OIT’s Effects Endure at Low Doses: Stanford Study
In a long-term follow-up study, oral immunotherapy (OIT) patients who were treated for up to five food allergies were able to maintain a high level of desensitization to their allergens, even those taking very low “doses” of their allergens.
“We did this study because, up to now, there hasn’t been a lot of data on long-term follow-up for food oral immunotherapy,” Dr. Kari Nadeau, director of the Sean N. Parker Center for Allergy & Asthma Research at Stanford University, told a press conference at the AAAAI allergists’ meeting in Los Angeles.
The Stanford team followed up on 70 multiple-allergen OIT patients in two phase 1 clinical trial groups over a period ranging from 18 months to six years. Both groups had followed multiple-allergen OIT protocols, with the second group having followed the “rapid” process, which involved pre-treatment with the anti-IgE medication Xolair.
Nadeau and her colleague Dr. Sharon Chinthrajah explained that to take part in the follow-up study, patients had to successfully reach and stay on two grams daily of each of their allergens – their designated “maintenance dose” – for four to six months. They were then asked whether they wanted to stay at that level, or try reducing their intake to a range of between 300 milligrams and two grams (for peanut, that’s roughly one to 10 peanuts). Forty-four percent chose the reduced range.
“What we were excited to find out was that going down to 300 [mg] was just as protective for most patients,” said Nadeau. The study says that all participants “remained desensitized to at least 2 grams of their food allergens on repeat food challenging, even those who chose to consume home doses as low as 300 mg of their allergens three times per week.”
Although some other OIT follow-ups have shown a tendency for patients to gravitate away from continuing their allergen maintenance doses, “a lot of our patients continue regular dosing of their OIT mix,” says Nadeau. “A lot of that may have been because of the flexibility and their ability to take a smaller dose and know that they’re still able to maintain desensitization.”
While patients on the center’s Xolair treatment protocol reached the maintenance level more quickly – in nine months vs. two years for the regular OIT group – Nadeau and Chinthrajah said lower maintenance dosing worked well for both groups. Participants in the phase 1 trials were treated for up to five allergens, and a range of 15 food allergies was seen among the study participants.