By combining standard desensitization of up to five food allergies with antibody-based medication omalizumab, it may be possible to treat multiple food allergies in a shorter timeframe. This is according to a Phase 1 trial, with 25 patients, published in open access journal Allergy, Asthma & Clinical Immunology.
Food allergies affect up to 8% of children in the US, and 30% of those affected have more than one allergy. It has been estimated that food allergies cost US$25 billion each year, with approximately US$20 million borne by patients' families. In recent studies, people with food allergies have been given small but increasing amounts of an allergen as a way of desensitizing them. This form of treatment is called oral immunotherapy (OIT). But people with multiple food allergies would need to go through sequential rounds of OIT over many years" this study demonstrates a combined treatment that took months.
Food allergies can occur when the immune system reacts to food protein by producing the antibody IgE, which treats the protein as an invading pathogen causing an allergic reaction. Omalizumab is a manufactured antibody that binds to IgE reducing the severity of a reaction. In this Phase 1 trial, led by researchers at the Stanford University School of Medicine, 25 children and adults were given eight weeks of omalizumab treatment prior to the commencement of OIT. The purpose of the trial was to determine the safety and tolerability of this regimen.
After eight weeks, the children underwent rapid oral desensitization with up to five food allergens in a hospital, while continuing with omalizumab for another eight weeks. This began with giving the children food allergen protein in the form of a flour, they were give a 5mg of total protein - divided equally for each allergen. This was increased to 1250mg over a 2.5 hour period, while vital signs were constantly monitored. Antihistamines, steroids and injectable epinephrine were available at all times. The children were observed for two hours after the maximum allergen dose was given.
The participants continued with home dosing of allergens by ingesting their maximum tolerated dose after each meal. After two weeks, they returned to the hospital where the doses were escalated if the daily food protein doses were well tolerated. During the trial, no serious adverse events were reported, and of the allergic reactions recorded 94% were mild (i.e. itching). Most home reactions occurred during the first months of therapy, and reactions dropped by 70% after 6 months. All participants reached a 10-fold equivalent dose of each of their allergens after 2 months of OIT.
The researchers noted the limitations of this study. This is a small single site, open label, Phase 1 study, so further larger, multi site Phase 2 studies need to be conducted. The authors caution that multi-food OIT is experimental and should only be conducted in a hospital setting with trained personnel and should be conducted as per national regulatory and local regulatory guidelines.
Senior author Kari Nadeau says: "In this Phase 1 safety study, we have shown that the study participants allergic to multiple foods were safely and rapidly desensitized to up to five food allergens simultaneously, using an OIT protocol with concomitant treatment with omalizumab. This is the first published study on using multiple-OIT and omalizumab in combination. These findings are particularly relevant considering the already high, and likely growing, number of food-allergic participants who are sensitized to more than one food allergen."