November 19, 2018 / 4:49 PM / a month ago

Experimental treatment may desensitize allergic kids to peanuts

(Reuters Health) - Peanut allergy can be life-threatening, but a new study suggests that peanut protein itself can be used to slowly dial down the intensity of the allergic reaction.

After daily exposure for 24 weeks to the equivalent of one peanut in the form of a powder sprinkled on food, two-thirds of the volunteers in the study were able to tolerate the amount of peanut protein found in two peanuts daily. Only 4 percent who got a dummy, or placebo, powder had this response.

The treatment did not work for adults, however. And side effects such as abdominal pain and vomiting prompted nearly 12 percent to withdraw from the study (versus 2 percent in the placebo group), and 14 percent needed epinephrine to halt severe allergic reactions.

“This is not something to start at home,” said Dr. Michael Perkin of St. George’s University of London in an editorial in the New England Journal of Medicine, where the study also appears. The details were released Sunday at the annual meeting of the American College of Allergy, Asthma & Immunology (ACAAI) in Seattle.

Aimmune Therapeutics, which makes the peanut powder known as AR101, paid for the study, which involved 551 adults and children. The company announced a summary of the results in February. The new details will help experts gauge the risks and limitations of the therapy.

Even when it works, it’s not clear how long the benefit persists once a person stops taking the peanut powder daily. Coauthor Dr. Brian Vickery, director of the Children’s Healthcare of Atlanta Food Allergy Program, said the researchers are planning a follow-up study to see if less-frequent consumption of the powder will be just as effective.

For now, “sustained, potentially lifelong, regular consumption may be needed to maintain allergen tolerance,” Perkin said.

Much smaller studies have suggested that tiny amounts of a ground-up peanut may increase tolerance and some allergists are already giving that to patients, Vickery said. “There’s an ongoing debate on whether that’s the right thing to do.”

A standardized powder like AR101 makes it easier to adjust the dose because the amount of allergen is tightly controlled and you know there’s no contamination from tree nuts and microbes, he said. “Once you’ve completed the updosing, could you switch people over to peanuts? That may happen; probably will.”

Peanut allergy accounts for the majority of food allergy deaths and the condition affects about 2 percent of children in the United States. In about 1 percent, the reaction is severe. In extreme cases, inhaling peanut dust can cause a crisis.

“There are children who will react to milligram quantities of peanuts. For these children, life can be hellish because even with the best care in the world, they can come across micro-contamination of food and react,” said Dr. Gideon Lack, head of pediatric allergy at King’s College London who was not involved in the new research. “So for these children, I think this is a real step forward.”

The treatment is not for the faint of heart.

The need for an epinephrine injection to reverse the allergic reaction more than doubled in children getting the peanut powder. Fourteen percent of the children needed the injection once, 5 percent had two or more episodes, including two children who had six episodes.

The treatment is “a big commitment,” Vickery said. “It requires a lot of changes to lifestyle, a lot of doctor visits, a lot of supervision. This is definitely a don’t-try-this-at-home treatment.”

But the experience can be transformative for people, he added. “It can really liberate people in ways they’ve never experienced,” alleviating fears of traveling by plane, sleeping over at a friend’s house and other experiences that carry the specter of accidental exposure. “It allows people to be comfortable in situations that would otherwise be really challenging for them.”

SOURCE: bit.ly/2qUA6BA and bit.ly/2FsBAgr The New England Journal of Medicine, online November 18, 2018.

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