Two novel treatments for chronic obstructive pulmonary disease — administering an antioxidant supplement and treating patients for bacteria colonizing the lungs — may help reduce acute exacerbations, according to two studies.

In the first study, the antioxidant supplement N-acetylcysteine cut acute COPD exacerbations 22%, Nan-Shan Zhong, MD, of China’s First Affiliated Hospital of Guangzhou Medical University, and colleagues reported online in Lancet Respiratory Medicine.

They randomly assigned 1,006 moderate-to-severe COPD patients at 34 hospitals to double-blind treatment with N-acetylcysteine (one 600-mg tablet, twice daily) or matched placebo for one year in the Chinese PANTHEON trial.

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Patients in the N-acetylcysteine group had fewer acute COPD exacerbations compared with the placebo group — 1.16 vs. 1.49 per patient per year (risk ratio 0.78; 95% CI: 0.67-0.90), the researchers found.

Adverse event rates were similar between groups (29% vs. 26%, serious events 48 vs. 46). The most common serious adverse event, acute exacerbation of COPD, was also similar between the N-acetylcysteine and placebo groups (6% vs. 7%).

“Our findings show that in Chinese patients with moderate-to-severe COPD, long-term use of N-acetylcysteine 600 mg twice daily can prevent exacerbations, especially in disease of moderate severity. Future studies are needed to explore efficacy in patients with mild COPD (GOLD I),” Zhong and colleagues concluded.

In the second study, Himanshu Desai, MD, of Virginia’s Chesapeake Pulmonary and Critical Care Medicine, and colleagues, found that colonization with certain bacterial pathogens correlated with higher COPD symptom scores and airway inflammation:

  • Nontypeable Haemophilus influenzae
  • Moraxella catarrhalis
  • Streptococcus pneumoniae
  • Pseudomonas aeruginosa

After adjusting for exacerbations and other factors, average symptom scores were significantly higher among those colonized with the pathogens compared with those who were not (average 5.28 vs. 4.46 on the Breathlessness, Cough and Sputum Scale, P=0.008).

Airway inflammation as measured by sputum interleukin-8 levels also correlated with bacterial colonization; however, causality could not be established in the longitudinal observational study, which involved 41 COPD patients.

Although prophylactic antibiotics could cut COPD symptoms based on these findings, Desai and colleagues cautioned against such an approach due to concerns about antimicrobial resistance.

“Therapies that augment innate lung defence mechanisms, making the airway milieu less hospitable to bacterial colonization, could have significant impact on the daily symptom burden and unreported exacerbations of COPD,” they wrote. “Development of such therapies would be welcome and could have these additional benefits besides reducing clinical exacerbations.”


  1. Zheng J-P et al. Lancet Respir Med. 2014; doi:1016/S2213-2600(13)70286-8. 
  2. Desai H et al. Ann Am Thorac Soc. 2014; doi:10.1513/AnnalsATS.201310-350OC.