Spiriva, a drug that is already widely used to treat chronic obstructive pulmonary disease, can provide significant relief of symptoms for adult asthmatics who have difficulty obtaining relief with other drugs, researchers said Sunday.
Some physicians already have begun prescribing the drug for asthmatics because of the lack of suitable alternatives, but the new results from a major clinical trial provide a sound underpinning for such uses, experts said.
In particular, the drug is expected to provide an alternative to long-acting beta-agonists, such as Serevent, Advair and Symbicort, which have been shown occasionally to exacerbate asthma symptoms, leading to hospitalization and even death.
A particular strength of Spiriva, known generically as tiotropium bromide, is that its effects last for 24 hours or more, providing long-lasting relief for patients, said Dr. Michael Roth, a professor of pulmonary and critical care medicine at the University of California at Los Angeles' David Geffen School of Medicine, who was not involved in the research. "It provides daylong relief, so that patients don't have to think about getting in trouble part way through the day," he said.
The new study, published online in the New England Journal of Medicine and reported Sunday at a meeting in Barcelona, Spain, of the European Respiratory Society, means that "people who shied away from using this now have an alternative for symptom relief," said Dr. Paryus Patel, a pulmonary specialist at Marina Del Rey Hospital in Marina Del Rey, Calif.
About 17 million Americans, 12 million of them adults, suffer from asthma, which is characterized by coughing and difficulty breathing caused by inflammation of the airways. About 85 percent of them can be successfully managed with existing approved drugs, said Robert Smith, program director for the National Heart, Lung and Blood Institute's asthma clinical research network.
The conventional treatment is low to moderate doses of inhaled steroids. When those are inadequate, current guidelines call for increasing the dose of steroids or adding a long-acting beta-agonist. But higher doses of steroids do not work for all patients and they increase the risk of sore throats and pneumonia. Beta-agonists present other risks.
In the new study, a team headed by Dr. Stephen Peters of Wake Forest University Baptist Medical Center enrolled 210 adults whose asthma was not well-controlled by low doses of inhaled steroids.
Patients received each of the following three treatments for 14 weeks, with two-week breaks in between to flush drugs out of their systems: a doubling of the low-dose steroids, continuation of low-dose steroids with the addition of the beta-agonist salmeterol, and continuation of steroids with the addition of tiotropium.
Tiotropium was shown to be effective by a number of measures, including the number of days in which patients had no asthma symptoms and did not need to use their albuterol rescue inhalers. At the beginning of the trial, the number of such days averaged 77 per year. Doubling the dose of steroids gave patients another 19 symptom-free days, on average, while adding tiotropium gave them an additional 48.
The tiotropium was also at least as good as the salmeterol, the researchers found. "It was not only working, but working as well as the long-acting beta-agonists," Peters said.
There have been some concerns in the last couple of years about a potential for increased risk of heart attacks, stroke and death associated with tiotropium. But in an article Thursday in the New England Journal of Medicine, scientists from the Food and Drug Administration summarized their analysis of the existing data and concluded that those risks had not been confirmed.
Peters noted that the asthma clinical research network is now gearing up for longer trials of the drug to ensure that there are no unforeseen side effects. A major result of the study, he added, is that "other drug companies may start looking at similar compounds. … Asthma is an important disease and a lot of people can benefit from these medications."
The $5.3 million study was funded by the National Heart, Lung and Blood Institute. Boehringer Ingelheim manufactures Spiriva, which is approved for emphysema and other chronic lung conditions, but not asthma. Serevent is manufactured by Glaxo, which declined to participate in the study.
Information from the Associated Press was used in this report.