At the recent American Academy of Allergy, Asthma, and Immunology annual meeting, Dr. Robert Wood of Johns Hopkins Medical Center presented data that oral desensitization / immunotherapy for milk allergy appears to lose effectiveness over time:
SAN ANTONIO -- Among children who underwent oral immunotherapy for milk allergies, fewer than half were able to regularly consume milk without symptoms in the long term, according to updated results from an earlier trial. After 4 to 5 years of follow-up, only 43% of the children in the trial, ages 6 to 16, were able to consume a single serving of milk a day after oral immunotherapy for milk allergy, according to Robert Wood, MD, of Johns Hopkins University, and colleagues.
In addition, some of the participants became far more reactive than they had been earlier in the course of the oral immunotherapy, the authors said. Intolerance of milk consumption was accompanied by frequent reactions in 40% of the kids, systemic reactions in 30%, and the need for epinephrine in 20%, Wood said during a press conference at American Academy of Allergy, Asthma, and Immunology (AAAAI) meeting. "Some of the more dramatic failures were the kids who looked like absolute successes at the end of the study, where they were tolerating huge amounts of milk and they were ... as close to cured as we could possibly imagine," Wood noted, adding that some participants had to go back to strict milk avoidance.
Preliminary results of the study, which compared oral immunotherapy treatment against sublingual dosing of milk proteins, were reported during the 2011 AAAAI meeting. In the earlier presentation, researchers found oral immunotherapy allowed nine of 15 (60%) of severely milk-allergic participants to drink an 8 oz glass of milk during the treatment challenge compared with one of 10 patients treated sublingually. AAAAI president Wesley Burks, MD, who was a co-author on the initial study done from 2006 to 2007, noted that the results gave families and researchers "hope that something could be done, but we're really not there yet."
As part of the study follow-up in 2012, researchers analyzed 13 participants' daily milk consumption status, regular and intermittent adverse reactions, and evaluated predictors of outcome at a median 4.5 years from the start of the study through a phone, in-person, or email interview, as well as a blood sample test for immunoglobulin E (IgE) and immunoglobulin G4 (IgG4). At follow-up, seven of 16 participants were able to consume at least one serving of milk daily, while four could consume some uncooked milk, two would only tolerate minimal amounts of milk, and three could not take any milk. Only 25% could consume milk without symptoms at 3 months, they reported. More than half of the follow-up participants reported frequent symptoms accompanying milk consumption including six systemic reactions and two reactions requiring epinephrine. One participant, who was not symptomatic after passing a 16-gram challenge during the study, became reactive at follow-up and presently only consumes minimal milk.
Long-term outcomes were not associated with baseline or follow-up milk IgE, follow-up milk IgG4, threshold during the food challenge experiment, or results of tolerance challenge after milk avoidance. At baseline, the initial oral food challenge threshold for milk protein for the participants was 40 mg (range 40-1,350 mg). Only food challenge threshold at 3 months of maintenance differed between the groups (P=0.03):
- Group without symptoms: median 8,140 mg (range 4,140-8,140 mg)
- Groups with symptoms or milk avoidance: median 6,140 mg (range 1,340-8,140 mg)
In the latter two groups, 38% reached full challenge dose.
"We're really worried that the [participants] will leave the study with a false sense of security," Wood said, adding that he'd seen participants lose protection in as early as 1 week off therapy. "Compounded with the fact that these kids don't like the foods they've been allergic to, there's a real inherent risk we need to recognize, and that risk actually scares me a lot more than the recognizable short-term risk" which patients face with monitored dose-escalation, he said. Wood noted that oral immunotherapy "is not yet ready for clinical practice," and that more research is needed with longer follow-up.
Primary source: American Academy of Allergy, Asthma, and Immunology. Source reference:
Keet C, et al "Long-term outcomes of milk oral immunotherapy in children" AAAAI 2013; Abstract 467
Dr. Kenneth Backman of Allergy and Asthma Care of Fairfield County comments: "Sublingual or oral desensitization for food allergy remains an exciting area of research, and we are very hopeful that this may be a clinical option in the near future. However, the above data emphasizes that much more remains to be learned about this procedure, and for now it is 'not ready for prime time,' and remains appropriate only in research settings."