US researchers have found a drug that is commonly used to treat asthma patients and can also help children with food allergies.

According to a new study led by scientists at Stanford University and Johns Hopkins University, regular use of omalizumab can protect people from severe allergic responses, such as difficulty breathing, if they accidentally eat a small amount of food they are allergic to.

Omalizumab, which the US Food and Drug Administration originally approved to treat diseases such as allergic asthma and chronic hives, is an injected antibody that binds and deactivates all types of immunoglobulin E, or IgE, the allergy-causing molecule in the blood and on the body’s immune cells.

Based on the new research, published in the New England Journal of Medicine, the FDA, last week, approved omalizumab for reducing the risk of allergic reactions to foods.

“Patients impacted by food allergies face a daily threat of life-threatening reactions due to accidental exposures. The study showed that omalizumab can be a layer of protection against small, accidental exposures,” said lead author Robert Wood, Professor of paediatrics at Johns Hopkins University School of Medicine.

For the study, the team included 177 children with at least three food allergies each, of whom 38 per cent were 1 to 5 years old, 37 per cent were 6 to 11 years old, and 24 per cent were 12 or older.

Two-thirds of the children were randomly assigned to receive omalizumab injections, and one-third received an injected placebo; the injections took place over 16 weeks.

Re-test between weeks 16 and 20 showed that 79 patients (66.9 per cent) who had taken omalizumab could tolerate at least 600 mg of peanut protein, the amount in two or three peanuts, compared with only four patients (6.8 per cent) who had the placebo.

Similar proportions of patients showed improvement in their reactions to the other foods in the study.

About 80 per cent of patients taking omalizumab were able to consume small amounts of at least one allergy-triggering food without inducing an allergenic reaction, 69 per cent of patients could consume small amounts of two allergenic foods and 47 per cent could eat small amounts of all three allergenic foods.