Published Online: February 1, 2015
Allergic bronchopulmonary aspergillosis (ABPA) is a condition in which the immune system evokes an exaggerated allergic response to the common soil-dwelling fungus Aspergillus. ABPA is characterized by severe symptoms of asthma or bronchitis associated with chronic airway inflammation and, if left untreated, the condition is likely to progress to irreversible airway damage and lung scarring. Patients who already suffer from asthma or cystic fibrosis are more likely to develop this disease, and this condition is characterized by the presence of high levels of Aspergillus targeted IgE antibodies in the blood; these are the key antibodies involved in allergy.
Current treatment of ABPA consists of prolonged courses of corticosteroids and anti-fungal therapy. However these courses can be associated with significant side effects.
Omalizumab is a drug designed to capture IgE antibodies and is currently used to treat severe asthma. Unfortunately, most ABPA sufferers have blood IgE levels that are above the current prescription dosing range for omalizumab, so it has not been known whether this treatment may be effective in ABPA.
In an article published in The Journal of Allergy and Clinical Immunology: In Practice, Voskamp, Gillman and colleagues report the results of a placebo-controlled clinical trial to determine the efficacy of omalizumab in treating ABPA-complicating chronic asthma. In this study, 13 patients with chronic ABPA underwent a 4-month treatment with omalizumab (750mg monthly, the maximum dose permitted under current guidelines) or placebo, followed by a 3-month wash-out period in a cross-over design. During the omalizumab treatment, 2 patients suffered a total 2 asthma exacerbations requiring treatment with oral corticosteroids—compared to 12 exacerbations in 6 patients during the placebo phase. In addition, laboratory analysis of blood basophils, the specific white blood cells that play a role in allergy, showed dramatically decreased levels of the allergic antibody IgE and the receptor for this molecule (FceRI) during omalizumab treatment.
Furthermore, another laboratory test, which determines basophil activation in response to allergens (representing histamine release from cells involved in the allergic reaction), showed decreased activation by the Aspergillus fungus after treatment with omalizumab, but not placebo.
Combined, these findings provide evidence that omalizumab is effective and safe in treating ABPA, despite the presence of very high levels of IgE in the blood. Moreover, the treatment was effective without exceeding the maximum dose according to current guidelines. This information is valuable to physicians and patients exploring new avenues in treating and managing symptoms associated with ABPA.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.