A Novel Approach to Treating Asthma
A study published yesterday in the New England Journal of Medicine gives asthma sufferers reason to hope there might someday be a new way to fight back. By singeing away smooth muscle from the bronchial airways in a procedure called bronchial thermoplasty, researchers were able to significantly reduce symptoms in people with moderate to severe asthma. "It's the beginning of a whole new category of treatment for asthma," predicts John Miller, head of thoracic surgery at St. Joseph's Healthcare Hamilton in Hamilton, Ontario, and coleader of the study (which was paid for by Asthmatx, the company that owns the proprietary technology used in the procedure).
Bronchial thermoplasty involves snaking a flexible catheter with an expandable wire basket at the tip through the mouth and into the major airways that feed the lungs, then expanding the basket so it fits snugly against an airway wall and zapping the tissue with a 10-second jolt of thermal energy produced by a controlled radio frequency. The aim is to kill smooth muscle, which contributes to asthma by contracting and narrowing the airway during an attack. In the study of 112 people, everyone continued daily medication, but half the group also underwent bronchial thermoplasty. Researchers followed the two groups for a year.
Although people who underwent the procedure experienced an immediate uptick in respiratory problems, including shortness of breath, wheezing, and coughing, the problems disappeared within a week in most cases. Over the year of follow-up, the thermoplasty group experienced 10 fewer asthma attacks than the other group, needed 400 fewer puffs of rescue medication, and experienced 86 more symptom-free days.
You can't call your doctor for an appointment just yet. The procedure is still in clinical testing and has not been approved by the Food and Drug Administration. "Although the technology is promising, more refinement will probably be necessary before it can be used on a widespread scale," says Julian Solway, associate dean for translational medicine at the University of Chicago and the co-author of an editorial that ran with Miller's paper.
The editorial, which encourages the medical community to also look for less invasive methods of targeting smooth muscle, notes some of the limitations of bronchial thermoplasty, including the fact that it can lead to complications and such temporary adverse effects as shortness of breath and irritation, and will probably be expensive. Solway's coauthor, Charles Irvin, director of the Vermont Lung Center at the University of Vermont College of Medicine, cautions that the invasive technique would only be appropriate for people with severe asthma at this point.
Miller, who has worked closely with Asthmatx in developing the technique, thinks the procedure will be of great interest to people with mild asthma once it is approved and refined. "Is bronchial thermoplasty going to be responsible for getting rid of all of asthma medications? I would say: 'No' because there are factors other than smooth muscle that play a role in asthma," he says. "But I do think it will play a big role in reducing the amount of medication people need."
That was the case for Brenda Donahue, 44, an administrative assistant who underwent the procedure five years ago during an early study of its safety. "I'd definitely recommend it," she says. "It's given me the freedom to spend more quality time outdoors with my nieces and nephews." Previously, Donahue needed her inhaler four or five times each day; she's now down to just once.