Relief from food allergies may come from antibody drug and food desensitization
12 Dec 2017 --- A clinical trial of 48 children with multiple food allergies which tested antibody drug omalizumab alongside food desensitization treatment resulted in more effective allergy relief compared to placebo, according to a study published in The Lancet Gastroenterology & Hepatology journal.
The findings come at a time when 30 percent of people with food allergies are allergic to multiple foods, putting them at higher risk of accidental exposure and anaphylaxis, which can be fatal. People with multiple food allergies can have allergies to similar foods – such as different tree nuts, like walnut, almond, hazelnut, cashew, pistachio and Brazil nuts – or to a range of foods. There is currently no treatment for people with food allergies.
Potential for facilitating desensitization
The authors say that the omalizumab drug may work by moderating the immune system's response to trigger foods, allowing people with allergies to begin food desensitization. This involves introducing small amounts of the trigger food (in flour form mixed into another food) into a person's diet, then gradually building up the amount with the aim of helping their immune system to tolerate the food.
“This phase 2 clinical trial shows the potential benefits of using omalizumab to facilitate food desensitization to multiple trigger foods in a shortened period of time,” says Dr. Sharon Chinthrajah, Director of the Clinical Translational Research Unit of the Sean N. Parker Center for Allergy and Asthma Research at Stanford University, US.
“While our results are promising, they are preliminary and suggest that children with multiple food allergies might one day be safely desensitized to their trigger foods using this treatment combination,” Dr. Chinthrajah adds.
Allergic reaction avoided
In the trial, 48 children aged 4 to 15 years old with two or more food allergies were given injections of either omalizumab or placebo for 16 weeks. In total, 36 children had omalizumab and 12 had a placebo. Eight weeks into their injections, they began food desensitization for two to five trigger foods until week 36 of the trial.
The food desensitization was tailored to each participant’s allergies and included equal proportions of each food protein for their trigger foods. This dose increased up to 2g of protein for each trigger food.
The children had a food challenge which involved eating 2g of protein of each of their trigger foods 36 weeks into the trial.
The researchers found that more children in the omalizumab group than the placebo group were able to eat the protein for at least two foods without an allergic reaction – 83 percent, or 30 out of 36 children, versus 33 percent, or four out of 12 children.
These effects were also seen when testing the children for more than two foods. Among children who had more than two food allergies, more of those in the omalizumab group showed tolerance for their other trigger foods’ allergens. For example, in the omalizumab group, 81 percent (21 out of 26) of children with allergies to three or more foods passed the food test for at least three foods, compared to 29 percent (two out of seven) children in the placebo group. Meanwhile, 76 percent (13 out of 17) children with four allergies who had omalizumab passed the food test, but none of the five children in the placebo group did.
On average, the children who had omalizumab tolerated higher levels of trigger food protein in the first week of food desensitization, compared to children given placebo (250mg versus 11mg per food), and were able to tolerate the highest dose of their trigger food protein (2g) sooner (in 12 weeks, compared to 20 weeks).
The children who had allergies to similar foods also showed that desensitization to one food type had effects on the related food allergy – 83 percent (20 out of 24) of children treated for cashew allergies passed a food test for pistachio, and all children (17 out of 17) who were treated for a walnut allergy passed a pecan nut food challenge. The authors note that further research will be needed to understand this potential effect.
Limited but promising
The authors note some limitations, including that children who failed food desensitization started open-label omalizumab with food desensitization afterwards, which may affect the results relating to adverse events in the study. It is still unclear how omalizumab works to treat food allergies, as the study included only limited assessments of the effects of the drug on the immune system. More studies are needed for a full understanding of how biological medications could improve food immunotherapy.
The researchers are still researching the drug to see if extending the course of treatment improves the effects.
