to this group, including beclomethasone, ciclesonide, and flunisolide. Other inhaled steroid formulations include budesonide, fluticasone propionate, fluticasone furoate, and mometasone.
Combination therapy (ICS + LABA) inhalers also are widely available. They include budesonide/formoterol, fluticasone proprionate/salmeterol, mometasone/formoterol, and the newer fluticasone furoate/vilanterol, a once-daily combination approved for those aged ≥ 18 years.
Conclusion
The treatment of severe asthma has progressed from simple manipulation of avoidance, bronchodilators, and corticosteroids to include many other treatments that have improved QOL for patients with refractory asthma. Although many of these options are delivered in coordination with an allergy and pulmonary specialist, it is important for the PCP to have a good knowledge base and awareness of additional treatments that are currently available.
