March 1, 2014
Asthma Drug Helps Desensitize People To Multiple Food Allergens At Once
Brett Smith for redOrbit.com - Your Universe Online
New research from Stanford University and Johns Hopkins Medical School has shown that an asthma drug can be used to help desensitize people to several food allergens all at once, according to a new report in the journal Allergy, Asthma & Clinical Immunology.
The new findings expand on previous research from the same team that showed a technique called oral immunotherapy could be used to desensitize someone to multiple food allergens – instead of one at a time as had been shown previously.
"Parents came up to me and said things like, 'It's great that you're desensitizing children to their peanut or milk allergies, but my daughter is allergic to wheat, cashews, eggs and almonds. What can you do about that?'" said study author Dr. Kari Nadeau, associate professor of pediatrics at Stanford’s medical school.
Oral immunotherapy is considered experimental and patients in other studies took as long as three years to become desensitized to a single allergen – meaning several foods, one at a time, could take decades. In the newest study, Stanford scientists succeeded in safely desensitizing patients to quite a number of food allergens at once and accelerate this process by supplementing oral immunotherapy with injections of the asthma drug omalizumab.
In the earlier study involving patients not given omalizumab – 25 children and adults with multiple allergies ate very small doses of multiple allergens each day. The overall dose was evenly split between the allergens so that each study volunteer got the same overall quantity of food protein, despite the quantity of allergens they were being desensitized to. The scientists found some mild allergic reactions, such as itching in the mouth, the more severe of which were treated with epinephrine. The food dose was gradually made greater until volunteers could eat 4 grams of each food protein, or up to 20 grams of the allergenic food proteins without experiencing a reaction – at a median of 85 weeks.
In the latest study, the same amount of volunteers with multiple food allergies underwent a similar procedure – but 8 weeks before being exposed to the allergens, the patients started receiving shots of omalizumab. Participants getting omalizumab were found to accept larger primary doses of allergens than those in the non-omalizumab study, and their desensitization advanced faster. These patients also consumed food powders until they could safely eat 4 grams of each food protein – at a median of 18 weeks.
"It's efficient," said study author Dr. Philippe Bégin, a visiting scientist at Stanford. "It's exciting that we could perhaps have a treatment that's actually doable on a large scale."
The researchers also noted that some participants were desensitized to specific nuts and also to related tree nuts that were not included in their immunotherapy.
"We saw this 'bystander effect' in about 60 percent of patients, where, for example, we gave someone pecan powder and the person became desensitized to walnut, too," Nadeau said. "In the future, we'll be trying to understand why some people have the bystander effect during clinical trials and some don't."
The researchers pointed out that further testing is necessary before the procedure is ready for widespread clinical use.