Researchers reported at a recent medical meeting that Xolair, a 20-year-old asthma drug by Roche and Novartis, significantly reduced allergic reactions in severe food allergy patients during a late-stage trial.

Based on the results presented at the American Academy of Allergy, Asthma & Immunology meeting in Washington, the U.S. Food and Drug Administration (FDA) approved the drug earlier this month for adults and children aged one year or older to reduce allergic reactions that may occur from accidental exposure.

Xolair, a monoclonal antibody known chemically as omalizumab, was first approved by the FDA in 2003 for treating asthma.

People using the drug will still need to avoid foods they are allergic to, but they can worry less about unknowingly consuming tiny bits of those foods, said study leader Dr. Robert Wood of Johns Hopkins Children's Center in Baltimore.

"There are a lot of patients and families for whom this will make a big difference in their lives," Wood said.

The U.S. Department of Agriculture estimates that food allergies affect about 2% of U.S. adults and 4% to 8% of children. Each year, the most severe allergic reactions result in 30,000 emergency room visits, 2,000 hospitalizations, and 150 deaths.

The trial included 177 children ages 1 to 18 and three adults, all with severe food allergies.

At the start, participants reacted to less than 100 milligrams of peanut protein, the equivalent of about one-third of a peanut and less than 300 mg of at least two other allergens, including milk, egg, cashew, walnut, hazelnut and wheat.

Following treatment, 67% of participants who received omalizumab could consume the equivalent of about four peanuts without experiencing moderate to severe allergic reactions, compared to only 7% of patients who received a placebo.

Some 44% of those treated with the medicine could consume the equivalent of about 25 peanuts, researchers reported.

Patterns were similar when patients were challenged with the other foods.

In the Xolair group, 41% of those with cashew allergy could consume 1,000 mg without a moderate or severe reaction, compared with 3% in the placebo group. It was 66% versus 10% for milk. In those with egg allergies, 68% could tolerate exposure after treatment compared with no one in the placebo group, the researchers found.

Participants received 16 to 20 weeks of treatment with Xolair or placebo every two or four weeks, based on their weight and the amount of allergy-related antibodies in their blood.

Following additional treatment for another 24 weeks in 38 children, "most participants (showed) stable or increased challenge thresholds," the researchers said.