On The Horizon: Respiratory Health

Content provided by the Faculty of the Harvard Medical School

On the horizon

Researchers have learned a tremendous amount about the underlying biology of chronic obstructive pulmonary disease (COPD), and this information has opened the door to potential treatments. While finding a cure is not likely, the realistic goal is to find new drugs that prevent or reverse some of the respiratory damage caused by the illness. Advances are likely to include new bronchodilators that are more convenient or more effective than the medications used today. On another front, researchers are studying agents that can stop the progress of lung disease by attacking specific molecules involved in the disease process that are unaffected by existing medications. Research is in the early stages; very few of these agents have been tested on humans. So far, though, the following categories of drugs look promising.

Mediator antagonists. These drugs block one or more of the chemicals that contribute to the inflammatory process of COPD. They include leukotriene B₄ antagonists, CXC-chemokine antagonists, and tumor necrosis factor inhibitors.

Protease inhibitors. These substances have the potential to prevent lung damage by protecting elastin and other proteins that are essential to the structure of the lungs. The only protease inhibitor in use today is replacement treatment for alpha-1-antitrypsin deficiency, the genetic disorder that causes emphysema in some people. Several other protease inhibitors are in development for potential use by COPD patients who do not have the genetic flaw.

Anti-inflammatory drugs. Researchers are investigating several alternatives to corticosteroids that would reduce inflammation of the airways, ideally with fewer side effects. The only ones that have been tested in clinical trials are phosphodiesterase-4 (PDE-4) inhibitors, which block the activity of cells that set off the inflammatory process that causes lung damage. Unfortunately, these drugs did not perform well in preliminary clinical trials.

Antioxidants. Damage from oxidation plays a role in the degenerative process of COPD. Therefore, antioxidants — compounds that prevent oxidative stress — have the potential to control the disease. In studies with rats, an antioxidant called acetylcysteine reduced the frequency of acute exacerbations. Drugs derived from selenium, an antioxidant mineral, are also under study.

Last updated:	May 23, 2007