Arthritis Drug May Ease Severe Asthma
Researchers Say Enbrel May Provide Relief by Blocking Immune System Chemical
Sept. 14, 2005 - A drug commonly used to treat rheumatoid arthritis may also help people with a difficult-to-treat form of severe asthma, according to early research.
A small study in the journal Thorax shows that people with severe asthma treated with twice- weekly injections of the drug Enbrel experienced a significant improvement in asthma symptoms, and some were able to cut back on their other asthma medications.
About one in 10 people with asthma suffer from a severe form of the disease that often requires treatment with escalating doses of steroids in order to keep their asthma symptoms under control.
Researchers say that if further studies confirm these results, drugs like Enbrel may offer a new treatment approach for people with severe asthma.
New Approach in Asthma Treatment
Enbrel works by blocking a chemical released by the immune system called tumor necrosis factor alpha (TNF-a). Elevated levels of the chemical are associated with a range of autoimmune disorders such as rheumatoid arthritis, Crohn's disease, and psoriasis.
“Because of Enbrel’s effect on the immune system, its use can make a person more susceptible to serious infections, especially if you already have another medical condition such as diabetes. There is also a higher risk for developing lymphoma (a kind of cancer) in people who use medications such as Enbrel.”
Researchers say TNF-a generally isn't associated with asthma, but as the disease progresses and becomes severe it adopts new characteristics that may affect production of the chemical.
To test their theory, researchers measured levels of TNF-a taken from 26 healthy people, 67 people with mild asthma, and 51 people with severe asthma.
The study showed that TNF-a levels were significantly higher in people with severe asthma, particularly in one type of immune cell involved in asthma's inflammatory reaction in the lungs.
Enbrel May Ease Severe Asthma
In the next stage of their study, researchers examined the effects of treating severe asthma with the addition of Enbrel, a drug that blocks TNF-a. It was given by skin injections twice a week.
Researchers gave Enbrel for 12 weeks to 17 people with severe asthma who still had symptoms despite having been treated previously with several drugs. The Enbrel was added to the medicines already being used by the study's participants.
The results showed that the participants experienced a significant improvement in their asthma symptoms and lung function. Two of the participants were also able to stop using one of their asthma drugs.
Results of this small study suggest that Enbrel treatment curbed the inflammatory reaction in people with severe asthma, and there were few side effects. The most commonly reported side effects of the Enbrel treatment included respiratory tract infections, asthma exacerbations, and reactions at the medication injection sites.
Researchers say the findings suggest that elevated TNF-a levels in people with severe asthma may be a characteristic of a chronic form of the disease that is resistant to steroid treatment rather than a feature of the disease itself.
The next step will be to verify these findings in larger clinical studies.