Another recent study by the same team showed people with multiple food allergies can be desensitized to several foods at once. Both of these phase-1 safety trials give the first evidence for a potential new method of treating people for multiple food allergies.
Researchers found that patients who took the omalizumab, also known by the brand name Xolair, became desensitized to multiple food allergens at a median of 18 weeks, while those who did not take the drug became desensitized at a median of 85 weeks.
The desensitization method used in both studies, known as oral immunotherapy, builds allergic patients tolerance to a food by ingesting it in small, gradually increasing doses under a doctor’s supervision in a hospital setting.
Over a period of time, the body no longer reacts, and the patient is able to eat the food safely. Several researchers have shown that this therapy works on a single food allergen, but it had not been tested on multiple food allergens. The Stanford team tried the new technique because nearly 4 million Americans are allergic to more than one food.
Current Treatment Options Limited
“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 Kari Nadeau, MD, PhD, an immunologist at Stanford Hospital & Clinics and Lucile Packard Children’s Hospital Stanford. Nadeau is the senior author of the new study.
Current options for dealing with food allergies are limited. Doctors advise patients to avoid allergy triggers and carry injectable epinephrine at all times because they are at risk of anaphylactic shock from accidental consumption.
Alternatively, oral immunotherapy is still experimental and quite slow. In prior studies, patients took as long as three years to become desensitized to one food. Being desensitized to several foods, one at a time, could prospectively take decades.
Stanford researchers have now succeeded in safely desensitizing patients to several food allergens at once and were able to speed up desensitization by supplementing oral immunotherapy with injections of omalizumab.
Multiple Food Allergens
In the previous study, patients were not given omalizumab. 25 children and adults with multiple allergies ate tiny doses of their allergens, as many as five, in the form of highly purified food powders each day.
The dose was evenly divided between the allergens so that each subject got the same total quantity of food protein, regardless of the number of foods they were being desensitized to.
Researchers monitored the treatment’s safety, noting some mild allergic reactions, such as itching in the mouth, and a small number of severe reactions that were treated with epinephrine.
The food dose was gradually raised until subjects could eat 4 grams of each food protein, or up to 20 grams of the allergenic food proteins in total, without experiencing a reaction. This occurred at a median of 85 weeks after food doses began.
Ramping Up Oral Immunotherapy
The second and most recent study involved 25 children and adults with multiple food allergies. They underwent a similar protocol, but with an added step. Eight weeks before being introduced to food allergens, the patients began receiving injections of omalizumab.
The drug reduces activity of the body’s IgE molecules, the antibodies involved in allergic responses, and had been shown in a previous Stanford study to speed the success of oral immunotherapy for children with milk allergies.
Patients getting omalizumab tolerated larger initial doses of allergens than those in the non-omalizumab study, and desensitization progressed faster.
The drug was discontinued after eight weeks of oral immunotherapy; this discontinuation was not associated with additional allergic reactions. The patients continued consuming food powders until they could safely eat 4 grams of each food protein. This occurred at a median of 18 weeks after the food doses began.
“It’s efficient,” said lead author Philippe Bégin, MD. “It’s exciting that we could perhaps have a treatment that’s actually doable on a large scale.”
The new regimen will need further testing in randomized, blinded, controlled phase-2 studies before it is ready for widespread clinical use, he and Nadeau cautioned.
“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,” said Nadeau. “In the future, we’ll be trying to understand why some people have the bystander effect during clinical trials and some don’t.”