March 28, 2012 (Orlando, Florida) — Children who undergo a prolonged trial of sublingual immunotherapy (SLIT) before undertaking oral immunotherapy (OIT) for milk allergy have fewer treatment-related symptoms, particularly severe ones, than those on OIT alone, according to a study reported here at the American Academy of Allergy, Asthma and Immunology (AAAAI) 2012 Annual Meeting.
"We found that prolonged SLIT before OIT improved safety and reduced severe symptoms but did not eliminate all symptoms." There was also no difference in food-challenge thresholds, reported Shannon Seopaul, a research assistant at Johns Hopkins University in Baltimore, Maryland. "At this time, we can't say that prolonged SLIT before OIT is any more effective than OIT itself."
The study was part of a larger study that compared SLIT alone with SLIT followed by OIT (J Allergy Clin Immunol. 2012;129:448-455).
Patients (median age, 8 years) were randomized to SLIT (goal, 7 mg daily) or OIT (goal, 2000 mg daily) for 1 year.
"All subjects started on therapy, escalated to the top dose, and continued on the top dose for a year. They then had a series of food challenges right after therapy, 1 week off therapy, and then 6 weeks off therapy," she said.
SLIT therapy consisted of "a milk extract in a prefilled vial with a pump that dispenses a specific amount of liquid under the tongue, which is then held and swallowed," explained Seopaul.
OIT was no-fat milk powder that was dispensed in specific amounts and mixed with a beverage.
The parent study found that "OIT was more efficacious for desensitization to [cow's milk] than SLIT alone, but was accompanied by more systemic side effects. Clinical desensitization was lost in some cases within 1 week off therapy," Seopaul reported.
In the substudy by Seopaul and colleagues, 7 SLIT patients who failed a food challenge in the parent study were given the option of crossing over to the OIT group.
These patients then went through the same dose escalation with OIT to a goal of 1000 mg or 2000 mg daily, stayed on maintenance for another 60 weeks, and then started food challenges again, she said.
For the OIT group, 14 of 18 subjects passed that first food challenge, 12 of those 14 passed the second, and 8 of those 12 passed the third, she said.
For the SLIT crossover patients, "2 are still on treatment, so have yet to make it to that first food challenge, but of those who did, all 5 passed the first, 3 passed the second, and 1 passed the third challenge."
It is clear that with either therapy, tolerance is lost, she noted. "It didn't matter if you had that prolonged SLIT, they still lost tolerance."
Compared with patients in the parent study, where the posttreatment food-challenge threshold was about 2500 mg of milk for the SLIT group, and 8000 mg for the OIT group, the subgroup that crossed over reached the same threshold as the OIT group, she said.
However, there was a difference in dosing symptoms.
"Overall, the OIT group had more symptoms than the crossover group," she said. "Looking at the more severe symptoms — upper and lower respiratory, GI, and multisystem symptoms — the OIT group had significantly more severe symptoms than the crossover group."
Prolonged SLIT before OIT took about double the time of OIT alone, with no difference in the amount of desensitization, said Corinne Keet, MD, assistant professor of pediatrics at Johns Hopkins University, lead author of the parent study, and a coinvestigator of the substudy.
Dr. Keet added that, "going forward, we will need to confirm that the side effects are indeed less after prolonged SLIT, and then determine whether the decreased rate of reactions is worth the longer time on therapy that prolonged SLIT would require."
"This is an important study in defining the role of SLIT with OIT in milk-allergic patients," said Michael Blaiss, MD, who works in private practice and is a clinical professor of pediatrics and medicine at the University of Tennessee Health Sciences Center in Memphis. "Although one would like to have seen better efficacy with SLIT prior to OIT vs OIT alone, the improved safety in the SLIT group is a definite plus for the patient. It will be interesting to see if the same results occur with immunotherapy to other foods, such as peanuts, or if it is unique for milk."
Ms. Seopaul and Dr. Keet have disclosed no relevant financial relationships. Dr. Blaiss reports serving on the speaker's bureau for AstraZeneca, Merck, GSK, Sunovion, Nycomed, ISTA, Nestle's, and Genentech; and being a consultant for Sanofi, Merck, Sunovion, Allergan, Alcon, Proctor & Gamble, Nycomed, ISTA, JDP Therapeutics, Pfizer, and PMD Healthcare.
American Academy of Allergy, Asthma and Immunology (AAAAI) 2012 Annual Meeting: Abstract 478. Presented March 4, 2012.
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