The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health today announced the beginning of a study to determine the best long-term strategy for treating adults with mild asthma who experience symptoms more than occasionally. The 2-year "Improving Asthma Control Trial (IMPACT)" is designed to determine whether these patients should be taking anti-inflammatory medications on a daily basis and whether a newer class of medications provides the same benefit as older drugs.
According to NHLBI Director Dr. Claude Lenfant, "This study has major implications for the long-term health of these patients. We know that daily anti-inflammatory therapy has benefits, but we don't know whether daily use is really necessary for people with mild asthma. This study should provide the answer."
"Obviously," he added, "the study also has substantial cost implications."
Asthma is a chronic lung disease that currently affects more than 15 million Americans, approximately half of whom have mild, but persistent asthma (symptoms more than twice a week). It is currently estimated to cost the U.S. economy $11.3 billion in health costs and lost productivity. The additional cost of treating all patients with mild persistent asthma with daily medication is estimated at $2 billion.
It is only within the past 20 years that scientists have learned that asthma is due to an inflammatory process in the bronchial air passages of the lungs that causes chronic irritation and narrowing of the airways, resulting in loss of lung function. In 1991, the NHLBI's "Guidelines for the Diagnosis and Management of Asthma" emphasized for the first time the role of inflammation in asthma and called for the use of anti-inflammatory agents to reduce inflammation over the long term, in addition to medications to provide symptom relief.
In 1997, the updated Guidelines recommended that patients with mild persistent asthma take daily medication, such as inhaled corticosteroids or anti-leukotrienes, to prevent or reverse airway inflammation. Since anti-leukotrienes were a relatively new class of medication, the guidelines also called for additional research on them.
In the IMPACT study, 234 adults with mild asthma who have more than occasional symptoms will be enrolled in six clinical research centers. Following an initial evaluation, patients will be randomized to receive either a twice daily inhaled corticosteroid, a twice daily anti-leukotriene, or a placebo. All patients will receive treatment for symptoms if and when they occur. The results should demonstrate whether medication is required on a daily basis by these patients, and if so, whether inhaled corticosteroids and leukotriene modifiers are equally effective.
The study is being conducted by the NHLBI's Asthma Clinical Research Network, which was created in 1993 to facilitate design and implementation of clinical trials on approaches to managing asthma. The centers that participate in the Network are: Brigham and Women's Hospital, Boston; Harlem Lung Center, New York City; National Jewish Medical and Research Center, Denver; University of Wisconsin, Madison; Jefferson Medical College, Philadelphia; and University of California, San Francisco. The data coordinating center is at the M.S. Hershey Medical Center, Hershey, PA.
Inhaled corticosteroids and anti-leukotrienes are medications that are currently the first and second most commonly prescribed controller medications for asthma respectively. The medications for IMPACT are being donated by Astra-Zeneca Pharmaceuticals, headquartered in Wayne, PA.
For more information about IMPACT, contact the NHLBI Communications Office at 301-496-4236, or the nearest participating center.