Children and adults with food allergies can be gradually desensitized to the foods that trigger their allergic reactions, a series of Phase 1 and Phase 2 clinical trials at the Sean N. Parker Center for Allergy and Asthma Research at Stanford has shown.
The studies, by Kari Nadeau, MD, PhD, and her team, tested a treatment called oral immunotherapy -- in which patients ingest tiny, gradually increasing doses of the foods that trigger their allergies -- combined with a drug called omalizumab that reduces immune reactions during the process. Building tolerance to food allergens takes several months, a big investment of time and energy for patients. Many patients feel it's worthwhile because their new freedom to eat anything can be life-changing, as I reported in a recent Scope post about a teenager who participated in one of Nadeau's trials.
But how well does the treatment last?
That question was the focus of two new studies (following patients who had and had not received omalizumab) published last week in Allergy, Asthma & Clinical Immunology. Prior research had shown that if patients completely stopped eating their allergy triggers after oral immunotherapy, their allergic reactions would probably return.
In the new studies, the team followed patients who had enrolled in two of the Phase 1 oral immunotherapy trials, one trial in which patients received omalizumab during oral immunotherapy and another trial without the medication. The original trials were published in 2014.
At the end of the trials, patients were eating 2 grams per day of their food allergens. If that allergen was peanuts, for example, the patient had to eat about 8 peanuts per day.
The researchers wanted to know what would happen after completing oral immunotherapy in "real world" conditions in which patients might not want to keep eating as much of their allergens every day. The team consulted with each patient to decide if the patient would keep eating a 2 grams per day or a lower dose of 300 mg per day of each of their allergens. Some patients also switched to eating the food every other day instead of daily.
The patients returned to the clinic for allergy tests every six to 12 months for up to six years. (The median follow-up time was four years.) All participants were able to maintain their tolerance to their allergens regardless of whether they were ingesting the lower or higher allergen doses. The patients did not have any severe allergic reactions during either follow-up trial, although some mild and moderate reactions were reported, and patients were advised to keep carrying injectable epinephrine with them as a safety measure.
"It was important that we could show this feasibility in a real-life situation," said Monali Manohar, PhD, co-lead author on the new research. "This follow-up was carried out in a very patient-friendly manner, with the long-term maintenance dose decided by consensus of the participant, family and clinical team."
The lower dose may help patients stick to the treatment, the researchers write:
Many children have aversions to the high maintenance dose of each food allergen due to taste, convenience, sense of fullness, etc. A lower maintenance dose might increase not only an individual's quality of life but also an individual's adherence with continued ingestion of allergens long-term.
"Participants and their families no longer have to live in fear of what might happen after accidental exposure to a food allergen, even several years after they graduated from the original oral immunotherapy trials," said co-lead author Sandra Andorf, PhD. "It's an exciting result."
The team is also conducting studies to understand the molecular pathways behind tolerance, which should help them further refine the treatment.
Previously: In Stanford clinical trial, children successfully desensitized to food allergens, Taking a bite out of food allergies: Stanford doctors exploring new way to help sufferers and Batman has his utility belt -- and I have my EpiPen
Photo by Dean Hochman