People with asthma can mitigate their symptoms and reduce and in some cases completely eliminate the need for oral corticosteroids with anti-IgE therapy, according to the results of a US study (N Engl J Med 1999;341:1966-73).
"IgE serves a critical role in activating allergic response. If we remove IgE from circulation, the allergic response is inhibited and patients have better symptom control," says Dr. Henry Milgrom, lead author and senior staff physician with the National Jewish Medical and Research Center in Denver.
The multicentre study involved 300 participants with moderate to severe asthma who were taking corticosteroids. During the first 12 weeks of the study the control group and the 2 treatment groups continued to use corticosteroids, in addition to either a low- or high-dose anti-IgE therapy or a placebo. Each group was weaned off corticosteroids over the following 8 weeks of the study.
Forty-three per cent of participants in the low-dose group and 33% in the high-dose group completely eliminated their use of oral corticosteroids by the end of the study period, compared with only 17% in the control group. Overall, those receiving anti-IgE were able to reduce corticosteroid use by more than 50% in 57% of cases in the low-dose group and in 78% of those in the high-dose group. As well, symptoms such as tightness of the chest, excessive coughing and wheezing improved in 40% of participants in the low-dose group and 42% of those in the high-dose group. Thirty per cent of participants in the control group experienced an improvement in these symptoms.
The only side effects associated with the anti-IgE therapy were rashes and hives that appeared with the first administration of the drug and then disappeared, says Milgrom, a professor of pediatrics at the University of Colorado.
IgE sets off an allergic reaction by attaching itself to particular cells, and when they come in contact with an allergen, allergic reactions occur. Anti-IgE treatment binds to IgE, effectively removing it from circulation. In the case of the 2 treatment groups, IgE in the blood was reduced by more than 95% overall.
It's not surprising that anti-IgE therapy is effective, says Milgrom. "This is how the drug was conceived. The surprise is that it is working as well as it is." Donalee Moulton, Halifax
© 2000 Canadian Medical Association or its licensors