Children, adults achieve similar desensitization with peanut oral immunotherapy

Children and adults exhibited the same likelihood of reaching desensitization via peanut oral immunotherapy, with similar rates of adverse events, according to study findings.

Also, children and adults did not experience any differences in immune profile changes over time, R. Sharon Chinthrajah, MD, director of the Clinical Translational Research Unit at the Sean N. Parker Center for Allergy and Asthma Research at Stanford University, said during the presentation at the European Academy of Allergy and Clinical Immunology Hybrid Congress.

“There’s a question of how effective peanut oral immunotherapy can be, as we see that it’s certainly effective in children,” said Chinthrajah, who is also an associate professor at Stanford Medicine. “There was a question of whether or not it was effective in adults as well.”

The POISED study enrolled 120 participants with peanut allergy between April 15, 2014, and March 2, 2016. Children in the study were aged 7 to 18 years.

“We looked at 22 adults out of these 120 peanut-allergic individuals, which is not a very large number, but actually is probably the largest number in a long peanut allergy study,” Chinthrajah said.

“If anybody does clinical trials with children and adults, you will know that it is much harder to get adults to come in for research studies, but they are more willing to bring their children in,” she said.

During the first year, participants were desensitized with doses of up to 4 g of peanut or placebo, with desensitization maintained at that level in the second year.

In the third year, 60 participants were prescribed daily peanut avoidance (peanut-0), including nine adults; 35 were prescribed 300 mg of peanut (peanut-300), including eight adults; and 35 were prescribed placebo. The participants in these groups had similar comorbid allergic diseases.

The researchers also took blood samples at baseline and at weeks 104 and 117. Immune profile analyses included IgE, basophil activation tests (BATs) and high-dimensional mass cytometry.

After two years of OIT, the researchers began administering double-blinded placebo-controlled food challenges (DBPCFCs) every 13 weeks. The researchers compared proportions of children and adults who passed a tolerance threshold of 4,000 mg during the follow-up DBPCFCs.

During the first year, the children and adults experienced comparable rates of adverse events. During the second year, however, children in the active peanut group experienced a higher rate of adverse events (median, 0.01 vs. 0; P = .012).

There were no differences between the children and adults in passing the 4,000 mg tolerance threshold, nor were there any significant differences between the children and adults in their total or peanut-specific IgE, BATs or mass cytometry data through the course of the study.

“We looked at over 34 different markers on mass cytometry, and the only marker that showed some difference between children and adults was the percentage of CD38 expressed on peanut-reactive CD4-positive T cells,” Chinthrajah said.

Overall, Chinthrajah and her colleagues concluded, children and adults are comparably likely to achieve desensitization after peanut OIT, with no differences in adverse events or in the mechanisms behind sensitization.